HIGH-RATE DEPOSITION OF HAFNIUM NITRIDE BY ACTIVATED REACTIVE EVAPORATION (ARE)

Cemented carbide inserts are being successfully coated with HfN using the chemical vapor deposition process. Their machining performance is much better than that of uncoated tools. To coat high speed steels with HfN at low deposition temperatures and high rates, we have to resort to physical vapor deposition processes. This paper is concerned with the synthesis of HfN by the activated reactive evaporation (ARE) process and characterization of the deposits. Hafnium was evaporated from an electron beam source in the presence of the reactive gas, nitrogen, the vapor species being activated in the ARE process. The evaporation rate of the metal, reactive gas pressure, deposition temperature and the substrate material were the experimental variables. On stainless steel and high speed steel substrates HfN could be deposited, whereas on tantalum substrates, only mixtures of hafnium, Hf3N2, Hf4N3 and HfN could be deposited. The microhardness of the deposits varied from 1850 to 2420 KHN. © 1979.