US2496845A - Bath for brass immersion coating on aluminum and aluminum alloy - Google Patents
Bath for brass immersion coating on aluminum and aluminum alloy Download PDFInfo
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- US2496845A US2496845A US675826A US67582646A US2496845A US 2496845 A US2496845 A US 2496845A US 675826 A US675826 A US 675826A US 67582646 A US67582646 A US 67582646A US 2496845 A US2496845 A US 2496845A
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- sodium
- brass
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- 238000000576 coating method Methods 0.000 title claims description 28
- 239000011248 coating agent Substances 0.000 title claims description 20
- 229910001369 Brass Inorganic materials 0.000 title description 23
- 239000010951 brass Substances 0.000 title description 23
- 229910000838 Al alloy Inorganic materials 0.000 title description 20
- 238000007654 immersion Methods 0.000 title description 18
- 229910052782 aluminium Inorganic materials 0.000 title description 17
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 title description 17
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 50
- KXZJHVJKXJLBKO-UHFFFAOYSA-N chembl1408157 Chemical compound N=1C2=CC=CC=C2C(C(=O)O)=CC=1C1=CC=C(O)C=C1 KXZJHVJKXJLBKO-UHFFFAOYSA-N 0.000 claims description 13
- 238000000151 deposition Methods 0.000 claims description 13
- 229910000004 White lead Inorganic materials 0.000 claims description 12
- DOBRDRYODQBAMW-UHFFFAOYSA-N copper(i) cyanide Chemical compound [Cu+].N#[C-] DOBRDRYODQBAMW-UHFFFAOYSA-N 0.000 claims description 12
- RYZCLUQMCYZBJQ-UHFFFAOYSA-H lead(2+);dicarbonate;dihydroxide Chemical compound [OH-].[OH-].[Pb+2].[Pb+2].[Pb+2].[O-]C([O-])=O.[O-]C([O-])=O RYZCLUQMCYZBJQ-UHFFFAOYSA-H 0.000 claims description 12
- HVTHJRMZXBWFNE-UHFFFAOYSA-J sodium zincate Chemical compound [OH-].[OH-].[OH-].[OH-].[Na+].[Na+].[Zn+2] HVTHJRMZXBWFNE-UHFFFAOYSA-J 0.000 claims description 12
- 239000000126 substance Substances 0.000 claims description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 11
- 238000006073 displacement reaction Methods 0.000 claims description 10
- 150000003839 salts Chemical class 0.000 description 20
- 235000011121 sodium hydroxide Nutrition 0.000 description 15
- 229940083608 sodium hydroxide Drugs 0.000 description 14
- 239000000203 mixture Substances 0.000 description 9
- 239000003518 caustics Substances 0.000 description 7
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 6
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- 229910052802 copper Inorganic materials 0.000 description 6
- 239000010949 copper Substances 0.000 description 6
- 239000011734 sodium Substances 0.000 description 6
- 229910052708 sodium Inorganic materials 0.000 description 6
- 239000012535 impurity Substances 0.000 description 5
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 4
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- 230000008021 deposition Effects 0.000 description 4
- 229910052710 silicon Inorganic materials 0.000 description 4
- 239000010703 silicon Substances 0.000 description 4
- 239000011701 zinc Substances 0.000 description 4
- 229910052725 zinc Inorganic materials 0.000 description 4
- 229910052742 iron Inorganic materials 0.000 description 3
- 229910052749 magnesium Inorganic materials 0.000 description 3
- 239000011777 magnesium Substances 0.000 description 3
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 2
- NGRSIWGPWLJMKS-UHFFFAOYSA-N [Na].N#C[Cu]C#N Chemical compound [Na].N#C[Cu]C#N NGRSIWGPWLJMKS-UHFFFAOYSA-N 0.000 description 2
- 239000007795 chemical reaction product Substances 0.000 description 2
- 238000005530 etching Methods 0.000 description 2
- 239000004615 ingredient Substances 0.000 description 2
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910017604 nitric acid Inorganic materials 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical class F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 1
- 239000004115 Sodium Silicate Substances 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 238000010306 acid treatment Methods 0.000 description 1
- 230000001464 adherent effect Effects 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-N carbonic acid Chemical compound OC(O)=O BVKZGUZCCUSVTD-UHFFFAOYSA-N 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229940046892 lead acetate Drugs 0.000 description 1
- 150000002611 lead compounds Chemical class 0.000 description 1
- 229910000464 lead oxide Inorganic materials 0.000 description 1
- 229910021514 lead(II) hydroxide Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- YEXPOXQUZXUXJW-UHFFFAOYSA-N oxolead Chemical compound [Pb]=O YEXPOXQUZXUXJW-UHFFFAOYSA-N 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 1
- 229910052911 sodium silicate Inorganic materials 0.000 description 1
- UGZADUVQMDAIAO-UHFFFAOYSA-L zinc hydroxide Chemical compound [OH-].[OH-].[Zn+2] UGZADUVQMDAIAO-UHFFFAOYSA-L 0.000 description 1
- 229910021511 zinc hydroxide Inorganic materials 0.000 description 1
- 229940007718 zinc hydroxide Drugs 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
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
- C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
- C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
- C23C18/48—Coating with alloys
Definitions
- This invention relates to an improved immersion deposition particularly for aluminum and aluminum alloys.
- the invention pertains to an improved brass immersion deposition of this kind.
- One of the main objects of the invention is to provide an immersion bath by which coatings of brass having improved bearing properties can be readily formed on aluminum and aluminum alloy surfaces.
- Another object of the invention is to provide a bath of this character from which coatings of brass may be deposited on and integrally bonded to surfaces comprising aluminum and aluminum alloys.
- a further object of the invention is to provide a brass immersion bath of this kind which is conveniently controllable to predetermine the color and character of the deposit formed thereby.
- a brass coating bath embodying the invention may be made as follows, the quantities of materials specified being in amounts sufficient to produce one gallon of the finished bath. Approximately 30 ounces of a composition commercially known as Wyandotte ZA-30 manufactured by Wyandotte Chemical Company of Wyandotte, Michigan, are dissolved in approximately one pint of water. This composition comprises the reaction product of substantially 30% zinc oxide and 54%sodiumhydroxide, the reaction product 2 being NazZnOz in the-presence of an excess of NaOH. Solution of the foregoing ingredient in a relatively small amount of water in the order of 10% to 25% of the volume of the final bath avoids precipitation of zinc hydroxide from the solution.
- a solution of approximately 3.17 ounces of sodium cyanide in substantially one pint of water is then prepared and to it is slowly added during stirring approximately 1.75 ounces of cuprous cyanide Cu2(CN)z.
- the resulting sodium copper cyanide (NazCu(CN) a) is then mixed with the above mentioned solution of sodium zincate and sodium hydroxide (Na2ZnO2+NaOH) and suflicient water is added during constant stirring to make the total solution up to one gallon.
- any lead salt which is soluble in caustic solution such as lead oxide, lead acetate or lead hydroxide can be used in its molecular equivalent in place of basic lead carbonate and combinations of such soluble lead compounds may also be used.
- This lead salt containing solution is then introduced into the previously formed sodium zincate-sodium hydroxide and sodium copper cyanide solution to form the finished immersion bath.
- the lead salt is dissolved in the diluted bath solution in order to avoid reducing its solubility in the concentrated solution.
- the foregoing bath is particularly compounded to produce on high alloy content aluminumalioys, brass immersion coatings of generally yellow coloration having desirable bearing properties
- a coating of approximately .0001 inch to .00015 inch thickness is produced on such aluminum alloys by an immersion time of about five minutes.
- a coating formed by this bath has been found to be particularly suitable for pistons having the following composition: copper 6.25% to 7.75%, silicon 5% to 6%, magnesium .15% to .40%, iron 1.5% maximum, impurities including zinc 375% maximum, and the remainder aluminum.
- the above bath is thus compounded'irom ingredients comprising 15.8 oz. per gallon sodium zincate, 16.2 oz. per gallon of sodium hydroxide, 1.75 oz. per gallon of copper cyanide, 3.17 oz. per gallon of sodium cyanide and .014 oz. per gallon of basic lead carbonate.
- the formula may vary as follows:
- Example I Sodium zincate-from 13 oz. to 16 oz. per gallon Sodium hydroxide-from 13 oz. to 20 oz. per
- Variation of the lead content of the above described bath composition has the following effect upon color and thickness characteristics.
- the lead metal content is between .003 oz. per gallon and .016 oz. per gallon
- the deposit is yellow in color and has a maximum thickness of .00015 inch which will be formed in an immersion time of about five minutes at about 115 F.
- the lead metal content is above .016 oz. per gallon
- the deposit is green in color and has a maximum thickness of .0001 inch which will be formed in an immersion time of about five minutes at 115 F.
- With a lead content below .003 oz. per gallon the deposit tends to be pink and attains a thickness of about .0002 inch in approximately five minutes at 115 F.
- the upper limit of the lead salt content is established by the lead salt concentration at which pure lead is deposited in a powdery form upon the brass deposit.
- the upper limit of lead salt content is about .03 oz. per gallon.
- the upper limit of the lead salt content increases with increased aluminum content of aluminum alloy being coated.
- the lead salt content may be as high as .1 oz..per gallon but this value should not be substantially exceeded.
- Example I Sodium zincate8 oz. to 45 oz. per gallon Sodium hydroxide-25 oz. to 125 oz. per gallon Coppercyanide.1 oz. to 6 oz. per gallon Sodium cyanide.1 oz. to 12 oz. per gallon Basic lead carbonate-.003 oz. to .1 oz. per gallon Immersion coatings formed on aluminum alloy of the type previously recited by a bath within the range of composition specified in Example I:
- Quantities of lead salts referred to herein are inclusive of lead salt impurities and such impurities should be taken account of in compounding the solution.
- Articles to be coated by immersion are preferably cleaned in one of two ways.
- an etching type cleaner is preferably employed, such as an equeous sodium hydroxide solution.
- a nonetching type cleaner containing sodium carbonate and sodium silicate for example, is employed.
- the cleaning operation should be followed by treatment in an acid dip containing nitric and hydrofluoric acids in order to remove the resulting smut.
- the coated part is momentarily immersed in a dilute nitric acid solution, about one-half of one per cent by volume, and then washed in water.
- the dilute nitric acid treatment preserves the color of the immersion deposition.
- a bath for depositing a brass coating by chemical displacement comprising from approximately 8 oz. to oz. per gallon sodium zincate, from approximately 25 oz. to 125 oz. per gallon of sodium hydroxide, from approximately .1 oz. to 6 oz. per gallon of copper cyanide, from approximately .1 oz. to 12 oz. per gallon of sodium cyanide, from approximately .003 oz. to .1 oz. per gallon of basic lead carbonate, and the remainder water.
- a bath for depositing a brass coating by chemical displacement on aluminum alloy of the class which includes of the order of 6.25% to 7.75% copper, 5% to 6% silicon, .15% to .40% magnesium, up to 1.5% iron, up to .75% impurities including zinc and the remainder aluminum; comprising approximately 15.8 oz. per gallon of sodium zincate, 16.2 oz. per gallon of sodium hydroxide, 1.75 oz. per gallon of copper cyanide, 3.17 oz. per gallon of sodium cyanide and an amount of lead salt soluble in caustic solution and equivalent to .014 oz. per gallon of basic lead carbonate.
- a bath for depositing a brass coating by chemical displacement on aluminum alloy of the class which includes of the order of 6.25% to 7.75% copper, 5% to 6% silicon, .15% to .40%
- '- magnesium up to 1.5% iron, up to impurities including zinc and the remainder aluminum; comprising approximately from 13 oz. to 16 oz. per gallon of sodium zincate, from 13 oz. to 20 oz. per gallon of sodium hydroxide, from 1.5 oz. to 2 oz. per gallon of copper cyanide, from 2.75 oz. to 3.5 oz. per gallon of sodium cyanide and an amount of a lead salt soluble in caustic solution equivalent to .01 oz. to .03 oz. of basic lead carbonate.
- a bath for depositing a pink colored brass coating by chemical displacement on an aluminum alloy comprising approximately 15.8 oz. per gallon of sodium zincate, 16.2 oz. per gallon of sodium hydroxide, 1.75 oz. per gallon of copper cyanide, 3.17 oz. per gallon of sodium cyanide and an amount of lead salt soluble in caustic solution equivalent to not more than .003 oz. per gallon of basic lead carbonate.
- a bath for depositing a yellow colored brass coating by chemical displacement on an aluminum alloy comprising approximately 15.8 oz. per gallon of sodium zincate, 16.2 oz. per gallon of sodium hydroxide, 1.75 oz. per gallon of copper cyanide, 3.17 oz. per gallon of sodium cyanide and an amount of lead salt soluble in caustic solution equivalent to .003 oz. to .016 oz. per gallon of basic lead carbonate.
- a bath for depositing a green colored brass coating by chemical displacement on an aluminum alloy comprising approximately 15.8 oz. per
- the method of brass coating aluminum and aluminum alloy which comprises depositing brass thereon by chemical displacement in a bath comprising from approximately 8 oz. to oz. per gallon sodium zincate, from approximately 25 oz. to oz. per gallon of sodium hydroxide, from approximately .1. oz to 6 oz. per gallon of copper cyanide, from approximately .1 oz. to 12 oz. per gallon of sodium cyanide, from approximately .003 oz. to .1 oz. per gallon of basic lead carbonate, and the remainder water.
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- 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)
- Other Surface Treatments For Metallic Materials (AREA)
Description
Patented Feb. 7, 1950 BATH FOR BRASS IMMERSION COATING ON ALUMINUM AND ALUMINUM ALLOY Alvin R. Balden, Plymouth, and Leland M. Morse,
Pontiac, Mich., assignors to Chrysler Corporation, Highland Park, Mich., a corporation of Delaware No Drawing. Application June 10, 1946, Serial No. 675,826
8 Claims.
This invention relates to an improved immersion deposition particularly for aluminum and aluminum alloys.
More specifically, the invention pertains to an improved brass immersion deposition of this kind.
One of the main objects of the invention is to provide an immersion bath by which coatings of brass having improved bearing properties can be readily formed on aluminum and aluminum alloy surfaces.
Another object of the invention is to provide a bath of this character from which coatings of brass may be deposited on and integrally bonded to surfaces comprising aluminum and aluminum alloys.
A further object of the invention is to provide a brass immersion bath of this kind which is conveniently controllable to predetermine the color and character of the deposit formed thereby.
We have found that the presence of critical amounts of lead salts in brass immersion coating baths from which brass is deposited by chemical displacement produces coatings on aluminum and aluminum alloy surfaces which are extremely adherent to such surfaces and have excellent bearing properties. It has also been found that the appearance of the resulting coatings can be controlled within ranges of color varying from pink through yellow, to green, by suitable control of the lead salt content of the bath. The thickness characteristics of the resulting deposit can correspondingly be controlled by the lead salt content of the bath. When the lead salt content is such as to produce a pink deposit, the coating can be built upon aluminum and aluminum alloy surfaces, to a greater thickness than those of yellow and green deposits, the yellow deposit being capa ble of being built up to -a greater thickness than the green.
A brass coating bath embodying the invention may be made as follows, the quantities of materials specified being in amounts sufficient to produce one gallon of the finished bath. Approximately 30 ounces of a composition commercially known as Wyandotte ZA-30 manufactured by Wyandotte Chemical Company of Wyandotte, Michigan, are dissolved in approximately one pint of water. This composition comprises the reaction product of substantially 30% zinc oxide and 54%sodiumhydroxide, the reaction product 2 being NazZnOz in the-presence of an excess of NaOH. Solution of the foregoing ingredient in a relatively small amount of water in the order of 10% to 25% of the volume of the final bath avoids precipitation of zinc hydroxide from the solution.
A solution of approximately 3.17 ounces of sodium cyanide in substantially one pint of water is then prepared and to it is slowly added during stirring approximately 1.75 ounces of cuprous cyanide Cu2(CN)z. The resulting sodium copper cyanide (NazCu(CN) a) is then mixed with the above mentioned solution of sodium zincate and sodium hydroxide (Na2ZnO2+NaOH) and suflicient water is added during constant stirring to make the total solution up to one gallon.
To one-half pintof the last mentioned solution is added .014 ounces of basic lead carbonate. Any lead salt which is soluble in caustic solution, such as lead oxide, lead acetate or lead hydroxide can be used in its molecular equivalent in place of basic lead carbonate and combinations of such soluble lead compounds may also be used. This lead salt containing solution is then introduced into the previously formed sodium zincate-sodium hydroxide and sodium copper cyanide solution to form the finished immersion bath. The lead salt is dissolved in the diluted bath solution in order to avoid reducing its solubility in the concentrated solution.
The foregoing bath is particularly compounded to produce on high alloy content aluminumalioys, brass immersion coatings of generally yellow coloration having desirable bearing properties In this bath, a coating of approximately .0001 inch to .00015 inch thickness is produced on such aluminum alloys by an immersion time of about five minutes. A coating formed by this bath has been found to be particularly suitable for pistons having the following composition: copper 6.25% to 7.75%, silicon 5% to 6%, magnesium .15% to .40%, iron 1.5% maximum, impurities including zinc 375% maximum, and the remainder aluminum.
The above bath is thus compounded'irom ingredients comprising 15.8 oz. per gallon sodium zincate, 16.2 oz. per gallon of sodium hydroxide, 1.75 oz. per gallon of copper cyanide, 3.17 oz. per gallon of sodium cyanide and .014 oz. per gallon of basic lead carbonate. For coating alloys of the 3 above specified type the formula may vary as follows:
Example I Sodium zincate-from 13 oz. to 16 oz. per gallon Sodium hydroxide-from 13 oz. to 20 oz. per
gallon Copper cyanide-from 1.5 oz. to 2 oz. per gallon Sodium cyanidefrom 2.75 oz. to 3.5 oz. per
gallon Basic lead carbonate or equivalent-from .01 oz.
to .03 oz. per gallon.
Variation of the lead content of the above described bath composition has the following effect upon color and thickness characteristics. When the lead metal content is between .003 oz. per gallon and .016 oz. per gallon, the deposit is yellow in color and has a maximum thickness of .00015 inch which will be formed in an immersion time of about five minutes at about 115 F. When the lead metal content is above .016 oz. per gallon, the deposit is green in color and has a maximum thickness of .0001 inch which will be formed in an immersion time of about five minutes at 115 F. With a lead content below .003 oz. per gallon the deposit tends to be pink and attains a thickness of about .0002 inch in approximately five minutes at 115 F. This latter deposit does not as strongly adhere to the aluminum alloys as the above mentioned yellow and green deposits. While the pinkish deposit may be useful for ornamental purposes, its lack of bond reduces its value for mechanical purposes such as piston and bearing surfaces. The upper limit of the lead salt content is established by the lead salt concentration at which pure lead is deposited in a powdery form upon the brass deposit. When coating aluminum alloy of the foregoing composition with the bath described for that purpose, the upper limit of lead salt content is about .03 oz. per gallon. The upper limit of the lead salt content increases with increased aluminum content of aluminum alloy being coated. When immersion coating pure aluminum, the lead salt content may be as high as .1 oz..per gallon but this value should not be substantially exceeded.
While the foregoing bath composition has been found to be preferable in forming brass immersion coatings on pistons of the above composition,
it has also been determined that exceptionally satisfactory results are obtainable in forming brass coatings for various purposes on diverse aluminum alloys, with baths having the following range of compositions:
Sodium zincate8 oz. to 45 oz. per gallon Sodium hydroxide-25 oz. to 125 oz. per gallon Coppercyanide.1 oz. to 6 oz. per gallon Sodium cyanide.1 oz. to 12 oz. per gallon Basic lead carbonate-.003 oz. to .1 oz. per gallon Immersion coatings formed on aluminum alloy of the type previously recited by a bath within the range of composition specified in Example I:
Per cent Copper to 40 Lead V .1 to 2 Zinc Remainder of the solution as the purity of aluminum in the alloy being coated increases. Likewise, as the aluminum content of the alloy increases the sodium zincate and sodium hydroxide content of the bath should also be increased in order to obtain optimum results.
Quantities of lead salts referred to herein are inclusive of lead salt impurities and such impurities should be taken account of in compounding the solution.
Articles to be coated by immersion are preferably cleaned in one of two ways. In the coating of mechanical parts in which adhesion is more important than appearance, an etching type cleaner is preferably employed, such as an equeous sodium hydroxide solution. Where it is desired to retain the bright finish of a part, a nonetching type cleaner containing sodium carbonate and sodium silicate, for example, is employed. When an etching type cleaner is used on aluminum containing copper and/or silicon, the cleaning operation should be followed by treatment in an acid dip containing nitric and hydrofluoric acids in order to remove the resulting smut. After the brass immersion deposition has been formed, the coated part is momentarily immersed in a dilute nitric acid solution, about one-half of one per cent by volume, and then washed in water. The dilute nitric acid treatment preserves the color of the immersion deposition.
Although but several specific embodiments of the invention are herein described, it will be understood that various changes in the sequence of operations, steps and materials employed may be made without departing from the spirit of the invention.
We claim:
1. A bath for depositing a brass coating by chemical displacement comprising from approximately 8 oz. to oz. per gallon sodium zincate, from approximately 25 oz. to 125 oz. per gallon of sodium hydroxide, from approximately .1 oz. to 6 oz. per gallon of copper cyanide, from approximately .1 oz. to 12 oz. per gallon of sodium cyanide, from approximately .003 oz. to .1 oz. per gallon of basic lead carbonate, and the remainder water.
2. A bath for depositing a brass coating by chemical displacement on aluminum alloy of the class which includes of the order of 6.25% to 7.75% copper, 5% to 6% silicon, .15% to .40% magnesium, up to 1.5% iron, up to .75% impurities including zinc and the remainder aluminum; comprising approximately 15.8 oz. per gallon of sodium zincate, 16.2 oz. per gallon of sodium hydroxide, 1.75 oz. per gallon of copper cyanide, 3.17 oz. per gallon of sodium cyanide and an amount of lead salt soluble in caustic solution and equivalent to .014 oz. per gallon of basic lead carbonate.
3. A bath for depositing a brass coating by chemical displacement on aluminum alloy of the class which includes of the order of 6.25% to 7.75% copper, 5% to 6% silicon, .15% to .40%
'- magnesium, up to 1.5% iron, up to impurities including zinc and the remainder aluminum; comprising approximately from 13 oz. to 16 oz. per gallon of sodium zincate, from 13 oz. to 20 oz. per gallon of sodium hydroxide, from 1.5 oz. to 2 oz. per gallon of copper cyanide, from 2.75 oz. to 3.5 oz. per gallon of sodium cyanide and an amount of a lead salt soluble in caustic solution equivalent to .01 oz. to .03 oz. of basic lead carbonate.
4. The method of making a bath for depositing a brass coating by chemical displacement on aluminum and aluminum alloys which consists of dissolving sodium zincate and sodium hydroxide in an amount of water corresponding to to 25% of the final volume of the bath, dissolving sodium cyanide in a separate container in a substantially equal amount of water, dissolving copper cyanide in said sodium cyanide solution, mixing said foregoing solutions, adding water to make up bath volume, and dissolving in the resulting solution a lead salt soluble in caustic solutions.
5. A bath for depositing a pink colored brass coating by chemical displacement on an aluminum alloy comprising approximately 15.8 oz. per gallon of sodium zincate, 16.2 oz. per gallon of sodium hydroxide, 1.75 oz. per gallon of copper cyanide, 3.17 oz. per gallon of sodium cyanide and an amount of lead salt soluble in caustic solution equivalent to not more than .003 oz. per gallon of basic lead carbonate.
6. A bath for depositing a yellow colored brass coating by chemical displacement on an aluminum alloy comprising approximately 15.8 oz. per gallon of sodium zincate, 16.2 oz. per gallon of sodium hydroxide, 1.75 oz. per gallon of copper cyanide, 3.17 oz. per gallon of sodium cyanide and an amount of lead salt soluble in caustic solution equivalent to .003 oz. to .016 oz. per gallon of basic lead carbonate.
7. A bath for depositing a green colored brass coating by chemical displacement on an aluminum alloy comprising approximately 15.8 oz. per
gallon of sodium zincate, 16.2 oz. per gallon of sodium hydroxide, 1.75 oz. per gallon of copper cyanide, 3.17 oz. per gallon of sodium cyanide and an amount of lead salt soluble in caustic solution equivalent to .016 oz. to .03 oz. per gallon of basic lead carbonate.
8. The method of brass coating aluminum and aluminum alloy which comprises depositing brass thereon by chemical displacement in a bath comprising from approximately 8 oz. to oz. per gallon sodium zincate, from approximately 25 oz. to oz. per gallon of sodium hydroxide, from approximately .1. oz to 6 oz. per gallon of copper cyanide, from approximately .1 oz. to 12 oz. per gallon of sodium cyanide, from approximately .003 oz. to .1 oz. per gallon of basic lead carbonate, and the remainder water.
ALVIN R. BALDEN. LELAND M. MORSE.
REFERENCES CITED The following references are of record in the I file of this patent:
UNITED STATES PATENTS Number Name Date 1,947,981 Fischer Feb. 20, 1934 2,086,841 Bagley July 13, 1937 2,230,602 Sullivan Feb. 4, 1941 OTHER REFERENCES Meyer et al., The Electrochemical Soc. Preprint, pp. 299, 300, 312, 314, 320, 321 (1938).
Claims (1)
1. A BATH FOR DEPOSITING A BRASS COATING BY CHEMICAL DISPLACEMENT COMPRISING FROM APPROXIMATELY 8 OZ. TO 45 OZ. PER GALLON SODIUM ZINCATE, FROM APPROXIMATELY 25 OZ. TO 125 OZ. PER GALLON OF SODIUM HYDROXIDE, FROM APPROXIMATELY .1 OZ. TO 6 OZ. PER GALLON OF COPPER CYANIDE, FROM APPROXIMATELY .1 OZ. TO 12 OZ. PER GALLON OF SODIUM CYANIDE, FROM APPROXIMATELY .003 OZ. TO .1 OZ. PER GALLON OF BASIC LEAD CARBONATE, AND THE REMAINDER WATER.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US675826A US2496845A (en) | 1946-06-10 | 1946-06-10 | Bath for brass immersion coating on aluminum and aluminum alloy |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US675826A US2496845A (en) | 1946-06-10 | 1946-06-10 | Bath for brass immersion coating on aluminum and aluminum alloy |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2496845A true US2496845A (en) | 1950-02-07 |
Family
ID=24712116
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US675826A Expired - Lifetime US2496845A (en) | 1946-06-10 | 1946-06-10 | Bath for brass immersion coating on aluminum and aluminum alloy |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US2496845A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2654701A (en) * | 1950-06-08 | 1953-10-06 | Edwin R Calderon | Plating aluminum |
| US2676916A (en) * | 1949-09-23 | 1954-04-27 | Aluminum Co Of America | Electroplating on aluminum |
| US2745799A (en) * | 1951-03-16 | 1956-05-15 | Pechiney Prod Chimiques Sa | Processes for coating aluminum and alloys thereof |
| US2938841A (en) * | 1956-04-13 | 1960-05-31 | Olin Mathieson | Preparation of zirconium for cold working |
| EP1408139A1 (en) * | 2002-10-10 | 2004-04-14 | Centro de Investigaci n en Materiales Avanzados S.C. | Electroless brass plating method |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1947981A (en) * | 1930-11-07 | 1934-02-20 | Siemens Ag | Plating aluminum |
| US2086841A (en) * | 1933-12-15 | 1937-07-13 | Bagley Berdan Company | Bearing metal, bearing and method of producing same |
| US2230602A (en) * | 1938-03-31 | 1941-02-04 | Battelle Memorial Institute | Method of coating metals with lead |
-
1946
- 1946-06-10 US US675826A patent/US2496845A/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1947981A (en) * | 1930-11-07 | 1934-02-20 | Siemens Ag | Plating aluminum |
| US2086841A (en) * | 1933-12-15 | 1937-07-13 | Bagley Berdan Company | Bearing metal, bearing and method of producing same |
| US2230602A (en) * | 1938-03-31 | 1941-02-04 | Battelle Memorial Institute | Method of coating metals with lead |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2676916A (en) * | 1949-09-23 | 1954-04-27 | Aluminum Co Of America | Electroplating on aluminum |
| US2654701A (en) * | 1950-06-08 | 1953-10-06 | Edwin R Calderon | Plating aluminum |
| US2745799A (en) * | 1951-03-16 | 1956-05-15 | Pechiney Prod Chimiques Sa | Processes for coating aluminum and alloys thereof |
| US2938841A (en) * | 1956-04-13 | 1960-05-31 | Olin Mathieson | Preparation of zirconium for cold working |
| EP1408139A1 (en) * | 2002-10-10 | 2004-04-14 | Centro de Investigaci n en Materiales Avanzados S.C. | Electroless brass plating method |
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