Abstract: A method is provided for selective removal of copper contaminants from aqueous activator solutions which also contain palladium and tin. It comprises placement of insoluble electrodes in the aqeuous solution and application of a low voltage, preferably ranging from between 0.05 to 5.0 volts across the electrodes, whereby metallic copper is selectively deposited upon the cathode, with palladium and tin remaining in the aqueous solutions. Typically, the soluble copper ions are present as contaminants in activator solutions utilized in various electroless metal plating processes.

Abstract: Improved solutions are provided for selectively stripping alloys containing nickel with gold, phosphorous or chromium from substrates formed from alloys containing iron with chromium and in some instances nickel, or nickle rich, chromium bearing alloys, some of which also contain iron. These solutions comprise concentrated nitric acid, at least one chloride salt, an organic corrosion inhibitor and, optionally, an organic surface active agent. An improved method utilizing the solutions of the invention is also provided and facilitates stripping of these alloys in substantially reduced time, without degradation of the underlying substrate.

Abstract: An improved non-cyanide, alkali type zinc plating bath and method is provided, wherein a water-soluble polyamine sulfone compound and a quaternary pyridine compound are added to the zinc plating bath, which is thereafter subjected to electro-deposition conditions and wherein the polyamine sulfone is represented by the general formula ##STR1## WHEREIN EACH OF R.sub.1 and R.sub.2 is a member selected from the group consisting of hydrogen, an allyl group, straight-chain and branched-chain alkyl groups each having 1 to 16 carbon atoms, an aralkyl group, and hydroxyalkyl groups of the general formula HO --CH.sub.2) m, where m is an integer of 1 to 6;X.sup.- is a member selected from the group consisting of halogen ion, HSO.sub.4.sup.-, HSO.sub.3.sup.-, HCOO and CH.sub.3 COO.sup.

Abstract: Solar collector including a copper or copper alloy base and a selective solar heat energy-absorptive coating or film of improved stability to liquid water on the base. The selective film is characterized by having a solar absorptivity of 0.90 or higher, infrared emissivity no more than 0.20, and a stability such that its selectivity is not significantly reduced after contact with liquid water condensate over a prolonged, cumulative, non-continuous time in excess of 15,000 hours.

Abstract: Acidic solutions for selectively stripping tin or tin-lead alloys from copper substrates comprising an aqueous solution of at least one nitro-substituted aromatic compound; an inorganic acid capable of readily reacting with tin and lead to form water-soluble salts thereof and incapable of reacting with tin and lead to form a water-insoluble compound film on the tin or tin-lead alloy surface, preferably fluoboric acid; a thiourea; an organic acid of the formula RCOOH wherein R is 1-2C alkyl or hydrogen; and a haloacetic acid wherein the halogen is chloro or bromo. The haloacetic acid in combination with the acid of the formula RCOOH result in a pronounced synergism in accelerating the rate of stripping the tin or tin-lead alloy deposit from the copper substrate.

Abstract: Surfaces intended to be electrolessly metal plated, for instance the surfaces of through holes on through hole printed circuit boards, are treated with a colloidal catalyst metal-free acid liquid solution of a soluble, lower alkanol-modified noble metal-tin chloride complex until the surface is rendered catalytic. The noble metal of the complex is a noble metal which is catalytic to the deposition of the metal destined to be electrolessly plated on the surface.

Abstract: Non-cyanide alkaline aqueous solutions for stripping non-ferrous metals, especially copper, from ferrous metal such as, for example, steel. The stripper solution comprises a water-soluble nitrate, a water-soluble compound of the formula ##EQU1## wherein R represents a valence bond, --CH.sub.2).sub.x wherein x is an integer of 1 to 2, ##EQU2## WHEREIN Y IS AN INTEGER OF 1 TO 2, OR ##EQU3## and M is a compatible, hydrophilic, i.e. water-loving or water-solubilizing, cation, a water-soluble persulfate, a water-soluble urea compound, and ammonium hydroxide. Brass, cadmium and zinc can also be stripped from steel by the stripper or dissolving solutions herein.