CUTTING TOOL HAVING EXCELLENT IMPACT RESISTANCE MADE OF SURFACE COATED TUNGSTEN CARBIDE-BASE SINTERED HARD ALLOY

摘要

PURPOSE:To manufacture the title cutting tool having excellent impact resistance at the time of covering the surface of a tungsten carbide-base sintered hard alloy matrix with a hard layer by forming the hard layer with a ceramic whisker layer. CONSTITUTION:A hard layer consisting of a single layer constituted of one kind among the carbide, oxide and boride of (Ti, Zr, Rf and Al) or a complex layer constituted of two or more kinds among those is formed on the surface of a WC-base sintered hard alloy matrix contg. preferably about 4 to 15% of one or more kinds among iron metals, contg., at need, about 0.5 to 40% of one or more kinds among (Ti, Ta, Nb, W)C.N and the balance WC with inevitable impurities into about 0.5 to 20mum average layer thickness by a chemical vapor deposition method or the like to prepare a cutting tool. At this time, the whole body or the outermost layer of the hard layer is constituted of a ceramic whisker layer having about 0.5 to 10mu average layer thickness formed by a chemical deposition method. By this method, the cutting tool having excellent impact resistance and excellent cutability for a long period of time can be obtd.