Hard metal alloy

摘要

A hard metal alloy based on Cr/Al/Ni is described which consists of 18 to 48 % by weight of chromium, of less than 30 % by weight of iron, of 2.5-4.5 % by weight of aluminium and of the remainder of nickel; the structure has a Vickers hardness of over 500 and contains no dispersed solid chromium particles of a particle size of a little over 1 mu m. The hard metal alloy can be used as the protective layer or external covering layer of clocks and watches.