Growth of hard amorphous Ti-Al-Si-N thin films by cathodic arc evaporation

Ti1- x - y Al x Si y N z (0.02 less than or equal to x less than or equal to 0.46, 0.02 less than or equal to y less than or equal to 0.28, and 1.08 less than or equal to z less than or equal to 1.29) thin films were grown on cemented carbide substrates in an industrial scale cathodic arc evaporation system using Ti--Al, Ti--Si, and Ti--Al--Si 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 12at.% Si and 18at.% Al, the films assume an X-ray amorphous state. Post-deposition anneals show that the films are thermally stable up to 900 degree C. The films exhibit age hardening up to 1100 degree C with an increase in hardness from 19.4GPa for as-deposited films to 27.1GPa at 1100 degree C. At 1100 degree C out-diffusion of Co and W from the substrate occur, and the films crystallize into c-TiN and h-AlN.