Microstructural characteristics and wear-resistant mechanisms of WC-TiC-co coatings with varying TiC contents

Abstract

In this work, the microstructural characteristics and tribological properties of HVOF-sprayed WC-TiC-Co coatings with varying amounts of TiC addition were studied, along with a comparison with those of the traditional WC-Co coating. The incorporated TiC exhibited a diverse presence in the coatings, including (Ti,W)C solid solution particles and interfacial layers, residual TiC particles, as well as Ti-monolayer that induced planar defects within WC grains. The high stability of (Ti,W)C layers at the WC/Co interfaces effectively suppressed the formation of W2C in the WC-TiC-Co coatings. Notably, the coating with 10 wt% TiC demonstrated superior wear resistance owing to the hardening effects of (Ti,W)C particles and interfacial layers. This effectively mitigated the wear mechanisms such as plastic deformation, extrusion, and micro-cutting of the Co binder, which would otherwise lead to the pull-out of WC particles and accelerate the wear process. These findings provide valuable insights into the microstructure design and performance optimization of WC-based coatings.