CVD COATING OF CERAMIC LAYERS ON CERAMIC CUTTING TOOL MATERIALS

Abstract
When forming cutting tool materials based on ceramic components, one must take into considration the combination of wear resistance and mechanical properties which can withstand unfavorable cutting conditions at the same time maintaining high strength and fracture toughness. Ceramic cutting tools which are designed for machining at high cutting speeds and which have high strength and fracture toughness can be formed by applying a thin layer of ceramic materials on the substrate in order to increase tool life. The good adhesion of the C.V.D. layer and the good mechanical properties of the combined coating cutting tools enable the same increase in efficiency by cemented carbide coated cutting tools. In this paper we show results for the mechanical properties, the machining results and metallographic microstructures for C.V.D coatings of aluminum oxide on different ceramic materials such as Si₃N₄ base materials and Al₂O₃ base material.