EP1106710A2 - Aluminium wheel surface conditioner, method of coating therewith, and unpigmented aluminium wheel - Google Patents
Aluminium wheel surface conditioner, method of coating therewith, and unpigmented aluminium wheel Download PDFInfo
- Publication number
- EP1106710A2 EP1106710A2 EP00403422A EP00403422A EP1106710A2 EP 1106710 A2 EP1106710 A2 EP 1106710A2 EP 00403422 A EP00403422 A EP 00403422A EP 00403422 A EP00403422 A EP 00403422A EP 1106710 A2 EP1106710 A2 EP 1106710A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- wheel
- surface conditioner
- mass
- aluminum wheel
- aluminum
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
- C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
- C23C22/40—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing molybdates, tungstates or vanadates
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C22/73—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals characterised by the process
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C22/82—After-treatment
- C23C22/83—Chemical after-treatment
Definitions
- This invention is related to a surface conditioner for aluminum wheel capable of producing a high rust-preventive effect even when the chromium coverage is so low as to cause no coloration, a coating method comprising a treatment with said surface conditioner, and a clear coated aluminum wheel.
- the surface of an aluminum wheel is machined to a Rmax of 100 ⁇ m or less and a colorless chromate film is formed on the aluminum wheel by a cathodic electrolysis using an acidic solution containing not less than 2 g/l of hexavalent chromium ion and 20 to 2000 ppm of sulfate ion and having a pH of 0.6 to 1.7 at a current density of 0.5 to 15 A/dm 2 .
- an aluminum wheel is subjected to colorless chromate treatment with a chemical conversion reagent solution (pH 1.5 to 3.0) containing 0 .1 to 0.5 g/l of hexavalent chromium ion, 0.0i to 0.5 g /l of Zr as fluorozirconate ion, 0.1 to 0.5 g /l of F as fluoride ion, and 0.01 to 0.1 g/l of Si as a water-soluble silicon compound.
- a chemical conversion reagent solution pH 1.5 to 3.0
- the range of chromium coverage is as high as 50 to 250 mg/m 2 .
- the amount of chromium deposition is acceptable, namely 13 to 15 mg/m 2 , but from the standpoint of environmental protection, it is desirable that this amount be further reduced.
- the present invention has for its object to provide a surface conditioner for aluminum wheel capable of producing a high rust-preventive effect even when the chromium coverage is so low as to cause no coloration, a coating method comprising a treatment with this surface conditioner, and a clear coated aluminum wheel.
- the surface conditioner for aluminum wheel of the present invention is an aqueous solution comprising 0.01 to 10 mass % of a molybdic acid compound and 0.1 to 30 mass % of sulfuric acid and having a pH of less than 1 and a mass ratio of said molybdic acid compound to sulfuric acid within the range of 0.01 to 1 (former/latter).
- the coating method of an aluminum wheel according to the present invention comprises treating a degreased aluminum wheel with said surface conditioner, washing the treated wheel with water, chromating the same at a chromium coverage of 1 to 10 mg/m 2 , washing the chromated wheel with water, drying the same and applying a clear coating.
- the clear coated aluminum wheel of the present invention is a wheel fully retaining the original brightness of substrate aluminum as obtainable using the above coating method.
- the surface conditioner of the present invention contains 0.01 to 10 mass %, preferably 0.1 to 5 mass %, more preferably 0.1 to 2 mass %, of a molybdic acid compound.
- the amount is less than 0.01 mass %, no sufficient resistance to filiform corrosion can be imparted.
- it exceeds 10 mass % not only the risk of sludge formation is increased but a point of saturation is reached in the anticorrosive effect to cause an economic disadvantage.
- the species of molybdic acid compound which can be used includes molybdic acid, ammonium molybdate, sodium molybdate, potassium molybdate, calcium molybdate, magnesium molybdate, and lithium molybdate, among others.
- the use of a molybdic acid compound is essential to the present invention, and should any other metal oxide such as tungstic acid and permanganic acid be substituted for said molybdic acid compound, no comparable effect could be obtained.
- Sulfuric acid is formulated in a proportion of 0.1 to 30 mass %, preferably 1 to 20 mass %, and the conditioner is adjusted with this amount of sulfuric acid to pH not over 1, preferably pH 0.3 to 0.8. In so doing, it is also necessary to bring the mass ratio (molybdic acid compound/sulfuric acid) into the range of 0.01 to 1, preferably 0.05 to 0.5.
- the pH of the conditioner is not less than 1, the aluminum oxide film-removing effect of sulfuric acid is insufficient.
- the mass ratio is less than 0.01, the concentration of the molybdic acid compound is too low to insure a sufficient etching action on the aluminum surface so that no sufficient resistance to filiform corrosion may be obtained.
- the sulfuric acid concentration is relatively decreased to make it difficult to maintain the pH of the conditioner less than 1.
- the use of phosphoric acid in lieu of sulfuric acid is not acceptable because the treated aluminum surface is contaminated with residues of molybdenum to detract from corrosion resistance.
- the surface conditioner may contain a variety of additives.
- an inorganic acid such as nitric acid, which is expected to double as a corrosion inhibitor for stainless steel vessels and an etching aid, acetic acid as a sludge retarder, an organic acid such as polyacrylic acid, an oxidizing agent such as hydrogen peroxide which is added for oxidizing the Mo (IV) formed on bath aging to Mo (VI), and metal ions, such as cerium, manganese and other ions, which are used as corrosion inhibitors.
- the coating method of an aluminum wheel according to the present invention is now described.
- the aluminum wheel is first treated with a degreasing agent for removing soils and oils from its surface. After degreasing, the degreasing agent is washed with water and, thereafter, the wheel is treated with the surface conditioner of the present invention.
- This treatment may be carried out in an immersion process or in a spray process.
- the bath temperature for the immersion process and the solution temperature for the spray process may both be 20 to 80 °C, preferably 50 to 70 °C, while the immersion or spraying time may be 10 to 600 seconds, preferably 30 to 300 seconds.
- the temperature is lower than 20 °C or the treating time is less than 10 seconds, the effect of treatment is decreased to thereby lose an acceptable resistance to filiform corrosion.
- the treatment at a temperature over 80 °C or exceeding 600 seconds is no more than a waste of energy.
- the wheel is washed with water and chromated at a chromium coverage of 1 to 10 mg/m 2 .
- the chromate which can be used for this purpose may for example be the known CrO 3 -hydrogen fluoride system, the chromate type system comprising the above syscem supplemented with K 3 Fe (CN) 6 , zirconium hydrofluoride (salt) or the like, or the chromium phosphate type system comprising CrO 3 , hydrogen fluoride and phosphoric acid.
- the aluminum wheel treated by the above method is chromium-lean and retains the characteristic silvery gloss of the aluminum.
- the chromated aluminum wheel is washed thoroughly and dried and a clear coating is applied.
- the coating which can be used for this purpose is not particularly restricted and the coating method may also be any of spray coating, brush coating, electrostatic coating and electrodeposition.
- a clear powder coating is preferred because a sufficiently thick coat can be built up for enhanced chipping resistance.
- the clear coated aluminum wheel thus obtained retains the gloss of substrate aluminum and has good resistance to filiform corrosion, good resistance to hot water, and the additional advantage of a low chromium film content.
- the surface conditioner for aluminum wheel of the present invention contains a molybdic acid compound and sulfuric acid in an amount and mass ratio within the specific range and has a pH of less than 1. Therefore, when the treatment process with this surface conditioner is applied to the general process (degreasing ⁇ chromating ⁇ coating) after degreasing, the aluminum wheel as obtained is excellent in the resistance to filiform corrosion and hot water.
- molybdic acids may be considered to act as an oxidizing agent for removing the oxidized film from the aluminum surface to thereby enhance the etching by sulfuric acid, so it can be supposed that this action leads to an increased activity on the aluminum surface to thereby improve the effect of the resistance to filiform corrosion by chromating treatment.
- other metal oxide such as tungstic acid and permanganic acid has no effects, therefore molybdic acids may have an action for leveling the etching in addition to the oxidizing force.
- Ammonium molybdate and sulfuric acid were dissolved in deionized water at final concentrations of 2% and 10%, respectively, to prepare an aqueous surface conditioner.
- the pH of this aqueous conditioner was 0.6 and the mass ratio of ammonium molybdate to sulfuric acid was 0.2.
- the aluminum test panel A1100 (manufactured by Japan Test Panel) was immersed in a degreasing bath of 3 mass % concentration (Surf Creaner 53, Nippon Paint) at 45 °C for 30 seconds and the degreased panel was rinsed with water. The rinsed panel was then immersed in a bath comprising said surface conditioner at 50 °C for 30 seconds to condition its surface. The panel was rinsed with water and immersed in a chemical conversion bath comprising a 0.1% solution of chromating reagent ("Alsurf 1000", Nippon Paint) at 40 °C for 1 minute. The treated panel was rinsed with water and dried at 80 °C for 10 minutes. The chromate-coating amount was about 5 mg/m 2 . Then, a powder coating ("Powdax A400 Clear", Nippon Paint) was applied in a coat thickness of 100 ⁇ m by the corona electrostatic coating technique and baked at 160 °C for 20 minutes to prepare a coated panel.
- the coated panel prepared above was evaluated as follows.
- the coated surface of the panel was cross-cut and subjected to a 24-hour salt spray test in accordance with JIS Z 2371.
- the panel was then allowed to sit for 1000 hours in a humid atmosphere at 40 °C and 70 to 75% R.H.
- the maximum width of corrosion was measured. The panel was regarded as acceptable when the maximum width of corrosion was not over 0.5 mm.
- the coated panel was immersed in deionized water at 50 °C for 120 hours and, then, left sitting to dry for 24 hours. Thereafter, using a cutter knife, the coated surface was scored at a pitch of 2 mm in a crisscross pattern of 11x11 lines to make 100 squares.
- a transparent adhesive tape (“Cellophane tape", Nichiban) was affixed to the surface to cover all the squares and, then, peeled off in a perpendicular direction, and the intact squares were counted. When at least 97 of the 100 squares remained unpeeled, the panel was regarded as being acceptable.
- the surface conditioning treatment was omitted in Comparative Example 1; the molybdic acid compound was not used in Comparative Example 2; sulrufic acid was not used in Comparative Example 3; tungstic acid was used in lieu of molybdic acid compound in Comparative Example 4; and the concentration of molybdic acid compound was set at 0.005 mass % in Comparative Example 5. Otherwise the procedure of Example 1 was repeated to treat test panels and evaluate coated panels. The recipes used and the results of evaluation are shown in Table 2.
Landscapes
- Chemical & Material Sciences (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Chemical Treatment Of Metals (AREA)
Abstract
This invention provides a surface conditioner for
aluminum wheel comprising 0.01 to 10 mass % of a molybdic acid
compound and 0.1 to 30 mass % of sulfuric acid and having a pH
of less than 1 and a mass ratio of said molybdic acid compound
to sulfuric acid within the range of 0.01 to 1 (former/latter),
and further provides a coating method of an aluminum wheel which
comprises treating a degreased aluminum wheel with the surface
conditioner as mentioned above, washing the treated wheel with
water, chromating the same at a chromium coverage of 1 to 10
mg/m2, washing the chromated wheel with water, drying the same
and applying a clear coating.
Description
This invention is related to a surface conditioner for
aluminum wheel capable of producing a high rust-preventive
effect even when the chromium coverage is so low as to cause
no coloration, a coating method comprising a treatment with said
surface conditioner, and a clear coated aluminum wheel.
Since aluminum wheels require high corrosion resistance,
chromates have been preferentially used in the chemical
conversion treatment for surface preparation. However, in
order that the bright finish of the substrate aluminum wheel
may be fully preserved, yellow coloration due to chromating is
a drawback. When, to avoid this disadvantage, the chromium
coverage was reduced to the extent causing no coloration, there
was a problem that the corrosion resistance was reduced.
Furthermore, in consideration of the risk for environmental
pollution, the amount of use of chromium is preferably as low
as possible.
For example, in the invention disclosed in Japanese Kokai
Publication Hei-7-18492, the surface of an aluminum wheel is
machined to a Rmax of 100 µm or less and a colorless chromate film
is formed on the aluminum wheel by a cathodic electrolysis using
an acidic solution containing not less than 2 g/l of hexavalent
chromium ion and 20 to 2000 ppm of sulfate ion and having a pH
of 0.6 to 1.7 at a current density of 0.5 to 15 A/dm2.
Furthermore, in the invention described in Japanese Kokai
Publication Hei-11-6078, an aluminum wheel is subjected to
colorless chromate treatment with a chemical conversion reagent
solution (pH 1.5 to 3.0) containing 0 .1 to 0.5 g/l of hexavalent
chromium ion, 0.0i to 0.5 g /l of Zr as fluorozirconate ion,
0.1 to 0.5 g /l of F as fluoride ion, and 0.01 to 0.1 g/l of
Si as a water-soluble silicon compound.
In the above invention disclosed in Japanese Kokai
Publication Hei-7-18492, the range of chromium coverage is as
high as 50 to 250 mg/m2. In the invention according to Japanese
Kokai Publication Hei-11-6078, the amount of chromium
deposition is acceptable, namely 13 to 15 mg/m2, but from the
standpoint of environmental protection, it is desirable that
this amount be further reduced.
The present invention has for its object to provide a
surface conditioner for aluminum wheel capable of producing a
high rust-preventive effect even when the chromium coverage is
so low as to cause no coloration, a coating method comprising
a treatment with this surface conditioner, and a clear coated
aluminum wheel.
The surface conditioner for aluminum wheel of the present
invention is an aqueous solution
comprising 0.01 to 10 mass % of a molybdic acid compound and 0.1 to 30 mass % of sulfuric acid
and having a pH of less than 1 and a mass ratio of said molybdic acid compound to sulfuric acid within the range of 0.01 to 1 (former/latter).
comprising 0.01 to 10 mass % of a molybdic acid compound and 0.1 to 30 mass % of sulfuric acid
and having a pH of less than 1 and a mass ratio of said molybdic acid compound to sulfuric acid within the range of 0.01 to 1 (former/latter).
The coating method of an aluminum wheel according to the
present invention comprises treating a degreased aluminum wheel
with said surface conditioner, washing the treated wheel with
water, chromating the same at a chromium coverage of 1 to 10
mg/m2, washing the chromated wheel with water, drying the same
and applying a clear coating. The clear coated aluminum wheel
of the present invention is a wheel fully retaining the original
brightness of substrate aluminum as obtainable using the above
coating method.
The present invention is now described in detail.
The surface conditioner of the present invention contains
0.01 to 10 mass %, preferably 0.1 to 5 mass %, more preferably
0.1 to 2 mass %, of a molybdic acid compound. When the amount
is less than 0.01 mass %, no sufficient resistance to filiform
corrosion can be imparted. When it exceeds 10 mass %, not only
the risk of sludge formation is increased but a point of
saturation is reached in the anticorrosive effect to cause an
economic disadvantage. The species of molybdic acid compound
which can be used includes molybdic acid, ammonium molybdate,
sodium molybdate, potassium molybdate, calcium molybdate,
magnesium molybdate, and lithium molybdate, among others. The
use of a molybdic acid compound is essential to the present
invention, and should any other metal oxide such as tungstic
acid and permanganic acid be substituted for said molybdic acid
compound, no comparable effect could be obtained.
Sulfuric acid is formulated in a proportion of 0.1 to 30
mass %, preferably 1 to 20 mass %, and the conditioner is adjusted
with this amount of sulfuric acid to pH not over 1, preferably
pH 0.3 to 0.8. In so doing, it is also necessary to bring the
mass ratio (molybdic acid compound/sulfuric acid) into the
range of 0.01 to 1, preferably 0.05 to 0.5. When the pH of the
conditioner is not less than 1, the aluminum oxide film-removing
effect of sulfuric acid is insufficient. When the mass ratio
is less than 0.01, the concentration of the molybdic acid
compound is too low to insure a sufficient etching action on
the aluminum surface so that no sufficient resistance to
filiform corrosion may be obtained. On the other hand, when
the mass ratio is more than 1, the sulfuric acid concentration
is relatively decreased to make it difficult to maintain the
pH of the conditioner less than 1. Incidentally, the use of phosphoric
acid in lieu of sulfuric acid is not acceptable because the
treated aluminum surface is contaminated with residues of
molybdenum to detract from corrosion resistance.
In addition to the above components, the surface
conditioner may contain a variety of additives. As examples,
there can be mentioned an inorganic acid, such as nitric acid,
which is expected to double as a corrosion inhibitor for
stainless steel vessels and an etching aid, acetic acid as a
sludge retarder, an organic acid such as polyacrylic acid, an
oxidizing agent such as hydrogen peroxide which is added for
oxidizing the Mo (IV) formed on bath aging to Mo (VI), and metal
ions, such as cerium, manganese and other ions, which are used
as corrosion inhibitors.
The coating method of an aluminum wheel according to the
present invention is now described. The aluminum wheel is first
treated with a degreasing agent for removing soils and oils from
its surface. After degreasing, the degreasing agent is washed
with water and, thereafter, the wheel is treated with the
surface conditioner of the present invention. This treatment
may be carried out in an immersion process or in a spray process.
The bath temperature for the immersion process and the solution
temperature for the spray process may both be 20 to 80 °C,
preferably 50 to 70 °C, while the immersion or spraying time
may be 10 to 600 seconds, preferably 30 to 300 seconds. When
the temperature is lower than 20 °C or the treating time is less
than 10 seconds, the effect of treatment is decreased to thereby
lose an acceptable resistance to filiform corrosion. The
treatment at a temperature over 80 °C or exceeding 600 seconds
is no more than a waste of energy.
After the above treatment with the surface conditioner,
the wheel is washed with water and chromated at a chromium
coverage of 1 to 10 mg/m2. The chromate which can be used for
this purpose may for example be the known CrO3-hydrogen fluoride
system, the chromate type system comprising the above syscem
supplemented with K3Fe (CN)6, zirconium hydrofluoride (salt) or
the like, or the chromium phosphate type system comprising CrO3,
hydrogen fluoride and phosphoric acid. The aluminum wheel
treated by the above method is chromium-lean and retains the
characteristic silvery gloss of the aluminum.
Then, the chromated aluminum wheel is washed thoroughly
and dried and a clear coating is applied. The coating which
can be used for this purpose is not particularly restricted and
the coating method may also be any of spray coating, brush
coating, electrostatic coating and electrodeposition.
However, a clear powder coating is preferred because a
sufficiently thick coat can be built up for enhanced chipping
resistance. The clear coated aluminum wheel thus obtained
retains the gloss of substrate aluminum and has good resistance
to filiform corrosion, good resistance to hot water, and the
additional advantage of a low chromium film content.
The surface conditioner for aluminum wheel of the present
invention contains a molybdic acid compound and sulfuric acid
in an amount and mass ratio within the specific range and has
a pH of less than 1. Therefore, when the treatment process with
this surface conditioner is applied to the general process
(degreasing → chromating → coating) after degreasing, the
aluminum wheel as obtained is excellent in the resistance to
filiform corrosion and hot water.
As the result of the analysis of the aluminum surface
after the above surface treatment, molybdenum is not detected,
so the mechanism of said conditioner cannot be unraveled.
However, molybdic acids may be considered to act as an oxidizing
agent for removing the oxidized film from the aluminum surface
to thereby enhance the etching by sulfuric acid, so it can be
supposed that this action leads to an increased activity on the
aluminum surface to thereby improve the effect of the resistance
to filiform corrosion by chromating treatment. Furthermore,
as mentioned hereinabove, other metal oxide such as tungstic
acid and permanganic acid has no effects, therefore molybdic
acids may have an action for leveling the etching in addition
to the oxidizing force.
The above characteristics do not deteriorate even if the
chromium coverage is decreased to 1 to 10 mg/m2 in the chromating
treatment, therefore a clear coated aluminum wheel excellent
in gloss can be obtained.
The following examples and comparative examples
illustrate the present invention in further detail. It should
be understood that all formulating quantities are by weight
(mass %) unless otherwise specified.
Ammonium molybdate and sulfuric acid were dissolved in
deionized water at final concentrations of 2% and 10%,
respectively, to prepare an aqueous surface conditioner. The
pH of this aqueous conditioner was 0.6 and the mass ratio of
ammonium molybdate to sulfuric acid was 0.2.
The aluminum test panel A1100 (manufactured by Japan Test
Panel) was immersed in a degreasing bath of 3 mass %
concentration (Surf Creaner 53, Nippon Paint) at 45 °C for 30
seconds and the degreased panel was rinsed with water. The
rinsed panel was then immersed in a bath comprising said surface
conditioner at 50 °C for 30 seconds to condition its surface.
The panel was rinsed with water and immersed in a chemical
conversion bath comprising a 0.1% solution of chromating
reagent ("Alsurf 1000", Nippon Paint) at 40 °C for 1 minute.
The treated panel was rinsed with water and dried at 80 °C for
10 minutes. The chromate-coating amount was about 5 mg/m2.
Then, a powder coating ("Powdax A400 Clear", Nippon Paint) was
applied in a coat thickness of 100 µm by the corona electrostatic
coating technique and baked at 160 °C for 20 minutes to prepare
a coated panel.
The coated panel prepared above was evaluated as follows.
Using a sharp-edged cutter knife, the coated surface of
the panel was cross-cut and subjected to a 24-hour salt spray
test in accordance with JIS Z 2371. The panel was then allowed
to sit for 1000 hours in a humid atmosphere at 40 °C and 70 to
75% R.H. The maximum width of corrosion (on one side of the
cutting line) was measured. The panel was regarded as
acceptable when the maximum width of corrosion was not over 0.5
mm.
The coated panel was immersed in deionized water at 50 °C
for 120 hours and, then, left sitting to dry for 24 hours.
Thereafter, using a cutter knife, the coated surface was scored
at a pitch of 2 mm in a crisscross pattern of 11x11 lines to
make 100 squares. A transparent adhesive tape ("Cellophane
tape", Nichiban) was affixed to the surface to cover all the
squares and, then, peeled off in a perpendicular direction, and
the intact squares were counted. When at least 97 of the 100
squares remained unpeeled, the panel was regarded as being
acceptable.
Except that, in the surface conditioner recipe, the
species and concentration of molybdic acid compound, the
concentration of sulfuric acid and the ratio of molybdic acid
compound to sulfuric acid were changed, the test panels were
treated in otherwise the same manner as in Example 1 and the
coated panels were evaluated also as in Example 1. The recipes
used and the results of evaluation are shown in Table 1.
The surface conditioning treatment was omitted in
Comparative Example 1; the molybdic acid compound was not used
in Comparative Example 2; sulrufic acid was not used in
Comparative Example 3; tungstic acid was used in lieu of
molybdic acid compound in Comparative Example 4; and the
concentration of molybdic acid compound was set at 0.005 mass %
in Comparative Example 5. Otherwise the procedure of Example
1 was repeated to treat test panels and evaluate coated panels.
The recipes used and the results of evaluation are shown in Table
2.
It will be apparent from Tables 1 and 2 that the panels
treated with the surface conditioners according to the above
Examples have sufficient filiform corrosion resistance and warm
water resistance for use as aluminum wheel.
Claims (3)
- A surface conditioner for aluminum wheelwhich is an aqueous solutioncomprising 0.01 to 10 mass % of a molybdic acid compound and 0.1 to 30 mass % of sulfuric acidand having a pH of less than 1 and a mass ratio of said molybdic acid compound to sulfuric acid within the range of 0.01 to 1 (former/latter) .
- A coating method of an aluminum wheel
which comprises treating a degreased aluminum wheel with the surface conditioner according to Claim 1, washing the treated wheel with water, chromating the same at a chromium coverage of 1 to 10 mg/m2, washing the chromated wheel with water, drying the same and applying a clear coating. - A clear coated aluminum wheel
which is obtainable by the coating method according to Claim 2.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP35055499A JP2001164378A (en) | 1999-12-09 | 1999-12-09 | Surface conditioner for aluminum wheel, coating method and uncolored aluminum wheel |
| JP35055499 | 1999-12-09 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP1106710A2 true EP1106710A2 (en) | 2001-06-13 |
| EP1106710A3 EP1106710A3 (en) | 2003-07-09 |
Family
ID=18411286
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP00403422A Withdrawn EP1106710A3 (en) | 1999-12-09 | 2000-12-06 | Aluminium wheel surface conditioner, method of coating therewith, and unpigmented aluminium wheel |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP1106710A3 (en) |
| JP (1) | JP2001164378A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1120479A3 (en) * | 2000-01-28 | 2003-07-09 | Nippon Paint Co., Ltd. | Method of coating aluminum wheels and clear coated aluminium wheels |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2927874A (en) * | 1958-08-14 | 1960-03-08 | Turco Products Inc | Process for producing aluminum surface coatings |
| US3443998A (en) * | 1963-07-05 | 1969-05-13 | Exxon Research Engineering Co | Fuel cell with pt-au anode and molybdate-containing electrolyte |
| US3374155A (en) * | 1965-02-19 | 1968-03-19 | Ludwig J. Weber | Modified oxide-coated aluminum and the method of modifying |
| JPS5698480A (en) * | 1980-01-11 | 1981-08-07 | Kobe Steel Ltd | Rust preventive treatment of galvanized steel material |
| EP0587099A1 (en) * | 1992-09-08 | 1994-03-16 | Herberts Gesellschaft mit beschränkter Haftung | Method for varnishing pieces made of chromalizable metals |
| JPH07329502A (en) * | 1994-06-13 | 1995-12-19 | Nissan Motor Co Ltd | Bright aluminum road wheel manufacturing method |
| JPH116078A (en) * | 1997-06-12 | 1999-01-12 | Nippon Paint Co Ltd | Chemical conversion treatment agent for aluminum and chemical conversion treatment method |
-
1999
- 1999-12-09 JP JP35055499A patent/JP2001164378A/en active Pending
-
2000
- 2000-12-06 EP EP00403422A patent/EP1106710A3/en not_active Withdrawn
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1120479A3 (en) * | 2000-01-28 | 2003-07-09 | Nippon Paint Co., Ltd. | Method of coating aluminum wheels and clear coated aluminium wheels |
Also Published As
| Publication number | Publication date |
|---|---|
| EP1106710A3 (en) | 2003-07-09 |
| JP2001164378A (en) | 2001-06-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US3964936A (en) | Coating solution for metal surfaces | |
| EP1433875B1 (en) | Chemical conversion coating agent and surface-treated metal | |
| US5374347A (en) | Trivalent chromium solutions for sealing anodized aluminum | |
| EP1433876B1 (en) | Chemical conversion coating agent and surface-treated metal | |
| EP1404894B1 (en) | Corrosion resistant coatings for aluminum and aluminum alloys | |
| US5304257A (en) | Trivalent chromium conversion coatings for aluminum | |
| EP0713541B1 (en) | Composition and method for treatment of phosphated metal surfaces | |
| JPS5949315B2 (en) | Aluminum coating method and coating composition | |
| EP0664348A1 (en) | Method and composition for treatment of metals | |
| US4600447A (en) | After-passivation of phosphated metal surfaces | |
| JP4187162B2 (en) | Chemical conversion treatment agent and surface treatment metal | |
| US6755918B2 (en) | Method for treating magnesium alloy by chemical conversion | |
| US5756218A (en) | Corrosion protective coating for metallic materials | |
| CA1322147C (en) | Zinc-nickel phosphate conversion coating composition and process | |
| US3720547A (en) | Permanganate final rinse for metal coatings | |
| JP3088623B2 (en) | Method for forming zinc phosphate film on metal surface | |
| JPH04341574A (en) | Treatment of zinc phosphate onto metal surface | |
| WO1995027809A1 (en) | Method of pre-treating metal substrates prior to painting | |
| EP0904425B1 (en) | Moderate temperature manganese phosphate conversion coating composition and process | |
| JPH11501366A (en) | Chromium-free treatment method to improve paint adhesion after thin layer anodic oxidation | |
| EP1106710A2 (en) | Aluminium wheel surface conditioner, method of coating therewith, and unpigmented aluminium wheel | |
| US5888315A (en) | Composition and process for forming an underpaint coating on metals | |
| CA1197674A (en) | Composition and process for the treatment of phosphatized metal surfaces | |
| EP1120479A2 (en) | Method of coating aluminum wheels and clear coated aluminium wheels | |
| AU699822B2 (en) | Composition and process for forming an underpaint coating on metals |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
| AK | Designated contracting states |
Kind code of ref document: A2 Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR |
|
| AX | Request for extension of the european patent |
Free format text: AL;LT;LV;MK;RO;SI |
|
| PUAL | Search report despatched |
Free format text: ORIGINAL CODE: 0009013 |
|
| AK | Designated contracting states |
Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR |
|
| AX | Request for extension of the european patent |
Extension state: AL LT LV MK RO SI |
|
| RIC1 | Information provided on ipc code assigned before grant |
Ipc: 7C 23C 22/83 B Ipc: 7C 23C 22/73 B Ipc: 7C 23C 22/40 A |
|
| 17P | Request for examination filed |
Effective date: 20031022 |
|
| AKX | Designation fees paid |
Designated state(s): DE ES IT |
|
| 17Q | First examination report despatched |
Effective date: 20070402 |
|
| STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
|
| 18D | Application deemed to be withdrawn |
Effective date: 20070814 |