Evolution of microstructure and mechanical performance of plasma-sprayed Ti–Cr–Si–C coatings annealed at 800 °C and 1100 °C

• Published in: Vacuum 2022-02, Vol.196, p.110781, Article 110781
• Main Authors: Li, Suyun, Fang, Haixiao, Jiao, Qi, He, Jining, Zhao, Hongjian, Qin, Yanfang, Yin, Fuxing
• Format: Article
• Language: English
• Subjects: Annealing; Fracture toughness; Microstructure; Plasma spraying; Ti-Cr-Si-C coating
• ISSN: 0042-207X; 1879-2715
• DOI: 10.1016/j.vacuum.2021.110781

In this work, Ti–Cr–Si–C coatings were plasma sprayed from Ti/Cr/Si/graphite powders and their microstructure evolution and mechanical properties after annealing at 800 °C and 1100 °C were studied. Ti–Cr–Si–C coatings were sprayed with a lamellar structure and they consisted of TiC, Ti5Si3, MAX-Ti3SiC2, Cr, unreacted Si and graphite. After annealing at 800 °C and 1100 °C, MAX-Ti3SiC2 phase increased and the microstructure became more uniform because of Ti/Si/C/Cr element diffusion. The average micro-hardness of plasma-sprayed 3Ti–Si–2C–Cr coating improved by 2% after annealing at 800 °C and its average fracture toughness improved by 18%. The average micro-hardness of plasma-sprayed 3Ti–Si–2C-1.5Cr coating improved by 9% after annealing at 1100 °C and its average fracture toughness improved by 22%. The improved mechanical properties were because of the increased MAX-Ti3SiC2 phase, the uniform microstructure and the micro-cracks healing, indicating the annealing treatments were positive for the performance of Ti–Cr–Si–C coatings. •MAX phase increased and the microstructure became more uniform after annealing.•The micro-cracks tended to heal after annealing.•The micro-hardness and fracture toughness of Ti–Cr–Si–C coatings improved by 2–9% and 15–22% after annealing.