Microtexture and hardness of CVD deposited α-Al2O3 and TiCxN1−x coatings

The microstructures of chemical vapor deposited coatings on four tool inserts have been comprehensively characterized using electron backscatter diffraction mapping. Nanoindentation was used to measure the hardness of the TiCxN1−x and α-Al2O3 layers in each coating. The TiCxN1−x layers have weak [112] or [101] textures in the growth direction and are highly twinned. In these layers, coherent twins make up 13%–20% of the total grain boundary length. The alumina layers have [101¯4] or [0001] textures in the growth direction that are 4.2–8.8 times random. The hardest coatings consist of highly twinned TiCxN1−x layers with weak [112] texture and α-Al2O3 with strong [101¯4] texture.