US2942990A - Metal plating by chemical reduction with borohydrides - Google Patents
Metal plating by chemical reduction with borohydrides Download PDFInfo
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- US2942990A US2942990A US788715A US78871559A US2942990A US 2942990 A US2942990 A US 2942990A US 788715 A US788715 A US 788715A US 78871559 A US78871559 A US 78871559A US 2942990 A US2942990 A US 2942990A
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- United States
- Prior art keywords
- nickel
- borohydride
- cobalt
- hydroxide
- plating
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- Expired - Lifetime
Links
- 238000007747 plating Methods 0.000 title claims description 27
- 229910052751 metal Inorganic materials 0.000 title claims description 13
- 239000002184 metal Substances 0.000 title claims description 13
- 238000006722 reduction reaction Methods 0.000 title description 8
- 239000003638 chemical reducing agent Substances 0.000 title description 3
- 239000007864 aqueous solution Substances 0.000 claims description 18
- 239000010941 cobalt Substances 0.000 claims description 13
- 229910017052 cobalt Inorganic materials 0.000 claims description 13
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 13
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims description 11
- 239000000908 ammonium hydroxide Substances 0.000 claims description 11
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims description 10
- 229910052700 potassium Inorganic materials 0.000 claims description 10
- 239000011591 potassium Substances 0.000 claims description 10
- 150000003839 salts Chemical class 0.000 claims description 9
- 229910000033 sodium borohydride Inorganic materials 0.000 claims description 9
- 239000012279 sodium borohydride Substances 0.000 claims description 9
- 229910052783 alkali metal Inorganic materials 0.000 claims description 7
- 239000000463 material Substances 0.000 claims description 7
- 239000000243 solution Substances 0.000 claims description 7
- -1 CARBOXYL GROUPS Chemical group 0.000 claims description 5
- 238000001556 precipitation Methods 0.000 claims description 5
- 150000001340 alkali metals Chemical class 0.000 claims description 4
- FLLNLJJKHKZKMB-UHFFFAOYSA-N boron;tetramethylazanium Chemical compound [B].C[N+](C)(C)C FLLNLJJKHKZKMB-UHFFFAOYSA-N 0.000 claims description 4
- 238000005234 chemical deposition Methods 0.000 claims description 4
- 239000003795 chemical substances by application Substances 0.000 claims description 4
- WGTYBPLFGIVFAS-UHFFFAOYSA-M tetramethylammonium hydroxide Chemical compound [OH-].C[N+](C)(C)C WGTYBPLFGIVFAS-UHFFFAOYSA-M 0.000 claims description 4
- 150000008044 alkali metal hydroxides Chemical class 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 claims description 3
- 150000001735 carboxylic acids Chemical class 0.000 claims description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical group [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 42
- 229910052759 nickel Inorganic materials 0.000 description 19
- 235000011114 ammonium hydroxide Nutrition 0.000 description 11
- 239000001509 sodium citrate Substances 0.000 description 9
- NLJMYIDDQXHKNR-UHFFFAOYSA-K sodium citrate Chemical compound O.O.[Na+].[Na+].[Na+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O NLJMYIDDQXHKNR-UHFFFAOYSA-K 0.000 description 9
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 239000000919 ceramic Substances 0.000 description 6
- 150000002500 ions Chemical class 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 5
- 150000001868 cobalt Chemical class 0.000 description 5
- 230000009467 reduction Effects 0.000 description 5
- VEQPNABPJHWNSG-UHFFFAOYSA-N Nickel(2+) Chemical compound [Ni+2] VEQPNABPJHWNSG-UHFFFAOYSA-N 0.000 description 4
- 239000011521 glass Substances 0.000 description 4
- 229910001453 nickel ion Inorganic materials 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- LGQLOGILCSXPEA-UHFFFAOYSA-L nickel sulfate Chemical compound [Ni+2].[O-]S([O-])(=O)=O LGQLOGILCSXPEA-UHFFFAOYSA-L 0.000 description 3
- 229910000363 nickel(II) sulfate Inorganic materials 0.000 description 3
- 230000001603 reducing effect Effects 0.000 description 3
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 2
- KRKNYBCHXYNGOX-UHFFFAOYSA-K Citrate Chemical compound [O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O KRKNYBCHXYNGOX-UHFFFAOYSA-K 0.000 description 2
- 229910021503 Cobalt(II) hydroxide Inorganic materials 0.000 description 2
- FEWJPZIEWOKRBE-JCYAYHJZSA-N Dextrotartaric acid Chemical compound OC(=O)[C@H](O)[C@@H](O)C(O)=O FEWJPZIEWOKRBE-JCYAYHJZSA-N 0.000 description 2
- BDAGIHXWWSANSR-UHFFFAOYSA-M Formate Chemical compound [O-]C=O BDAGIHXWWSANSR-UHFFFAOYSA-M 0.000 description 2
- OAKJQQAXSVQMHS-UHFFFAOYSA-N Hydrazine Chemical compound NN OAKJQQAXSVQMHS-UHFFFAOYSA-N 0.000 description 2
- OFOBLEOULBTSOW-UHFFFAOYSA-N Malonic acid Chemical compound OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 2
- 229910002651 NO3 Inorganic materials 0.000 description 2
- 229910021586 Nickel(II) chloride Inorganic materials 0.000 description 2
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 2
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 2
- FEWJPZIEWOKRBE-UHFFFAOYSA-N Tartaric Acid Chemical compound [H+].[H+].[O-]C(=O)C(O)C(O)C([O-])=O FEWJPZIEWOKRBE-UHFFFAOYSA-N 0.000 description 2
- MQRWBMAEBQOWAF-UHFFFAOYSA-N acetic acid;nickel Chemical compound [Ni].CC(O)=O.CC(O)=O MQRWBMAEBQOWAF-UHFFFAOYSA-N 0.000 description 2
- WNLRTRBMVRJNCN-UHFFFAOYSA-N adipic acid Chemical compound OC(=O)CCCCC(O)=O WNLRTRBMVRJNCN-UHFFFAOYSA-N 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- 239000002585 base Substances 0.000 description 2
- QDWJUBJKEHXSMT-UHFFFAOYSA-N boranylidynenickel Chemical group [Ni]#B QDWJUBJKEHXSMT-UHFFFAOYSA-N 0.000 description 2
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 2
- 229940011182 cobalt acetate Drugs 0.000 description 2
- UFMZWBIQTDUYBN-UHFFFAOYSA-N cobalt dinitrate Chemical compound [Co+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O UFMZWBIQTDUYBN-UHFFFAOYSA-N 0.000 description 2
- 229910001429 cobalt ion Inorganic materials 0.000 description 2
- 229910001981 cobalt nitrate Inorganic materials 0.000 description 2
- XLJKHNWPARRRJB-UHFFFAOYSA-N cobalt(2+) Chemical compound [Co+2] XLJKHNWPARRRJB-UHFFFAOYSA-N 0.000 description 2
- QAHREYKOYSIQPH-UHFFFAOYSA-L cobalt(II) acetate Chemical compound [Co+2].CC([O-])=O.CC([O-])=O QAHREYKOYSIQPH-UHFFFAOYSA-L 0.000 description 2
- ASKVAEGIVYSGNY-UHFFFAOYSA-L cobalt(ii) hydroxide Chemical compound [OH-].[OH-].[Co+2] ASKVAEGIVYSGNY-UHFFFAOYSA-L 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 229940078494 nickel acetate Drugs 0.000 description 2
- QMMRZOWCJAIUJA-UHFFFAOYSA-L nickel dichloride Chemical compound Cl[Ni]Cl QMMRZOWCJAIUJA-UHFFFAOYSA-L 0.000 description 2
- 229910000480 nickel oxide Inorganic materials 0.000 description 2
- WLJVNTCWHIRURA-UHFFFAOYSA-N pimelic acid Chemical compound OC(=O)CCCCCC(O)=O WLJVNTCWHIRURA-UHFFFAOYSA-N 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- HELHAJAZNSDZJO-OLXYHTOASA-L sodium L-tartrate Chemical compound [Na+].[Na+].[O-]C(=O)[C@H](O)[C@@H](O)C([O-])=O HELHAJAZNSDZJO-OLXYHTOASA-L 0.000 description 2
- 239000001433 sodium tartrate Substances 0.000 description 2
- 229960002167 sodium tartrate Drugs 0.000 description 2
- 235000011004 sodium tartrates Nutrition 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229940095064 tartrate Drugs 0.000 description 2
- HFVMEOPYDLEHBR-UHFFFAOYSA-N (2-fluorophenyl)-phenylmethanol Chemical compound C=1C=CC=C(F)C=1C(O)C1=CC=CC=C1 HFVMEOPYDLEHBR-UHFFFAOYSA-N 0.000 description 1
- BJEPYKJPYRNKOW-REOHCLBHSA-N (S)-malic acid Chemical compound OC(=O)[C@@H](O)CC(O)=O BJEPYKJPYRNKOW-REOHCLBHSA-N 0.000 description 1
- RTBFRGCFXZNCOE-UHFFFAOYSA-N 1-methylsulfonylpiperidin-4-one Chemical compound CS(=O)(=O)N1CCC(=O)CC1 RTBFRGCFXZNCOE-UHFFFAOYSA-N 0.000 description 1
- PXRKCOCTEMYUEG-UHFFFAOYSA-N 5-aminoisoindole-1,3-dione Chemical compound NC1=CC=C2C(=O)NC(=O)C2=C1 PXRKCOCTEMYUEG-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 1
- 229920005479 Lucite® Polymers 0.000 description 1
- KDYFGRWQOYBRFD-UHFFFAOYSA-N Succinic acid Natural products OC(=O)CCC(O)=O KDYFGRWQOYBRFD-UHFFFAOYSA-N 0.000 description 1
- 230000001464 adherent effect Effects 0.000 description 1
- BJEPYKJPYRNKOW-UHFFFAOYSA-N alpha-hydroxysuccinic acid Natural products OC(=O)C(O)CC(O)=O BJEPYKJPYRNKOW-UHFFFAOYSA-N 0.000 description 1
- JFCQEDHGNNZCLN-UHFFFAOYSA-N anhydrous glutaric acid Natural products OC(=O)CCCC(O)=O JFCQEDHGNNZCLN-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 150000001732 carboxylic acid derivatives Chemical class 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Natural products OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229910001651 emery Inorganic materials 0.000 description 1
- 239000003112 inhibitor Substances 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 239000001630 malic acid Substances 0.000 description 1
- 235000011090 malic acid Nutrition 0.000 description 1
- 229910052987 metal hydride Inorganic materials 0.000 description 1
- 150000004681 metal hydrides Chemical class 0.000 description 1
- LFETXMWECUPHJA-UHFFFAOYSA-N methanamine;hydrate Chemical compound O.NC LFETXMWECUPHJA-UHFFFAOYSA-N 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- CLVOYFRAZKMSPF-UHFFFAOYSA-N n,n-dibutyl-4-chlorobenzenesulfonamide Chemical compound CCCCN(CCCC)S(=O)(=O)C1=CC=C(Cl)C=C1 CLVOYFRAZKMSPF-UHFFFAOYSA-N 0.000 description 1
- 150000002815 nickel Chemical class 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- 229910052755 nonmetal Inorganic materials 0.000 description 1
- 150000002843 nonmetals Chemical class 0.000 description 1
- ACVYVLVWPXVTIT-UHFFFAOYSA-M phosphinate Chemical compound [O-][PH2]=O ACVYVLVWPXVTIT-UHFFFAOYSA-M 0.000 description 1
- ACVYVLVWPXVTIT-UHFFFAOYSA-N phosphinic acid Chemical class O[PH2]=O ACVYVLVWPXVTIT-UHFFFAOYSA-N 0.000 description 1
- 239000004926 polymethyl methacrylate Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 125000001453 quaternary ammonium group Chemical group 0.000 description 1
- 238000007790 scraping Methods 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
- C23C18/31—Coating with metals
- C23C18/32—Coating with nickel, cobalt or mixtures thereof with phosphorus or boron
- C23C18/34—Coating with nickel, cobalt or mixtures thereof with phosphorus or boron using reducing agents
Definitions
- This invention relates to chemical deposition of nickel, cobalt and mixtures thereof upon metals, glass, ceramics and plastics by the reducing action of a borohydride in an'aqueous solution of a salt of nickel and/0r cobalt.
- a process for chemical plating nickel and cobalt upon metallic surfaces has been proposed which involves the reducing action of hypophosphites in a solution of a nickel or cobalt salt, a temperature of 90 C. or more being used to start the reaction.
- a process also has been proposed involving the reducing actions of hypophosphite and hydrazine, a noble metal catalyst being used to start the reaction.
- the present invention is based upon the discovery that under certain conditions the water soluble alkali metal borohydrides, such as sodium borohydride, potassium borohydride and tetramethylammonium borohydride, are highly effective reducing agents for use in chemical plating of nickel and cobalt upon both metals and non-metals, such as glass, ceramics and plastics. It has been discovered that if the pH of the aqueous solution of the nickel and/or cobalt salt and the borohydride is adjusted to between about 12.0 and 13.0, the boride formation is suppressed and the reduction product is principally elemental metal. The pH of the solution is adjusted to between 12.0 and 13.0 by the'presence therein of an alkaline material, such as ammonium hydroxide.
- an alkaline material such as ammonium hydroxide.
- the precipitation of the hydroxide of nickel or cobalt is inhibited by conventional means, such as by the presence in the solution of an alkali metal salt of an organic carboxylic acid having at least two carboxyl groups, such as the alkali metal salt of citric, tartaric, adipic, succinic, malonic, oxalic, glutaric, pimelic or malic acid.
- An effective amount of such inhibitor in terms of normality is at least equal to the normality of the nickel or cobalt salt.
- the present invention therefore, provides a bath for plating by chemical deposition comprising an aqueous solution of a salt of nickel and/or cobalt having a pH between about 12.0 and 13.0, a Water soluble borohydride and a compound which inhibits the precipitation of nickel or cobalt hydroxide.
- any water soluble salt of nickel or cobalt may be used, such as the sulfate, chloride, nitrate, acetate, formate, citrate or tartrate.
- alkali metal hydroxides or quaternary ammonium hydroxides may be used, such as sodium hydroxide, potassium hydroxide or tetra- 2,942,990 Patented June 28, 1960 methylammonium hydroxide.
- Any water soluble borohydride may be used, such as sodium borohydride', potassium borohydride or tetramethylammonium borohydride.
- the plating bath of the invention is stable for a limited time at normal room temperature, it is preferred to prepare a separate aqueous solution of the borohydride having its pH adjusted to between 12.0 and 13.0 by the addition of an alkaline material if necessary and a second aqueous solution containing the salt of nickel and/or cobalt and having its pH adjusted to between 12.0 and 13.0 by the presence of ammonium hydroxide or other alkaline material and also containing a compound, such as sodium citrate, for inhibiting the precipitation of nickel and/or cobalt hydroxide.
- the plating bath is made up when desired by combining aliquots of these two solutions in desired proportions.
- the plating reaction may be started by heating the bath to a temperature of about 40 C.
- the reaction normally is completed in 30 to 45 minutes, that is, when the borohydride is used up.
- Adherence of the nickel or cobalt plate is especially good when the surface plated is an unglazed ceramic. Scraping of the surface with a knifeedge does not remove the plated metal.
- the adherence of the plate is improved if the surface is first roughened with an abrasive, such as emery paper.
- the invention is illustrated by the following examples.
- the reaction was started by heating the plating bath to a temperature of 40 C. and heating was continued at a temperature in the range between 40 C. and 50 C. for a period of 30 to 45 minutes.
- the base material was coated with an adherent, continuous plate of the plating metal.
- the continuity of the -.plate on the non-metallic base materials of Examples 3-6 was tested by checking their electrical resistance with an ohmmeter. Resistivities of the order of 3 to 10 ohms were found.
- the resulting plating bath was 0.123 N in nickel sulfate, 0.22 N in sodium citrate and 0.155 N in potassium borohydride and had a pH of 12.3, the molar ratio of BH; ions to nickel ions being 1.3.
- the bath was used for plating nickel on copper.
- Example 2 Five parts by volume of an aqueous solution 0.081 N in nickel acetate, 0.146 N in sodium citrate and 6.5 N in ammonium hydroxide were combined with one part by volume of an aqueous solution 0.93 N in potassium borohydride.
- the resulting plating bath was 0.067 N in nickel acetate, 0.121 N in sodium citrate and 0.155 N in potassium borohydride and had a pH of 12.4, the molar ratio of BH, ions to nickel ions being 2.3.
- the bath was used for plating nickel on mild steel.
- Example 3 23 parts by volume of an aqueous solution 0.131 N in nickel chloride, 0.213 N in sodium citrate and 8.5 N
- Example 4 Five parts by volume of an aqueous solution 0.046 N in cobalt acetate, 0.127 N in sodium tartrate and 6.9 N
- Example 5 12.4, the molar ratio of BH; ions to nickel ions being 2.7.
- the bath was used for plating nickel on Lucite.
- Example 6 Five parts by volume of an aqueous solution 0.105 N 30 in cobalt nitrate, 0.213 N in sodium citrate and 8.2 N
- a bath for plating by chemical deposition consisting essentially of an aqueous solution of a salt of a metal selected from the group consisting of nickel and cobalt in a concentration between about 0.02 and 0.15 normal, at borohydride selected from the group consisting of sodium borohydride, potassium borohydride and tetramethylammonium borohydride, an alkaline material selected from the group consisting of ammonium hydroxide, an alkali metal hydroxide and tetramethylammonium hydroxide in an amount sufficient to bring the pH of the solution to between about 12.0 and 13.0, and an agent adapted to inhibit precipitation of the hydroxide of said selected metal, said agent being selected from alkali metal salts of carboxylic acids having at least two carboxyl groups and being present in a concentration in. terms of normality at least equal to the normality of the salt of said selectedmetal.
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)
- Chemically Coating (AREA)
Description
United States Patent Metal Hydrides Incorporated, Beverly, Mass, a corporation of Massachusetts No Drawing. Filed .Ian. 26, 1959, Ser. No. 788,715
2 Claims. (Cl. 106-1) This invention relates to chemical deposition of nickel, cobalt and mixtures thereof upon metals, glass, ceramics and plastics by the reducing action of a borohydride in an'aqueous solution of a salt of nickel and/0r cobalt.
A process for chemical plating nickel and cobalt upon metallic surfaces has been proposed which involves the reducing action of hypophosphites in a solution of a nickel or cobalt salt, a temperature of 90 C. or more being used to start the reaction. A process also has been proposed involving the reducing actions of hypophosphite and hydrazine, a noble metal catalyst being used to start the reaction.
Sodium borohydride has been used extensively for effecting reductions of many compounds in aqueous solu tion. It is known that the alkali metal borohydrides reduce nickel salts but the reduction product is nickel boride. Thus, the United States patent to H. I. Schlesinger and H. C. Brown No. 2,461,661, column 5, lines 2 to 5, states: One characteristic reduction reaction of the alkali metal borohydrides is the reduction of nickel sulfate in solution to a black precipitate of nickel boride, Ni B.
The present invention is based upon the discovery that under certain conditions the water soluble alkali metal borohydrides, such as sodium borohydride, potassium borohydride and tetramethylammonium borohydride, are highly effective reducing agents for use in chemical plating of nickel and cobalt upon both metals and non-metals, such as glass, ceramics and plastics. It has been discovered that if the pH of the aqueous solution of the nickel and/or cobalt salt and the borohydride is adjusted to between about 12.0 and 13.0, the boride formation is suppressed and the reduction product is principally elemental metal. The pH of the solution is adjusted to between 12.0 and 13.0 by the'presence therein of an alkaline material, such as ammonium hydroxide. The precipitation of the hydroxide of nickel or cobalt is inhibited by conventional means, such as by the presence in the solution of an alkali metal salt of an organic carboxylic acid having at least two carboxyl groups, such as the alkali metal salt of citric, tartaric, adipic, succinic, malonic, oxalic, glutaric, pimelic or malic acid. An effective amount of such inhibitor in terms of normality is at least equal to the normality of the nickel or cobalt salt.
The present invention, therefore, provides a bath for plating by chemical deposition comprising an aqueous solution of a salt of nickel and/or cobalt having a pH between about 12.0 and 13.0, a Water soluble borohydride and a compound which inhibits the precipitation of nickel or cobalt hydroxide.
In the practice of the invention, any water soluble salt of nickel or cobalt may be used, such as the sulfate, chloride, nitrate, acetate, formate, citrate or tartrate. In place of ammonium hydroxide, alkali metal hydroxides or quaternary ammonium hydroxides may be used, such as sodium hydroxide, potassium hydroxide or tetra- 2,942,990 Patented June 28, 1960 methylammonium hydroxide. Any water soluble borohydride may be used, such as sodium borohydride', potassium borohydride or tetramethylammonium borohydride.
While the plating bath of the invention is stable for a limited time at normal room temperature, it is preferred to prepare a separate aqueous solution of the borohydride having its pH adjusted to between 12.0 and 13.0 by the addition of an alkaline material if necessary anda second aqueous solution containing the salt of nickel and/or cobalt and having its pH adjusted to between 12.0 and 13.0 by the presence of ammonium hydroxide or other alkaline material and also containing a compound, such as sodium citrate, for inhibiting the precipitation of nickel and/or cobalt hydroxide. The plating bath is made up when desired by combining aliquots of these two solutions in desired proportions. Satisfactory results have been obtained with a plating bath in which the concentration of the nickel or cobalt salt is between about 0.02- and 0.15 normal, the concentration of the borohydride being between about 0.05 to 0.60 normal but sufficient to effect substantially complete reduction of the nickel or cobalt salt.
In the use of the plating bath of the invention, the plating reaction may be started by heating the bath to a temperature of about 40 C. The reaction normally is completed in 30 to 45 minutes, that is, when the borohydride is used up. Adherence of the nickel or cobalt plate is especially good when the surface plated is an unglazed ceramic. Scraping of the surface with a knifeedge does not remove the plated metal. When plating smooth surfaces, such as other metals, glass or glazed ceramics, the adherence of the plate is improved if the surface is first roughened with an abrasive, such as emery paper.
The invention is illustrated by the following examples. In these examples the reaction was started by heating the plating bath to a temperature of 40 C. and heating was continued at a temperature in the range between 40 C. and 50 C. for a period of 30 to 45 minutes. In each example, the base material was coated with an adherent, continuous plate of the plating metal. The continuity of the -.plate on the non-metallic base materials of Examples 3-6 was tested by checking their electrical resistance with an ohmmeter. Resistivities of the order of 3 to 10 ohms were found.
Example Five parts by volume of an aqueous solution 0.148 N in nickel sulfate, 0.264 N in sodium citrate and 7.6 N in ammonium hydroxide were combined with one part by volume of an aqueous solution 0.93 N in potassium borohydride. The resulting plating bath was 0.123 N in nickel sulfate, 0.22 N in sodium citrate and 0.155 N in potassium borohydride and had a pH of 12.3, the molar ratio of BH; ions to nickel ions being 1.3. The bath was used for plating nickel on copper.
Example 2 Five parts by volume of an aqueous solution 0.081 N in nickel acetate, 0.146 N in sodium citrate and 6.5 N in ammonium hydroxide were combined with one part by volume of an aqueous solution 0.93 N in potassium borohydride. The resulting plating bath was 0.067 N in nickel acetate, 0.121 N in sodium citrate and 0.155 N in potassium borohydride and had a pH of 12.4, the molar ratio of BH, ions to nickel ions being 2.3. The bath was used for plating nickel on mild steel.
Example 3 23 parts by volume of an aqueous solution 0.131 N in nickel chloride, 0.213 N in sodium citrate and 8.5 N
in ammonium hydroxide were combined with one part by volume of an aqueous solution 4.44 N in sodium borohydride and containing about 40 percent by Weight of sodium hydroxide. The resulting plating bath was 0.125 N in nickel chloride, 0.206 N in sodium citrate and 0.185 N in sodium borohydride and had a 'pH of 12.8, the molar ratio of BH, ions to nickel ions being 1.5. The bath was used for plating nickel on unglazed ceramic.
Example 4 Five parts by volume of an aqueous solution 0.046 N in cobalt acetate, 0.127 N in sodium tartrate and 6.9 N
in ammonium hydroxide were combined with one part by volume of an aqueous solution 1.32 N in sodium borohydride and 6.8 N in ammonium hydroxide. The resulting plating bath was 0.038 N in cobalt acetate, 0.106 N in sodium tartrate and 0.22 N in sodium borohydride'and had a pH of 12.5, the molar ratio of EH ions to cobalt ions being 5.8. The bath was used for plating cobalt on glass.
Example 5 12.4, the molar ratio of BH; ions to nickel ions being 2.7. The bath was used for plating nickel on Lucite.
Example 6 Five parts by volume of an aqueous solution 0.105 N 30 in cobalt nitrate, 0.213 N in sodium citrate and 8.2 N
in ammonium hydroxide were combined with one part by volume of an aqueous solution 0.93 N in potassium borohydride. The resulting plating bath was 0.087 N in cobalt nitrate, 0.177 N in sodium citrate and 0.155 N in potassium borohydride and had a pH of 12.4, the molar ratio of EH ions to cobalt ions being 1.8. The bath was used for plating cobalt on unglazed ceramic.
I claim:
l. A bath for plating by chemical deposition consisting essentially of an aqueous solution of a salt of a metal selected from the group consisting of nickel and cobalt in a concentration between about 0.02 and 0.15 normal, at borohydride selected from the group consisting of sodium borohydride, potassium borohydride and tetramethylammonium borohydride, an alkaline material selected from the group consisting of ammonium hydroxide, an alkali metal hydroxide and tetramethylammonium hydroxide in an amount sufficient to bring the pH of the solution to between about 12.0 and 13.0, and an agent adapted to inhibit precipitation of the hydroxide of said selected metal, said agent being selected from alkali metal salts of carboxylic acids having at least two carboxyl groups and being present in a concentration in. terms of normality at least equal to the normality of the salt of said selectedmetal.
2. A plating bath as described by claim 1 wherein said salt of the selected metal is selected from the group consisting of sulfate, chloride, nitrate, acetate, formate, citrate and tartrate.
References Cited in the file of this patent UNITED STATES PATENTS 2,726,170 Warf et a1. Dec. 6, 1955 Notice ef Adverse Decisien in Interference In Interference No. 92,380 involving Patent No. 2,942,990, E. A. Sullivan, Metal plating by chemical reduction with borohydrides, final judgment adverse to the patentee was rendered Aug. 20, 1962, as to claims 1 and 2.
[Ofiicial Gazette September 18, 1962.]
Claims (1)
1. A BATH FOR PLATING BY CHEMICAL DEPOSITION CONSISTING ESSENTIALLY OF AN AQUEOUS SOLUTION OF A SALT OF A METAL SELECTED FROM THE GROUP CONSISTING OF NICKEL AND COBALT IN A CONCENTRATION BETWEEN ABOUT 0.02 AND 0.15 NORMAL, A BOROHYDRIDE SELECTED FROM THE GROUP CONSISTING OF SODIUM BOROHYDRIDE, POTASSIUM BOROHYDRIDE AND TETRAMETHYLAMMONIUM BOROHYDRIDE, AN ALKALINE MATERIAL SELECTED FROM THE GROUP CONSISTING OF AMMONIUM HYDROXIDE, AN ALKALI METAL HYDROXIDE AND TETRAMETHYLAMMONIUM HYDROXIDE IN AN AMOUNT SUFFICIENT TO BRING THE PH OF THE SOLUTION TO BETWEEN ABOUT 12.0 AND 13.0, AND AN AGENT ADAPTED TO INHIBIT PRECIPITATION OF THE HYDROXIDE OF SAID SELECTED METAL, SAID AGENT BEING SELECTED FROM ALKALI METAL SALTS OF CARBOXYLIC ACIDS HAVING AT LEAST TWO CARBOXYL GROUPS AND BEING PRESENT IN A CONCENTRATION IN TERMS OF NORMALITY AT LEAST EQUAL TO THE NORMALITY OF THE SALT OF SAID SELECTED METAL.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US788715A US2942990A (en) | 1959-01-26 | 1959-01-26 | Metal plating by chemical reduction with borohydrides |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US788715A US2942990A (en) | 1959-01-26 | 1959-01-26 | Metal plating by chemical reduction with borohydrides |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2942990A true US2942990A (en) | 1960-06-28 |
Family
ID=25145332
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US788715A Expired - Lifetime US2942990A (en) | 1959-01-26 | 1959-01-26 | Metal plating by chemical reduction with borohydrides |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US2942990A (en) |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3096182A (en) * | 1958-10-01 | 1963-07-02 | Du Pont | Chemical plating solution and process for plating therewith |
| US3140188A (en) * | 1960-08-29 | 1964-07-07 | Bayer Ag | Bath compositions for chemical plating of metals containing boron nitrogen compounds nd an organic solubilizing compound |
| US3216834A (en) * | 1960-10-05 | 1965-11-09 | Engelhard Ind Inc | Palladium decorating compositions |
| DE1239766B (en) * | 1962-07-12 | 1967-05-03 | Telefunken Patent | Method for applying a firmly adhering nickel layer to a glossy carbon resistance layer applied to a ceramic carrier |
| US3338726A (en) * | 1958-10-01 | 1967-08-29 | Du Pont | Chemical reduction plating process and bath |
| US3423214A (en) * | 1965-06-30 | 1969-01-21 | Ibm | Magnetic cobalt and cobalt alloy plating bath and process |
| US3446657A (en) * | 1964-06-18 | 1969-05-27 | Ibm | Coating method |
| US3637472A (en) * | 1970-03-16 | 1972-01-25 | Ventron Corp | Chemical plating baths containing an alkali metal cyanoborohydride |
| US4157262A (en) * | 1976-04-28 | 1979-06-05 | Fuji Photo Film Co., Ltd. | Intensification of photographic silver images by physical development and improvement in physical developer solution for use therein |
| FR2413194A1 (en) * | 1977-12-28 | 1979-07-27 | Cbs Sony Records Inc | METHOD FOR MANUFACTURING RECORDING DISCS INCLUDING AN ENGRAVING |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2726170A (en) * | 1954-09-07 | 1955-12-06 | Superweld Corp | Method of coating steel with nickel-boron |
-
1959
- 1959-01-26 US US788715A patent/US2942990A/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2726170A (en) * | 1954-09-07 | 1955-12-06 | Superweld Corp | Method of coating steel with nickel-boron |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3096182A (en) * | 1958-10-01 | 1963-07-02 | Du Pont | Chemical plating solution and process for plating therewith |
| US3338726A (en) * | 1958-10-01 | 1967-08-29 | Du Pont | Chemical reduction plating process and bath |
| US3140188A (en) * | 1960-08-29 | 1964-07-07 | Bayer Ag | Bath compositions for chemical plating of metals containing boron nitrogen compounds nd an organic solubilizing compound |
| US3216834A (en) * | 1960-10-05 | 1965-11-09 | Engelhard Ind Inc | Palladium decorating compositions |
| DE1239766B (en) * | 1962-07-12 | 1967-05-03 | Telefunken Patent | Method for applying a firmly adhering nickel layer to a glossy carbon resistance layer applied to a ceramic carrier |
| US3446657A (en) * | 1964-06-18 | 1969-05-27 | Ibm | Coating method |
| US3423214A (en) * | 1965-06-30 | 1969-01-21 | Ibm | Magnetic cobalt and cobalt alloy plating bath and process |
| US3637472A (en) * | 1970-03-16 | 1972-01-25 | Ventron Corp | Chemical plating baths containing an alkali metal cyanoborohydride |
| US4157262A (en) * | 1976-04-28 | 1979-06-05 | Fuji Photo Film Co., Ltd. | Intensification of photographic silver images by physical development and improvement in physical developer solution for use therein |
| FR2413194A1 (en) * | 1977-12-28 | 1979-07-27 | Cbs Sony Records Inc | METHOD FOR MANUFACTURING RECORDING DISCS INCLUDING AN ENGRAVING |
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