Plasma sprayed TiC–Ti5Si3–Ti3SiC2–SiC composite coatings using annealed Ti–SiC composite powders based on SiC content

Abstract

The TiC–Ti5Si3–Ti3SiC2–SiC ceramic composite coatings were prepared with in-situ reaction by plasma spraying annealed Ti–SiC–C composite powders. The effect of SiC content in the annealed composite powders at 1200 °C on the microstructure and properties of the coatings was studied. With the increase of SiC content, the phases in the annealed Ti–SiC composite powders changed from Ti, SiC, TiC and Ti5Si3 to SiC, TiC, Ti5Si3 and Ti3SiC2. The phases of the sprayed coatings were mainly composed of TiC, Ti5Si3, Ti3SiC2 and a small amount of residual Si, and their content were closely related to SiC. The coating hardness first increased and then decreased, while their mass loss showed an opposite trend to that of hardness. The T1SCC (molar ratio of Ti-SiC-C is 3:1:1) coating had the highest hardness of HV 1509 and the lowest mass loss of 0.0019 g, whereas its fracture toughness was 3.51 MPa m−2.