U.S. patent application number 16/982128 was filed with the patent office on 2021-03-11 for surface treatment agent, and aluminum or aluminum alloy material having surface treatment coating and method of producing the same.
The applicant listed for this patent is Nihon Parkerizing Co., Ltd.. Invention is credited to Masaya Miyazaki, Yusuke Yamamoto.
Application Number | 20210071304 16/982128 |
Document ID | / |
Family ID | 1000005260061 |
Filed Date | 2021-03-11 |
United States Patent
Application |
20210071304 |
Kind Code |
A1 |
Yamamoto; Yusuke ; et
al. |
March 11, 2021 |
Surface Treatment Agent, and Aluminum or Aluminum Alloy Material
Having Surface Treatment Coating and Method of Producing the
Same
Abstract
The present invention addresses the problem of providing a
surface treatment agent for aluminum or aluminum alloy materials,
which is capable of forming, on an aluminum or an aluminum alloy
material, a surface treatment coating that has excellent corrosion
resistance and has excellent corrosion resistance even when the
coating is exposed to a high temperature. The problem is solved by
a surface treatment agent which is used for surface treatment of an
aluminum or an aluminum alloy material and which contains a
trivalent chromium-containing ion (A), at least one ion (B)
selected from a titanium-containing ion and a zirconium-containing
ion, a zinc-containing ion (C), a free fluorine ion (D), and a
nitrate ion (E).
Inventors: |
Yamamoto; Yusuke; (Tokyo,
JP) ; Miyazaki; Masaya; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Nihon Parkerizing Co., Ltd. |
Tokyo |
|
JP |
|
|
Family ID: |
1000005260061 |
Appl. No.: |
16/982128 |
Filed: |
March 20, 2019 |
PCT Filed: |
March 20, 2019 |
PCT NO: |
PCT/JP2019/011666 |
371 Date: |
September 18, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C22C 21/00 20130101;
C23C 2222/10 20130101; C23C 22/34 20130101 |
International
Class: |
C23C 22/34 20060101
C23C022/34 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 29, 2018 |
JP |
2018-065075 |
Claims
1. A surface treatment agent used for surface treatment of an
aluminum or an aluminum alloy material, wherein the surface
treatment agent comprises a trivalent chromium-containing ion (A),
at least one ion (B) selected from a titanium-containing ion and a
zirconium-containing ion, a zinc-containing ion (C), a free
fluorine ion (D), and a nitrate ion (E).
2. A method of producing an aluminum or an aluminum alloy material
having a surface treatment coating, the method comprising a contact
step of contacting the surface treatment agent according to claim 1
on or over a surface of an aluminum or an aluminum alloy
material.
3. An aluminum or an aluminum alloy material having a surface
treatment coating obtainable by the method according to claim 2.
Description
TECHNICAL FIELD
[0001] The present invention relates to a surface treatment agent
used for surface treatment of an aluminum or an aluminum alloy
material, an aluminum or an aluminum alloy material which has a
surface treatment coating formed by the surface treatment agent,
and a method of producing the aluminum or the aluminum alloy
material.
BACKGROUND ART
[0002] Conventionally, metallic material surface treatment agents
containing trivalent chromium have been developed as surface
treatment agents for aluminum and aluminum alloy materials in a
wide range of fields, such as aircraft materials, construction
materials, and automobile parts.
[0003] For example, Patent Document 1 discloses a chemical
conversion treatment liquid for metallic materials, which contains
a component (A) comprising a water-soluble trivalent chromium
compound, a component (B) comprising at least one selected from a
water-soluble titanium compound and a water-soluble zirconium
compound, a component (C) comprising a water-soluble nitrate
compound, a component (D) comprising a water-soluble aluminum
compound and a component (E) comprising a fluorine compound, and
which has pH controlled in a range of 2.3 to 5.0.
[0004] Patent Document 2 discloses a chemical conversion treatment
liquid which contains a predetermined amount of a specific
trivalent chromium compound, a specific zirconium compound, and a
specific dicarboxylic acid compound.
RELATED ART DOCUMENTS
Patent Documents
[0005] [Patent Document 1] Japanese Unexamined Patent Application
Publication No. 2006-328501
[0006] [Patent Document 2] Japanese Unexamined Patent Application
Publication No. 2006-316334
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0007] However, according to the coatings formed on aluminum or
aluminum alloy materials using the respective surface treatment
agents disclosed in the Patent Documents 1 and 2, the corrosion
resistance may be reduced due to exposure to a high temperature
environment, depending on the use of the aluminum or the aluminum
alloy materials.
[0008] An object of the present invention is to provide a surface
treatment agent capable of forming, on an aluminum or an aluminum
alloy material, a surface treatment coating that has excellent
corrosion resistance and has excellent corrosion resistance even
when the coating is exposed to a high temperature, an aluminum or
an aluminum alloy material which has a surface treatment coating
formed by the surface treatment agent, and a method of producing
the aluminum or the aluminum alloy material.
Means for Solving the Problems
[0009] The present inventors intensively studied to solve the
above-described problems and consequently discovered that a surface
treatment agent containing a trivalent chromium-containing ion (A),
at least one ion (B) selected from a titanium-containing ion and a
zirconium-containing ion, a zinc-containing ion (C), a free
fluorine ion (D), and a nitrate ion (E) is capable of forming, on
an aluminum or aluminum alloy material, a surface treatment coating
that has excellent corrosion resistance and has excellent corrosion
resistance even when the coating is exposed to a high temperature,
thereby completing the present invention.
[0010] In order to solve the above-described problems, the present
invention encompasses the followings:
[0011] (1) A surface treatment agent used for surface treatment of
an aluminum or an aluminum alloy material, wherein the surface
treatment agent contains a trivalent chromium-containing ion (A),
at least one ion (B) selected from a titanium-containing ion and a
zirconium-containing ion, a zinc-containing ion (C), a free
fluorine ion (D), and a nitrate ion (E);
[0012] (2) A method of producing an aluminum or an aluminum alloy
material having a surface treatment coating, the method including a
contact step of contacting the surface treatment agent according to
(1) on or over a surface of an aluminum or an aluminum alloy
material; and
[0013] (3) An aluminum or an aluminum alloy material having a
surface treatment coating obtainable by the method according to
(2).
Advantageous Effects of the Invention
[0014] According to the present invention, the followings can be
provided: a surface treatment agent capable of forming, on an
aluminum or an aluminum alloy material, a surface treatment coating
that has excellent corrosion resistance and has excellent corrosion
resistance even when the coating is exposed to a high temperature;
an aluminum or an aluminum alloy material which has a surface
treatment coating formed by the surface treatment agent; and a
method of producing the aluminum or the aluminum alloy
material.
DESCRIPTION OF EMBODIMENTS
(1) Surface Treatment Agent
[0015] The surface treatment agent of the present embodiment is a
treatment agent for performing a surface treatment of an aluminum
or an aluminum alloy material. The surface treatment agent can also
be utilized as a chemical conversion treatment agent. The surface
treatment agent contains a trivalent chromium-containing ion (A),
at least one ion (B) selected from a titanium-containing ion and a
zirconium-containing ion, a zinc-containing ion (C), a free
fluorine ion (D), and a nitrate ion (E). The surface treatment
agent may be obtained by mixing an aqueous medium with sources of
these ions exclusively, or by mixing an aqueous medium with sources
of these ions and other components. The respective components,
formulations (contents) thereof, and liquid properties are
described below in detail. Examples of the above-described
metal-containing ions include metal ions, metal oxide ions, metal
hydroxide ions, and metal complex ions.
(Trivalent Chromium-Containing Ion)
[0016] In the surface treatment agent, a supply source of the
trivalent chromium-containing ion (A) is not particularly limited
as long as it is capable of providing the ion (A) by mixing with an
aqueous medium. Examples of the supply source include chromium
fluoride, chromium nitrate, chromium sulfate, and chromium
phosphate. These supply sources may be used singly, or in
combination of two or more thereof. The content of the ion (A) in
the surface treatment agent is not particularly limited, however,
it is usually in a range of 5 to 1,000 mg/L, preferably in a range
of 20 to 700 mg/L, in terms of chromium-equivalent mass
concentration. In the present embodiment, it is preferred that the
surface treatment agent does not contain hexavalent chromium ions.
It is noted here that "does not contain hexavalent chromium ions"
does not mean that the content of the hexavalent chromium ions is
0, but unavoidable incorporation of hexavalent chromium ions is
acceptable. Specifically, the content of hexavalent chromium ions
may be 10 mg/L or less, 5 mg/L or less, 1 mg/L or less, 0.5 mg/L or
less, or 0.1 mg/L or less.
(At Least One Ion Selected from Titanium-Containing Ion and
Zirconium-Containing Ion)
[0017] In the surface treatment agent, a supply source of at least
one ion (B) selected from a titanium-containing ion and a
zirconium-containing ion is not particularly limited as long as it
is capable of providing the ion (B) by mixing with an aqueous
medium. Examples of the supply source include titanium sulfate,
titanium oxysulfate, titanium ammonium sulfate, titanium nitrate,
titanium oxynitrate, titanium ammonium nitrate, hexafluorotitanic
acid, hexafluorotitanium complex salts, zirconium sulfate,
zirconium oxynitrate, zirconium ammonium sulfate, zirconium
nitrate, zirconium oxynitrate, zirconium ammonium nitrate,
hexafluorozirconic acid, hexafluorozirconium complex salts,
titanium lactate, titanium acetylacetonate, titanium
triethanolaminate, titanium octyl glycolate, tetraisopropyl
titanate, tetra-n-butyl titanate, zirconyl acetate, zirconyl
lactate, zirconium tetraacetylacetonate, zirconium
tributoxyacetylacetonate, tetra-n-butoxy zirconium, and
tetra-n-propoxy zirconium. These supply sources may be used singly,
or in combination of two or more thereof. The content of the ion
(B) in the surface treatment agent is not particularly limited,
however, it is usually in a range of 5 to 1,000 mg/L, preferably in
a range of 20 to 700 mg/L, in terms of metal-equivalent mass
concentration (total metal-equivalent mass concentration when two
or more supply sources are combined).
(Zinc-Containing Ion)
[0018] In the surface treatment agent, a supply source of the
zinc-containing ion (C) is not particularly limited as long as as
it is capable of providing the ion (C) by mixing with an aqueous
medium. Examples of the supply source include metallic zinc, zinc
oxide, zinc carbonate, zinc nitrate, zinc chloride, zinc sulfate,
zinc fluoride, zinc iodide, zinc dihydrogen phosphate, and zinc
acetylacetonate. These supply sources may be used singly, or in
combination of two or more thereof. The content of the ion (C) in
the surface treatment agent is not particularly limited, however,
it is usually in a range of 20 to 10,000 mg/L and may be in a range
of 50 to 10,000 mg/L, preferably in a range of 300 to 8,000 mg/L,
more preferably in a range of 700 to 5,000 mg/L, in terms of
zinc-equivalent mass concentration.
(Free Fluorine Ion)
[0019] In the surface treatment agent, a supply source of the free
fluorine ion (D) is not particularly limited as long as it is
capable of providing the free fluorine ion (D) by mixing with an
aqueous medium. Examples of the supply source include hydrofluoric
acid, ammonium fluoride, chromium fluoride, hexafluorotitanic acid,
hexafluorotitanium complex salts, hexafluorozirconic acid,
hexafluorozirconium complex salts, magnesium fluoride, aluminum
fluoride, hexafluorosilicic acid, sodium fluoride, potassium
fluoride, and zinc fluoride. These supply sources may be used
singly, or in combination of two or more thereof. The free fluorine
ion (D) may be provided by the same compound as the above-described
supply source(s) of (A), (B) and/or (C), or may be provided by a
different compound. In the surface treatment agent, the
fluorine-equivalent mass concentration of the free fluorine ion (D)
is preferably 3 to 100 mg/L, more preferably 5 to 70 mg/L.
(Nitrate Ion)
[0020] In the surface treatment agent, a supply source of the
nitrate ion (E) is not particularly limited as long as it is
capable of providing the nitrate ion (E) by mixing with an aqueous
medium. Examples of the supply source include nitric acid, sodium
nitrate, potassium nitrate, magnesium nitrate, ammonium nitrate,
cerium nitrate, manganese nitrate, strontium nitrate, calcium
nitrate, cobalt nitrate, aluminum nitrate, and zinc nitrate. These
supply sources may be used singly, or in combination of two or more
thereof. The nitrate ion (E) may be provided by the same compound
as the above-described supply source(s) of (A), (B) and/or (C), or
may be provided by a different compound. The content of the nitrate
ion (E) in the surface treatment agent is not particularly limited,
however, it is usually in a range of 100 to 30,000 mg/L in terms of
nitric acid-equivalent mass concentration.
(Other Components)
[0021] In the surface treatment agent of the present embodiment, a
variety of metal components and additives may be incorporated as
long as they do not impair the effects of the present invention.
Examples of the metal components include vanadium, molybdenum,
tungsten, manganese, cerium, magnesium, calcium, cobalt, nickel,
strontium, lithium, niobium, yttrium, and bismuth. Examples of the
additives include hydroxy group-containing compounds, formyl
group-containing compounds, benzoyl group-containing compounds,
amino group-containing compounds, imino group-containing compounds,
cyano group-containing compounds, azo group-containing compounds,
thiol group-containing compounds, sulfo group-containing compounds,
nitro group-containing compounds, and urethane bond-containing
compounds. These metal components and additives may be used singly,
or in combination of two or more thereof. These additives are
incorporated within a range that does not impair the effects of the
present invention, therefore, the content thereof is at most
several percent by mass with respect to a total amount of the
surface treatment agent.
[0022] Meanwhile, the surface treatment agent of the present
embodiment preferably does not contain carboxyl group-containing
compounds, preferably does not contain amidino group-containing
compounds, preferably does not contain aromatic ring-containing
compounds, and more preferably does not contain organic matters. By
using the surface treatment agent which does not contain organic
matters, a reduction in the corrosion resistance of the resulting
coating can be suppressed. It is noted here that "does not contain
organic matters" does not necessarily mean that the content of
organic matters is 0, and it is acceptable that the surface
treatment agent contains organic matters within a range that does
not significantly impair the effects of the present invention.
Specifically, the content of organic matters may be 10 mg/L or
less, 5 mg/L or less, 1 mg/L or less, 0.5 mg/L or less, or 0.1 mg/L
or less, or 0 mg/L. The term "organic matters" used herein refers
to compounds containing carbon as a main component, and may
encompass derivatives of such compounds.
(Liquid Properties)
[0023] The pH of the surface treatment agent of the present
embodiment is not particularly limited, however, it is preferably
2.3 to 5.0, more preferably 3.0 to 4.5. In the present
specification, the pH means a value measured at a temperature at
which the surface treatment agent is contacted on or over a surface
of an aluminum or an aluminum alloy material. The pH can be
measured using, for example, a portable electrical conductivity/pH
meter (WM-32EP, manufactured by DKK-TOA Corporation).
[0024] Thus far, formulations of the surface treatment agent of the
present embodiment have been described, moreover, another aspect of
the present invention is a surface treatment agent which is used
for surface treatment of an aluminum or an aluminum alloy material,
and which is obtainable by mixing a source of a trivalent
chromium-containing ion (A), a supply source of at least one ion
(B) selected from a titanium-containing ion and a
zirconium-containing ion, a supply source of a zinc-containing ion
(C), a supply source of a free fluorine ion (D), and a supply
source of a nitrate ion (E). The supply source of the free fluorine
ion (D) may be the same compound as the supply source(s) of (A),
(B) and/or (C), or may be a different compound. Further, the supply
source of the nitrate ion (E) may be the same compound as the
supply source(s) of (A), (B) and/or (C), or may be a different
compound.
(2) Method of Producing Surface Treatment Agent
[0025] The surface treatment agent of the present embodiment can be
obtained by mixing an aqueous medium with appropriate amounts of
supply sources of the above-described trivalent chromium-containing
ion (A), at least one ion (B) selected from a titanium-containing
ion and a zirconium-containing ion, zinc-containing ion (C), free
fluorine ion (D), and nitrate ion (E), and stirring the resulting
mixture. In the production, solid supply sources may be added to
the aqueous medium, or the solid supply sources may be dissolved in
the aqueous medium in advance and then added as an aqueous medium
solution. The pH of the resulting surface treatment agent is
preferably adjusted to be in the above-described range using a pH
modifier, such as nitric acid, hydrofluoric acid, ammonium hydrogen
carbonate, or aqueous ammonia, however, the pH modifier is not
limited to these components. Such a pH modifier may be used singly,
or two or more thereof may be used in combination.
[0026] As the aqueous medium, water is typically used. The aqueous
medium may contain a water-miscible organic solvent within a range
that does not impair the effects of the present invention, however,
the aqueous medium is preferably water. When the aqueous medium
contains a water-miscible organic solvent, the content thereof may
be 10 mg/L or less, 5 mg/L or less, 1 mg/L or less, 0.5 mg/L or
less, or 0.1 mg/L or less.
(3) Method of Producing Aluminum or Aluminum Alloy Material Having
Surface Treatment Coating
[0027] A method of producing an aluminum or an aluminum alloy
material having a coating formed by the surface treatment agent of
the present embodiment includes a contact step of contacting the
surface treatment agent of the present embodiment on or over a
surface of an aluminum or an aluminum alloy material. By this step,
a surface treatment coating is formed on or over the surface of the
aluminum or an aluminum alloy material. Pretreatment steps, such as
the degreasing step, the pickling step, and the like may also be
performed prior to the contact step. The water-washing step may be
performed after each step, and the drying step may be performed
after each water-washing step.
(Aluminum or Aluminum Alloy Material)
[0028] An aluminum or an aluminum alloy material to be treated with
the surface treatment agent is not particularly limited, and the
surface treatment agent is particularly effective for aluminum
die-cast materials which have a thick surface oxide film and in
which an alloy component is segregated. The use of the aluminum or
the aluminum alloy material is not particularly limited, and
examples thereof include ship propulsion engines and peripherals
thereof, as well as components of motorcycle internal combustion
engines.
(Degreasing Step)
[0029] In the production method of the present embodiment, it is
preferred to perform, prior to the contact step, the degreasing
step of contacting a known degreasing agent on or over the surface
of the aluminum or the aluminum alloy material. A degreasing method
is not particularly limited, and examples thereof include solvent
degreasing and alkali degreasing.
(Contact Step)
[0030] In the contact step of the production method of the present
embodiment, the contact temperature and the contact time are not
particularly limited, however, usually, the surface treatment agent
is contacted on or over the surface of the aluminum or the aluminum
alloy material at 30 to 80.degree. C., preferably at 40 to
70.degree. C., for 10 to 600 seconds. After this step, as required,
the aluminum or the aluminum alloy material may be washed with
water and then with deionized water, followed by drying. The drying
temperature is not particularly limited, however, it is preferably
50 to 140.degree. C. A method of contacting the surface treatment
agent on or over the surface of the aluminum or the aluminum alloy
material is not particularly limited, and examples thereof include
an immersion method, a spray method, and a flow-coating method.
(4) Aluminum or Aluminum Alloy Material Having Surface Treatment
Coating
[0031] An aluminum or an aluminum alloy material having a surface
treatment coating, which is produced by the above-described
production method, is another embodiment of the present invention.
The amount of the adhered surface treatment coating on the aluminum
or the aluminum alloy material is not particularly limited,
however, a total mass of Cr, Ti, and/or Zr, Zn that are contained
in the surface treatment coating per unit area is preferably 1 to
200 mg/m.sup.2.
[0032] The aluminum or the aluminum alloy material having the
surface treatment coating according to the present embodiment has
excellent corrosion resistance even without performing a painting
step of applying paintings onto the surface treatment coating, and
has excellent corrosion resistance even when the coating is exposed
to a high temperature, however, a painting step may be performed as
well.
[0033] The painting step is not particularly limited and can be
performed by, for example, a painting method such as aqueous
painting, solvent painting, powder painting, anionic
electrodeposition painting, cationic electrodeposition painting, or
the like using a known painting composition.
EXAMPLES
[0034] Examples and Comparative Examples of the present invention
will now be described. It is noted here, however, that the present
invention is not limited to the below-described Examples by any
means.
<Aluminum Material>
[0035] Aluminum die-cast material (JIS ADC12)
<Surface Treatment Agents>
[0036] The supply sources shown in Tables 1 to 5 were mixed with
water to obtain surface treatment agents of Examples 1 to 20 and
Comparative Examples 1 to 3 which had the respective ion
concentration values shown in Table 6. As a pH modifier, aqueous
ammonia was used. The free fluorine ion concentration was measured
using a commercially available fluorine ion meter [ion electrode:
fluoride ion composite electrode F-2021 (manufactured by DKK-TOA
Corporation)].
TABLE-US-00001 TABLE 1 Code Compound name Manufacturer A1 chromium
(III) fluoride trihydrate Showa Chemical Co., Ltd. A2 chromium
(III) nitrate nonahydrate Wako Pure Chemical Industries, Ltd. A3
chromium (III) sulfate Junsei Chemical Co., Ltd.
TABLE-US-00002 TABLE 2 Code Compound name Manufacturer B1
hexafluorozirconic acid Morita Chemical Industries Co., Ltd. B2
hexafluorotitanic acid Morita Chemical Industries Co., Ltd.
TABLE-US-00003 TABLE 3 Code Compound name Manufacturer C1 zinc
nitrate hexahydrate Wako Pure Chemical Industries, Ltd. C2 zinc
sulfate heptahydrate Wako Pure Chemical Industries, Ltd. C3 zinc
chloride Tokyo Chemical Industry Co., Ltd.
TABLE-US-00004 TABLE 4 Code Compound name Manufacturer D1
hydrofluoric acid Wako Pure Chemical Industries, Ltd.
TABLE-US-00005 TABLE 5 Code Compound name Manufacturer E1 nitric
acid Sumitomo Chemical Co., Ltd. E2 aluminum sulfate Wako Pure
Chemical Industries, Ltd. nonahydrate
TABLE-US-00006 TABLE 6 Ion (A) Ion (B) Ion (C) Ion (D) Ion (E)
chromium- metal- zinc- fluorine- nitric acid- equivalent equivalent
equivalent equivalent equivalent mass mass mass mass mass Surface
concen- concen- concen- concen- concen- Contact Treatment supply
tration supply tration supply tration supply tration supply tration
Temperature Agent source (mg/L) source (mg/L) source (mg/L) source
(mg/L) source (mg/L) pH (.degree. C.) Example 1 A1 150 B1 100 C1
1700 D1 15 E1, C1 4224 4 50 Example 2 A2 150 B1 100 C1 1700 D1 15
E1, A2, C1 4760 4 50 Example 3 A3 150 B2 100 C1 1700 D1 15 E1, C1
4224 4 50 Example 4 A2 150 B1 100 C2 1700 D1 15 E1, A2 1537 4 50
Example 5 A2 150 B1 100 C3 1700 D1 15 E1, A2 1537 4 50 Example 6 A2
150 B1 100 C1 1700 D1 15 E2, A2, C1 4760 4 50 Example 7 A2 5 B1 100
C1 1700 D1 15 E1, A2, C1 4760 4 50 Example 8 A2 20 B1 100 C1 1700
D1 15 E1, A2, C1 4760 4 50 Example 9 A2 150 B1 5 C1 1700 D1 15 E1,
A2, C1 4760 4 50 Example 10 A2 150 B1 20 C1 1700 D1 15 E1, A2, C1
4760 4 50 Example 11 A2 150 B1 100 C1 50 D1 15 E1, A2, C1 4760 4 50
Example 12 A2 150 B1 100 C1 300 D1 15 E1, A2, C1 4760 4 50 Example
13 A2 150 B1 100 C1 700 D1 15 E1, A2, C1 4760 4 50 Example 14 A2
150 B1 100 C1 1700 D1 2 E1, A2, C1 4760 4 50 Example 15 A2 150 B1
100 C1 1700 D1 150 E1, A2, C1 4760 4 50 Example 16 A2 150 B1 100 C1
1700 D1 15 E1, A2, C1 4760 2.2 50 Example 17 A2 150 B1 100 C1 1700
D1 15 E1, A2, C1 4760 5.1 50 Example 18 A2 150 B1 100 C1 1700 D1 15
E1, A2, C1 4760 4 35 Example 19 A2 150 B1 100 C1 1700 D1 15 E1, A2,
C1 4760 4 75 Example 20 A2 150 B1 100 C1 20 D1 15 E1, A2, C1 4760 4
50 Comparative -- -- B1 100 C1 1700 D1 15 E1, C1 4224 4 50 Example
1 Comparative A2 150 -- -- C1 1700 D1 15 E1, A2, C1 4760 4 50
Example 2 Comparative A2 150 B1 100 -- -- D1 15 E1, A2 1537 4 50
Example 3
>>Production of Aluminum Die-Cast Materials Having Surface
Treatment Coating>>
[0037] Using each of the surface treatment agents of Examples 1 to
20 and Comparative Examples 1 to 3, aluminum die-cast materials
having surface treatment coatings were produced as test pieces 1 to
23.
[0038] Specifically, the above-described aluminum die-cast material
was immersed in an alkali degreasing agent [20-g/L aqueous solution
of FINE CLEANER 315E (manufactured by Nihon Parkerizing Co., Ltd.)]
at 60.degree. C. for 2 minutes, and the surface thereof was cleaned
by rinsing with tap water. Subsequently, each surface treatment
agent was sprayed onto or over the surface of the aluminum die-cast
material at the contact temperature shown in Table 6 to perform the
contact step. Thereafter, the aluminum die-cast material was washed
with running tap water (at normal temperature for 30 seconds) and
then washed with deionized water (at normal temperature for 30
seconds), followed by drying in an electric oven (at 80.degree. C.
for 5 minutes), whereby aluminum die-cast materials having surface
treatment coatings (test pieces 1 to 23) were each produced.
[0039] With regard to the amount of the adhered surface treatment
coating on each of the thus obtained test pieces 1 to 23, a total
mass of Cr, Ti, and/or Zr, Zn that were contained in the surface
treatment coating was measured using a scanning X-ray fluorescence
spectrometer (ZSX Primus II, manufactured by Rigaku Corporation).
The measurement results are shown in Table 7.
TABLE-US-00007 TABLE 7 Surface Treatment Amount of Adhered Coating
Test Piece Agent (mg/m.sup.2) Test Piece 1 Example 1 35 Test Piece
2 Example 2 35 Test Piece 3 Example 3 35 Test Piece 4 Example 4 35
Test Piece 5 Example 5 35 Test Piece 6 Example 6 35 Test Piece 7
Example 7 37 Test Piece 8 Example 8 35 Test Piece 9 Example 9 13
Test Piece 10 Example 10 20 Test Piece 11 Example 11 35 Test Piece
12 Example 12 35 Test Piece 13 Example 13 35 Test Piece 14 Example
14 35 Test Piece 15 Example 15 35 Test Piece 16 Example 16 35 Test
Piece 17 Example 17 35 Test Piece 18 Example 18 35 Test Piece 19
Example 19 35 Test Piece 20 Example 20 35 Test Piece 21 Comparative
Example 1 20 Test Piece 22 Comparative Example 2 2 Test Piece 23
Comparative Example 3 35
[0040] Further, for the test pieces 1 to 23, the following tests
were conducted to determine the corrosion resistance and the
post-heating corrosion resistance of each surface treatment coating
were evaluated. The results thereof are shown in Table 8.
>>Evaluation Methods>>
<Corrosion Resistance>
[0041] A 240-hour neutral salt spray test (JIS Z2371:2015) was
performed on the test pieces 1 to 23. After the test pieces 1 to 23
were dried, the ratio of white rust generated on the surface of
each test piece was visually measured. The ratio of white rust is
the ratio of the area of generated white rust with respect to the
area of the observed part. The evaluation criteria were as follows.
The evaluation results are shown in Table 8.
<Evaluation Criteria>
[0042] 5: Ratio of white rust=10% or lower
[0043] 4: Ratio of white rust=higher than 10% but 30% or lower
[0044] 3: Ratio of white rust=higher than 30% but 50% or lower
[0045] 2: Ratio of white rust=higher than 50% but 70% or lower
[0046] 1: Ratio of white rust=higher than 70%
<Post-Heating Corrosion Resistance>
[0047] The test pieces were each heated in an electric oven (at
180.degree. C. for 20 minutes) and then subjected to a 240-hour
neutral salt spray test (JIS Z2371:2015). After the test pieces
were dried, the ratio of white rust generated on the surface of
each test piece was visually measured. The ratio of white rust is
the ratio of the area of generated white rust with respect to the
area of the observed part. The evaluation criteria were as follows.
The evaluation results are shown in Table 8.
<Evaluation Criteria>
[0048] 5: Ratio of white rust=10% or lower
[0049] 4: Ratio of white rust=higher than 10% but 30% or lower
[0050] 3: Ratio of white rust=higher than 30% but 50% or lower
[0051] 2: Ratio of white rust=higher than 50% but 70% or lower
[0052] 1: Ratio of white rust=higher than 70%
TABLE-US-00008 TABLE 8 Evaluation Items Corrosion Post-Heating Test
Piece Resistance Corrosion Resistance Test Piece 1 5 5 Test Piece 2
5 5 Test Piece 3 5 5 Test Piece 4 5 5 Test Piece 5 5 5 Test Piece 6
5 5 Test Piece 7 3 3 Test Piece 8 4 4 Test Piece 9 3 3 Test Piece
10 4 4 Test Piece 11 4 3 Test Piece 12 4 4 Test Piece 13 5 4 Test
Piece 14 4 4 Test Piece 15 3 3 Test Piece 16 3 3 Test Piece 17 5 5
Test Piece 18 3 3 Test Piece 19 5 5 Test Piece 20 4 3 Test Piece 21
1 1 Test Piece 22 1 1 Test Piece 23 2 1
* * * * *