A silver alloy containing (by weight): more than 93.5 - 95.5 % silver, 0.5-3 % Ge, with the balance, apart from grain refiner and impurities being copper. The grain refiner may be 1-40 ppm of boron. The surface of the alloy is treated with an alkanethiol, alkyl thioglycollate, dialkyl sulfide or dialkyl disulfide, for example stearyl mercaptan, cetyl mercaptan (octadecyl mercaptan), stearyl thioglycollate or cetyl thioglocollate. The sulphur containing molecule may be dissolved in an organic solvent such as n-propyl bromide, contained in a polish or impregnated into a cloth. Alternatively it may be dissolved in an organic solvent and then adding a relatively concentrated aqueous soap or detergent. The resulting mixture may then be diluted with water.
展开▼
