CAST BASE FOR BIOMEDICAL USE FORMED OF COBALT-CHROMIUM BASED ALLOY AND HAVING EXCELLENT DIFFUSION HARDENING TREATABILITY, SLIDING ALLOY MEMBER FOR BIOMEDICAL USE AND ARTIFICIAL JOINT

摘要

A cast base for biomedical use, which is formed of a cobalt-chromium based alloy and has excellent diffusion hardening treatability, characterized by containing 0.1 mass % or greater of nitrogen (N) and having a volume fraction of an fcc (face centered cubic lattice) phase in the metallic structure thereof of 50% or greater. Even in the case of subjecting the aforesaid cobalt-chromium based alloy cast base in the as-cast state, the structure of which is liable to be non-uniform, to a diffusion hardening treatment, it is possible to obtain a sliding alloy member for biomedical use, wherein a uniform hardened layer has been formed, by the diffusion hardening treatment. Thus, a sliding alloy member for biomedical use and so on, which can stably and continuously exhibit high strength, excellent abrasion resistance and, moreover, excellent corrosion resistance, can be provided.