Evaluation of the microstructure and friction properties of coated cemented carbide with CoCrMoW high entropy alloy binder

Abstract

In the paper, the effect of CoCrMoW high entropy alloy (HEA) binder in cemented carbide on the microstructure and wear-resistant and oxidation-resistant properties of the coating is investigated to provide reference for the exploration and development of new wear resistance and oxidation-resistant materials. The results indicate that the coated WC-HEA has a dense coating structure and possesses excellent high-temperature wear resistance. Compared with the Ni or Co binder phase, the coated cemented carbide containing HEA binder phase has a large difference in the matrix microstructure, cross-section morphology, mechanical properties and friction and wear properties. It is also found that a significant amount of W in the substrate diffuses through grain boundaries into the TiN coating and TiCN coatings and forms a TixWxN solid solution at the interface between the TiN coating and the matrix. In particular, the uniformity of the distribution of HEA binder in the matrix directly affects the nucleation growth of the coatings. Nanohardness results indicate that the wear resistance of TiN/TiCN/Al₂O₃ coating is in the order of WC-Ni < WC-HEA < WC- Co. These differences come from the effect of binder on the nucleation growth and textured orientation of the coating. The comprehensive mechanical properties of the WC-HEA are similarly that of WC- Co, and it has great potential to replace WC- Co. Compared with Ni and Co binder phases, the WC-HEA coating sample is more wear-resistant at 750 °C.