| 摘要 |
The present invention relates to a hard diamond sintered body for use in tools such as cutting tools, excavating tools and wire drawing dies and a method for producing the same. A sintered body obtained by sintering fine powders of diamond under a superhigh pressure has been already used in cutting tools, drill bits, wire drawing dies and the like of nonferrous metals and similars. However, they have said that such a diamond sintered body is inferior in heat-resistance. The present invention was achieved from the investigation aiming at the elimination of the above described defect of being inferior in heat-resistance of the conventional diamond sintered body. That is to say, according to the present invention, synthetic diamond powders containing a diamond synthesizing catalyst consisting of VIII group ferrous metals of the periodic table or Cr, Mn or Ta or alloys containing them used in the synthesis of diamond at a ratio of 0.01 to 10% by weight are exposed to a high temperature under the condition wherein diamond is unstable to graphitize a part or whole thereof and then the resulting raw materials are filled in a reaction vessel consisting of at least one kind of metals selected from a group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and the like and sintered at a superhigh pressure of 50 Kb or more and high temperature of 1,400 DEG C. or more, under which diamond is stable, to obtain a diamond sintered body. In short, the present invention relates to a hard diamond sintered body, characterized by comprising intermetallic compounds consisting of metals or alloys thereof contained in said diamond as a raw material and metals composing a reaction vessel at a ratio of 0.01 to 12% by weight, and a method for producing the same. A hard diamond sintered body obtained according to the present invention is superior in heat-resistance and abrasion-resistance, in particular heat-resistance, of which lowness has been a disadvantage of the conventional diamond sintered body, can be remarkably and successfully improved without reducing the strength.
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