Investigating the high-temperature and self-lubricating properties of TiAlSiCN hard coating coordinated using double amorphous phases

In this work, the competitive relationship between the double amorphous phases is systematically investigated to increase the high-temperature wear resistance of the self-lubricating TiAlSiCN coating. These double amorphous phases combine the SiN_x phase with high-temperature resistance and the C-related phase with a low friction coefficient. An increase in the Si content facilitates the change in the phase composition. The resultant coating exhibits an adhesion strength of 153 N, a friction coefficient of 0.24 and a hardness of 25.24 GPa upon generation of the TiAlN(C), the SiN_x and the C-related phase. In this case, the TiAlSiCN coating achieves long-term self-lubrication at high temperatures with the titanium alloy friction pair. This mechanism stems from the SiN_x phase replacing the portion of the easily oxidized amorphous C-related phase, which yields an enhanced high-temperature wear resistance. The cutting distance of this TiAlSiCN is 120% higher than that of the TiAlCN during the high-speed cutting of the titanium alloy. This outcome provides an effective solution for high-temperature applications of self-lubricating coatings.