Growth of hard amorphous TiAlSiN thin films by cathodic arc evaporation

Ti1 − x − yAlxSiyNz (0.02 ≤ x ≤ 0.46, 0.02 ≤ y ≤ 0.28, and 1.08 ≤ z ≤ 1.29) thin films were grown on cemented carbide substrates in an industrial scale cathodic arc evaporation system using TiAl, TiSi, and TiAlSi cathodes in a N2 atmosphere. The microstructure of the as-deposited films changes from nanocrystalline to amorphous by addition of Al and Si to TiN. Upon incorporation of 12 at.% Si and 18 at.% Al, the films assume an X-ray amorphous state. Post-deposition anneals show that the films are thermally stable up to 900 °C. The films exhibit age hardening up to 1100 °C with an increase in hardness from 19.4 GPa for as-deposited films to 27.1 GPa at 1100 °C. At 1100 °C out-diffusion of Co and W from the substrate occur, and the films crystallize into c-TiN and h-AlN.