U.S. patent application number 13/906793 was filed with the patent office on 2013-12-12 for coated stainless steel member.
The applicant listed for this patent is HONDA MOTOR CO., LTD.. Invention is credited to Yasuhiro Arai, Manabu Inoue, Mitsutada Kaneta, Tsutomu Miyadera.
Application Number | 20130327435 13/906793 |
Document ID | / |
Family ID | 49714349 |
Filed Date | 2013-12-12 |
United States Patent
Application |
20130327435 |
Kind Code |
A1 |
Kaneta; Mitsutada ; et
al. |
December 12, 2013 |
COATED STAINLESS STEEL MEMBER
Abstract
The present invention provides a method for producing a coated
stainless steel member, comprising: performing Wood's strike nickel
plating on a stainless steel substrate, and then performing
cationic electrodeposition on a formed Wood's strike nickel plating
layer.
Inventors: |
Kaneta; Mitsutada;
(Urayasu-shi, JP) ; Arai; Yasuhiro; (Chiba-shi,
JP) ; Inoue; Manabu; (Tokyo, JP) ; Miyadera;
Tsutomu; (Sakura-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HONDA MOTOR CO., LTD. |
Tokyo |
|
JP |
|
|
Family ID: |
49714349 |
Appl. No.: |
13/906793 |
Filed: |
May 31, 2013 |
Current U.S.
Class: |
138/145 ;
205/188 |
Current CPC
Class: |
C23C 28/322 20130101;
B60K 2015/047 20130101; F16L 9/02 20130101; C25D 13/20 20130101;
C09D 5/44 20130101; F16L 58/08 20130101; B60K 15/04 20130101; C25D
5/36 20130101; C25D 7/04 20130101; C25D 13/22 20130101; C23C 28/345
20130101; C23C 28/00 20130101; C25D 13/14 20130101; C25D 5/48
20130101; C25D 3/12 20130101; F16L 9/147 20130101; B60K 15/01
20130101 |
Class at
Publication: |
138/145 ;
205/188 |
International
Class: |
B60K 15/01 20060101
B60K015/01; C25D 7/04 20060101 C25D007/04; F16L 9/147 20060101
F16L009/147; C23C 28/00 20060101 C23C028/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 8, 2012 |
JP |
2012-130937 |
Claims
1. A coated stainless steel member comprising: a stainless steel
substrate; and a Wood's strike nickel plating layer and a cationic
electrodeposition coating layer which are stacked in this order on
the stainless steel substrate.
2. The coated stainless steel member according to claim 1, which is
obtained by subjecting a surface of the Wood's strike nickel
plating layer to a zinc phosphate treatment after formation of the
Wood's strike nickel plating layer.
3. The coated stainless steel member according to claim 1, which is
a stainless steel fuel inlet pipe for an automobile fuel tank.
4. The coated stainless steel member according to claim 2, which is
a stainless steel fuel inlet pipe for an automobile fuel tank.
5. A method for producing a coated stainless steel member,
comprising: performing Wood's strike nickel plating on a stainless
steel substrate; and then performing cationic electrodeposition on
a formed Wood's strike nickel plating layer.
6. The production method according to claim 5, comprising:
degreasing the stainless steel substrate; performing the Wood's
strike nickel plating on the degreased stainless steel substrate;
and performing the cationic electrodeposition on the formed Wood's
strike nickel plating layer; followed by baking.
7. The production method according to claim 6, further comprising
subjecting the Wood's strike nickel plating layer to a zinc
phosphate treatment before the cationic electrodeposition is
performed.
8. The production method according to claim 5, wherein the coated
stainless steel member is a fuel inlet pipe for an automobile fuel
tank.
9. The production method according to claim 6, wherein the coated
stainless steel member is a fuel inlet pipe for an automobile fuel
tank.
10. The production method according to claim 7, wherein the coated
stainless steel member is a fuel inlet pipe for an automobile fuel
tank.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a coated stainless steel
member, and more specifically a stainless steel member having a
coating excellent in adhesion and corrosion prevention. In
particular, the present invention relates to a stainless steel fuel
inlet pipe (FIP) for an automobile fuel tank.
[0003] 2. Brief Description of the Related Art
[0004] In one kind of the conventionally known methods for coating
a stainless steel member, strike nickel plating is performed on a
stainless steel substrate. For example, several methods are known
such as a method including Wood's strike nickel plating, a
subsequent chromate treatment and phosphate treatment, and spray
coating (Japanese Patent Application Publication No. Sho
63-192877); a method including strike nickel plating, subsequent
nickel plating, and coating (Japanese Patent Application
Publication No. Hei 9-268398 and Japanese Patent Application
Publication No. 2005-144895), and a method including Wood's strike
nickel plating, and subsequent coating by forming a thin polymer
film by reduction-electrolytic polymerization (Japanese Patent
Application Publication No. 2000-212799). However, in any of these
methods, coating is performed on a strike nickel plating after a
treatment for improving the adhesion is performed on the strike
nickel plating. This is because of the conventional recognition
that "a coating film easily peels off when coating is performed
directly on a nickel strike plating" (in Lower Left column on Page
2 of Japanese Patent Application Publication No. Sho
63-192877).
[0005] In general, for coating a material with good adhesion, a
pre-coating surface treatment such as a zinc phosphate treatment, a
chromate treatment, or a zirconium treatment is carried out. When
the material is made of iron or aluminum, a chemical conversion
film is formed by a reaction (dissolution and deposition) between
the material and a surface treatment liquid. The coating adhesion
with the material is secured by hydrogen bonding or an anchor
effect caused by the chemical conversion film. However, in a case
of coating on stainless steel, a surface treatment film such as a
zinc phosphate film formed for enhancing the coating adhesion
cannot be formed, and hence a sufficient coating adhesion cannot be
obtained, because a stable oxide film is formed on a surface of the
stainless steel . For this reason, peeling and corrosion occur in a
secondary adhesion test for hot-salt water resistance or a chipping
test. As shown in Japanese Patent Application Publication No.
2006-231207, thick coating in a thickness of 150 to 400 .mu.m has
been attempted for improvement in chipping resistance, prevention
of permeation of salt water, and improvement in adhesion. However,
such a method is not economical.
[0006] In the Meantime, in areas heavily inflicted with salt injury
due to sea-shore salt or snow melting salt spread in a large
amount, stainless steel FIPs have been used instead of conventional
iron FIPs. However, even in the case of stainless steel FIPs, the
corrosion resistance is insufficient at welded portions and the
like. Hence, electrodeposition coating as shown in Japanese Patent
Application Publication No. 2002-242779 has been carried out. The
coating is conducted by other methods such as cationic
electrodeposition coating or hexavalent chromium-free water-soluble
acrylic-based silicone coating shown in Japanese Patent Application
Publication No. 2004-230419, and coating using an acrylic paint, an
alkyd paint, a urethane paint, an epoxide paint, or the like in the
form of a cationic aqueous solution or emulsion shown in Japanese
Patent Application Publication No. 2005-206064. However, it is
difficult to perform electrodeposition excellent in adhesion and
corrosion prevention on a stainless steel substrate, as described
above.
SUMMARY OF THE INVENTION
[0007] An object of the present invention is to provide a coating
method capable of performing coating excellent in adhesion and
corrosion resistance on a stainless steel substrate by an
economical and simple process. The coating method makes it possible
to obtain sufficient coating adhesion and sufficient corrosion
resistance even with a thin film coating of 25 to 30 .mu.m, for
example. Another object of the present invention is to provide a
coated stainless steel member being chromium-free and having high
corrosion resistance, and in particular, a coated stainless steel
FIP.
[0008] The present inventors have conducted earnest study to
achieve the above objects. As a result, the present inventors have
found the following fact. Specifically, by performing Wood's strike
nickel plating excellent in adhesion to stainless steel on a
stainless steel member, a hard oxide film formed on the stainless
steel can be removed, and reformation of the oxide film can be
prevented. Subsequently, cationic electrodeposition is performed on
such a Wood's strike nickel plating film. In this manner, extremely
excellent adhesion between the cationic electrodeposition and the
Wood's strike nickel plating can be achieved without forming any
film for improving coating film adhesion, and sufficient coating
adhesion and corrosion resistance can be obtained on a stainless
steel substrate by thin film coating. This finding has led to the
completion of the present invention. Specifically, the present
invention provides a coated stainless steel member comprising: a
stainless steel substrate; and a Wood's strike nickel plating layer
and a cationic electrodeposition coating layer which are stacked in
this order on the stainless steel substrate.
[0009] Moreover, the present invention provides a method for
producing a coated stainless steel member, the method comprising:
performing Wood's strike nickel plating on a stainless steel
substrate; and then performing cationic electrodeposition coating
on a formed Wood's strike nickel plating layer.
[0010] In a case of coating on stainless steel, the present
invention makes it possible to obtain sufficient coating adhesion
and corrosion resistance with a thin film coating of 25 to 30
.mu.m.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0011] A method for producing a coated stainless steel member of
the present invention comprises: performing Wood's strike nickel
plating on a stainless steel substrate; and then performing
cationic electrodeposition on a formed Wood's strike nickel plating
layer. The method of the present invention makes it possible to
provide a coated stainless steel member comprising: a stainless
steel substrate; and a Wood's strike nickel plating layer and a
cationic electrodeposition coating layer which are stacked in this
order on the stainless steel substrate.
[0012] As for a basic bath composition for the Wood's strike nickel
plating used in the present invention, a known Wood's strike nickel
plating bath can be used, and the bath is composed of nickel
chloride and hydrochloric acid. The concentration of nickel
chloride in the bath is preferably 200 to 300 g/L, and more
preferably 220 to 240 g/L. Meanwhile, the concentration of
hydrochloric acid (35% aqueous hydrogen chloride solution) in the
bath is preferably 100 ml/L to 300 ml/L, and more preferably 125 to
230 ml/L. In addition, boric acid serving as a buffering agent and
an anti-mist agent can also be added to the Wood's strike nickel
plating bath. The concentration of boric acid in the bath is, for
example, 10 to g/L, and preferably 25 to 35 g/L. Meanwhile, the
concentration of the anti-mist agent in the bath is, for example,
0.1 to 10 g/L, and preferably 0.5 to 3 g/L. Moreover, the kind of
the anti-mist agent is not limited, and an example thereof is DS-55
(manufactured by DIPSOL CHEMICALS Co., Ltd.). The pH of the Wood's
strike nickel plating bath is generally 1 or lower.
[0013] The temperature at which the Wood's strike nickel plating is
performed by using the Wood's strike nickel plating bath may be
normal temperature, and preferably 20.degree. C. to 60.degree. C.,
and more preferably 40 to 50.degree. C. The cathode current density
for performing the plating is, for example, 0.5 A/dm.sup.2 or
higher, preferably 1 to 10 A/dm.sup.2, and more preferably 3 to 8
A/dm.sup.2. The time for which the plating is performed is
preferably set so that the product of the plating time and the
cathode current density can be 100 (second.times.A/dm.sup.2) or
larger. The product is more preferably 150 to 1000
(second.times.A/dm.sup.2). The thickness of a nickel plating film
obtained under such plating conditions is generally in the range
from 0.005 to 0.3 .mu.m, and preferably from 0.02 to 0.25.
[0014] Cationic electrodeposition is performed on the Wood's strike
nickel plating layer. As the cationic electrodeposition, a known
cationic electrodeposition can be employed. For example, a
stainless steel member subjected to the Wood's strike nickel
plating is immersed in a cationic electrodeposition paint composed
of a resin, a pigment, and the like, which meet the purpose of the
coating. An article to be coated is used as a cathode (-), and an
electrode plate set in a diaphragm chamber in an electrodeposition
tank is used as an anode (+). A direct current is applied across
the cathode (-) and the anode (+), so that a coating film is
deposited on the article to be coated. After that, a water-washing
step is conducted. Then, the deposited coating film is dried and
cured by baking in a baking furnace. Thus, a coating film excellent
in adhesion to the stainless steel can be obtained. Examples of the
cationic electrodeposition paint include acrylic paints, alkyd
paints, urethane paints, epoxy paints, and the like. The paints are
provided as cationic aqueous solutions or emulsions.
[0015] In the method for producing a coated stainless steel member
of the present invention, the Wood's strike nickel plating layer
may be subjected to a zinc phosphate treatment, before the cationic
electrodeposition is performed. This makes it possible to prevent
decrease in adhesion of the coating due to an electric corrosion
reaction caused by contact with other metal. As the zinc phosphate
treatment, known zinc phosphate treatments used for ordinary
coating can be used as they are.
[0016] In the method for producing a coated stainless steel member
of the present invention, it is preferable to degrease the
stainless steel substrate, before the Wood's strike nickel plating
is performed on the stainless steel substrate. By removing oil on
the stainless steel, the effect of the Wood's strike nickel plating
layer can be exerted more efficiently. As a degreasing agent and a
degreasing method employed in the present invention, any known
degreasing agent and any known degreasing method can be employed as
appropriate. Examples of the degreasing agent include alkaline
immersion degreasing agents, alkaline electrolysis degreasing
agents, acidic emulsion degreasing agents, solvent cleaning agents,
and the like. However, the degreasing agent is not limited thereto.
Preferably, an alkaline cathode electrolysis degreasing agent is
used. As the degreasing method, for example, an electrolysis
immersion treatment is conducted generally at 30 to 55.degree. C.
for about several minutes. If needed, a preliminary degreasing
treatment can also be conducted before the degreasing
treatment.
[0017] The present invention is applicable to stainless steel
members required to have high corrosion resistance. In particular,
the present invention is preferable for a stainless steel fuel
inlet pipe for an automobile fuel tank.
[0018] Next, the present invention is described while showing
Examples and Comparative Examples.
EXAMPLES
[0019] The present invention will be described in detail below with
reference to the following non-limiting Examples and
[0020] Comparative examples. It will be apparent to those skilled
in the art that many changes can be made in the embodiments
described without departing from the scope of the present
invention.
Examples 1 to 5
[0021] By using 50 g/L of a degreasing agent HD-37 (manufactured by
DIPSOL CHEMICALS Co., Ltd.), an SUS436 panel (50 mm.times.100
mm.times.0.3 mm in thickness) is subjected to cathode electrolysis
degreasing under conditions of 50.degree. C., 10 minutes, and a
cathode current density of 1 A/dm.sup.2. Subsequently, the panel
was washed with water. After that, Wood's strike nickel plating was
performed (40.degree. C.) under plating conditions shown in Table 1
by using a bath having the following composition.
TABLE-US-00001 Nickel chloride (NiCl.sub.2) 220 g/L 35%
hydrochloric acid (HCl) 230 ml/L Boric acid (H.sub.3BO.sub.3) 30
g/L DS-55 (manufactured by DIPSOL CHEMICALS Co., Ltd.) 1 ml/L
[0022] After that, the panel was washed with water, and subjected
to cationic electrodeposition (25 to 30 .mu.m) in a usual manner,
by using an electrodeposition paint CFA 590-034 manufactured by
PPG. After washed with water, the panel was baked and dried at
200.degree. C. for 25 minutes. The obtained coated panel was
immersed in 5% aqueous sodium chloride at 55.degree. C. for 240
hours, and the coating adhesion was evaluated. Table 1 shows the
results.
TABLE-US-00002 TABLE 1 Plating Conditions and Results of Evaluation
of Coating Adhesion Plating conditions Current Plating Coating
adhesion density time Maximum peeling width, (A/dm.sup.2) (second)
both sides (mm) Example 1 1 180 2.0 to 5.0 Example 2 3 60 2.0 to
4.0 Example 3 5 30 2.0 to 4.0 Example 4 5 90 1.0 to 3.0 Example 5 5
180 1.0 to 2.0 *The evaluation was made based on the maximum
peeling width between both sides (5 mm or less is desirable).
Example 6
[0023] By using 50 g/L of a degreasing agent HD-37 (manufactured by
DIPSOL CHEMICALS Co., Ltd.), an SUS436 panel (50 mm.times.100
mm.times.0.3 mm in thickness) was subjected to cathode electrolysis
degreasing under conditions of 50.degree. C., 10 minutes, and a
cathode current density of 1 A/dm.sup.2. Subsequently, the panel
was washed with water. After that, Wood's strike nickel plating was
performed (40.degree. C.) under plating conditions shown in Table 2
by using a bath having the following composition.
TABLE-US-00003 Nickel chloride (NiCl.sub.2) 220 g/L 35%
hydrochloric acid (HCl) 230 ml/L Boric acid (H.sub.3BO.sub.3) 30
g/L DS-55 (manufactured by DIPSOL CHEMICALS Co., Ltd.) 1 ml/L
[0024] After that, the panel was washed with water, and subjected
to cationic electrodeposition (25 to 30 pm) in a usual manner, by
using an electrodeposition paint CFA 590-034 manufactured by PPG.
After being washed with water, the panel was baked and dried at
200.degree. C. for 25 minutes. The obtained coated panel was
immersed in 5% aqueous sodium chloride at 55.degree. C. for 240
hours, and the coating adhesion was evaluated. Table 2 shows the
results.
Comparative Example 1
[0025] By using 50 g/L of a degreasing agent HD-37 (manufactured by
DIPSOL CHEMICALS Co., Ltd.), an SUS436 panel (50 mm.times.100
mm.times.0.3 mm in thickness) was subjected to cathode electrolysis
degreasing under conditions of 50.degree. C., 10 minutes, and a
cathode current density of 1 A/dm.sup.2. Subsequently, the panel
was washed with water. After that, the panel was subjected to
cationic electrodeposition (25 to 30 .mu.m) in a usual manner, by
using an electrodeposition paint CFA 590-034 manufactured by PPG.
After being washed with water, the panel was baked and dried at
200.degree. C. for 25 minutes. The obtained coated panel was
immersed in 5% aqueous sodium chloride at 55.degree. C. for 240
hours, and the coating adhesion was evaluated. Table 2 shows the
results.
Comparative Example 2
[0026] By using 50 g/L of a degreasing agent HD-37 (manufactured by
DIPSOL CHEMICALS Co., Ltd.), a SUS436 panel (50 mm.times.100
mm.times.0.3 mm in thickness) was subjected to cathode electrolysis
degreasing under conditions of 50.degree. C., 10 minutes, and a
cathode current density of 1 A/dm.sup.2. Subsequently, the panel
was washed with water. After that, an acid electrolysis treatment
was conducted (60.degree. C.) by using sulfuric acid (120 ml/L) at
a cathode current density of 1 A/dm.sup.2 for 4minutes. After that,
the panel was washed with water, and subjected to cationic
electrodeposition (25 to 30 .mu.m) in a usual manner by using an
electrodeposition paint CFA 590-034 manufactured by PPG. After
being washed with water, the panel was baked and dried at
200.degree. C. for 25 minutes. The obtained coated panel was
immersed in 5% aqueous sodium chloride at 55.degree. C. for 240
hours, and the coating adhesion was evaluated. Table 2 shows the
results.
TABLE-US-00004 TABLE 2 Evaluation results of coating adhesion in a
case where a Zn--Ni- plated bolt was fixed to each coated panel by
a steel nut. Plating conditions Current Plating Coating adhesion
density time Maximum peeling width, (A/dm.sup.2) (second) both
sides (mm) Example 7 5 180 5 Comp. Ex. 1 -- -- 10 or more Comp. Ex.
2 -- -- 10 or more *The evaluation was made based on the maximum
peeling width between both sides (5 mm or less is desirable).
INDUSTRIAL APPLICABILITY
[0027] The present invention makes it possible to enhance coating
adhesion to a stainless steel FIP, and thereby obtain corrosion
resistance which meets the LEV-II regulations. In addition, since
the film is chromium-free and has a high corrosion resistance, the
film can be used as an environmentally friendly film in wide
applications.
* * * * *