Patent ID: 10967433

Abstract:
A cutting tool comprises a substrate and a coating that coats the substrate, the coating including an α-alumina layer, the α-alumina layer including crystal grains of α-alumina, the α-alumina layer including a lower portion and an upper portion, the upper portion being occupied in area at a ratio of 50% or more by crystal grains of α-alumina having (006) plane with a normal thereto having a direction within ±15° with respect to a direction of a normal to the second interface, the lower portion being occupied in area at a ratio of 5% or more and less than 50% by crystal grains of α-alumina having (012) plane, (104) plane, (110) plane, (113) plane, (116) plane, (300) plane, (214) plane and (006) plane each with a normal thereto having a direction within ±15° with respect to the direction of the normal to the second interface.