Effect of counterparts on the tribological properties of TiCN coatings with low carbon concentration in water lubrication

TiN and TiCN coatings have long been used for wear reduction in application like tooling, but there are other potential industrial applications in aqueous environments. Therefore, the current investigation explores the friction and wear compatibility of TiN and TiCN coatings against potential sliding partners in water. 316 L discs coated with TiN and TiCN (containing 2.46 at% C) slid against fixed balls of Al2O3, SiC, Si3N4, and SUS440C in water. In terms of mean steady-state friction coefficient, the ranking from low to high was: SIC Si3N4 Al2O3 SUS440C regardless of coating type. It is proposed that due to lubrication by silica gel, the friction coefficients and wear rates of TiCN coatings against SiC and Si3N4 balls were lower than those against Al2O3 and SUS440C balls. For the TiCN/SUS440C tribopairs, tribo-oxidation occurred easily for SUS440C ball, and the oxides on the wear track caused the highest friction coefficient and the roughest wear surfaces. But wear of the TiCN/Al2O3 tribopairs, which had the highest wear rate of the coatings, was dominated by abrasion. In terms of the friction and wear behavior under water-lubricated test conditions, SIC was the most suitable counterpart for TiCN-coated stainless steel. (C) 2015 Elsevier B.V. All rights reserved.