A method for producing metallic, electrically conductive or semiconducting and / or magnetic coatings on non-metallic substrates by chemical deposition

摘要

A substrate of e.g. synthetic or natural resins, glass, wood, ceramic, paper is coated with a metal, e.g. gold, silver, nickel, chromium, iron, copper or zinc, by chemical deposition after first treating the substrate with a seeding metal compound, e.g. stannous chloride, in a solvent e.g. sulphuric, trichloroacetic or hydrofluoric acids or acetone, which also attacks the surface of the substrate. In an Example a polyesterterephthalate sheet is washed in an aqueous tetrasodium pyrophosphate, detergent and sodium carbonate solution, and then after rinsing immersed in a solution of 900 c.c. of sulphuric acid (conc.), 100 c.c. of hydrochloric acid (conc.), and 0.5 grms. of stannous chloride. The sheet is then rinsed in a sulphuric, hydrochloric acid solution and then in water. After further seeding in another stannous chloride solution, and rinsing, the sheet is immersed in a palladium chloride, hydrochloric acid solution and finally in a copper-plating solution comprising one part of 170 gms. copper sulphate, 189 c.cs. formaldehyde and water to make 1 gallon, and one part of 65 to 70 gms. nickel chloride, 155 to 160 gms. sodium hydroxide, 700 to 750 gms. Rochelle salts, 70 to 75 gms. sodium carbonate and water to make 1 gallon.