| 摘要 |
PURPOSE:To manufacture the sintered body for high hardness tools excellent in strength and wear resistance, at the time of obtaining a superhigh pressure sintered body by specified ratios of cubic boron nitride and binder powder, by forming the binder of specified ratios of Al, Hf, HfC or the like. CONSTITUTION:By volume, 45 to 75% cubic boron nitride(cBN) powder and the balance binder powder are subjected to superhigh pressure sintering to manufacture a sintered body. At this time, the binder contains, by weight, 4 to 20% Al and 5 to 20% Hf and, as the balance, contains HfC and a compound expressed by (Ti1-xMx)Cz (M denotes the 4A, 5A and 6A group elements excluding Hf in a periodic table as well as 0<=x<=0.15 and 0.55<=z<=0.9 are satisfied) by 9:1 to 1:2 volume ratio. Furthermore, as for the cBN powder, the average grain size is regulated to <=4mu and the ones of at least <=1mu are included by 35 to 80wt.% and the ones of 3 to 6mu by 20 to 65wt.%. As for the binder, the average grain size is regulated to the one less than 1/3 the average grain size of the cBN powder. In this way, the sintered body for high hardness tools showing excellent cuttability for cast iron can be obtd. |
