Method of colouring tin and tin-containing articles
AssigneeUniversity of Plymouth
InventorTrish Woods
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Abstract
A method of coloring the surface of a tin-containing article is provided, the method comprising contacting at least a portion of the surface of the article with a solution comprising a thiosulphate, preferably under substantially neutral or acidic conditions. In one embodiment, the solution contains sodium thiosulphate and citric acid and further comprises a copper salt, together with acetone and/or glycerol. The method is preferably conducted at elevated temperatures, in particular by heating the solution to a temperature of from 45 to 85° C. The method is particularly suitable for the coloring of pewter articles, but may be applied to a wide range of tin-containing materials and tin alloys.
Claims21
A method of colouring the surface of a tin-containing article, the method comprising contacting at least a portion of the surface of the article with an aqueous solution comprising a thiosulphate and a polyol;
- wherein the thiosulphate is present in the solution in an amount in the range of from 5 to 50 g per 100 ml;
- wherein the polyol is present in an amount of from 0.1 to 2 ml per 100 ml of solution;
- and
- wherein the solution further comprises an aldehyde or a ketone, the aldehyde or ketone present in the solution in an amount of from 0.5 to 10 ml per 100 ml of solution.
Dependencies are inferred from the claim text.