SURFACE-COATED BORON NITRIDE SINTERED BODY TOOL

摘要

A surface-coated boron nitride sintered tool, wherein at least a cutting edge portion is provided with a cubic boron nitride sintered compact and a coating film which is formed on the surface of the cubic boron nitride sintered compact. The coating film comprises a layer (A) and a layer (B), and the layer (A) is configured of columnar grains having a grain size of from 10 nm to 400 nm (inclusive), while the layer (B) is configured of columnar grains having a grain size of from 5 nm to 70 nm (inclusive). In addition, the layer (B) is obtained by alternately laminating two or more kinds of compound layers having different compositions, and each compound layer has a thickness of from 0.5 nm to 300 nm (inclusive).