Silver alloy compositions and processes

摘要

A silver alloy suitable for use in jewellery manufacture which comprises (by weight): 50-97 % silver, 0.35-5 % germanium, and the remainder being predominantly copper and unavoidable impurities. Germanium is included in a sufficient amount to impart a significant increase in the whiteness and/or brightness of the alloy as measured using the CIELab colour measurement system, with respect to the a* parameter where the silver content is below 90 % by weight, or with respect to the L* parameter where the silver content is 90 % by weight or greater, and as compared to an alloy with copper in place of the germanium, and with the same proportion of silver. The alloy can further comprise 1-40 ppm boron, 0-1 % in total of Au, Pd, Pt and Zn and/or incidental amounts of Al, Ba, Be, Cd, Co, Cr, Er, Ga, In, Mg, Mn, Ni, Pb, Si, Sn, Ti, V, Y, Yb and Zr.