Effect of SiC Content on Microstructure and Tribological Properties of Plasma Sprayed TiC/Ti 5 Si 3 /Ti 3 SiC 2 Composite Coatings

Abstract

In this work, TiC/Ti₅Si₃/Ti₃SiC₂ composite coatings were fabricated by plasma spraying using Ti-SiC-graphite powders. The effect of SiC content on the microstructure, mechanical and tribological properties of the composite coatings was investigated. Results show that the as-sprayed composite coatings are mainly composed of TiC, Ti₅Si₃ and Ti₃SiC₂ phases. The composite coatings share a heterogeneous structure with a good bonding interface between layers. With the increase in SiC content, the hardness and fracture toughness of the composite coatings first decrease and then increase. The maximum hardness of 1195 HV_0.2 and fracture toughness of 2.37 MPa \(\cdot\) m^1/2 are obtained for 3Ti-0.5SiC-C coating. The mass loss of the composite coatings first increases and then decreases with the increase in SiC content, coupling with a friction coefficient of 0.4-0.5. The wear mechanism of the composite coatings shows a combination of adhesive, abrasive and oxidation wear.