| 摘要 |
PROBLEM TO BE SOLVED: To provide a cutting tool excellent in adhesion and chipping resistance of a coating layer.SOLUTION: A cutting insert 1 comprises a base body 2 composed of a silicon nitride-quality sintered body of including a silicon nitride particle as a main body and a coating layer 3 coated on a surface of the base body 2, and in a cross section vertical to a surface of the base body 2, the silicon nitride particle is composed of a surface particle 4 existing on the outermost surface of the base body 2 and contacting with the coating layer and an inside particle 5 of not contacting with the coating layer 3, and a ratio (w1/w2) of an average particle width w1 parallel to the surface of the base body 2 of the surface particle 4 and an average particle width w2 parallel to the surface of the base body 2 of the inside particle 5, is 0.2-0.6, and a ratio (L1/w1) of the average particle width w1 of the surface particle 4 and an average particle length L1 is 0.1-0.6, and among particles for constituting the coating layer 3, a ratio (w1/d1) of an average particle width d1 parallel to the surface of the base body 2 of a first coating layer 7 for contacting with the base body 2 and an average particle width w1 of the surface particle 4, is 0.8-2.1.SELECTED DRAWING: Figure 1 |
