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
• • 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
  • C23C18/36—Coating with nickel, cobalt or mixtures thereof with phosphorus or boron using reducing agents using hypophosphites

Definitions

• ABSTRACT [52] US. Cl. ..106/1, 1 17/130 E, 1 17/130 B, A Stabilized chemical bath containing a Solution f a nicks] 1 17/160 salt and selenium compounds as stabilizers.
• baths which contain in solution a nickel salt, a reducing agent, complex formers and other additions, deposit nickel on the base metal or substrate upon contact of the bath with a catalytically active metal surface.
• a disadvantage of the bath compositions or reductive nickel baths that have heretofore been known is their low stability, so that they are often discarded after the metal has been once spent.
• Additives for the stabilization of these baths are known.
• sulfur compounds or if traces of sulfur are already present in the solution, compounds which are able to form sulfur compounds in any form with the sulfur present in the solution.
• These additives may be added only in small quantities, since higher concentrations may greatly reduce the rate of deposition of the metal or even prevent the smooth deposition. Only in a very narrow concentration range, are xanthogenates and lead ions of the proposed stabilizers said to bring about, besides the stabilization, a slight increase of the rate of deposition, which however is not satisfactory for use in the art.
• a reductive, aqueous, nickel bath containing a solution of nickel salt, complex formers, buffer substances, reducing agents and possibly wetting and brightening agents, bases or acids characterized by a content of one or more selenium-containing compounds, in which the selenium has the degree of oxidation of minus one or minus two, possesses a very good stability, which is greater than that of the known baths.
• nickel layers of constant thickness can be deposited from the bath. These coatings are very decorative and distinguish themselves by a bright metallic luster.
• degree of oxidation of the selenium in the characterized selenium compounds is understood the socalled oxidation number or change value, i.e., the charge which an atom would possess in a molecule if the latter were composed only of ions.
• Suitable selenium compounds with the degree of oxidation minus one are, for example, compounds of the general formula R Se Se R wherein R, and R, are identical or different and signify a univalent metal equivalent or an organic radical.
• Suitable selenium compounds with the degree of oxidation minus two" are, for example, compounds of the general formula RI] Se R g wherein R and R' are identical or different and have the same meaning as R and R R representing in addition hydrogen, the radical CN or the radical SO Me, where Me is a univalent metal equivalent.
• selenium compounds with the degree of oxidation minus two are, for example, the selenonium compounds of the general formula wherein R,, R" and R are identical or different and designate an organic radical and X designates an acid radical.
• univalent metal equivalents there enter into consideration for example: Na, K, Ca/2 or Al/3, etc.; as organic radicals there may be mentioned, for example: aliphatic, cycloaliphatic, aromatic, and araliphatic radicals, which may possibly also be substituted and/or interrupted by one or more heteroatoms, such as oxygen or nitrogen and/or one or more heteroatom groups, such as as well as the acryl radical and the CN group.
• organic radicals there may be mentioned, for example: aliphatic, cycloaliphatic, aromatic, and araliphatic radicals, which may possibly also be substituted and/or interrupted by one or more heteroatoms, such as oxygen or nitrogen and/or one or more heteroatom groups, such as as well as the acryl radical and the CN group.
• Substituents for the mentioned organic radicals are, for example, halogen atoms such as chlorine, bromine, etc., hydroxyl radicals, alkyl radicals, such as methyl and ethyl, etc;, aryloxy radicals, such as phenoxy, etc., alkoxy radicals, such as methoxy and ethoxy etc., acyloxy radicals, such as acetoxy etc., the nitro and cyano group, the carboxyl and the sulfonic acid group in free or functionally modified form; e.g., as esters, or as salts, heterocyclic radicals, such as tetrahydrofuryl, sulfolan, etc., as well as the radicals H NCO-NH-CO- Ar NH CO
• the selenonium compounds there may be used the usual acid radicals of the onium compounds, e.g., those of the inorganic acids, advantageously of the halogen hydracids.
• Potassium selencyunpropionic-acotnto Potassium selencyanundecanic-ncotato. Potassium selencyanpropylsulfonic-acctato. Potassium selencyunothylsulionicncotuto.
• Phen lselenoc anate Phen lselenoc anate.
• Reductive nickel baths containing one or more of these compounds are ex- Dimethylbenzylselenonlum-bromide.
• the additives for stabilizing reductive nickel baths or ordinary composition may be used in concentrations of about 0.0001 g/liter to 0.3 g/liter, preferably from 0.001 to 0.010 g/liter of bath liquid, the compounds being added either alone or mixed with one another.
• the nickel baths stabilized according to the present invention contain in addition the usual constituents i.e., nickel salts, reducing agents, buffer substances, complexformcrs as well as wetting and brightening agents,
• the p11 value of the baths stabilized according to the invention may be in the acid, neutral,'or alkaline range.
• the acid baths work preferably in a pH range of to 6, the alkaline in a preferred pH range of 8 to 9.5. Depending on the reducing agent used, lower or higher pH values may be selected.
• the adjustment of the desired pH value is effected, if desired, by the addition of suitable bases or acids, such as soda lye -or hydrochloric acid.
• suitable bases or acids such as soda lye -or hydrochloric acid.
• common bufier substances e.g., Na,B O are also added to the bath.
• reducing agents are used, such as, alkali metal hypophosphite, such as sodium hypophosphite in the acid and alkaline range, or hydrazine, the salts thereof, borazanes or alkali borohydride, preferably sodium borohydride, in the alkaline range.
• concentration of the reducing agent used is about 0.01 to 0.5 mollliter.
• nickel salts nickel chloride, nickel sulfate and nickel acetate, etc., are used in concentrations of about 0.01 to 0.5
• nickel salts can, as is known, be maintained in solution only by complex formers. For this there enter into consideration, for example, lactic acid, glycocol, sodium acetate, trisodium citrate and triethanolamine, etc.
• concentrations for this are 0.01 to 0.5 moi/liter respectively 0.02 mollliter to-,1.0 mollliter. Higher concentrations are readily possible,'the maximum concentration being the effect of the solubility of the complex former.
• nickel bath may additionally contain salts of alloy metals, such as water-soluble salts of cobalt. Also, such a bath distinguishes itself by the described advantageous properies andcan be used for the reductive deposition of nickel alloys. With the nickel baths stabilized according to the invention, it is possible to nickel-plate objects of metals, plastics or other materials in a well known manner.
• the materials to be nickel-plated are introduced into the designated baths.
• the deposition is carried out at a bath temperature of about 20 to 95 C until the desired layer thickness is obtained.
• a bath temperature of about 20 to 95 C until the desired layer thickness is obtained.
• temperatures below 65 C.
• Non-conductive materials such as, plastic parts, require pretreatment of their surfaces. This is done in a manner known in itself, such as by chemical roughening with a heated chromic acid-containing sulfuric acid and chemical activation with a tin-ll chloride and a palladium-ll chloride solution or with a modified palladium solution.
• EXAMPLE 14 40 What is claimed is: v 1. in an aqueous electroless nickel plating bath containing a 0.15 ml/me, c q source of nickel ions, a complexing agent and a reducing agent 0.15 mollliter lactic acid capable of reducing said ions to metallic nickel on the surface i Naflzppfmo of an object immersed in said bath, the improvement which 2 mg/hter potassmm butylselenosulfate 55 comprlses a stablhzmg agent 1n sa1d.bath 1n an amount sufficient to substantially prevent spontaneous precipitation of nickel inthe absence of said immersed object, said stabilizer EXAMPLE 15 being selected from the group consisting of organic selenium compounds and the selenides, diselenides, selenosulfate and selenocyanates of an alkali metal, the oxidation state of the 0.2 moi/liter NiCl,-7 11,0 selenium being 1 or 2.
• dimethxl-phenyl-acetyl-seleniumd1 p methoxyphenyl)dlselemde' bromide di-(p-nitrophenyl)diselenide; bis-( o-acetylphenyl)diselenide;
• potassium p-methoxybenzylselenosulfate potassium p-ethoxybenzylselenosulfate; potassium p-cyanobenzylselenosulfate; potassium p-ethyi-benzylselenosulfate; potassium p-bromobenzylselenosulfate; potassium ethylselenosulfate;

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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)
• Chemically Coating (AREA)
• Electroplating And Plating Baths Therefor (AREA)

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Citations (4)

• 1970
  • 1970-04-07 CH CH510870A patent/CH533172A/de not_active IP Right Cessation
  • 1970-04-29 US US33088A patent/US3661596A/en not_active Expired - Lifetime
  • 1970-05-21 IE IE670/70A patent/IE34219B1/xx unknown
  • 1970-05-21 ES ES379897A patent/ES379897A1/es not_active Expired
  • 1970-05-21 SE SE06994/70A patent/SE356764B/xx unknown
  • 1970-05-21 FR FR7018460A patent/FR2048610A5/fr not_active Expired
  • 1970-05-21 AT AT455270A patent/AT293132B/de not_active IP Right Cessation
  • 1970-05-21 GB GB2464570A patent/GB1315548A/en not_active Expired
  • 1970-05-22 NL NL7007482.A patent/NL165508C/xx not_active IP Right Cessation
  • 1970-05-22 JP JP45043898A patent/JPS4943172B1/ja active Pending

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