| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a plug electrode material for an internal combustion engine which suppresses high-temperature/oxidization-caused exhaustion. <P>SOLUTION: In manufacturing the plug electrode material, a material having an extremely long pillarlike crystal resulting from unidirectional solidification is provided as a starting material to be subjected to hot-drawing working. In the hot-drawing working for plug electrode manufacturing, a working temperature and workability are determined to keep a working temperature at 1,000°C or higher under which the material is worked to suppress a residual working distortion. Hence a hardening factor representing a ratio between hardness after working and hardness after heat treatment at 1,100°C for 20 hours that simulates a plug electrode use condition satisfies the expression: hardening factor=ä(hardness Hv after working)/(hardness Hv after heat treatment at 1,100°C for 20 hours that simulates the plug electrode use condition)}×100(%)≤130%. The plug electrode material for the internal combustion engine meeting the above conditions includes a pillar-like crystal as long as a chip, suppresses high-temperature/oxidization-caused exhaustion, includes a long life, and inhibits accidental fire. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
