SURFACE HARDENED PT ALLOY MEMBER FOR DECORATION

摘要

PURPOSE:To provide a titled alloy member having extremely high surface hardness and excellent wear resistance by forming a surface-hardened layer consisting of the texture dispersed therein with hard CrB on the surface of a Pt- Cr alloy member consisting of a specific compsn. CONSTITUTION:The surface of a Pt alloy member having the compsn. contg. 0.5-15wt% Cr, further contg. either one or both of 0.5-25% Pd and 0.5-15% =1 kind among Cu, Ag, Ni, Co, Fe, Au and Ir according to need and the balance consisting of Pt and unavoidable impurities is subjected to a boriding treatment, then the B diffused and intruded from the surface reacts with the Cr solutionized mainly in the base, thereby forming hard CrB. A surface-hardened layer having extremely high hardness of about 1,000-1,500Hv dispersed with hard CrB is formed on the surface of the above-mentioned Pt alloy member and the beautiful decorative metallic gloss is maintained semipermanently.