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Microstructure and Properties of Nanocrystalline Hard Coatings and Thin Film Nanocomposites
Dopita, Milan
In this work, microstructure and properties of M-Al-(Si-)N nanocrystalline hard coatings and thin film nanocomposites deposited by cathodic arc evaporation (CAE) process at different positions of substrates in the deposition apparatus were investigated using the combination of electron probe microanalysis, X-ray diffraction, transmission electron microscopy with high resolution and hardness measurement. Six series of specimens that differed in the transition metal type (Cr, Ti and Zr) and in the amount of Si and Al were deposited using the CAE process in the deposition apparatus π-80 produced by Platit AG. The essential microstructural parameters; the chemical and phase composition, the residual stress, preferred orientation of crystallites, crystallite size and mutual disorientation of crystallites were determined in all coatings under study. The derived microstructural parameters were correlated with the hardness of coatings. Finally, the microstructural model of the nanocrystalline hard coatings and thin film nanocomposites formation was developed. Depending on the sample chemical composition, three regions with different phase compositions exist in the coatings. In the transition metal richest samples, a single fcc M1-x- yAlxSiyN phase exists in the coating. With increasing Al content,...
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