| 摘要 |
<p>1298410 Modifying metallic surfaces ALLEGHENY LUDLUM INDUSTRIES Inc 23 Dec 1970 [2 Jan 1970] 61090/70 Heading C7U A method of providing a protective layer on a metallic surface comprises coating the surface with an aqueous solution containing ions of magnesium, ammonium, chromate, and phosphate, and curing the resulting layer so as to render it substantially water-insoluble. The preferred composition of the solution is 0À01-28 mole per cent magnesium, 5-22 mole per cent ammonium, 4-26 mole per cent chromate, 33-67 mole per cent phosphate, at a concentration of 0À01-1À5 moles of said ions per 100 ml of water. The metallic surface is of stainless steel, brass, aluminium,silver, zinc, copper, plain carbon steel, lead, chromium, nickel, gold, or platinum, or an alloy thereof. The curving is effected by heating at a temperature of 400-1900‹F for 2 seconds-4 hours. Pigments or dyes may be present in the solution. In an embodiment, a stainless steel trim member is coated to prevent galvanic corrosion in a carbon steel car body with which it is in contact. Reference is made to Specification 1298409.</p> |
