Patent attributes
A surface-coated cutting tool includes a base material and a coating formed on a surface of the base material. The coating includes a first hard coating layer including crystal grains having a sodium chloride-type crystal structure. The crystal grain has a layered structure in which a first layer composed of nitride or carbonitride of AlxTi1−x and a second layer composed of nitride or carbonitride of AlyTi1−y are stacked alternately into one or more layers. The first layer each has an atomic ratio x of Al varying in a range of 0.76 or more to less than 1. The second layer each has an atomic ratio y of Al varying in a range of 0.45 or more to less than 0.76. The largest value of difference between the atomic ratio x and the atomic ratio y is 0.05≤x−y≤0.5.
