Microstructure evolution and mechanical properties of reactive plasma sprayed Ti3SiC2-Ti5Si3-TiC composite coatings

The Ti3SiC2-Ti5Si3-TiC composite coatings with various Si content were in-situ prepared by reactive plasma spraying with the mixture of Ti-graphite-Si powders. Results showed that the sprayed coatings consisted of Ti3SiC2, Ti5Si3 and TiC phases. With increasing in Si contents, the content percent of Ti3SiC2 phase increased, and TiC and Ti5Si3 phases decreased. The sizes of the crystallized phases were 50-100 nm. The Ti3SiC2-Ti5Si3-TiC composite coatings had a lamellar structure with good-bonding interfaces. The increased Si contents enhanced the fracture toughness and wear resistance of the Ti3SiC2-Ti5Si3-TiC composite coatings, and failed to enhance their hardness. The wear mechanism of Ti3SiC2-Ti5Si3-TiC composite coatings were abrasive wear, accompanied by adhesive wear and tribo-oxidation wear.