Preparation and properties of reactive plasma sprayed TiC–Ti5Si3–Ti3SiC2/Al coatings from Ti–Si–C–Al mixed powders

Abstract

TiC–Ti5Si3–Ti3SiC2/Al composite coatings were reactive plasma sprayed from 3Ti–Si–2C-xAl (x = 0, 0.2, 0.5, 1.0, 1.5) powders. The microstructure, micro-hardness, fracture toughness, and tribological performance depending upon the added metal Al content were studied. The results revealed that all the RPS coatings exhibited the lamellar structure and consisted of three dominant phases (TiC, Ti5Si3, and Ti3SiC2) and few residual Si. After adding metal Al, Ti3SiC2 phase increased and TiC phase decreased. The hardness of the RPS coatings first increased and then decreased slightly after adding metal Al, but their fracture toughness were improved by ~23–51% and mass loss decreased maximally from 0.6 × 10−3 g to 0.1 × 10−3 g. The wear mechanism could be described as the dominant abrasive and adhesive wear, and partial tribo-oxidation wear.