| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a surface treatment method for easily controlling the surface hardness of bulky or filmy cobalt-containing tungsten carbide widely used for a machining tool or a die material for mold working, with high precision. <P>SOLUTION: This surface treatment method includes locally heating the surface of a workipiece prepared through a sintering process, or the surface of cobalt-containing tungsten carbide 3 (which contains 0.2 to 30 wt.% but preferably 6 wt.% or more cobalt) prepared by coating a base metal through a physical evaporation method, a chemical evaporation method, a sputtering method or a plasma spraying method, in a short period of time; by using a temperature difference thereby formed on the surface, locally moving and diffusing cobalt atoms on the surface; and locally increasing or decreasing the surface hardness of the cobalt-containing tungsten carbide. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
