| 摘要 |
A surface-coated cutting tool of the invention is a surface-coated cutting tool in which a hard coating layer that is composed of a lower layer and an upper layer is deposited on a surface of a tool body that is made of a WC-based cemented carbide or a TiCN-based cermet, (a) the lower layer has at least one Ti compound layer made of a TiCN layer, (b) the upper layer is made of an ±-type Al 2 O 3 layer, (c) in a case where, regarding Al 2 O 3 crystal grains of the entire upper layer, a constituent atom-sharing lattice point distribution is measured, a highest peak is present in ˆ‘3, and a distribution ratio of ˆ‘3 is 70% or more, and (d) a ratio of a ˆ‘3-coincidence grain boundary continuing from an interface between the lower layer and the upper layer to an outermost surface of the upper layer is 60% or more of a ˆ‘3-coincidence grain boundary of the upper layer. In addition, it is preferable that an outermost surface layer of the lower layer be made of an oxygen-containing TiCN layer, and in a case where an inclined angle frequency distribution is measured regarding the Al 2 O 3 crystal grains of the upper layer, a frequency ratio of the Al 2 O 3 crystal grains in an inclined angle division of 0 to 10 degrees be 70% or greater, and an area ratio of Al 2 O 3 crystal grains of the upper layer that have an aspect ratio of 5 or more be 80% or more. |
