Surface-coated cutting tool with hard coating layer having excellent abrasion resistance

摘要

In a surface-coated cutting tool, (a) a Ti compound layer as a lower layer and (b) an α-type Al<Sub>2</Sub>O<Sub>3</Sub> layer as an upper layer having a crystal grain structure of an even polygonal shape (including an even hexagonal shape) and an elongate shape and containing Zr are deposited on the surface of a tool substrate. In the surface-coated cutting tool, the above mentioned crystal grains of which insides arc divided by at least one crystal lattice interface with the constituent atom covalent lattice point type expressed by Σ3 occupying 60% or more as an area ratio in the crystal grains of the upper layer.