| 摘要 |
PURPOSE: To improve toughness by unevenly compressing material powder so that its density increases relatively in a region where a cutting blade of finished compact of hard layer of carbonate, nitride, oxide of metals of IVB, VB VIB group in the periodic table is constituted. CONSTITUTION: A cutting blade composed of 50 vol.% of hard layer containing one metal of IVB, VB, VIB group in the periodic table or a plurality of carbide, nitride, oxide or a mixture thereof, and a binder layer containing Co, Ni, Fe is unevenly compressed so that it has a higher density than that of circumferential material region after the pressure forming process. When the temperature is increased the material starts to swell unevenly, and thus stress generates to disapear deviation which generates cracking while a process progresses at the sintering temperature, thereby making the cracks smooth or round and generating partial bonding during the sintering for reducing a bad influency, resulting in only a surface defect as well as decrease in the chipping characteristic. The crack of about 2-10μm in width and 500μm in depth is liable to occur on the surface of chip breaker, and a crack wall is covered with the binder layer of about 1-5μm in thickness. |
