| 摘要 |
1,187,861. Coating with metals. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. May 4, 1967 [May 7, 1966], No.20715/67. Heading C7F. [Also in Division G2] A metal nobler than cadmium and less noble than mercury, e.g. Co, Pb, Sn, Cu, Ni, Tl, In, Mo, Ge, is deposited selectively on an image of mercury and/or silver nuclei from an aqueous solution containing reducing metal ions, e.g. Fe, V, Ti, Cr or Eu, which in the solution have a reduction potential less than 780mV but more than -43OmV. The process is carried out in a non- oxidizing atmosphere. In an example, a saponified cellulose triacetate foil is sensitized by impregnating in a solution containing per litre 0À4 mol. of the sodium salt of p-methoxybenzenediazosulphonic acid, 0À1 mol. of Cd lactate, 0À1 mol. of Ca lactate, and 0À1 mol. of lactic acid, exposed behind a line negative to a high pressure mercury vapour lamp, and then treated with an aqueous solution containing, per litre; 0À005 mol. of mercurous nitrate, 0À01 mol. of silver nitrate, and 0À01 mol. of nitric acid. After washing, the foil is treated with calcium nitrate to replace silver and mercurous ions absorbed by the cellulose, with calcium ions. After again washing, the latent silver amalgam image is intensified by contacting, in a nitrogen atmosphere, with a solution comprising (parts by volume) 2 of an aqueous solution of (50%by weight) tin hexafluoride, 0À8 of an aqueous solution of 0À5% by weight of each of a cationic and a non-ionic surface active agent, 5À2 of oxygen free water, and 2 of a solution prepared by dissolving vanadyl sulphate in water and then adding sulphuric acid. The resulting tin pattern can be brightened by rubbing. |
