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Tuesday, August 3, 2004 - 2:30 PM
SES 12.3

Development of Enhanced Tribological Properties in TiC-W Cermet Thin Film Coatings

J. Sinchak, B. Mishra, J. ZHOU, Colorado School of Mines, Golden, CO; F. M. Kustas, Engineered Coatings, Inc., Parker, CO

Co-deposited thin films of TiC and W have been fabricated using pulsed magnetron sputtering, under conditions of varied working gas pressures, substrate bias and metal concentrations to develop high fracture toughness in combination with high hardness, good adhesion and enhanced wear-resistance. Films have exhibited good adhesion with critical scratch adhesion values from 50-70N. Nanoindentation of the cermet coatings resulted in hardness values in the range of 20-30 GPa, with higher values for coatings that have higher metal content. Reciprocating sliding wear tests were performed on the coatings using a tungsten carbide-cobalt ball counterface. At a lower initial stress of 1.33 GPa, addition of metal to the carbide matrices resulted in higher wear factors. The enhancement in tribological properties has been correlated with the toughening mechanism in ceramic matrix material with nanocrystalline metal phase.

Summary: Synthesis and characterization of TiC-W cermet coatings have been performed to develop superior tribological properties. The mechanism of toughening in cermet thin films by incorporation of metals has been explained through the formation of naon-crystalline metallic particles in ceramic substrate.