CA1043287A - Method and composition for electroplating auminum alloys - Google Patents
Method and composition for electroplating auminum alloysInfo
- Publication number
- CA1043287A CA1043287A CA223,195A CA223195A CA1043287A CA 1043287 A CA1043287 A CA 1043287A CA 223195 A CA223195 A CA 223195A CA 1043287 A CA1043287 A CA 1043287A
- Authority
- CA
- Canada
- Prior art keywords
- acid
- article
- acetic acid
- anodizing
- electroplating
- 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.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/34—Pretreatment of metallic surfaces to be electroplated
- C25D5/42—Pretreatment of metallic surfaces to be electroplated of light metals
- C25D5/44—Aluminium
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
- C25D11/02—Anodisation
- C25D11/04—Anodisation of aluminium or alloys based thereon
- C25D11/06—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Electroplating Methods And Accessories (AREA)
- Electroplating And Plating Baths Therefor (AREA)
- Electrochemical Coating By Surface Reaction (AREA)
Abstract
METHOD AND COMPOSITION FOR ELECTROPLATING
ALUMINUM ALLOYS
ABSTRACT
A method of and a bath composition for conditioning the surface of an aluminium alloy article to substantially increase the adhesion to the conditioned surface of subsequently applied electrodeposited surface layer. More specifically the surface of the article is anodized in a solution having three components, i.e. phosphoric acid, sulfuric acid and an organic acid selected from the group consisting of acetic acid, hydroxy acetic acid and amino acetic acid. The anodizing operation typically is followed by a nickel strike deposit, and this deposit may be subsequently electroplated under conventional operating conditions.
ALUMINUM ALLOYS
ABSTRACT
A method of and a bath composition for conditioning the surface of an aluminium alloy article to substantially increase the adhesion to the conditioned surface of subsequently applied electrodeposited surface layer. More specifically the surface of the article is anodized in a solution having three components, i.e. phosphoric acid, sulfuric acid and an organic acid selected from the group consisting of acetic acid, hydroxy acetic acid and amino acetic acid. The anodizing operation typically is followed by a nickel strike deposit, and this deposit may be subsequently electroplated under conventional operating conditions.
Description
;3 Z87 : ~
It has recently been proposed that bumpers and other exterior automotive components be made from aluminum alloys, particularly alloys from the "7000"series. Such alloys generally have the following typical analyses:
Alloy 7046 Alloy 7016 Si 0.4 max 0.3 max Fe 0.35 max 0.1 max Cu 0.1 (0.25 max) 1.0 Mn 0.3 0.3 max Mg 1.3 l.l Cd 0.12 -Zn 6.6 - 7.6 4.0 - 5.0 Zr 0.12 Ti ~ 0.03 0.03 max '~ Al Balance Balance i:l . . ' . ' - Such aluminum alloy components must be finished by elec-, troplating with nickel-chromium or similar bright plating. Yet `I conventional electroplating techniques do not form completely 1;~`
adherent electrodeposited layers on such alloys.
' 20 It has now been discovered that adherent electrodeposi- ;
;¦ ted layers can be formed on!such alloys by initially anodizing the ~! aluminum surface in an anodizing bath containing a mixture of !, phosphoric acid, sulfuric acid, and an organic acid.
; As used hereinafter, all percentages given are expressed -~
as volume percent. ~ `
; More specifically, the sur~ace of the aluminum alloy which~is to be electroplated is flrst cleaned, acid etched and then r~ sed. Next, the article surface is anodized in a three I
component bath containing from about 5% to about 12% H3P04, plus -30 from~about 0.4YO to abou~ 2.0% H2S04, plus from about 1% to about 7% of~an aliphatic mono carboxylic acid or a hydroxy or amino ~ deEiva~ive of such an acid having a solubility of at least 10 ':' . "
... .. .
~4;~Z87 grams per liter in the inorganic acid mixture. To be more pre- -cise, the three component bath contains, as a preferred ingred-I ient, and in addition to the phosphoric acid and the sulfuric acid, from about 1% to about 7% of an organic acid selected from ~;
the group consisting of acetic acid, hydroxy acetic acid, and amino acetic acid.
- It should be emphasized that the anodizing treatment proposed by the present invention is a preliminary or condition-ing treatment intended primarily for utillzation as an under-coating for a subsequently applied electrodeposited final layer or coating.
:
Thus, the present treatment differs substantially from the earlier proposed anodizing treatments which are intended to form integral colored anodic coatings on the surface of aluminum or its alloys. For example, in British Patent ~o. 1,022,423, a final "hard coat" is provided by anodizing aluminum or its alloys . . . .
in a bath containing a mineral acid, an organic acid, and organic acid salts. Similarly, mixtures of either sulfuric acid or phos- ~
phoric acid together with certain organic acids have been proposed ~;
to achieve a hard, dense, anodic coating as a final surface treat-ment in U.S. Patent No. 3,524,799. In each of these instances, the baths are utilized as totally different concentrations than ~
in the present invention and for entirely different purposes. Also ~ -it has been proposed in U.S. Patent ~o. 3,349,014 that a mixture of phosphoric acid, acetic acid and sulfuric acid be utilized to~
impregnate a porous pad which is then incorporated into an ano-dizlng circuit and rubbed over a previously damaged surface of an .~. ., : : , .
aluminum alloy part. Here again, the intent is to form a final anodized coating, and the ingredients are utilized in proportions ~`'7~ 30 and amounts entirely outside the range of the present invention.
he anodizing conditions of the present invention typi- `
:, .
Z cally carry out the treatment at a temperature of from about 100 ,',' ~ ' .
It has recently been proposed that bumpers and other exterior automotive components be made from aluminum alloys, particularly alloys from the "7000"series. Such alloys generally have the following typical analyses:
Alloy 7046 Alloy 7016 Si 0.4 max 0.3 max Fe 0.35 max 0.1 max Cu 0.1 (0.25 max) 1.0 Mn 0.3 0.3 max Mg 1.3 l.l Cd 0.12 -Zn 6.6 - 7.6 4.0 - 5.0 Zr 0.12 Ti ~ 0.03 0.03 max '~ Al Balance Balance i:l . . ' . ' - Such aluminum alloy components must be finished by elec-, troplating with nickel-chromium or similar bright plating. Yet `I conventional electroplating techniques do not form completely 1;~`
adherent electrodeposited layers on such alloys.
' 20 It has now been discovered that adherent electrodeposi- ;
;¦ ted layers can be formed on!such alloys by initially anodizing the ~! aluminum surface in an anodizing bath containing a mixture of !, phosphoric acid, sulfuric acid, and an organic acid.
; As used hereinafter, all percentages given are expressed -~
as volume percent. ~ `
; More specifically, the sur~ace of the aluminum alloy which~is to be electroplated is flrst cleaned, acid etched and then r~ sed. Next, the article surface is anodized in a three I
component bath containing from about 5% to about 12% H3P04, plus -30 from~about 0.4YO to abou~ 2.0% H2S04, plus from about 1% to about 7% of~an aliphatic mono carboxylic acid or a hydroxy or amino ~ deEiva~ive of such an acid having a solubility of at least 10 ':' . "
... .. .
~4;~Z87 grams per liter in the inorganic acid mixture. To be more pre- -cise, the three component bath contains, as a preferred ingred-I ient, and in addition to the phosphoric acid and the sulfuric acid, from about 1% to about 7% of an organic acid selected from ~;
the group consisting of acetic acid, hydroxy acetic acid, and amino acetic acid.
- It should be emphasized that the anodizing treatment proposed by the present invention is a preliminary or condition-ing treatment intended primarily for utillzation as an under-coating for a subsequently applied electrodeposited final layer or coating.
:
Thus, the present treatment differs substantially from the earlier proposed anodizing treatments which are intended to form integral colored anodic coatings on the surface of aluminum or its alloys. For example, in British Patent ~o. 1,022,423, a final "hard coat" is provided by anodizing aluminum or its alloys . . . .
in a bath containing a mineral acid, an organic acid, and organic acid salts. Similarly, mixtures of either sulfuric acid or phos- ~
phoric acid together with certain organic acids have been proposed ~;
to achieve a hard, dense, anodic coating as a final surface treat-ment in U.S. Patent No. 3,524,799. In each of these instances, the baths are utilized as totally different concentrations than ~
in the present invention and for entirely different purposes. Also ~ -it has been proposed in U.S. Patent ~o. 3,349,014 that a mixture of phosphoric acid, acetic acid and sulfuric acid be utilized to~
impregnate a porous pad which is then incorporated into an ano-dizlng circuit and rubbed over a previously damaged surface of an .~. ., : : , .
aluminum alloy part. Here again, the intent is to form a final anodized coating, and the ingredients are utilized in proportions ~`'7~ 30 and amounts entirely outside the range of the present invention.
he anodizing conditions of the present invention typi- `
:, .
Z cally carry out the treatment at a temperature of from about 100 ,',' ~ ' .
- 2 -i~ .
, .
.. . .
, '~'""'` '`'"'"''`'"'`"";"' :~C)43;2~37 to about 110F., at a vo,ltage of from 25 to 30 volts and at a current density of from about 15 to about 20 amperes per square foot for a period of time of from about 5 to about 10 minutes.
Following the surface treatment of the present invention, the surface is subsequentjly plated with nickel and chromium or with any other surface treatment which may be desired. Typically, the surfac0 may be plated with one mil of semi-bright nickel, 0.5 mils of bright nickel, or 0.01 mils of chromium. The result-ing deposit is uniformly bright and smooth, and the adhesion of the final electrodeposition to the surface is excellent.
It is,therefore, an important object of the present invention to provide an improved method for electroplating arti-cles made from aluminum alloys, and wherein the surface of the article is anodized prior to electroplating in a bath containing a mixture of phosphoric acid, sulfuric acid, and an aliphatic , mono carboxylic acid or the hydroxy or amino derivatives of such y an acid.
Another important object of the present invention is to ` provide a bath composition for subjecting an aluminum surface `` 20 to a pre-electrodeposition treatment, the bath containing from about 5% to about 12% phosphoric acid, from about 0.4 to about ~ 2% sulfuric acid, and from about 1 to about 7% of an organic i~ acid selected from the group consisting of aliphatic mono car-`, boxylic acids, hydroxy derivatives and amino derivatives of such acids having a solubility of at least 10 grams per liter in the phosphoric and sulfuric acid mixture. ;~
It is a further important object of the present inven- ~ ;
, ~ tion to provide a met~hod of electroplating articles made from aluminum alloys by anodizing the article in a three component ~3 30 a~ueous bath containing phosphoric acid, sulfuric acid, and an `~ organic acid selected from the group consisting essentially of acetic acid, hydroxy acetic acid and amino acetic acid, and then ;
. . .... .
.
., , . : . . . . , . , , . , - ~
~LfC~43Z~7 electroplating the anodized article.
It is yet another object of the instant invention to provide a method of electroplating an article made from an alum-. inum alloy by anodizing the article prior to electrodeposition by placing the article as an anode in an aqueous bath consisting . of from about 5 to about 12% phosphoric acid, from about 0.4 to about 2% sulfuric acid, and from about 1 to about 7% of an or-. - ganic acid selected from the group consisting of acetic acid, .. hydroxy acetic acid and amino acetic acid, and anodizing the . . .
article at a temperature of from about 100 to about 110F. at . a voltage of about 25 to about 30 volts, at a current density of :; , .
about 15 to about 20 amperes per square foot, for a period of ::~
:. ., time of from about 5 to about 10 minutes.
As above explained, the present invention proposes a specific anodizing treatment for aluminum alloys as a pre-treat-ment for a subsequent plating operation. It has been found that :~
such initial anodizing greatly increases the adherence of the ~
subsequently applied electrodeposit to the underlying aluminum ~-alloy surface.
Specifically, the anodizing solution consists of three components, namely phosphoric acid (H3P04) at a concentration of from:5 to about 12%, and at a preferred concentration of about 7%. The second ingredient is sulfuric acid (H2S04) at a c~ncen-tratlon ranging from about 0.4% to about 2% and at a preferred concentration of about 1%. The third ingredient is a saturated ~ :
aliphatic mono carboxylic acid or a hydroxy derivative of such ::'j :~ an acid or an amino derivative of such an acid, any one of these ;. i third ingredients necesciarily having a solubility of at least ~ .
10 grams per liter in the acid solution. Preferred specific .
saturated aliphatic mono carboxylic acids and derivatives are ' ;l ; ~ acetlc acid (CH3COOH), hydroxy acetic acid (OHCH2COOH) and ~lycine or amino acetic acid (~H2CH2COOH). The saturated ali-: ~;ff r~
:~ ~ 4 -:, 4 3 Zf~f7 phatic mono carboxylic acid or its derivative is present in an amount ranging from about 1% to about 7% of the solution with a , preferred composition containing about 3.5%.
; The anodizing operation is carried out under operating ' conditions which generally include a temperature of from about 100F. to about 110F., and pre~erably 105F., at a voltage of from about 2_f to 30 volts, at a current density of from about 15 ' to about 20 amperes per square foot, and for a period of time of from about 5 to about 10 minutes, preferably for a period of ~ ' about 7 to 8 minutes. ' Of course, the surface must be initially cleaned, whichl -^ can be carried out by either soaking or by power spraying with ~;
an alkaline solution or by any other preferred cleaning method.
After cleaning, the surface is rinsed and preferably is acid ~
etched. This etching is carried out at room temperature for a ' ' sufficient period of time, on the order of 1.5 to 2 minutes and ,~ the etching solution preferably contains 50% by volume nitric , ~ . .
acid (HN03) and 50 grams per liter of ammonium bifluoride ' (NH4F-HF).
The article to be anodized, after cleaning and etching, ~ ' ` is immersed in the anodizing solution, and a direct current is ;, passed between the aluminum article as the anode and a cathode - ' ¦ immersed in the solution. The anodizing is carried out under ''~
::. .
'f the conditions set forth above.
; Next, the panel is rinsed and then plated. The plating can~be carried out in a number of different'ways. For example, a nlckel strike may be made from a low chloride Watts nickel bath, '~
f ' and~subsequent plating with semi bright nickel, bright nickel and ~' '' . ~
chromlum may be applied. Alternatively, the anodized article may ~''' - ' be plated directly with nickel using a Watts nickelf solution, pre~
¦~ ferably containing coumarin, to produce a semi-bright deposit, '`"-''~
` ~ followed by a bright nickel deposit. Subsequent chrome ~lating '`
:1 . . , :.. .
, 5 `'l :
~43ZZ~7 onto the bright nlckel deposit results in an adhesive, integral, composite electrodeposited layer.
` The following examples point out specific operating conditions and illustrate the practice of the invention, but these examples are not to be considered as limiting the scope of the invention.
EXAMPLE I
A 4 inch ~,y 6 inch panel of 7046 aluminum alloy was soaked and cleaned in an alkaline cleaner for one-half hour.
Next, the panel was etched for 2 minutes in an acid solution ; containing 50% by volume nitric acid and 50 grams per liter of ammonium bifluoride. ;The panel was then prepared for electroplating by plac-ing it, a~ the anode, in an aqueous anodizing solution having the following volumetric composition:
, .
.. . .
, '~'""'` '`'"'"''`'"'`"";"' :~C)43;2~37 to about 110F., at a vo,ltage of from 25 to 30 volts and at a current density of from about 15 to about 20 amperes per square foot for a period of time of from about 5 to about 10 minutes.
Following the surface treatment of the present invention, the surface is subsequentjly plated with nickel and chromium or with any other surface treatment which may be desired. Typically, the surfac0 may be plated with one mil of semi-bright nickel, 0.5 mils of bright nickel, or 0.01 mils of chromium. The result-ing deposit is uniformly bright and smooth, and the adhesion of the final electrodeposition to the surface is excellent.
It is,therefore, an important object of the present invention to provide an improved method for electroplating arti-cles made from aluminum alloys, and wherein the surface of the article is anodized prior to electroplating in a bath containing a mixture of phosphoric acid, sulfuric acid, and an aliphatic , mono carboxylic acid or the hydroxy or amino derivatives of such y an acid.
Another important object of the present invention is to ` provide a bath composition for subjecting an aluminum surface `` 20 to a pre-electrodeposition treatment, the bath containing from about 5% to about 12% phosphoric acid, from about 0.4 to about ~ 2% sulfuric acid, and from about 1 to about 7% of an organic i~ acid selected from the group consisting of aliphatic mono car-`, boxylic acids, hydroxy derivatives and amino derivatives of such acids having a solubility of at least 10 grams per liter in the phosphoric and sulfuric acid mixture. ;~
It is a further important object of the present inven- ~ ;
, ~ tion to provide a met~hod of electroplating articles made from aluminum alloys by anodizing the article in a three component ~3 30 a~ueous bath containing phosphoric acid, sulfuric acid, and an `~ organic acid selected from the group consisting essentially of acetic acid, hydroxy acetic acid and amino acetic acid, and then ;
. . .... .
.
., , . : . . . . , . , , . , - ~
~LfC~43Z~7 electroplating the anodized article.
It is yet another object of the instant invention to provide a method of electroplating an article made from an alum-. inum alloy by anodizing the article prior to electrodeposition by placing the article as an anode in an aqueous bath consisting . of from about 5 to about 12% phosphoric acid, from about 0.4 to about 2% sulfuric acid, and from about 1 to about 7% of an or-. - ganic acid selected from the group consisting of acetic acid, .. hydroxy acetic acid and amino acetic acid, and anodizing the . . .
article at a temperature of from about 100 to about 110F. at . a voltage of about 25 to about 30 volts, at a current density of :; , .
about 15 to about 20 amperes per square foot, for a period of ::~
:. ., time of from about 5 to about 10 minutes.
As above explained, the present invention proposes a specific anodizing treatment for aluminum alloys as a pre-treat-ment for a subsequent plating operation. It has been found that :~
such initial anodizing greatly increases the adherence of the ~
subsequently applied electrodeposit to the underlying aluminum ~-alloy surface.
Specifically, the anodizing solution consists of three components, namely phosphoric acid (H3P04) at a concentration of from:5 to about 12%, and at a preferred concentration of about 7%. The second ingredient is sulfuric acid (H2S04) at a c~ncen-tratlon ranging from about 0.4% to about 2% and at a preferred concentration of about 1%. The third ingredient is a saturated ~ :
aliphatic mono carboxylic acid or a hydroxy derivative of such ::'j :~ an acid or an amino derivative of such an acid, any one of these ;. i third ingredients necesciarily having a solubility of at least ~ .
10 grams per liter in the acid solution. Preferred specific .
saturated aliphatic mono carboxylic acids and derivatives are ' ;l ; ~ acetlc acid (CH3COOH), hydroxy acetic acid (OHCH2COOH) and ~lycine or amino acetic acid (~H2CH2COOH). The saturated ali-: ~;ff r~
:~ ~ 4 -:, 4 3 Zf~f7 phatic mono carboxylic acid or its derivative is present in an amount ranging from about 1% to about 7% of the solution with a , preferred composition containing about 3.5%.
; The anodizing operation is carried out under operating ' conditions which generally include a temperature of from about 100F. to about 110F., and pre~erably 105F., at a voltage of from about 2_f to 30 volts, at a current density of from about 15 ' to about 20 amperes per square foot, and for a period of time of from about 5 to about 10 minutes, preferably for a period of ~ ' about 7 to 8 minutes. ' Of course, the surface must be initially cleaned, whichl -^ can be carried out by either soaking or by power spraying with ~;
an alkaline solution or by any other preferred cleaning method.
After cleaning, the surface is rinsed and preferably is acid ~
etched. This etching is carried out at room temperature for a ' ' sufficient period of time, on the order of 1.5 to 2 minutes and ,~ the etching solution preferably contains 50% by volume nitric , ~ . .
acid (HN03) and 50 grams per liter of ammonium bifluoride ' (NH4F-HF).
The article to be anodized, after cleaning and etching, ~ ' ` is immersed in the anodizing solution, and a direct current is ;, passed between the aluminum article as the anode and a cathode - ' ¦ immersed in the solution. The anodizing is carried out under ''~
::. .
'f the conditions set forth above.
; Next, the panel is rinsed and then plated. The plating can~be carried out in a number of different'ways. For example, a nlckel strike may be made from a low chloride Watts nickel bath, '~
f ' and~subsequent plating with semi bright nickel, bright nickel and ~' '' . ~
chromlum may be applied. Alternatively, the anodized article may ~''' - ' be plated directly with nickel using a Watts nickelf solution, pre~
¦~ ferably containing coumarin, to produce a semi-bright deposit, '`"-''~
` ~ followed by a bright nickel deposit. Subsequent chrome ~lating '`
:1 . . , :.. .
, 5 `'l :
~43ZZ~7 onto the bright nlckel deposit results in an adhesive, integral, composite electrodeposited layer.
` The following examples point out specific operating conditions and illustrate the practice of the invention, but these examples are not to be considered as limiting the scope of the invention.
EXAMPLE I
A 4 inch ~,y 6 inch panel of 7046 aluminum alloy was soaked and cleaned in an alkaline cleaner for one-half hour.
Next, the panel was etched for 2 minutes in an acid solution ; containing 50% by volume nitric acid and 50 grams per liter of ammonium bifluoride. ;The panel was then prepared for electroplating by plac-ing it, a~ the anode, in an aqueous anodizing solution having the following volumetric composition:
3 4 7%
:! H2S04 1% ~ .
Acetic acid 3%
The panel was then anodized in the solution for 6 minutes :~
at a temperature of 105F. ~he anodizing was carried out at a constant potential of 25 volts.
Next, the panel was rinsed and plated in a low chloride Watt's nickel strike containing 2 ounces per gallon of Z NiZCl2.6H20~ This operation was carrled out at a pH of 4.5, at "! 105F. for 5 minutes. After the nickel strike, the panel was '~ --;~! subsequently plated with 1 mil of semi-bright nickel, 0.5 mils r i' ~Z
, ' o bright nickel, and 0.01 mils of chromium. The resulting de-~i, posit was uniformly bright and smooth, and the adhesion of the ':! total electrodeposit to the panel was excellent.
EXAMPLE II
A 6 inch by 4 inch aluminum panel of 7046 alloy was , 6 ''. , ~043Z~7 cleaned, rinsed and etched as explained in Example I.
The panel was then anodized in a solution having the composition:
Phosphoric acid 97.4 g/l Hydroxy acetic acid 33.6 g/l Sulfuric acid 19.3 g/l During anodizing, the panel was immersed in the bath for 10 minutes at 105F. The bath was operated at 25 volts and at a current density of 15 to 20 amperes per square foot. ;
;~ 10 After anodizing, the work piece was rinsed with water i ~` and plated directly with nickel. An initial plate was made from~
a Watts nickel solution containing coumarin to produce a semi-'A bright deposit w~ich constituted 7~/0 of the total desired nickel ~;~ deposit. Following the semi-bright deposit, a bright nickel de- ~
¦ posit was made incorporating the remaining 30% of the total -;
nickel deposit. After nickel plating, the work piece was rinsed with water and chromium plated. ;- -~l Adhesion tests were made by grinding the panel, and ; these tests showed that the deposit adhered very well to the basic metal. .
~;1 EXA~5PLE III ~.
;~l The procedure of Example I was followed except that -the aqueous anodizing solution had a volumetric composition com-pr~ising ~7% H3P04, 1% H2S04 and 50.0 g/l of amlno acetic acid.
The panel was then anodized for 6 minutes at a tempera-ture of 105F. at a constant potential of 25 volts. The panel was next~rinsed and placed in a low chIoride (2 oz/gal NiC12.6H20) ., ~
Watt~s~nickel strike for 5 minuteq at a pH of 4.5 and 105E'. After the~m ckel strike, the panel was plated with one mil of acid copper, 0.5 mils of bright nickel, and ~.01 mils of chromium. The ' resulting deposit was uniformly bright and smooth, and the adhe-:, . :I 7 ~; . , .~ .
~43Z87 sion of the total electrodeposit was excellent.
EXAMPLE IV
The above tests were repeated using the identical conditions mentioned except that 5% formic acid was used instead of the glycine tamino acetic acid). The resulting deposit was uniformly bright and smooth and the overall adhesion was again excellent.
It will be seen from the foregoing that the present invention provides a new, novel, and effective processing cycle for the plating of aluminum alloys, particularly aluminum alloys of the 7000 series. This processing cycle includes the anodiz-ing of the aluminum surface which is subsequently electroplated, this anodizing treatment being carried out as a preliminary to the final electroplating operation.
:, ~' ,.
. ~
~1 . ,~ - , . .
. ~
' : ~
1: ' .
'd' 'J
'i . `: .
:'' ' ' ' ~'. .
i . . ~.: .
~ . e~~~ ~ d~C i . ,~ " . I "~ ,~_~ _~,.,,,, ,, .,,, ", ,,
:! H2S04 1% ~ .
Acetic acid 3%
The panel was then anodized in the solution for 6 minutes :~
at a temperature of 105F. ~he anodizing was carried out at a constant potential of 25 volts.
Next, the panel was rinsed and plated in a low chloride Watt's nickel strike containing 2 ounces per gallon of Z NiZCl2.6H20~ This operation was carrled out at a pH of 4.5, at "! 105F. for 5 minutes. After the nickel strike, the panel was '~ --;~! subsequently plated with 1 mil of semi-bright nickel, 0.5 mils r i' ~Z
, ' o bright nickel, and 0.01 mils of chromium. The resulting de-~i, posit was uniformly bright and smooth, and the adhesion of the ':! total electrodeposit to the panel was excellent.
EXAMPLE II
A 6 inch by 4 inch aluminum panel of 7046 alloy was , 6 ''. , ~043Z~7 cleaned, rinsed and etched as explained in Example I.
The panel was then anodized in a solution having the composition:
Phosphoric acid 97.4 g/l Hydroxy acetic acid 33.6 g/l Sulfuric acid 19.3 g/l During anodizing, the panel was immersed in the bath for 10 minutes at 105F. The bath was operated at 25 volts and at a current density of 15 to 20 amperes per square foot. ;
;~ 10 After anodizing, the work piece was rinsed with water i ~` and plated directly with nickel. An initial plate was made from~
a Watts nickel solution containing coumarin to produce a semi-'A bright deposit w~ich constituted 7~/0 of the total desired nickel ~;~ deposit. Following the semi-bright deposit, a bright nickel de- ~
¦ posit was made incorporating the remaining 30% of the total -;
nickel deposit. After nickel plating, the work piece was rinsed with water and chromium plated. ;- -~l Adhesion tests were made by grinding the panel, and ; these tests showed that the deposit adhered very well to the basic metal. .
~;1 EXA~5PLE III ~.
;~l The procedure of Example I was followed except that -the aqueous anodizing solution had a volumetric composition com-pr~ising ~7% H3P04, 1% H2S04 and 50.0 g/l of amlno acetic acid.
The panel was then anodized for 6 minutes at a tempera-ture of 105F. at a constant potential of 25 volts. The panel was next~rinsed and placed in a low chIoride (2 oz/gal NiC12.6H20) ., ~
Watt~s~nickel strike for 5 minuteq at a pH of 4.5 and 105E'. After the~m ckel strike, the panel was plated with one mil of acid copper, 0.5 mils of bright nickel, and ~.01 mils of chromium. The ' resulting deposit was uniformly bright and smooth, and the adhe-:, . :I 7 ~; . , .~ .
~43Z87 sion of the total electrodeposit was excellent.
EXAMPLE IV
The above tests were repeated using the identical conditions mentioned except that 5% formic acid was used instead of the glycine tamino acetic acid). The resulting deposit was uniformly bright and smooth and the overall adhesion was again excellent.
It will be seen from the foregoing that the present invention provides a new, novel, and effective processing cycle for the plating of aluminum alloys, particularly aluminum alloys of the 7000 series. This processing cycle includes the anodiz-ing of the aluminum surface which is subsequently electroplated, this anodizing treatment being carried out as a preliminary to the final electroplating operation.
:, ~' ,.
. ~
~1 . ,~ - , . .
. ~
' : ~
1: ' .
'd' 'J
'i . `: .
:'' ' ' ' ~'. .
i . . ~.: .
~ . e~~~ ~ d~C i . ,~ " . I "~ ,~_~ _~,.,,,, ,, .,,, ", ,,
Claims (7)
1. The method of electroplating articles made from alumi-num alloys comprising the steps of acid etching the surface of the article, anodizing the article in a three component aqueous bath containing from about 5% to about 12% phosphoric acid, from about 0.4% to about 2% sulfuric acid, and from about 1% to 7% of an organic acid selected from the group consisting of a saturated aliphatic mono carboxylic acid, saturated aliphatic mono carboxyl-ic amino acids and saturated aliphatic mono carboxylic hydroxy acids, the organic acid being sufficiently soluble in the bath to provide at least 10 grams per liter, and electroplating the anodized article.
2. The method as defined in Claim 1, wherein the organic acid ingredient is selected from the group consisting of acetic acid, hydroxy acetic acid and amino acetic acid.
3. In a method of electroplating an article made from an aluminum alloy the improvement of anodizing the article as a pre-plate prior to electrodeposition by the steps of (1) placing the article as an anode in an aqueous bath consisting essentially of from about 5% to about 12% phosphoric acid, from about 0.40%
to about 2% sulfuric acid, and from about 1% to about 7% of an organic acid selected from the group consisting of acetic acid, hydroxy acetic acid, and amino acetic acid, and (2) anodizing the article at a temperature of from about 100°F. to 110°F., at a voltage of from about 25 to 30 volts, and at a current density of from about 15 to about 20 amperes per square foot, for a period of time of from about 5 to about 10 minutes.
to about 2% sulfuric acid, and from about 1% to about 7% of an organic acid selected from the group consisting of acetic acid, hydroxy acetic acid, and amino acetic acid, and (2) anodizing the article at a temperature of from about 100°F. to 110°F., at a voltage of from about 25 to 30 volts, and at a current density of from about 15 to about 20 amperes per square foot, for a period of time of from about 5 to about 10 minutes.
4. A three component aqueous anodizing bath for the anodiz-ing of aluminum alloy surfaces as a preliminary to a subsequent electrodeposition, consisting essentially of:
Phosphoric acid about 5% to about 12%
Sulfuric Acid about 0.40% to about 2%
An organic acid selected from the group consisting of saturated aliphatic mono carboxylic acids and their hydroxy and amino derivatives, said acids having a solu-bility in the bath of at least 10 grams per liter, about 1% to about 7%.
Phosphoric acid about 5% to about 12%
Sulfuric Acid about 0.40% to about 2%
An organic acid selected from the group consisting of saturated aliphatic mono carboxylic acids and their hydroxy and amino derivatives, said acids having a solu-bility in the bath of at least 10 grams per liter, about 1% to about 7%.
5. A bath for anodizing aluminum alloys prior to electro-plating consisting essentially of from about 5% to about 12% phos-phoric acid, from about 0.4% to about 2% sulfuric acid, and from about 1% to about 7% of at least one organic acid selected from the group consisting of acetic acid, hydroxy acetic acid and amino acetic acid.
6. In a method of electroplating an article made from an aluminum alloy, the improvement of anodizing the article as a pre-plate prior to electrodeposition by anodizing the article in an aqueous bath consisting essentially of from about 5% to about 12% phosphoric acid, from about 0.40% to about 2% sulfuric acid, and from about 1% to 7% of an organic acid selected from the group consisting of acetic acid, hydroxy acetic acid, and amino acetic acid.
7. In a method of electroplating an article made from an aluminum alloy, the improvement of anodizing the article as a pre-plate prior to electrodeposition by anodizing the article in an aqueous bath containing from about 5% to about 12% phosphoric acid, from about 0.4% to about 2% sulfuric acid, and from about 1% to 7% of an organic acid selected from the group consisting of a sat-urated aliphatic mono carboxylic acid, saturated aliphatic mono carboxylic amino acids and saturated aliphatic mono carboxylic hydroxy acids, the organic acid being sufficiently soluble in the bath to provide at least 10 grams per liter, and electroplating the anodized article.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US515129A US3915811A (en) | 1974-10-16 | 1974-10-16 | Method and composition for electroplating aluminum alloys |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1043287A true CA1043287A (en) | 1978-11-28 |
Family
ID=24050086
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA223,195A Expired CA1043287A (en) | 1974-10-16 | 1975-03-25 | Method and composition for electroplating auminum alloys |
Country Status (11)
| Country | Link |
|---|---|
| US (1) | US3915811A (en) |
| JP (1) | JPS5147549A (en) |
| BR (1) | BR7503268A (en) |
| CA (1) | CA1043287A (en) |
| DE (1) | DE2517779A1 (en) |
| ES (1) | ES436285A1 (en) |
| FR (1) | FR2288164A1 (en) |
| GB (1) | GB1506184A (en) |
| IT (1) | IT1035197B (en) |
| NL (1) | NL7504952A (en) |
| SE (1) | SE7503826L (en) |
Families Citing this family (25)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4049504A (en) * | 1976-02-23 | 1977-09-20 | Polychrome Corporation | Method of producing lithographic printing plates |
| US4293617A (en) * | 1979-12-26 | 1981-10-06 | Gould Inc. | Process for producing strippable copper on an aluminum carrier and the article so obtained |
| US4525247A (en) * | 1982-07-12 | 1985-06-25 | Rogers Corporation | Microwave circuit boards and method of manufacture thereof |
| US4976827A (en) * | 1984-03-16 | 1990-12-11 | Swiss Aluminium Ltd. | Process for pretreating strips and foils of aluminum or aluminum alloys |
| WO1986004618A1 (en) * | 1985-02-06 | 1986-08-14 | Fujitsu Limited | Process for forming composite aluminum film |
| US4793903A (en) * | 1986-10-24 | 1988-12-27 | The Boeing Company | Method of cleaning aluminum surfaces |
| US5230965A (en) * | 1990-01-02 | 1993-07-27 | General Electric Company | High density interconnect with electroplated conductors |
| JP2671612B2 (en) * | 1991-01-30 | 1997-10-29 | 住友金属工業株式会社 | Zinc-based direct electroplating method for aluminum strip |
| JP2725477B2 (en) * | 1991-02-07 | 1998-03-11 | 住友金属工業株式会社 | Zinc-based electroplating method for aluminum strip |
| EP0500015B1 (en) * | 1991-02-18 | 1998-09-16 | Sumitomo Metal Industries, Ltd. | Use of plated aluminum sheet having improved spot weldability |
| US5478414A (en) * | 1992-01-31 | 1995-12-26 | Aluminum Company Of America | Reflective aluminum strip, protected with fluoropolymer coating and a laminate of the strip with a thermoplastic polymer |
| US5637404A (en) * | 1992-01-31 | 1997-06-10 | Aluminum Company Of America | Reflective aluminum strip |
| US5955147A (en) * | 1992-01-31 | 1999-09-21 | Aluminum Company Of America | Reflective aluminum trim |
| US5575885A (en) * | 1993-12-14 | 1996-11-19 | Kabushiki Kaisha Toshiba | Copper-based metal polishing solution and method for manufacturing semiconductor device |
| EP0689096B1 (en) | 1994-06-16 | 1999-09-22 | Kodak Polychrome Graphics LLC | Lithographic printing plates utilizing an oleophilic imaging layer |
| DE19812951C2 (en) * | 1998-03-24 | 2002-12-19 | Heckler & Koch Gmbh | Firing pin safety in the lock |
| US20070066503A1 (en) * | 2005-08-19 | 2007-03-22 | Mores Basaly | Methods and compositions for acid treatment of a metal surface |
| US20070221507A1 (en) * | 2006-02-23 | 2007-09-27 | Greatbatch Ltd. | Anodizing Electrolytes Using A Dual Acid System For High Voltage Electrolytic Capacitor Anodes |
| CN102534722B (en) * | 2011-11-28 | 2014-09-10 | 珠海市奥美伦精细化工有限公司 | Pre-dyeing treatment agent for surface of blind hole workpiece in aluminum alloy welding area and application technology thereof |
| CN107287636B (en) * | 2016-04-12 | 2019-05-14 | 哈尔滨飞机工业集团有限责任公司 | A kind of chromic acid anodizing method of folded form aluminum alloy part |
| CN107287637A (en) * | 2016-04-12 | 2017-10-24 | 哈尔滨飞机工业集团有限责任公司 | A kind of sulfur acid anodizing method of 7050 aluminium alloy |
| CA3073008A1 (en) * | 2016-08-17 | 2018-02-22 | Cirrus Materials Science Limited | Method to create thin functional coatings on light alloys |
| CN106350849B (en) * | 2016-09-18 | 2019-03-05 | 佛山科学技术学院 | The oxidation film electro-deposition preparation method of aluminium surface high-selenium corn and low transmitting solar spectrum |
| JP6764517B1 (en) * | 2019-11-08 | 2020-09-30 | ドングァン ディーエスピー テクノロジー カンパニー リミテッド | Aluminum surface treatment method |
| US20220154361A1 (en) * | 2020-11-13 | 2022-05-19 | Raytheon Technologies Corporation | Mixed acid anodization |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1971761A (en) * | 1929-09-05 | 1934-08-28 | William J Travers | Protection of metals |
| BE412098A (en) * | 1934-11-17 | |||
| US2473163A (en) * | 1945-06-25 | 1949-06-14 | Ewald H Mccoy | Plating nickel on aluminum |
| US3222266A (en) * | 1958-08-20 | 1965-12-07 | Kaiser Aluminium Chem Corp | Method of enameling anodized aluminum |
| US3098804A (en) * | 1960-03-28 | 1963-07-23 | Kaiser Aluminium Chem Corp | Metal treatment |
| US3349014A (en) * | 1964-08-28 | 1967-10-24 | Mc Donnell Douglas Corp | Method and composition for the treatment of an aluminum surface |
| US3622473A (en) * | 1964-10-15 | 1971-11-23 | Honny Chemicals Co Ltd | Method of providing aluminum surfaces with coatings |
| US3524799A (en) * | 1969-06-13 | 1970-08-18 | Reynolds Metals Co | Anodizing aluminum |
-
1974
- 1974-10-16 US US515129A patent/US3915811A/en not_active Expired - Lifetime
-
1975
- 1975-03-25 CA CA223,195A patent/CA1043287A/en not_active Expired
- 1975-04-02 FR FR7510318A patent/FR2288164A1/en active Granted
- 1975-04-03 ES ES436285A patent/ES436285A1/en not_active Expired
- 1975-04-03 SE SE7503826A patent/SE7503826L/en unknown
- 1975-04-07 IT IT48953/75A patent/IT1035197B/en active
- 1975-04-22 DE DE19752517779 patent/DE2517779A1/en active Pending
- 1975-04-25 NL NL7504952A patent/NL7504952A/en not_active Application Discontinuation
- 1975-05-23 GB GB22802/75A patent/GB1506184A/en not_active Expired
- 1975-05-23 BR BR4181/75A patent/BR7503268A/en unknown
- 1975-06-12 JP JP50071382A patent/JPS5147549A/ja active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| IT1035197B (en) | 1979-10-20 |
| US3915811A (en) | 1975-10-28 |
| BR7503268A (en) | 1976-10-05 |
| NL7504952A (en) | 1976-04-21 |
| GB1506184A (en) | 1978-04-05 |
| DE2517779A1 (en) | 1976-04-22 |
| FR2288164A1 (en) | 1976-05-14 |
| FR2288164B1 (en) | 1979-06-29 |
| JPS5147549A (en) | 1976-04-23 |
| SE7503826L (en) | 1976-04-20 |
| ES436285A1 (en) | 1977-05-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1043287A (en) | Method and composition for electroplating auminum alloys | |
| JP3354767B2 (en) | Alkaline zinc and zinc alloy electroplating baths and processes | |
| US4359345A (en) | Trivalent chromium passivate solution and process | |
| CA1126682A (en) | Incorporating zinc in light weight metal and electroplating with brass strike | |
| US2391289A (en) | Bright copper plating | |
| US4938850A (en) | Method for plating on titanium | |
| US5246565A (en) | High adherence copper plating process | |
| US4765871A (en) | Zinc-nickel electroplated article and method for producing the same | |
| Schwartz | Deposition from aqueous solutions: an overview | |
| EP0497302A1 (en) | Process for direct zinc electroplating of aluminum strip | |
| KR100693902B1 (en) | A double nickel plating method of a permanent magnet with Nd-Fe-B | |
| EP0324533A1 (en) | Electrodeposited multilayer coating for titanium | |
| US3943039A (en) | Anodizing pretreatment for nickel plating | |
| US20040074775A1 (en) | Pulse reverse electrolysis of acidic copper electroplating solutions | |
| KR960015549B1 (en) | Method for direct plating of iron on aluminium | |
| GB2193974A (en) | Composite aluminium article | |
| US3790355A (en) | Coated metal article and method of coating | |
| US6284123B1 (en) | Electroplating formulation and process for plating iron onto aluminum/aluminum alloys | |
| GB2117406A (en) | Electrolytic stripping | |
| US6679952B2 (en) | Method of coating aluminum and aluminum alloy substrates and coated articles | |
| GB2077764A (en) | Electrodepositing cobalt-zinc alloys stimulating a chromium plating | |
| US4617095A (en) | Electrolytic post treatment of chromium substrates | |
| US2888387A (en) | Electroplating | |
| JPS6043439B2 (en) | Method for manufacturing wear-resistant zinc articles | |
| US3753882A (en) | Method for converting aluminum and aluminum base,and copper and copper base material surfaces from a hydrophobic to a hydraphilic state |