Tribological behaviour of thermally sprayed silicon carbide coatings

SiC coatings have been successfully deposited using thermal spray detonation technique with a newly patented feedstock. Their tribological performance was compared to bulk SiC for dry and lubricated conditions (polyalphaolefin and 3.5wt% NaCl solution). The lowest coefficient of friction (CoF=0.10) and wear-rate were detected with polyalphaolefin lubricant regardless of the test pair due to mixed fluid-film lubrication. Contradicting results were recorded under other test conditions. The coatings show low CoF of 0.20 in comparison to four times higher CoF of bulk SiC under dry sliding. Oppositely, SiC coatings in NaCl solution record five times higher CoF compared to bulk SiC CoF of 0.20. Such behaviour is associated with tribochemical reaction and tribo-corrosion mechanisms occurring in dry and NaCl sliding, respectively. •Thermal spray of SiC by detonation gun using newly patented feedstock powders.•Tribochemical reaction of SiC in dry sliding generates SiO2 tribo-layers.•Hydrodynamic lubrication on PAO lubricant sliding produces lowest CoF and wear-rate.•Tribocorrosion of the ball counterpart in NaCl sliding leads to largest wear rates.•SiC coating is superior in dry sliding as compared to bulk LPS–SiC.