U.S. patent application number 10/537329 was filed with the patent office on 2006-08-24 for treating solution for surface treatment of metal and a method for surface treatment.
Invention is credited to Toshiyuki Aishima, Takaomi Nakayama, Eisaku Okada, Hiroyuki Sato, Katsuhiro Shiota, Fumiya Yoshida.
Application Number | 20060185769 10/537329 |
Document ID | / |
Family ID | 32588165 |
Filed Date | 2006-08-24 |
United States Patent
Application |
20060185769 |
Kind Code |
A1 |
Nakayama; Takaomi ; et
al. |
August 24, 2006 |
Treating solution for surface treatment of metal and a method for
surface treatment
Abstract
Treating solution for surface treatment of metal to treat one
metal material selected from the group consisting of ferriferous
material, zinciferous material, aluminiferous material and
magnesiferous material or to treat two or more metal materials
selected from the group consisting of ferriferous material,
zinciferous material, aluminiferous material and magnesiferous
material at the same time, wherein the aqueous surface treating
solution contains from 5 to 5000 ppm of at least one compound
selected from the group consisting of zirconium compound and
titanium compound by the metal element, and from 0.1 to 100 ppm of
free fluorine ion, further the pH of the treating solution is from
2 to 6. To the treating solution, calcium compound, magnesium
compound, strontium compound, nitric acid group, oxygen acid and/or
salt of oxygen acid, polymer compound and surface active agent can
be added.
Inventors: |
Nakayama; Takaomi;
(Kanagawa, JP) ; Sato; Hiroyuki; (Kanagawa,
JP) ; Aishima; Toshiyuki; (Aichi, JP) ; Okada;
Eisaku; (Aichi, JP) ; Yoshida; Fumiya; (Osaka,
JP) ; Shiota; Katsuhiro; (Hyogo, JP) |
Correspondence
Address: |
FLYNN THIEL BOUTELL & TANIS, P.C.
2026 RAMBLING ROAD
KALAMAZOO
MI
49008-1631
US
|
Family ID: |
32588165 |
Appl. No.: |
10/537329 |
Filed: |
December 11, 2003 |
PCT Filed: |
December 11, 2003 |
PCT NO: |
PCT/JP03/15868 |
371 Date: |
December 2, 2005 |
Current U.S.
Class: |
148/247 |
Current CPC
Class: |
C23C 22/34 20130101;
C23C 22/83 20130101; C25D 9/08 20130101; C23C 22/44 20130101 |
Class at
Publication: |
148/247 |
International
Class: |
C23C 22/34 20060101
C23C022/34 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 13, 2002 |
JP |
2002-362640 |
Claims
1. Treating solution for surface treatment of metal, which is
aqueous surface treating solution to treat independently each metal
material or simultaneously two or more metal materials selected
from the group consisting of ferriferous material, zinciferous
material, aluminiferous material and magnesiferous material, the
treating solution containing 5 to 5000 ppm of at least one compound
selected from the group consisting of zirconium compound and
titanium compound calculated as metal element, and 0.1 to 100 ppm
of free fluorine ion, and having pH 2 to 6.
2. The treating solution for surface treatment of metal according
to claim 1, further containing at least one compound selected from
the group consisting of calcium compound, magnesium compound and
strontium compound, wherein concentration of the compound
calculated as metal element is 5 to 100 ppm in the case of the
calcium compound, 10 to 5000 ppm in the case of the magnesium and
10 to 5000 ppm in the case of the strontium compound.
3. The treating solution for surface treatment of metal according
to claim 1, further containing 1000 to 50000 ppm of nitrate
group.
4. The treating solution for surface treatment of metal according
to claim 1, further containing at least one oxygen acid and/or salt
of oxygen acid selected from the group consisting of HClO.sub.3,
HBrO.sub.3, HNO.sub.2, HNO.sub.3, HMnO.sub.4, HVO.sub.3,
H.sub.2O.sub.2, H.sub.2WO.sub.4, H.sub.2MoO.sub.4 and salts
thereof.
5. The treating solution for surface treatment of metal according
to claim 1, further containing at least one polymer compound
selected from the group consisting of water soluble polymer
compounds and water dispersible polymer compounds.
6. The treating solution for surface treatment of metal according
to claim 1, further containing at least one surface active agent
selected from the group consisting of nonionic surface active
agents, anionic surface active agents and cationic surface active
agents.
7. A method for surface treatment of metal comprising, contacting
independently each metal material or simultaneously two or more
metal materials selected from the group consisting of ferriferous
material, zinciferous material, aluminiferous material and
magnesiferous material with the treating solution for surface
treatment according to claim 1.
8. The method for surface treatment of metal according to claim 7,
comprising, further contacting the metal material or the two or
more metal materials with acidic aqueous solution of compound
containing at least one element selected from the group consisting
of cobalt, nickel, tin, copper, titanium and zirconium, after
contacting with the treating solution for surface treatment, with
or without washing by water.
9. The method for surface treatment of metal according to claim 7,
comprising, further contacting the metal material or the two or
more metal materials with treating solution containing at least one
polymer compound selected from water soluble polymer compounds and
water dispersible polymer compounds, after contacting with the
treating solution for surface treatment, with or without washing by
water.
10. A method for surface treatment of metal comprising,
electrolytic treating in the treating solution for surface
treatment claim 1, wherein independently each metal material or
simultaneously two or more metal materials selected from the group
consisting of ferriferous material, zinciferous material,
aluminiferous material and magnesiferous material are a
cathode.
11. The method for surface treatment of metal according to claim
10, comprising, further contacting the metal material or the two or
more metal materials with acidic aqueous solution of compound
containing at least one element selected from the group consisting
of cobalt, nickel, tin, copper, titanium and zirconium, after
electrolytic treating in the treating solution for surface
treatment, with or without washing by water.
12. The method for surface treatment of metal according to claim
10, comprising, further contacting the metal material or the two or
more metal materials with treating solution containing at least one
polymer compound selected from water soluble polymer compounds and
water dispersible polymer compounds, after electrolytic treating in
the treating solution for surface treatment, with or without
washing by water.
13. A method for surface treatment of metal comprising, contacting
independently each metal material or simultaneously two or more
metal materials selected from the group consisting of ferriferous
material, zinciferous material, aluminiferous material and
magnesiferous material, whose surface is not degreased and cleaned
with the treating solution for surface treatment according to claim
6.
14. A metal material having a surface treated film containing at
least one metal element selected from the group consisting of
titanium and zirconium formed on a surface of iron metal material
by the method for surface treatment according to claim 7, wherein
an adhesion amount of the surface treated film calculated as the
metal element is 30 mg/m.sup.2 or more.
15. A metal material having a surface treated film containing at
least one metal element selected from the group consisting of
titanium and zirconium formed on a surface of zinc metal material
by the method for surface treatment according to claim 7, wherein
an adhesion amount of the surface treated film calculated as the
metal element is 20 mg/m.sup.2 or more.
16. A metal material having a surface treated film containing at
least one metal element selected from the group consisting of
titanium and zirconium formed on a surface of aluminum metal
material by the method for surface treatment according to claim 7,
wherein an adhesion amount of the surface treated film calculated
as the metal element is 10 mg/m.sup.2 or more.
17. A metal material having a surface treated film containing at
least one metal element selected from the group consisting of
titanium and zirconium formed on a surface of magnesium metal
material by the method for surface treatment according to claim 7,
wherein an adhesion amount of the surface treated film calculated
as the metal element is 10 mg/m.sup.2 or more.
Description
TECHNICAL FIELD
[0001] The present invention relates to the treating solution for
surface treatment of metal which may deposit a surface treated film
having excellent corrosion resistance after being coated on the
surface of a metal material of a structural construction such as
car body consisting of a single material or two to four materials
selected from the group consisting of ferriferous material,
zinciferous material, aluminiferous material and magnesiferous
material independently or simultaneously.
BACKGROUND ART
[0002] As the method to form on metal surface a surface treated
film having excellent corrosion resistance after coated, a zinc
phosphate treatment and a chromate treatment are currently used as
ordinary methods. According to the zinc phosphate treatment, it is
possible to deposit a film having excellent corrosion resistance on
the surface of steel such as cold rolled steel plate, zinc plated
steel plate and some of aluminum alloys. However, in the zinc
phosphate treatment, the generation of sludge, which is the
byproduct of the reaction can not be avoided, and depending on the
kind of aluminum alloy, the sufficient corrosion resistance after
coated can not be obtained. While, in the case of aluminum alloy,
it is possible to obtain sufficient properties after coated by
applying the chromate treatment. Concerning the recent
environmental regulations, the chromate treatment which contains
harmful hexavalent chrome in the treating solution is more likely
to be avoided. As the method for metal surface treatment, which
does not contain harmful component in the treating solution,
various methods have been proposed as described below.
[0003] For example, in JP 2000-204485 A, a compound containing
nitrogen atom having a lone electron-pair and a non-chrome coating
agent for metal surface treatment containing said compound and
zirconium compound are suggested. This method may obtain a surface
treated film which is excellent in corrosion resistance and
adhesiveness after being coated, and yet does not contain harmful
hexavalent chrome by coating above mentioned coating agent.
However, in the case of the method, the metal material which can be
treated is limited to aluminum alloys only, and, it is difficult to
be applied to a structural construction having complex structure
such as car body, because the surface treated film is formed by
coating and drying.
[0004] Further, as the method to deposit a metal surface treated
film having excellent adhesiveness and corrosion resistance after
coated due to the chemical reaction, various methods such as those
disclosed in JP 56-136978 A, JP 8-176841 A, JP 9-25436 A and JP
9-31404 A have been suggested. However, in any of these methods,
the metal material which can be treated is limited to the aluminum
alloy only, originally having excellent corrosion resistance; these
methods may not deposit a surface treated film on the surface of
ferriferous material or zinciferous material.
[0005] Furthermore, proposed is a method to form a metal surface
treated film having excellent corrosion resistance and adhesion
after coated, by using a surface treating agent composed of metal
acetylacetonate and water soluble inorganic titanium compound or
water soluble inorganic zirconium compound (see JP 2000-199077). By
this method, metal materials to be treated may include magnesium,
magnesium alloy, zinc and zinc plated alloy other than aluminum
alloy. However, by this method, it is difficult to form a surface
treated film on a surface of ferriferous material such as cold
rolled steel, and is not possible to treat ferriferous material at
the same time.
[0006] Still further, a method for metal surface treatment by
chrome free coating acid composition by coating aqueous solution
containing component which can be a film having excellent corrosion
resistance over the surface of metal, then baking and drying
without rinsing with water so as the film to be fixed (see JP
5-195244 A). This method does not involve any chemical reaction to
form a film, so this method may form a film on the surface of metal
such as zinc plated steel plate, cold rolled steel plate or
aluminum alloy. However, similarly to the invention disclosed in
above mentioned JP 2000-204485 A, since the film is formed by
coating and drying, it is difficult to form a uniform film on the
surface of a structural construction having complex structure such
as car body.
[0007] As mentioned above, according to the prior arts, it was
impossible to perform surface treatment excellent in corrosion
resistance and adhesion on car body and the like composed of two to
four metal materials of ferriferous material such as cold rolled
steel plate, zinciferous material such as zinc plated steel plate,
aluminiferous material and magnesiferous material simultaneously
with a treating solution containing no harmful component to the
environment and not generating waste sludge.
DISCLOSURE OF THE INVENTION
[0008] The object of the present invention is to provide a treating
solution for surface treatment of metal to form a surface treated
film having excellent corrosion resistance after coated on the
surface of ferriferous material, zinciferous material,
aluminiferous material and magnesiferous material, which does not
contain harmful component to the environment and does not generate
sludge to be wasted, which was not accomplished by the prior arts.
Further, the object of the present invention is to provide a
treating solution for metal surface treatment to form a surface
treated film of a uniform component having excellent corrosion
resistance after coated on the surface of a metal material
composing a structural construction such as car body consisting of
two to four materials selecting from the group consisting of
ferriferous material, zinciferous material, aluminiferous material
and magnesiferous material by same component simultaneously under a
uniform condition. And another object of the present invention is
to provide a method for treatment using the treating solution.
[0009] The inventors of the present invention have conduced
intensive study to dissolve the above mentioned problem and have
accomplished a treating solution for surface treatment of metal and
a method for surface treatment which were not provided by the prior
art.
[0010] That is, the present invention is the treating solution for
surface treatment of metal, which is aqueous surface treating
solution to treat independently each metal material or
simultaneously two or more metal materials selected from the group
consisting of ferriferous material, zinciferous material,
aluminiferous material and magnesiferous material, the treating
solution containing 5 to 5000 ppm of at least one compound selected
from the group consisting of zirconium compound and titanium
compound calculated as metal element, and 0.1 to 100 ppm of free
fluorine ion, and having pH 2 to 6.
[0011] The treating solution for surface treatment of metal may
further contain at least one compound selected from the group
consisting of calcium compound, magnesium compound and strontium
compound, wherein concentration of the compound calculated as metal
element is 5 to 100 ppm in the case of the calcium compound, 10 to
5000 ppm in the case of the magnesium and 10 to 5000 ppm in the
case of the strontium compound. It is desirable that the treating
solution for surface treatment of metal further contains 1000 to
50000 ppm of nitrate group. And, it is desirable that the treating
solution for surface treatment of metal further contains at least
one oxygen acid and/or salt of oxygen acid selected from the group
consisting of HClO.sub.3, HBrO.sub.3, HNO.sub.2, HNO.sub.3,
HMnO.sub.4, HVO.sub.3, H.sub.2O.sub.2, H.sub.2WO.sub.4,
H.sub.2MoO.sub.4 and salts thereof. The treating solution for
surface treatment of metal may further contain at least one polymer
compound selected from the group consisting of water soluble
polymer compounds and water dispersible polymer compounds, and may
further contain at least one surface active agent selected from the
group consisting of nonionic surface active agents, anionic surface
active agents and cationic surface active agents.
[0012] And, the present invention is the method for surface
treatment of metal comprising, contacting independently each metal
material or simultaneously two or more metal materials selected
from the group consisting of ferriferous material, zinciferous
material, aluminiferous material and magnesiferous material with
the treating solution for surface treatment. In the method for
surface treatment, after contacting with the treating solution for
surface treatment, it is possible to further contact the metal
material or the two or more metal materials with acidic aqueous
solution of compound containing at least one element selected from
the group consisting of cobalt, nickel, tin, copper, titanium and
zirconium, with or without washing by water, or it is possible to
further contact the metal material or the two or more metal
materials with treating solution containing at least one polymer
compound selected from water soluble polymer compounds and water
dispersible polymer compounds.
[0013] Moreover, the present invention is the method for surface
treatment of metal comprising, electrolytic treating in the
treating solution for surface treatment, wherein independently each
metal material or simultaneously two or more metal materials
selected from the group consisting of ferriferous material,
zinciferous material, aluminiferous material and magnesiferous
material are a cathode. In the method for surface treatment, after
electrolytic treating in the treating solution for surface
treatment, it is possible to further contact the metal material or
the two or more metal materials with acidic aqueous solution of
compound containing at least one element selected from the group
consisting of cobalt, nickel, tin, copper, titanium and zirconium,
with or without washing by water, or it is possible to further
contact the metal material or the two or more metal materials with
treating solution containing at least one polymer compound selected
from water soluble polymer compounds and water dispersible polymer
compounds, with or without washing by water.
[0014] And, the present invention is the method for surface
treatment of metal comprising, contacting independently each metal
material or simultaneously two or more metal materials selected
from the group consisting of ferriferous material, zinciferous
material, aluminiferous material and magnesiferous material whose
surfaces are not degreased and cleaned, with the treating solution
for surface treatment containing at least one surface active agent
selected from the group consisting of the above described nonionic
surface active agents, anionic surface active agents and cationic
surface active agents.
[0015] Furthermore, the present invention is the metal material
having a surface treated film containing at least one metal element
selected from the group consisting of titanium and zirconium formed
on a surface of iron metal material by the method for surface
treatment, wherein an adhesion amount of the surface treated film
calculated as the metal element is 30 mg/m.sup.2 or more; in the
case where formed on a surface of zinc metal material, an adhesion
amount of the surface treated film calculated as the metal element
is 20 mg/m.sup.2 or more; in the case where formed on a surface of
aluminum metal material, an adhesion amount of the surface treated
film calculated as the metal element is 10 mg/m.sup.2 or more; and
in the case where formed on a surface of magnesium metal material,
an adhesion amount of the surface treated film calculated as the
metal element is 10 mg/m.sup.2 or more.
BRIEF DESCRIPTION OF DRAWINGS
[0016] FIG. 1 is a plane view of the test plate used in the
Examples and Comparative Examples.
[0017] FIG. 2 is an elevation view of the test plate.
BEST MODE FOR CARRYING OUT THE INVENTION
[0018] The present invention relates to the art characterizing to
deposit a surface treated film having excellent corrosion
resistance after coated, by surface treatment on independently each
metal material or simultaneously two or more metal materials
selected from the group consisting of ferriferous material,
zinciferous material, aluminiferous material and magnesiferous
material. In the present invention, ferriferous material is an iron
metal such as cold rolled steel plate, hot rolled steel plate, cast
iron or sintered steel. Zinciferous material is a die casting zinc
or a zinc contaiing plating. This zinc containing plating means a
metal plating with zinc or zinc alloy composed of zinc and other
metals (for example, at least one metal selected from the group
consisting of nickel, iron, aluminum, manganese, chromium,
magnesium, cobalt, lead or antimony) and inevitable impurities, and
the methods for such plating includes hot galvanizing, electric
plating and vapor deposition plating, and are not limited to these
methods. Further, the aluminiferous material is an aluminum alloy
board such as JIS 5000 series aluminum alloy or JIS 6000 series
aluminum alloy, or an aluminum alloy die cast represented by
ADC-12. Still more, the magnesiferous material is a metal board or
a die cast made of magnesium alloy.
[0019] The present invention can be applied to the structural
construction which contains one metal material mentioned above
alone in the composing parts or to the structural construction
which contains two to four metal materials mentioned above in the
composing parts. And, in the case to apply the present invention to
the structural construction which contains two to four metal
materials mentioned above, it is possible to treat the surfaces of
two to four metal materials at the same time. In the case to treat
the surfaces of two to four metal materials at the same time, the
different metals can be in the condition not contacting each other
or in the condition being joined and contacted by means of joining
method such as welding, adhesion or riveting.
[0020] The treating solution for surface treatment of metal of the
present invention contains 5 to 5000 ppm of at least one compound
selected from the group consisting of zirconium compound and
titanium compound calculated as the metal element, and 0.1 to 100
ppm of free fluorine ion, further having pH of 2 to 6. Here, as the
zirconium compound used in the present invention, ZrCl.sub.4,
ZrOCl.sub.2, Zr(SO.sub.4).sub.2, ZrOSO.sub.4, Zr(NO.sub.3).sub.4,
ZrO(NO.sub.3).sub.2, H.sub.2ZrF.sub.6, salt of H.sub.2ZrF.sub.6,
ZrO.sub.2, ZrOBr.sub.2 and ZrF.sub.4 can be mentioned. And as the
titanium compound, TiCl.sub.4, Ti(SO.sub.4).sub.2, TiOSO.sub.4,
Ti(NO.sub.3).sub.4, TiO(NO.sub.3).sub.2, TiO.sub.2OC.sub.2O.sub.4,
H.sub.2TiF.sub.6, salt of H.sub.2TiF.sub.6, TiO.sub.2 and TiF.sub.4
can be mentioned. In the present invention, zirconium compound is
desirably used.
[0021] The desirable concentration of at least one compound
selected from the group consisting of zirconium compound and
titanium compound is 5 to 5000 ppm calculated as the metal element
(that is, as zirconium and/or titanium), and the more desirable
concentration is 10 to 3000 ppm. The film obtained by using the
treating solution for surface treatment of metal and the method for
surface treatment of the present invention is oxide or hydroxide of
zirconium or titanium. Therefore, when the concentration of the
compound selected from the group consisting of zirconium compound
and titanium compound calculated as zirconium and/or titanium is
smaller than 5 ppm, it is difficult to obtain sufficient adhesion
amount to attain corrosion resistance in a practical period of time
for treating, because the concentration of main component of film
is too low. On the contrary, when the concentration is larger than
5000 ppm, the sufficient adhesion amount can be obtained, but it is
not effective to improve the corrosion resistance and is
disadvantageous from the economical view point.
[0022] The zirconium compound and the titanium compound can be
easily dissolved in the acidic solution, but are not stable in the
alkaline solution, and easily deposit as the oxide or the hydroxide
of zirconium or titanium. The desirable pH of the treating solution
for surface treatment of metal of the present invention is pH 2 to
6, more desirably pH 3 to 6. When the metal material to be treated
is in contact with the treating solution for surface treatment of
metal of the present invention in the pH range, the dissolving
reaction of the metal material to be treated occurs. And by the
dissolving of the metal material to be treated, the pH becomes
higher at the surface of the metal material to be treated, and the
oxide or the hydroxide of zirconium or titanium deposits as a film
on the surface of the metal material to be treated.
[0023] The treating solution for surface treatment of metal of the
present invention has free fluorine ion existing therein. To allow
free fluorine ion to exist, the fluorine compound is added into the
treating solution for surface treatment of metal. As the supplying
source of the free fluorine ion, hydrofluoric acid,
H.sub.2ZrF.sub.6 and salt of H.sub.2ZrF.sub.6, H.sub.2TiF.sub.6,
salt of H.sub.2TiF.sub.6, H.sub.2SiF.sub.6, salt of
H.sub.2SiF.sub.6, HBF.sub.4 and salt of HBF.sub.4, NaHF.sub.2,
KHF.sub.2, NH.sub.4HF.sub.2, NaF, KF and NH.sub.4F can be
mentioned. The free fluorine ion has an effect to improve the
stability of the zirconium compound and the titanium compound in
the treating solution for surface treatment of metal. Further, the
free fluorine ion has the function to promote the dissolving
reaction of any of ferriferous material, zinciferous material,
aluminiferous material and magnesiferous material which are the
metal materials to be surface treated in the present invention.
Therefore, by allowing free fluorine ion to exist therein by adding
fluorine compound, the stability of the treating solution for
surface treatment of metal of the present invention is improved,
and further the reactivity to the metal material to be treated can
be improved.
[0024] The inventors of the present invention have previously
suggested a composition for surface treatment and treating solution
for surface treatment of metal containing at least one of iron and
zinc in WO02/103080 as follows. That is, the composition for
surface treatment and treating solution for surface treatment of
metal use titanium compound or zirconium compound and fluorine
containing compound, wherein the ratio A/B is set within the
specific range from 0.06 to 0.18, where A refers to the total mole
weight of metal elements in the composition for surface treatment
and treating solution for surface treatment of metal and B refers
to the mole weight which when total fluorine atom in fluorine
containing compound is calculated as HF. According to the present
invention, it is possible to perform surface treatment on
independently one metal material or simultaneously two or more
metal materials selected from the group consisting of ferriferous
material, zinciferous material, aluminiferous material and
magnesiferous material, even if out of above mentioned specific
range of the ratio, by regulating the concentration of metal
element in the titanium compound and zirconium compound, pH and the
concentration of free fluorine ion.
[0025] It was impossible in the prior arts to perform the surface
treatment on two or more metal materials mentioned above at the
same time, because the respective reactivity of ferriferous
material, zinciferous material, aluminiferous material and
magnesiferous material are different. In the present invention, it
is possible to perform the surface treatment independently on each
metal material or simultaneously on each metal material or two or
more metal materials selected from the group consisting of
ferriferous material, zinciferous material, aluminiferous material
and magnesiferous material, because the stability of the treating
solution for surface treatment of metal and the reactivity can be
balanced arbitrarily by regulating the concentration of free
fluorine ion.
[0026] In the present invention, the concentration of free fluorine
ion means the concentration of fluorine ion measured by an ion
electrode which is on the market. The concentration of free
fluorine ion in the treating solution for surface treatment of
metal of the present invention is desirably 0.1 to 100 ppm, and
more desirably 2 to 70 ppm. In the case where the concentration of
free fluorine ion is higher than 100 ppm, the dissolving reaction
of the metal material to be treated is promoted. However, since
zirconium compound and titanium compound in the treating solution
for surface treatment of metal are very stable, even if the pH of
the surface of metal material to be treated increases, it becomes
difficult to deposit as a film. And, in the case where the
concentration of free fluorine ion is lower than 0.1 ppm, the
effect for the improvement of the stability of the treating
solution for surface treatment of metal and the reactivity thereof
is small, and thus, it is no longer advantageous for the treating
solution to contain free fluorine ion.
[0027] Other than the effect for improvement of the stability and
reactivation of the treating solution for surface treatment of
metal, the free fluorine ion of the present invention has a role to
keep the eluted component by dissolution of the metal material to
be treated stable in the treating solution for surface treatment of
metal. In the case of a zinc phosphate treatment of the prior arts,
sludge generates, because, for example, iron ion eluted from iron
metal material reacts with phosphoric acid and forms iron phosphate
which is an insoluble salt. The treating solution for surface
treatment of metal of the present invention may also contain
phosphoric acid group, but, if the concentration of phosphoric acid
group excesses 1.0 g/L, sludge can be generated. And, in the case
where the treating amount of the metal material to be treated is
remarkably large with respect to the volume of the bath for
treatment, one or more compounds selected from the group, for
example, consisting of inorganic acid such as sulfuric acid or
hydrochloric; organic acid such as acetic acid, oxalic acid,
tartaric acid, citric acid, succinic acid, gluconic acid or
phthalic acid; and chelating agent which can chelete eluted
component, may be added in the treating solution to thereby
solubilize the eluted component.
[0028] The treating solution for surface treatment of metal in the
present invention may contain at least one compound selected from
the group consisting of calcium compound, magnesium compound and
strontium compound. The present invention realizes to perform
surface treatment on each metal material independently or two to
four materials simultaneously selected from the group consisting of
ferriferous material, zinciferous material, aluminiferous material
and magnesiferous material by regulating the concentration of free
fluorine ion in the aqueous solution containing zirconium compound
and titanium compound of specific concentration within the
specified range. Here, the metal elements (calcium, magnesium or
strontium) contained in above mentioned calcium compound, magnesium
compound or strontium compound have a function to maintain the
concentration of free fluorine ion in aqueous solution to a certain
value by generating salt of fluorine and fluorinated compound in
the aqueous solution. Due to the function, when the surface of
various kinds of metal materials are treated at the same time, the
optimum deposit amount of film can be obtained on each metal
material to be treated, because certain concentration of free
fluorine ion can be maintained regardless of the ratio among the
materials used.
[0029] As the example of calcium compound, magnesium compound or
strontium compound which can be used in the present invention, for
example, oxide, hydroxide, chloride, sulfate, nitrate and carbonate
of these metal elements can be mentioned. Further, besides calcium
compound, magnesium compound and strontium compound, the compound
which has a function to maintain the concentration of free fluorine
ion constant can be used regardless of whether an organic compound
or an inorganic compound.
[0030] The concentration of the magnesium compound or the strontium
compound which can be used in the present invention is desirably 10
to 5000 ppm as the metal element, and more desirably is 100 to 3000
ppm. In the case of calcium compound, the desirable concentration
as calcium is 5 to 100 ppm and more desirable concentration is 5 to
50 ppm, because the solubility of calcium is remarkably small. When
the concentration of these compounds is higher than the upper
limit, the stability of the treating solution for surface treatment
of metal may decrease, and the continuous treatment is interrupted.
And, when the concentration of these compounds is lower than the
lower limit, the deposit amount of film particularly on ferriferous
material decreases.
[0031] In the treating solution for surface treatment of metal of
the present invention, desirably 1000 to 50000 ppm, more desirably
1000 to 30000 ppm of nitric acid group may be added. Nitric acid
group acts as an oxidizing agent, and has a function to promote
film depositing reaction of the present invention and a function to
improve the solubility of above mentioned calcium compound,
magnesium compound or strontium compound in the treating solution
for surface treatment of metal. Therefore, even if the
concentration of nitric acid group is lower than 1000 ppm, the film
having excellent corrosion resistance can be deposited. However, in
the case where the concentration of above mentioned calcium
compound, magnesium compound or strontium compound is high, the
stability of the treating solution for surface treatment of metal
may decrease. The concentration of nitric acid group of 50000 ppm
is sufficient, and it is disadvantageous to add more nitric acid
group from the economical view point.
[0032] Further, in the treating solution for surface treatment of
metal of the present invention, at least one oxygen acid and/or
salt of oxygen acid selected from the group consisting of
HClO.sub.3, HBrO.sub.3, HNO.sub.3, HNO.sub.2, HMnO.sub.4,
HVO.sub.3, H.sub.2O.sub.2, H.sub.2WO.sub.4, H.sub.2MoO.sub.4.
Oxygen acid or salt thereof acts as oxidizing agent to the
materials to be treated, and promotes the film forming reaction in
the present invention. The concentration of these oxygen acid or
salts thereof to be added is not restricted, but adding an amount
to 10 to 5000 ppm exhibits sufficient effect as the oxidizing
agent.
[0033] Still further, in the treating solution for surface
treatment of metal of the present invention, at least one polymer
compound selected from the group consisting of water soluble
polymer compounds and water dispersible polymer compounds may be
added. The metal element whose surface is treated by using the
treating solution for surface treatment of metal of the present
invention has an enough corrosion resistance, but, if additional
function such as lubricity is required, it is possible to improve
the physical property of the film by adding preferably selected
polymer according to the desired function. As the examples of above
mentioned water soluble polymer compounds and water dispersible
polymer compounds, polymer compounds which are generally used for
the surface treatment of metal such as polyvinyl alcohol,
poly(metha)acrylic acid, copolymer of acrylic acid and methacrylic
acid, copolymer of ethylene with acrylic monomer such as
(metha)acrylic acid or (metha)acrylate, copolymer of ethylene and
vinyl acetate, polyurethane, amino-modified phenol resin, polyester
resin and epoxy resin can be used.
[0034] The method for surface treatment of the present invention
can be illustrated as follows. Namely, the surface is merely
treated by degreasing treatment according to an ordinary method,
and the cleaned metal material to be treated is brought into
contact with the treating solution for surface treatment of metal.
Accordingly, the film composed of oxide and/or hydroxide of a metal
element selected from the group consisting of zirconium and
titanium is deposited and the surface treated film layer having
good adhesiveness and corrosion resistance is formed. As the
substantial method for this contacting process, any kind of
treatment, e.g., spraying treatment, immersion treatment or pouring
treatment can be used, and the properties of the product will not
be influenced by the treating method. From the chemical view point,
it is difficult to obtain the hydroxide of above mentioned metal as
a pure hydroxide, and in general, the oxide of above mentioned
metal to which hydrated water is attached is considered as
hydroxide. Therefore, the hydroxide of the metal finally becomes
the oxide by heating. The structure of the surface treated layer of
the present invention is considered to be a state where oxide and
hydroxide are mixed when dried at an ordinary temperature or at a
low temperature after surface treatment. And, when dried at a high
temperature after surface treatment, the structure of the surface
treated layer is considered to be a state of oxide alone or oxide
rich.
[0035] In the present invention, the condition to use the treating
solution for surface treatment of metal is not restricted. The
reactivity of the treating solution for surface treatment of metal
of the present invention can be voluntarily regulated by changing
the concentration of zirconium compound or titanium compound and
the concentration of free fluorine ion in the treating solution for
surface treatment of metal. Therefore, the treating temperature and
treating period of time can be changed voluntarily in combination
of the reactivity of the treating bath.
[0036] Further, to the treating solution for surface treatment of
metal, at least one surface active agent selected from the group
consisting of nonionic surface active agent, anionic surface active
agent and cationic surface active agent can be added. In the case
where the surface of a metal material is treated with this treating
solution for surface treatment of metal, a good film can be formed
without previous degreasing and cleaning treatment on the metal
material to be treated. That is, this treating solution for surface
treatment of a metal can be used also as a surface treating agent
and a degreasing agent.
[0037] Furthermore, for the treatment of the surface of metal using
the treating solution for surface treatment of metal of the present
invention, the method to carry out the electrolysis in the treating
solution for surface treatment of metal having a metal material to
be treated as a cathode. When the electrolysis treatment is carried
out using the metal material to be treated as a cathode, the
reduction occurs at the surface of the cathode and the pH goes up.
Along with the elevation of the pH, the stability of zirconium
compound and/or titanium compound at the surface of cathode is
deteriorated, and the surface treated film is deposited as an oxide
or a hydroxide containing water.
[0038] Still further, the effect of the present invention can be
improved when, after contacting with treating solution for surface
treatment of metal, or after being electrolyzed in the treating
solution for surface treatment of metal with or without washed by
water, the metal material is brought into contact with the acidic
solution of the compound containing at least one element selected
from the group consisting of cobalt, nickel, tin, copper, titanium
and zirconium, or with the treating solution containing at least
one polymer compound selected from the group consisting of water
soluble polymer compound and water dispersible polymer.
[0039] The surface treated film layer obtained by the present
invention is characterized in a thin film and exhibits excellent
coating property, but depending on the surface condition of the
metal material to be treated, sometimes tiny defects may be formed
on the surface treated film layer. By bringing the layer in contact
with the acidic solution of the compound containing at least one
element selected from the group consisting of cobalt, nickel, tin,
copper, titanium and zirconium or the treating solution containing
at least one polymer compound selected from the group consisting of
water soluble polymer compound and water dispersible polymer, the
tiny defects are covered and the corrosion resistance can be
further improved.
[0040] The compound containing at least one element selected from
the group consisting of cobalt, nickel, tin, copper, titanium and
zirconium is not restricted, and, it is possible to use oxide,
hydroxide, fluoride, complex fluoride, chloride, nitrate,
oxynitrate, sulfate, oxysulfate, carbonate, oxycarbonate,
phosphate, oxyphosphate, oxalate, oxyoxalate, and organic metal
compounds and the like. Further, desirably the pH of acidic
solution containing the metal element is 2 to 6, and can be
adjusted with acid such as phosphoric acid, nitric acid, sulfuric
acid, hydrofluoric acid, hydrochloric acid and organic acid or
alkali such as sodium hydroxide, potassium hydroxide, lithium
hydroxide, salts of alkali metal, ammonium salt or amines.
[0041] Further, as at least one polymer compound selected from
above mentioned water soluble polymer compound or water dispersible
polymer compound, for example, polyvinyl alcohol,
poly(metha)acrylic acid, copolymer of acrylic acid and methacrylic
acid, copolymer of ethylene with acrylic monomer such as
(metha)acrylic acid or (metha)acrylate, copolymer of ethylene and
vinyl acetate, polyurethane, amino-modified phenol resin, polyester
resin or epoxy resin, tannin and tannic acid and salts thereof, and
phytic acid can be used.
[0042] The present invention may remarkably improve the corrosion
resistance of metal material by providing a surface treated film
layer composed of oxide and/or hydroxide of metal elements selected
from zirconium and/or titanium on the surface of metal material to
be treated. The oxide and hydroxide of above mentioned metal
elements have a physical property characterized not to be damaged
by acid or alkali, and chemically stabilized. In the actual
corrosive environment for metal, at the anode where the metal
elution phenomenon occurs, the pH becomes lower, while, at the
cathode where reduction occurs, the pH becomes higher. Therefore,
the surface treated film of less resistant to acid and alkali may
be dissolved under the corrosive environment and its effect would
be lost. Since the main component of the surface treated film layer
of the present invention is resistive to acid or alkali, the
excellent effect can be maintained under the corrosive
environment.
[0043] And since the oxide and hydroxide of above mentioned metal
elements form a network structure mediated by metal and oxide, it
becomes a very good barrier film. The corrosion of metal material,
which can be varied depending on the environment for use,
generally, is oxygen demanding type corrosion in the atmosphere in
which water and oxygen exist, and the speed of corrosion is
promoted by the presence of the components such as chloride. Having
a barrier effect against water, an acid and a corrosion promoting
component, the surface treated film layer of the present invention
may exhibit excellent corrosion resistance.
[0044] For the purpose to enhance the corrosion resistance of iron
metal material such as cold rolled steel plate, hot rolled steel
plate, cast iron and sintered steel using above mentioned barrier
effect, the adhesion amount over 30 mg/m.sup.2 calculated as the
metal element is necessary, desirably over 40 mg/m.sup.2 and more
desirably over 50 mg/m.sup.2. And for the purpose to enhance the
corrosion resistance of zinc metal material such as zinc, zinc
plated steel plate and alloyed hot-dip zinc-coated steel plate, the
adhesion amount over 20 mg/m.sup.2 calculated as the metal element
is necessary, desirably over 30 mg/m.sup.2. Further, for the
purpose to enhance the corrosion resistance of aluminiferous
materials such as cast aluminum and aluminum alloy plate, the
adhesion amount over than 10 mg/m.sup.2 calculated as the metal
element is necessary, desirably over 20 mg/m.sup.2. For the purpose
to enhance the corrosion resistance of magnesiferous materials such
as magnesium alloy plate and cast magnesium, the adhesion amount
over than 10 mg/m.sup.2 calculated as the metal element is
necessary, desirably over than 20 mg/m.sup.2. Referring to the
adhesion amount, there is no upper limit. However, when the amount
exceeds 1 g/m.sup.2, cracks easily generate on the surface treated
film layer and it becomes difficult to form a uniform film.
Therefore, in any case of iron metal material and zinc metal
material and aluminiferous material, the desirable upper limit of
adhesion amount is 1 g/m.sup.2, more desirably 800 mg/m.sup.2.
EXAMPLES
[0045] The effects of the treating solution for surface treatment
of metal and the method for surface treatment of the present
invention will be illustrated specifically in accordance with the
Examples and Comparative Examples below. And a material to be
treated, a degreasing agent and a coating used therein are
arbitrarily selected from the materials which are on the market,
and not intending to restrict the actual uses of the treating
solution for surface treatment of metal and the method for surface
treatment of the present invention.
[Test Plate]
[0046] As the test plates, cold rolled steel plates, hot-dip
zinc-coated steel plates, aluminum alloy plates and magnesium alloy
plates are used in the Examples and Comparative Examples. The
abbreviations and specifications of these test plates are shown
below. For the evaluation of the appearance after surface
treatment, the test plate prepared by joining three metal materials
of SPC, GA and Al by a spot welding was used. For the evaluation of
adhesion amount of surface treated film layer, each test plate of
SPC, GA, Al and Mg, and the test plate prepared by joining three
metal materials of SPC, GA and Al by a spot welding were used. For
the evaluation of the coating property, the test plate prepared by
joining three metal materials of SPC, GA and Al by a spot welding
was used and the test from surface treatment, coating and
evaluation of coating property were carried out in series. FIG. 1
is the plane view of the test plate prepared by joining three metal
materials of SPC, GA and Al by a spot welding, and FIG. 2 is an
elevation view of it. The numeral 1 indicates a spot welded
portion.
[0047] SPC: cold rolled steel plate (JIS-G-3141)
[0048] GA: both-side alloyed hot-dip zinc-coated steel plate (45
g/m.sup.2)
[0049] Al: aluminum alloy plate (6000 series aluminum alloy)
[0050] Mg: magnesium alloy plate (JIS-H-4201)
[Treating Process]
[0051] Treating process of Examples and Comparative Examples are
shown as follows.
Examples 1-4, Example 7 and Comparative Examples 1-4: alkali
degreasing.fwdarw.rinsing by water.fwdarw.film forming
treatment.fwdarw.rinsing by water.fwdarw.rinsing by pure
water.fwdarw.drying
Example 5: alkali degreasing.fwdarw.rinsing by
water.fwdarw.electrolysis formation treatment.fwdarw.rinsing by
water.fwdarw.rinsing by Pure water.fwdarw.drying
Example 6: film formation treatment (used both as
degreasing).fwdarw.rinsing by water.fwdarw.rinsing by pure
water.fwdarw.drying
Example 8: alkali degreasing.fwdarw.rinsing by water.fwdarw.film
formation treatments.fwdarw.rinsing by water.fwdarw.after
treatment.fwdarw.rinsing by pure water.fwdarw.drying
Example 9: film formation treatment (and degreasing).fwdarw.rinsing
by water.fwdarw.after treatment.fwdarw.rinsing by pure water
.fwdarw.drying
Comparative Example 5: alkali degreasing.fwdarw.rinsing by
water.fwdarw.surface conditioning.fwdarw.zinc phosphate
treatment.fwdarw.rinsing by water.fwdarw.rinsing by pure
water.fwdarw.drying
[0052] In above mentioned processes for Examples and Comparative
Examples, alkali degreasing was carried out as follows. That is,
Fine Cleaner L4460 (Trade Mark: Product of Nihon Parkerizing) was
diluted to 2% concentration by city water, and was sprayed to a
plate to be treated at 40 .degree. C. for 120 sec. Rinsing by water
and rinsing by pure water after film formation treatment were
performed by spraying water and pure water on the plate to be
treated at a room temperature for 30 sec both in Examples and
Comparative Examples.
Example 1
[0053] Aqueous solution of zirconium with concentration of 200 ppm
was prepared using zirconium oxynitrate reagent and nitric acid.
After heating the aqueous solution to 45.degree. C., the pH was
adjusted to 3.0 using sodium hydroxide reagent and hydrofluoric
acid, and the concentration of free fluorine ion measured by a
fluorine ion meter (IM-55G; product of Toa Denpa Industries Co.,
Ltd) was adjusted to 1 ppm, thus obtaining the treating solution
for surface treatment of metal. The total fluorine concentration in
the treating solution for surface treatment of metal after
adjusting free fluorine ion was 50 ppm.
[0054] The test plate rinsed by water after degreasing was immersed
into the treating solution for surface treatment of metal for 120
seconds so as to carry out the surface treatment.
Example 2
[0055] Aqueous solution of zirconium with concentration of 100 ppm,
magnesium with concentration of 5000 ppm, strontium with
concentration of 2000 ppm and nitric acid group with concentration
of 28470 ppm was prepared using zirconium oxynitrate reagent,
magnesium nitrate reagent and strontium nitrate reagent. After
heating the aqueous solution to 50.degree. C., the pH was adjusted
to 4.0 using ammonium water reagent and hydrofluoric acid, and the
concentration of free fluorine ion measured by a fluorine ion meter
(IM-55G; product of Toa Denpa Industries Co., Ltd) was adjusted to
80 ppm, thus obtaining the treating solution for surface treatment
of metal. The total fluorine concentration in the treating solution
for surface treatment of metal after adjusting free fluorine ion
was 2000 ppm.
[0056] The test plate rinsed by water after degreasing was immersed
into the treating solution for surface treatment of metal for 60
seconds so as to carry out the surface treatment.
Example 3
[0057] Aqueous solution of zirconium with concentration of 1000
ppm, titanium with concentration of 2000 ppm, calcium with
concentration of 5 ppm and nitric acid group with concentration of
1000 ppm was prepared using aqueous solution of hexafluorozirconic
acid (IV), aqueous solution of titanium sulfate (IV) and calcium
sulfate reagent. After heating the aqueous solution to 40.degree.
C., the pH was adjusted to 5.0 using potassium hydroxide reagent
and hydrofluoric acid, and the concentration of free fluorine ion
measured by a fluorine ion meter (IM-55G; product of Toa Denpa
Industries Co., Ltd) was adjusted to 25 ppm, thus obtaining the
treating solution for surface treatment of metal. The total
fluorine concentration in the treating solution for surface
treatment of metal after adjusting free fluorine ion was 2250
ppm.
[0058] The test plate rinsed by water after degreasing was immersed
into the treating solution for surface treatment of metal for 90
seconds so as to carry out the surface treatment.
Example 4
[0059] Aqueous solution of titanium with concentration of 5000 ppm,
strontium with concentration of 5000 ppm, nitric acid group with
concentration of 7080 ppm and nitrous acid group with concentration
of 40 ppm was prepared using aqueous solution of hexafluorotitanium
acid (IV), strontium nitrate reagent, and sodium nitrite reagent.
After heating the aqueous solution to 35.degree. C., the pH was
adjusted to 4.0 using triethanol amine reagent and hydrofluoric
acid, and the concentration of free fluorine ion measured by a
fluorine ion meter (IM-55G; product of Toa Denpa Industries Co.,
Ltd) was adjusted to 10 ppm, thus obtaining the treating solution
for surface treatment of metal. The total fluorine concentration in
the treating solution for surface treatment of metal after
adjusting free fluorine ion was 11900 ppm.
[0060] The test plate was rinsed by water after degreasing, then
the obtained treating solution for surface treatment of metal was
sprayed to the surface thereof for 120 sec., thus carrying out the
surface treatment.
Example 5
[0061] Aqueous solution of zirconium with concentration of 5 ppm,
titanium with concentration of 5 ppm, magnesium with concentration
of 100 ppm, nitric acid group with concentration of 30520 ppm and
chloric acid group with concentration of 100 ppm was prepared using
zirconium oxynitrate reagent, aqueous solution of hexafluorotitanic
acid (IV), magnesium nitrate reagent, nitric acid and sodium
chloric acid reagent. After heating the aqueous solution to
30.degree. C., the pH was adjusted to 6.0 using ammonia water
reagent and hydrofluoric acid, and the concentration of free
fluorine ion measured by a fluorine ion meter (IM-55G; product of
Toa Denpa Industries Co., Ltd) was adjusted to 0.5 ppm, thus
obtaining the treating solution for surface treatment of metal. The
total fluorine concentration in the treating solution for surface
treatment of metal after adjusting free fluorine ion was 12
ppm.
[0062] Using the test plate rinsed by water after degreasing as a
cathode and a carbon electrode as an anode, the test plate was
electrolyzed in the treating solution for surface treatment of
metal for 5 seconds under the condition of 5 A/dm.sup.2, thus
carrying out the surface treatment.
Example 6
[0063] Aqueous solution of zirconium with concentration of 150 ppm,
magnesium with concentration of 10 ppm, nitric acid group with
concentration of 5200 ppm and hydrogen peroxide concentration of 10
ppm was prepared using zirconium oxynitrate reagent, magnesium
oxide reagent, nitric acid, and hydrogen peroxide reagent. After
heating the aqueous solution to 50.degree. C., the pH was adjusted
to 5.0 using ammonia water reagent and hydrofluoric acid, the
concentration of free fluorine ion measured by a fluorine ion meter
(IM-55G; product of Toa Denpa Industries Co., Ltd) was adjusted to
50 ppm and 2 g/L of polyoxyethylenenonylphenylether (ethylene oxide
addition mole number: 12 mol), which is nonionic surface active
agent, was added, thus obtaining the treating solution for surface
treatment of metal. The total fluorine concentration in the
treating solution for surface treatment of metal after adjusting
free fluorine ion was 170 ppm.
[0064] Undegreased test plate on which oil is coated, above
mentioned treating solution for surface treatment of metal was
applied to the surface by spray for 90 sec., thus the degreasing
and surface treatment were carried out at the same time.
Example 7
[0065] Aqueous solution of titanium with concentration of 100 ppm,
calcium with concentration of 50 ppm, magnesium with concentration
of 5000 ppm, nitric acid group with concentration of 25660 ppm and
permanganate with concentration of 10 ppm was prepared using
aqueous solution of titanium sulfate (IV), calcium nitrate reagent,
magnesium nitrate reagent and potassium permanganate reagent. Water
soluble acrylic polymer compound (Jurymer AC-10L: product of Nihon
Junyaku Co., Ltd.) was added in the aqueous solution so as the
concentration of solid to be 1%, then the aqueous solution was
heated to 50.degree. C. Thereafter, the pH was adjusted to 3.0
using sodium hydroxide reagent and hydrofluoric acid, and the total
free fluorine ion concentration in the aqueous solution to be
measured by a fluorine ion meter (IM-55G; product of Toa Denpa
Industries Co., Ltd) was adjusted to 95 ppm, thus obtaining the
treating solution for surface treatment of metal. After adjusting
the free fluorine ion concentration, the total fluorine
concentration in the treating solution for surface treatment of
metal was 2000 ppm.
[0066] The test plate rinsed by water after degreasing was immersed
into the treating solution for surface treatment of metal for 60
seconds so as to carry out the surface treatment.
Example 8
[0067] The aqueous solution with 1% of water soluble acrylic
polymer compound (Jurymer AC-10L: product of Nihon Junyaku Co.,
Ltd.) in solid concentration and 2 g/L of phosphoric acid reagent
as phosphoric acid group was prepared. This aqueous solution was
heated to 40.degree. C., then the pH was adjusted to 4.5 using
ammonia water reagent, thus obtaining the after treating solution.
The test plate on which film formation was carried out by the
surface treatment of Example 5 and rinsed by water was dipped into
the above mentioned after treating solution for 30 seconds so as to
carry out the after treatment.
Example 9
[0068] The aqueous solution of zirconium with concentration of 50
ppm and cobalt with concentration of 50 ppm was prepared using
aqueous solution of hexafluorozirconic acid (IV) and cobalt nitrate
reagent. After heating the aqueous solution to 40.degree. C., the
pH was adjusted to 5.0 with ammonia water reagent, thus obtaining
the after treating solution. The test plate on which film formation
was carried out by the surface treatment of Example 6 and rinsed by
water was immersed into the above mentioned after treating solution
for 30 seconds so as to carry out the after treatment.
Comparative Example 1
[0069] The aqueous solution of zirconium with concentration of 500
ppm, magnesium with concentration of 1000 ppm and nitric acid group
with concentration of 6780 ppm was prepared using zirconium
oxynitrate reagent, magnesium nitrate and nitric acid. After
heating the aqueous solution to 45.degree. C., the pH was adjusted
to 4.0 with sodium hydroxide solution, thus obtaining the treating
solution for surface treatment of metal. The free fluorine ion
concentration of the treating solution for surface treatment of
metal was measured by a fluorine ion meter on the market (IM-55G;
product of Toa Denpa Industries Co., Ltd), and the result was 0
ppm.
[0070] The test plate which was rinsed by water after degreasing
was immersed into the above mentioned treating solution for surface
treatment of metal for 120 seconds so as to carry out the surface
treatment.
Comparative Example 2
[0071] The aqueous solution of titanium with concentration of 2000
ppm was prepared by using aqueous solution of titanium sulfate
(IV). After heating the aqueous solution to 50.degree. C., the pH
was adjusted to 3.5 using ammonia water reagent and hydrofluoric
acid, and the concentration of free fluorine ion measured by a
fluorine ion meter (IM-55G; product of Toa Denpa Industries Co.,
Ltd) was adjusted to 400 ppm, thus obtaining the treating solution
for surface treatment of metal.
[0072] The test plate which was rinsed by water after degreasing
was immersed into the above mentioned treating solution for surface
treatment of metal for 90 seconds so as to carry out the surface
treatment.
Comparative Example 3
[0073] Alchrom 713 (Trade Mark, product of Nihon Parkerizing Co.,
Ltd.), which is the chromic chromate treating agent on the market,
was diluted by city water to the concentration of 3.6%, then total
acidity and free acid acidity were adjusted to the center value
described in the brochure.
[0074] The test plate was rinsed by water after degreasing, then
immersed into the chromate treating solution heated to the
temperature of 35.degree. C. and chromate treatment was carried out
for 60 sec.
Comparative Example 4
[0075] Palcoat 3756 (Trade Mark, product of Nihon Parkerizing Co.,
Ltd.), which is the chrome free treating agent on the market, was
diluted by city water to the concentration of 2%, then total
acidity and free acid acidity were adjusted to the center value
described in the brochure. The test plate was rinsed by water after
degreasing, then immersed into the chrome free treating solution
heated to the temperature of 40.degree. C. and chrome free
treatment was carried out for 60 sec.
Comparative Example 5
[0076] The test plate was rinsed by water after degreasing, then
the solution prepared by diluting Prepalene ZN (Trade Mark, product
of Nihon Pakerizing Co., Ltd.), which is a surface conditioning
agent, with city water to the concentration of 0.1% was sprayed
thereon at the room temperature for 30 sec. Palbond L3020 (Trade
Mark, product of Nihon Parkerizing Co., Ltd.) was diluted to the
concentration of 4.8% with city water. Further, sodium hydrogen
fluoride reagent as fluorine was added into the solution to 200
ppm, and then, total acidity and free acid acidity thereof were
adjusted to the center value described in the brochure. Thus the
zinc phosphate treating solution was prepared. Above mentioned test
plate was immersed into the zinc phosphate chemical treating
solution heated to the temperature of 42.degree. C., and zinc
phosphate film was deposited.
[Evaluation of Surface Treated Film]
[0077] The appearance of surface treated plates of the Examples and
Comparative Examples were evaluated by visual inspection. Results
are summarized in Table 1. Further, adhesion amounts of surface
treated film layers were measured by a fluorescent X-ray analyzer
(System 3270, product of Rigaku Denki Kogyo Co., Ltd.). Results are
summarized in Table 2 and Table 3. The adhesion amount of surface
treated film layer was measured in the case where metal materials
were not joined together and treated respectively (in the case
without joining) and in the case where materials were subjected to
joining treatment by means of spot welding (in the case with
joining). TABLE-US-00001 TABLE 1 appearance after surface treatment
on SPC on GA on Al Example 1 uniform uniform dark uniform white
interference black color Example 2 uniform uniform dark uniform
white interference black color Example 3 uniform uniform dark
uniform white interference black color Example 4 uniform uniform
dark uniform white interference black color Example 5 uniform
uniform dark uniform white interference black color Example 6
uniform uniform dark uniform white interference black color Example
7 uniform uniform dark uniform white interference black color
Comparative film not film not uneven white Example 1 deposited
deposited Comparative pale yellow uneven gray uneven white Example
2 Comparative film not slightly gold Example 3 deposited turned to
yellow Comparative film not film not uniform white Example 4
deposited deposited Comparative material uniform gray uneven white
Example 5 partially exposed
[0078] In Table 1, the appearance evaluation results of surface
treated films obtained by Examples and Comparative Examples are
shown. In the Examples, it is clear that the uniform films, were
obtained on all metal materials in all test plates. Further, on the
spot welded portions of test plates used in Examples, the
deposition of surface treated film was observed too. On the
contrary, in Comparative Examples, a uniform film was not formed on
all test plates. Especially, in Comparative Examples 3, 4 and 5,
the deposition of film on spot welded portions was not at all
observed. Further, the Comparative Example 5 used the zinc
phosphate chemical treating solution to be used in the case where
cold rolled steel plate, zinc plated steel plate and aluminum alloy
are treated at the same time. When the test plates were joined by
spot welding as illustrated in the present test, the portion where
the metal material was exposed, which is called as "Lack of
Hiding", was observed on the cold rolled steel plate.
TABLE-US-00002 TABLE 2 adhesion amount of surface treated film
layer (without joining) (total adhesion amount of Zr and Ti:
mg/m.sup.2) on SPC on GA on Al on Mg Example 1 122 67 48 45 Example
2 108 66 49 41 Example 3 61 58 42 38 Example 4 73 59 14 12 Example
5 41 52 38 26 Example 6 35 38 25 19 Example 7 31 29 24 18
Comparative trace trace trace trace Example 1 Comparative 25 15 15
10 Example 2 Comparative trace Cr 33 Cr 95 Cr 75 Example 3
Comparative trace trace 25 15 Example 4 Comparative weight weight
weight weight Example 5 of film of film of film of film 2.5
g/m.sup.2 4.5 g/m.sup.2 1.2 g/m.sup.2 0.5 g/m.sup.2
[0079] TABLE-US-00003 TABLE 3 Adhesion amount of surface treated
film layer (with joining) (total adhesion amount of Zr and Ti:
mg/m.sup.2) on SPC on GA on Al Example 1 125 67 48 Example 2 118 66
49 Example 3 65 58 42 Example 4 72 59 14 Example 5 45 52 38 Example
6 38 38 25 Example 7 32 29 24 Comparative trace trace trace Example
1 Comparative 28 17 12 Example 2 Comparative trace Cr 35 Cr 85
Example 3 Comparative trace trace 21 Example 4 Comparative weight
of weight of Weight of Example 5 film film film 2.8 g/m.sup.2 4.7
g/m.sup.2 0.7 g/m.sup.2
[0080] In Table 2 and Table 3, the results by the measurement of
adhesion amount of surface treated film obtained in Examples and
Comparative Examples. In the Examples, the aimed adhesion amounts
were be obtained on all metal materials in all test plates.
Further, the adhesion amount of surface treated film layer in
Examples was constant regardless of whether the test plates were
joined or not. On the contrary, as clearly understood from the
evaluation results for appearance of film in Comparative Example,
the uniform film was not deposited on all test plates.
[Evaluation of Coating Performance]
(Preparation of Evaluation Plate)
[0081] For the purpose to evaluate the coating property of surface
treated plates obtained in Examples and Comparative Examples,
coating was carried out by the following process: cationic
electrodeposition coating.fwdarw.rinsing with pure
water.fwdarw.baking.fwdarw.surfacer.fwdarw.baking.fwdarw.top
coating.fwdarw.baking.
[0082] Details of the cationic electrodeposition coating, surfacer,
and top coating are as follows:
[0083] Cationic electrodeposition coating: epoxy type cationic
electrodeposition coating (Elecron 9400, product of Kansai Paint
CO., LTD), electric voltage 200V, thickness of film 20 .mu.m, baked
at 175.degree. C. for 20 minutesm,
[0084] surfacer: aminoalkyd coating (AmilacTP-37 gray: product of
Kansai Paint CO., LTD.), spray coating, thickness of film 35 cm,
baked at 140.degree. C. for 20 minutes, and
[0085] top coating: aminoalkyd coating (Amilac.TM.-13 white,
product of Kansai Paint CO., LTD.), spray coating, thickness of
film 35 .mu.m, baked at 140.degree. C. for 20 minutes.
[Evaluation of Coating Performance]
[0086] The coating property in the Examples and Comparative
Examples was evaluated and the results thereof are shown in Table 4
and Table 5. Items evaluated and the abbreviations are described
below. Hereinafter, the coated film after electrodeposition coating
process is called as electrodeposition coated film and the coated
film after top coating is called as 3-coats film.
[0087] (1) SST: salt water spray test (electrodeposition coated
film)
[0088] (2) SDT: warm salt water dipping test (electrodeposition
coated film)
[0089] (3) 1st ADH: primary adhesion (3-coats film)
[0090] (4) 2nd ADH: water resistant secondary adhesion (3-coats
film)
[0091] SST: Cross cut line is notched using a sharp knife on the
electrodeposition coated plate, and 5% brine is sprayed to the
plate for 840 hours (according to JIS-Z-2371). After spraying,
maximum blister widths at both sides from the cross cut line were
measured.
[0092] SDT: The electrodeposition coated plate was soaked into
aqueous solution of 5 wt % of NaCl at 50.degree. C. for 840 hours.
After soaking, the test plate washed with city water and dried at
the room temperature. The whole surface of the test plate was
peeled off using an adhesive tape, and the removed area of coated
film on each metal material was evaluated by inspector's eye.
[0093] 1.sup.st ADH: Checker lines of 100 squares with 2 mm
intervals were marked using a sharpened knife on a 3-coats film.
The squares in the checker were peeled using a cellophane tape, and
numbers of peeled squares were counted.
[0094] 2.sup.nd ADH: A 3-coats film was soaked in pure water of
40.degree. C. for 240 hours. Then, 100 checker squares with 2 mm
interval were marked using a sharpened knife on it. The checker
squares were peeled using a cellophane tape, and numbers of peeled
squares were counted. TABLE-US-00004 TABLE 4 coating property of
electro deposition film SST max blister widths SDT removed at both
sides (mm) area (%) on SPC on GA on Al on SPC on GA on Al Example 1
2.0 0.5 0.5 5> 5> 5> Example 2 2.0 0.5 0.5 5> 5>
5> Example 3 3.0 0.5 0.5 5> 5> 5> Example 4 3.0 0.5 0.5
5> 5> 5> Example 5 3.0 0.5 0.5 5 5> 5> Example 6 3.5
1.0 0.5 10 5> 5> Example 7 3.5 1.0 0.5 10 5> 5> Example
8 2.5 0.5 0.5 5> 5> 5> Example 9 2.5 0.5 0.5 5> 5>
5> Comparative 6.5 3.5 3.0 70 40 15 Example 1 Comparative 4.5
2.0 0.5 30 10 5 Example 2 Comparative 10.0 5.0 0.5 80 40 5>
Example 3 Comparative 10.0 5.0 1.0 90 50 10 Example. 4 Comparative
5.0 2.0 2.0 40 10 20 Example 5
[0095] The results for evaluation of coating property of the
electrodeposition coated film are summarized in Table 4. Examples
showed good corrosive resistance on all test plates. On the
contrary, in Comparative Example 1, since free fluorine ions were
not contained in the treating solution for surface treatment of
metal at all, the deposition of surface treated film was not
sufficient and thus the corrosion resistance was not so good.
Further, in Comparative Example 2, since the concentration of free
fluorine ion in the treating solution for surface treatment of
metal was high, especially, the adhesion amount of film on SPC was
small and the corrosion resistance was not so good. The coating
properties of Examples 5 and 6 were superior to those of
Comparative Examples, but when compared with other Examples,
corrosive resistances after electrodeposition coating was inferior
to those of other Examples. However, as shown in Examples 8 and 9,
the corrosive resistance was further improved by carrying out the
after treatment.
[0096] Because in Comparative Example 3, a chromate treating agent
for aluminum alloy was used and in Comparative Example 4, a chrome
free treating agent for aluminum alloy was used, the corrosion
resistance of Al was good, but the corrosion resistance of other
test plates were obviously inferior to those of Examples. In
Comparative Example 5, a zinc phosphate treating agent, which is
now usually used as the base for coating was used. However,
Comparative Example 5, in the condition where each of the test
plates was joined by welding, showed the test results inferior to
those of Examples. TABLE-US-00005 TABLE 5 coating properties of
3-coats film 1st ADH 2nd ADH on SPC on GA on Al on SPC on GA on Al
Example 1 0 0 0 0 0 0 Example 2 0 0 0 0 0 0 Example 3 0 0 0 0 0 0
Example 4 0 0 0 0 0 0 Example 5 0 0 0 0 0 0 Example 6 0 0 0 0 0 0
Example 7 0 0 0 0 0 0 Example 8 0 0 0 0 0 0 Example 9 0 0 0 0 0 0
Comparative 0 0 0 5 8 0 Example 1 Comparative 0 0 0 0 0 0 Example 2
Comparative 6 0 0 17 3 0 Example 3 Comparative 0 0 0 5 0 0 Example
4 Comparative 5 0 0 8 0 6 Example 5
[0097] Table 5 shows the evaluation results of adhesion of a
3-coats plate. Examples showed good adhesion to all test plates.
Regarding to 1st ADH, good results were obtained in all Comparative
Examples. However, regarding to 2nd ADH, Comparative Examples did
not show the good level of adhesion to all test plates same as the
corrosive resistance of the electrodeposition coating. Further, in
Comparative Example 5, the generation of sludge, which is the
by-product of zinc phosphate treatment, was observed in the
treating bath after surface treatment. However, in Examples of the
present invention, the generation of sludge was not observed.
[0098] From above mentioned results, it is obviously understood
following facts. That is, simultaneous treatments of SPC, GA, and
Al and the deposition of surface treated film having good adhesion
and corrosion resistance on the surface thereof without changing
treating bath and treating condition are possible only by using the
treating solution for surface treatment of metal and the surface
treating method of the present invention. According to the present
invention, it is possible to deposit the surface treated film
having good corrosion resistance even on a welded portion. Further,
since the method for surface treatment of the present invention
requires only to bring the metal material to be treated in contact
with the treating solution for surface treatment of metal, it is
possible to deposit surface treated film and to improve the
corrosive resistance in the portion where the solution may not be
stirred such as inside of bag shape structure.
INDUSTRIAL APPLICABILITY
[0099] According to the treating solution for metal surface
treatment and the method for surface treatment of the present
invention, it is possible to deposit a surface treated film having
excellent corrosion resistance after coating on the surface of a
metal made of two or more, or each of ferriferous material,
zinciferous material, aluminiferous material and magnesiferous
material in the treating bath containing no harmful component to
the environment and without generating sludge, which have never
been achieved in the prior art. Further, since the present
invention does not need a process for surface conditioning on the
metal material to be treated, it is possible to shorten the
treatment time and to reduce space for the treatment.
* * * * *