Effect of micro-blasting on the tribological properties of TiN/MT-TiCN/Al2O3/TiCNO coatings deposited by CVD

Abstract

The effect of micro-blasting on the tribological properties of TiN/MT-TiCN/Al2O3/TiCNO coatings was studied. The multilayer coatings were deposited on cemented carbides by chemical vapor deposition. The microstructure, mechanical and tribological properties were investigated using X-ray diffraction, scanning electron microscopy (SEM), nano-mechanical testing system, scratch tester and reciprocating tribometer. The results show that micro-blasting significantly reduces the surface roughness and converts the residual tensile stress of Ti(C,N,O) top-layer and Al2O3 layer into compressive stress. Affected by the residual compressive stress, the hardness and adhesion strength are increased. More importantly, the friction coefficient is decreased attributed to the decreased surface roughness and improved hardness. Also, the wear resistance of micro-blasted TiN/MT-TiCN/Al2O3/TiCNO is superior due to higher hardness of Ti(C,N,O) top-layer, Al2O3 layer and adhesion strength of coatings. Especially for the total sliding time of 2 h, the wear volume and wear rate of micro-blasted coatings are 69.4% of as-deposited coatings, because micro-blasting helps to increase the adhesion strength and micro-cracking resistance, which play important roles in the improvement of wear resistance. Micro-blasting has a positive effect on the friction and wear properties of TiN/MT-TiCN/Al2O3/TiCNO multilayer coatings since the adverse impact of top-layer thinning is offset.