| 摘要 |
PURPOSE:To form a thick hardened layer as the surface layer of Ti and to enable mirror finishing by polishing by carrying out heat treatment at a proper temp. in an atmosphere of gaseous N2 mixed with small amounts of H2 and O2 or a small amount of steam under nearly atmospheric pressure. CONSTITUTION:A Ti article such as a watchcase or other external member is nitrided by heating to 800-880 deg.C in an atmosphere of gaseous N2 mixed with 5-500ppm gaseous O2 and 10-5,000ppm gaseous H2 or 50-5,000ppm steam under nearly atmospheric pressure. A hardened layer of about 100-150mum thickness corresponding to a margin for polishing for mirror finishing is formed as the surface layer of the Ti article, and the surface hardened Ti article can be mirror finished. |
