Tribological Behavior of WC-12Co Air Plasma–Sprayed Coating at Elevated Temperatures. Issue 1 (2nd January 2016) - Geng, Zhe
Abstract: The friction and wear performance of WC-12Co air plasma–sprayed (APS) coating at temperatures of 25–650°C under loads of 8 and 28 N in at atmospheric environment have been studied by a ball-on-disc tribometer. The effect of temperature and load on the tribological behavior of WC-Co coating was investigated. The results show that under a load of 8 N, the wear volume of the coating increases at 250°C due to the coating splat delamination and then it gradually decreases at 350–500°C. The friction could promote the formation of double oxide (CoWO4 ), which is beneficial to reduce friction and wear. At higher temperatures, the wear volume increases again due to the removal of oxides. Under a load of 28 N, the wear volume of the coating increases enormously at 250°C due to the serious splat delamination. At 350°C, the load promotes double oxide formation, resulting in an early decrease in the coefficient of friction and a rapid reduction in wear volume. Although the wear volume decreases at 350–500°C, it is 10-fold higher than that under a load of 8 N. Above 500°C, the differences of the wear volumes of coatings under the two loads become less obvious, and similar trends also appear for the coefficients of friction. The synergistic effect between the load and temperature on the friction and wear mechanism of WC-12Co APS coating is discussed.