Oxide coated cutting tool

摘要

According to the present invention there is provided a body at least partially coated with one or more refractory layers of which at least one layer essentially consist of alpha-Al₂O₃. Said alpha-Al₂O₃ layer consists of essentially equiaxed grains with an average grain size of <1 mum and with a bimodal grain size distribution with coarser grains with an average grainsize in the interval 0.5-1 mum and finer grains with an average grainsize of <0.5 mum. The Al₂O₃ layer further contains striated zones containing titanium (>5 at %) but no nitrogen or carbon. This particular microstructure is obtained by temporarily stopping the gases needed for the growth of the Al₂O₃ layer and introducing TiCl₄.