| 摘要 |
PROBLEM TO BE SOLVED: To provide a long lasting outstanding cutting performance, without causing a peeling of hard coating layer under severe conditions such as high- speed periodic cutting of cast iron, by providing an excellent cohesion of a hard coating layer to a base surface. SOLUTION: In a cutting tool made of surface coated Si3 N4 sintered material which is chemically evaporated and/or physically evaporated with the average 0.5∼20μm layer thickness of a hard coating layer formed with one or more kinds of Ti compound layers selected from the group of TiC layer, TiN layer, TiCN layer, TiO2 layer, TiCO layer, TiNO layer, and TiCNO layer alternatively a hard coating layer formed with one or more kinds selected from the group of the above-mentioned Ti compounds layers and Al2 O3 layer on the surface of the base composed of Si3 N4 sintered material whose content ratio is 75∼99.9 content %, a heated oxido coat whose Si3 N4 decreases to 4-40 area %, determined by a constitution of the above-mentioned base most surface on the above- mentioned base surface part observed by an electron microscope. |
