SURFACE-COATED CUTTING TOOL

摘要

This surface-coated cutting tool is provided with a substrate and with a coating film that is formed upon the substrate. The coating film includes an α-Al2O3 layer. The α-Al2O3 layer includes a plurality of α-Al2O3 crystal grains and is (001)-oriented. The grain boundaries of the crystal grains include CSL grain boundaries and general grain boundaries. Among the CSL grain boundaries, the length of the Σ3 crystal grain boundaries is greater than 80% of the length of the Σ3-29 crystal grain boundaries and is 10%-50% of the sum of the length of the Σ3-29 crystal grain boundaries and the length of the general grain boundaries, which is the total length of all the grain boundaries.