Alumina Coated Grade

摘要

An alpha-Al₂O₃ coated cutting tool insert combining a cemented carbide with a binder phase enriched surface zone and a textured alpha-Al₂O₃-layer is disclosed. The alpha-Al₂O₃ layer has a thickness ranging from about 2-9 mum and is composed of columnar grains having a length/width ratio from about 2-12. It is characterised by a strong (104) growth texture and by low intensity of the (012), (110) and (113) diffraction peaks. The textured alpha-Al₂O₃ is preferably deposited on an MTCVD Ti(C,N) layer having a thickness from about 2-10 mum. When the alumina layer is the uppermost layer, it may be wet-blasted to an R_a value of