| 摘要 |
PURPOSE:To improve bonding strength, by forming surface roughness of a cemented carbide alloy of a hard layer side more larger than a mean diameter of grains forming a hard layer or an intermediate bonded layer, in a sintered unit constituted by bonding the hard layer with the cemented carbide alloy directly or through an intermediate bonded phase. CONSTITUTION:Surface roughness of a cemented carbide alloy touching to either a hard layer or an intermediate bonded layer is formed more larger than a mean diameter of grains forming the hard layer or the intermediate bonded layer in case of manufacture of a sintered unit by bonding the hard layer containing 20vol% or more of diamond grains or high pressure phase type boron nitride grain. Then the diamond grains or the high pressure phase type boron nitride grains are placed on the above cemented carbide alloy directly or through the intermediate bonded layer, the whole of which is put within a ultrahigh pressure and temperature device and hotpressed under a high temperature and high pressure. With this construction, the hard layer containing the above mentioned grains is sintered and the cemented carbide alloy and the hard layer are bonded strongly. |
