THE STRUCTURE OF THIN-FILMS DEPOSITED FROM A SINTERED TUNGSTEN CARBIDE WITH A HIGH COBALT CONTENT (15 WT-PERCENT)

The microstructural and chemical composition characteristics of WCCo films deposited on high speed steel M2 (AISI) substrates by d.c. sputtering are discussed as functions of deposition rate, discharge power, discharge pressure, substrate bias and substrate temperature. Two different structures-α-W2C and amorphous-are found depending on deposition conditions. The α-W2C structure was only found for films deposited with high discharge pressures (19 Pa) and high negative substrate bias (greater than 200 V). The substrate bias has a fundamental role on the chemical composition of WCCo films, particularly on their cobalt content. © 1990.