PURPOSE: To impart excellent heat resistance and high toughness to a diamond sintered compact and to improve its heavy intermittent cutting characteristics to nonferrous materials, nonmetals or the like by specifying its compsn. and forming it into the one composed of diamond and Co bonding phases and in which precipitation hardening occurs by Co base intermetallic compounds.
CONSTITUTION: This sintered compact contains, by weight, 50 to 98% diamond, and the balance bonding metallic phases, and this bonding metallic phases contain 0.5 to 6% of one or ≥ two kinds selected from Si, Ti, Zr and Mo, and the balance Co. Moreover, the bonding metallic phases contain precipitated Co base intermetallic compounds. Furthermore, at the time of producing the sintered compact, these diamond powder and metallic powder are mixed, and in the powdery state as it is, or after compacting, sintering is executed under heating to ≥1350°C under ≥5GPa by using a superhigh temp. high pressure device. Moreover, the average grain size of the diamond powder and the metallic powder at this time is preferably regulated to about 5μm and 1μm respectively.
YOSHIMOTO TAKASHI
KOSHI MASAO
II SADANORI
