Coated pcbn cutting insert, coated pcbn cutting tool using such coated pcbn cutting insert, and method for making the same

Abstract

A coated polycrystalline cubic boron nitride cutting insert useful in a cutting tool for removing material from a workpiece, and a method for making the same. The cutting insert including a polycrystalline cubic boron nitride substrate with a rake surface and at least one flank surface, and a cutting edge formed at the juncture between the rake surface and the flank surface. A wear-resistant coating scheme is on the polycrystalline cubic boron nitride substrate. The wear-resistant coating scheme includes the following coating layers. An inner coating layer region is on at least some of the rake surface and at least some of the flank surface of the polycrystalline cubic boron nitride substrate. An alumina-containing coating layer region, which has at least one exposed alumina coating layer, is on the inner coating layer region. The exposed alumina coating layer exhibiting a post-blasted stress condition with stress ranging between about 50 MPa (tensile stress) and about −2 GPa (compressive stress) as measured by XRD using the Psi tilt method and the (024) reflection of alumina. The exposed coating layer is the result of wet blasting an outer titanium-containing coating layer from the surface of the alumina-containing coating layer region.