| 摘要 |
<p>In a process for chemically depositing nickel or cobalt on the surface of a silicate glass the glass surface is chemically etched, a sub-microporous siliceous film is formed on the etched surface by leaching it in the presence of fluoride ions to extract non-siliceous constituents therefrom, the surface is activated by alternately immersing it in an aqueous solution of a salt of a catalytic metal selected from nickel, cobalt and palladium and then in a solution of a reducing agent, and a coating of nickel or cobalt is then deposited from a solution containing a nickel or cobalt salt, hypophosphite ions and a carboxylic acid salt. As described, etching is effected in hydrofluoric acid; leaching is performed either by exposing the warm glass to hydrofluoric acid vapour or by exposing the glass to an aqueous solution of e.g., fluoboric acid or fluosilicic acid; the reducing agent is an alkali metal borohydride; and suitable coating solutions contain nickel or cobalt chloride, sodium hypophosphite, and sodium hydroxyacetate or sodium citrate. Specification 100,738, and U.S.A. Specifications 2,532,283, 2,532,284, 2,690,401 and 2,690,402 are referred to.</p> |
