Properties and performance of commercial TiCN coatings. Part 2: tribological performance

Tribological testing has been carried out on a range of commercial PVD and CVD TiCN coatings deposited on WC/Co, which were previously characterised in detail. Single-pass scratch tests were used to characterise adhesion, and pin-on-disc testing was used to determine friction coefficients and wear rates, respectively. The critical load for coating detachment depends on coating thickness, as expected for PVD coatings, but is unexpectedly low for a medium-temperature CVD layer. The friction coefficient against WC balls varies considerably between coatings produced by different processes, as does the wear rate. Maintaining the carbon content of the exposed surface during wear is critical in the reducing friction coefficient and wear rate after the run-in process is complete.