| 摘要 |
PROBLEM TO BE SOLVED: To provide an inexpensive superhard material by a method easier than the case of the conventional material. SOLUTION: A powder mixture of tungsten W and chromium boride or the one obtd. by blending this with any powder of Ni, Fe and Co is melted on a nonconsumable type substrate or on a soluble substrate by a heat source of a plasma arc to produce a boride superhard material formed of a W-Cr-B ternary system and having hardness higher than that of all the composing stocks. This product of a ternary system is composed of any of rhombic WCrB2, tetragonal WCrB and tetragonal W3Cr2B3 or the coexistance thereof, and an article of the highest grade has hardness equal to that of synthetic CBN of >=2,500 Vickers hardness Hv at ordinary temp. and >=1,400 Hv even at the high temp. of 1,000 deg.C and high temp. wear resistance.
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