Wear characteristic of alumina coated and alumina ceramic tools

The crater wear characteristic of an alumina coated cemented carbide tool and an alumina ceramic tool was investigated quantitatively based on the stress and temperature on the rake face, which were measured with a pair of divided tools and a thermocouple respectively. The cutting temperature was also calculated by finite difference method. The obtained wear characteristic indicated that the sintered alumina ceramic had several times higher resistance to crater wear than the CVD layer of alumina coated on the cemented carbide if the cutting temperature and stress were the same. The prediction of crater wear development using the wear characteristic of these tools, however, showed that the wear rate of the alumina coated tool depends on the thermal conductivity of the substrate and would be smaller than the wear rate of the alumina ceramic tool if a cemented carbide of high thermal conductivity is used as a substrate.