| 摘要 |
PURPOSE: A cutting tool is provided to secure the stable cutting performance for a long time even in such a condition in which a high load is applied and to reduce the production cost of the cutting tool. CONSTITUTION: A ceramic substrate(4) of a tool body(1) is made of silicon nitride ceramic, and the surface of the ceramic substrate is coated with a titanium carbide/nitride coating layer(1f). The coating layer has a structure made mainly of columnar crystal grains grown in the layer thickness direction, and when an average size of crystal grains observed on the surface is expressed by d and an average thickness of the coating layer by t, t is adjusted to between 0.5 and 3 micrometer and a d/t value to at least 0.1 and at most 0.5. Such a coating layer(1f) is formed by a chemical vapor deposition method at the formation temperature in the intermediate low temperature range of 750deg.C to 900deg.C. |
