Abstract: An efficient spray displacement tin plating process of copper printed circuit innerlayers is disclosed for the manufacture of multilayer printed circuit boards. The displacement tin plating solution is stabilized and replenished by incorporating free tin metal in the plating solution reservoir. Unwanted tin(IV) ions which are produced by aerial oxidation during the spray process, are reacted with tin metal in the reservoir to produce sufficient tin(II) ions to compensate for losses due to plating, oxidation and the like. Not only is the plating bath stabilized, but its useful life is extended dramatically.

Abstract: A stabilized spray displacement tin plating process of copper printed circuit innerlayers is disclosed for the manufacture of multilayer printed circuit boards. During prolonged use of spray tin plating, the plating solution becomes saturated with cupurous thiourea complex which precipitates interfering with spray nozzles and other mechanical components. The tin plating solution is stabilized by removing portions from the reservoir before saturation is reached, selectively precipitating the thiourea complex, and returning the remaining solution back to the reservoir. The precipitated cupurous thiourea complex is redissolved in acid and either disposed of by conventional waste treatment or the acid solution can be electrowinned to reclaim copper and oxidize thiourea to form a more acceptable acid solution for waste treatment.

Abstract: An additive composition is described with comprises a mixture of(a) poly(N-vinyl-2-pyrrolidone), and p0 (b) at least one sulfur-containing compound selected from compounds of the formulaeRS(R'O).sub.n H (I)orS--[(R'O).sub.n H].sub.2 (II)wherein R is hydrogen or an alkyl group containing up to about 24 carbon atoms, each R' is independently an alkylene group containing 2 or 3 carbon atoms, and each n is independently an integer of from 1 to about 100.This additive composition is useful in acidic plating baths containing zinc or a mixture of zinc ions and at least one additional metal selected from nickel and cobalt. The plating baths also contain chloride ions or a mixture of chloride and sulfate ions.

Abstract: An environmentally innocuous effective replacement for thiourea is disclosed for use as a complexing agent in displacement plating processes in which the plating solution is applied to the substrate surface to be plated by immersion or by spraying, cascading, pouring and the like. The replacement complexing agent is an imidazole-2-thione compound having the formula: ##STR1## wherein A and B are the same or different --R--Y groups, wherein R is linear, branched or cyclic alkenyl group containing 1 to 12 carbon atoms and Y is a hydrogen, halogen, cyano, vinyl, phenyl, or ether moiety. Of this class of compounds, 1-methyl-3-propyl-imidazole-2-thione is preferred for immersion tin plating. This class of complexing agents is particularly useful in spray displacement tin plating for the manufacture of printed circuit boards wherein free tin metal is added to the plating solution.

Abstract: Improved through-hole plating of printed circuit boards, wherein the ratio of the printed circuit board thickness to the diameter of at least one through hole is greater than 3 to 1, is achieved by a high-throw acid copper plating bath of this invention. The high-throw acid copper plating bath comprises an aqeuous solution of (A) copper sulfate, (B) sulfuric acid, (C) chloride ion, e.g., hydrochloric acid, (D) a carrier, (E) a brightener, and (F) an alkali metal salt; wherein the plating bath has a pH of not greater than about 1, the concentration of the hydrochloric acid is from about 6.0.times.10.sup.-4 to about 1.8.times.10.sup.-3 moles/liter, and the mole ratio of copper sulfate:sulfuric acid is not greater than about 1:25. Unlike previous high-throw acid copper plating baths, the bath of this invention contains an alkali metal salt. The use of the alkali metal salt makes it possible to maintain a lower acid concentration resulting in easier maintenance and more consistent plating.

Abstract: This invention relates to a paste composition, comprising:(A) at least 12% by weight of a paste forming compound and(B) at least one oxidizing agent which is a metal oxide or salt;(C) at least one reducing metal wherein (B) and (C) are capable of forming a metal coating;(D) at least one nonreactive, powder material capable of being incorporated into the coating formed from (B) and (C) wherein the material is selected from the group consisting of a metal, a metal alloy and a polymer; or(E) mixture of two or more thereof.The paste compositions control the pyrophoricity and explosive tendencies of the metal powders used in the process. Further, the paste affords easy handling of the materials. Delivery of the paste may be manual or automatic such as with a grease pump.

Abstract: For acid copper plating baths containing a brightener used to produce smooth copper coatings of high brilliancy, it has been found that the "break-in" period normally needed after a brightener is added to the plating bath, has been virtually eliminated by use of the brightener of this invention. This brightener consists essentially of a peroxide oxidation product of a dialkylamino-thioxomethyl-thioalkanesulfonic acid wherein each alkyl and alkane group individually contains 1 to 6 carbon atoms and wherein the peroxide oxidation of the dialkylamino-thioxomethyl-thioalkane-sulfonic acid is carried out in an acid, aqueous medium having a pH of not more than about 1. In an added embodiment of this invention the acid copper plating bath also contains hydrolysis products of the peroxide oxidation product of a dialkylamino-thioxomethyl-thioalkanesulfonic acid.

Abstract: It now has been found that a smooth, level, matte and/or bright deposit of tin, lead or tin-lead alloy can be deposited on a substrate from an aqueous plating bath which comprises(A) at least one bath-soluble metal salt selected from the group consisting of a stannous salt, a lead salt, or a mixture of stannous and lead salts; and(B) at least one alpha-acetylenic alcohol or glycol of the formulaR.sub.1 R.sub.2 C(OH)C.tbd.CR.sub.3 (I)whereinR.sub.1 and R.sub.2 are each independently H, an alkyl group, a cycloalkyl group or R.sub.1 and R.sub.2 together with the carbon atom form a cyclic group, provided that at least one of R.sub.1 and R.sub.2 is an alkyl group containing at least three carbon atoms, andR.sub.3 is H, an alkyl group or --C(OH)R.sub.1 R.sub.2.Preferably the plating baths do not contain fluoride or fluoborate ions, and the baths are also free of strong inorganic acids such as sulfuric acid.

Abstract: A co-deposit of aluminum, zinc and tin can be deposited onto metallic substrates including small metal parts, and the co-deposit is strongly adherent to the substrate and exhibits improved corrosion resistant properties. The co-deposits are plated onto metallic substrates by a process which comprises the steps of a. preparing the substrate to receive the co-deposit, b. forming a slurry comprising a soluble source of stannous ions, impact media, and aluminum and zinc in particulate form in a liquid medium maintained at a pH below about 4, c. mechanically impacting the slurry against the surface of the metallic substrate in a plating container to plate a co-deposit of tin, aluminum and zinc on a metal surface, d. renewing the stannous ions, aluminum and zinc in the slurry while maintaining the pH of the slurry below about 4 throughout the plating process until a co-deposit of the desired thickness is obtained.

Abstract: An aqueous acidic zinc-nickel plating bath is described. The plating baths generally comprise(A) zinc ions;(B) nickel ions;(C) an amount, sufficient to provide a level and bright zinc-nickel alloy electrodeposit, of at least one polymeric sulfur-containing compound having the general formulaRS(R'O).sub.n H (I)orS-[(R'O).sub.n H]2 (II)wherein r is an alkyl group containing up to about 24 carbon atoms, each R' is independently an alkylene group containing 2 or 3 carbon atoms, and each n is independently an integer of from 1 to about 100; and(D) a ductility-improviding amount of at least one acetylenic derivative obtained by sulfonating an intermediate obtained by(D-1) reacting an acetylenic alcohol or diol with a halogenated epoxide; or(D-2) reacting an acetylenic alcohol or diol with an alkylene oxide followed by reaction with a halogenated epoxide.Preferably, additional additives are included in the plating baths to improve the properties of the deposited alloy.

Abstract: Compositions are described which are useful particularly in improving the electrodeposition of zinc from aqueous alkaline plating baths. In one embodiment, the new composition comprises the reaction product of(A-1) at least one nitrogen-containing heterocyclic compound with(A-2) at least one hydroxyamine;(A-3) an epihalohydrin, glycerolhalohydrin or mixtures thereof; and(A-4) at least one amino compound containing at least one N--H group to form the desired polymeric composition.Aqueous alkaline zinc electroplating baths containing the compositions of the invention with or without cyanide present, deposit a bright and lustrous zinc coating on metal over a wide range of current densities.

Abstract: A method of electropolating a layer of copper on gravure rolls is provided with the so-plated layer being especially adapted to receive electronic engraving. The method comprises the steps of placing a gravure roll in an electroplating bath comprising from about 150 to about 225 g/l of copper sulfate as pentahydrate, from about 35 to about 90 g/l of sulfuric acid, from about 0.01 to about 1.0 g/l of a polyether surfactant having a molecular weight of from about 400 to about 10,000, from about 1 to about 100 mg/l of a sulfonated, sulfurized benzene brightener compound, and about 0.5 to about 5 mg/l of a grain refining compound having the nucleus ##STR1## in a heterocyclic ring structure, and a molecular weight between about 100 and about 180.

Abstract: Compositions are described which are useful particularly in improving the electrodeposition of zinc from aqueous alkaline plating baths. In one embodiment, the new composition comprises a polymeric composition prepared by the process which comprises the steps of(A) preparing an intermediate by reacting(A-1) at least one nitrogen-containing heterocyclic compound with(A-2) an epihalohydrin, glycerolhalohydrin or mixtures thereof, and(B) reacting said intermediate with at least one amidine compound to form the desired polymeric composition.Aqueous alkaline zinc electroplating baths containing the compositions of the invention with or without cyanide present, deposit a bright and lustrous zinc coating on metal over a wide range of current densities.

Abstract: An improved method of producing a tin/palladium catalyst for use in electroless plating baths is disclosed. The method comprises the steps:(a) preparing a mixture of stannous halide, an alkali metal halide and water,(b) reacting said mixture with a palladium halide salt at an elevated temperature,(c) adding a stannous salt of an organic carboxylic acid to the reaction mixture obtained in step (b), and(d) continuing the heating of the reaction mixture to complete the reaction.The catalysts so produced exhibit improved activity and resist decomposition.

Abstract: A method is provided for electrodepositing a layer of copper on a plastic substrate which method comprises: positioning the plastic substrate on a supporting member, with the supporting member being in contact at a plurality of spaced apart points with the substrate for the passage of electrical current therebetween; electrolessly depositing a thin layer of metal selected from the group consisting of copper, nickel, cobalt and mixtures thereof on a surface of the plastic substrate; positioning the supported substrate in an electroplating bath including from about 10.0 to about 45.0 g/l of copper ions, at least one acid selected from the group consisting of sulfuric acid, fluoroboric acid and sulfamic acid, with the acid being present in an amount sufficient to cause the electroplating bath to have a conductivity ranging from about 0.40 to about 0.

Abstract: An aqueous acidic plating bath for electrodeposition of tin, lead or tin-lead alloys on a substrate is described. The plating baths are free of fluoride and fluoborate ions and comprise (A) at least one bath-soluble metal salt selected from the group consisting of a stannous salt, a lead salt, or a mixture of stannous and lead salts, (B) at least one alkane sulfonic acid or alkanolsulfonic acid, (C) at least one surfactant, (D) an effective amount of at least one primary brightening agent selected from the group consisting of halogen substituted and dialkoxy and trialkoxy substituted benzaldehydes, (E) an effective amount of a secondary brightening agent which is at least one lower aliphatic aldehyde, and (F) an effective amount of an auxiliary brightening agent which is at least one of the group consisting of aniline and the amino-, carboxy-, halo-, alkyl- or alkoxy-substituted anilines. Methods for the electrodeposition of tin, lead, or tin-lead alloys from such baths also are described.

Abstract: An aqueous acidic plating bath for electrodeposition of tin, lead or tin-lead alloys on a substrate is described. The plating baths are free of fluoborate and comprise (a) at least one bath-soluble metal salt selected from the group consisting of a stannous salt, a lead salt, or a mixture of stannous and lead salts, (b) at least one alkane sulfonic acid or alkanolsulfonic acid, (c) at least one nonionic, cationic or amphoteric surfactant, (d) an effective amount of at least one primary brightening agent selected from the group consisting of aromatic aldehydes, acetophenones, and carbonyl compounds having the general formulaAr--C(H).dbd.C(H)--C(O)--CH.sub.3 (III)wherein Ar is a phenyl, naphthyl, pyridyl, thiophenyl or furyl group, and (e) an effective amount of a secondary brightening agent selected from the group consisting of lower aliphatic aldehydes and substituted olefins of the formula ##STR1## wherein R.sub.

Abstract: A composition is provided which is especially adapted for use in stripping a polysulfide basecoat (sealant) from a surface. The composition comprises, as essential ingredients, a chlorinated solvent and an effective amount of at least one activator selected from the group consisting of lower alkyl phosphite and aryl phosphine.A method of stripping or removing a polysulfide basecoat (sealant) from a surface is also provided. The polysulfide basecoat may have associated therewith a polyurethane topcoat.

Abstract: A composite particle is provided which comprises a matrix of puffed borax having a porous surface, with the matrix having retained on the porous surface thereof a plurality of individual grains of metal oxide. A method of producing such a composite particle is also provided.

Abstract: A process is provided for the production of antimony oxide from antimony sulfide which comprises the steps of comminuting the antimony sulfide to form a plurality of antimony sulfide containing particles, mixing the antimony sulfide containing particles with substantially pure oxygen, reacting the antimony sulfide with oxygen to form a gaseous stream of antimony oxide and sulfur dioxide, cooling the gaseous stream below the boiling point of antimony oxide, separating the condensed antimony oxide from the sulfur dioxide, further cooling the separated sulfur dioxide and utilizing the cooled sulfur dioxide to cool the gaseous stream of antimony oxide and sulfur dioxide. Apparatus for accomplishing this process is also provided.