Spraying Power Effect on Micro-Structure and Mechanical Property of TaSi₂ Coating Prepared by Supersonic Air Plasma Spraying for SiC-Coated C/C Composites

In order to further improve the oxidation resistance of SiC-coated C/C composites used in extreme environments, TaSi₂ coatings were deposited on the surfaces of SiC-coated C/C composites by supersonic air plasma spraying (SAPS) with different spraying power parameters, under other fixed parameter (gas flow, power feed rate, spraying distance and nozzle diameter) conditions. The micro-structures and phase characteristics of the TaSi₂ coatings prepared with the four kinds of spraying powers (40 kW, 45 kW, 50 kW and 55 kW) were analyzed. Also, the inter-facial bonding strengths and fracture modes between the four TaSi₂ coatings and the SiC coating were studied. The results showed that with an increase in the spraying power, the morphologies of the TaSi₂ coatings appeared from loose to dense to loose. When the spraying power was 50 kW, the deposition rate reached a maximum of 39.8%. The TaSi₂ coating presented an excellent micro-structure without obvious pores and microcracks, and its inter-facial bonding strength was 15.3 ± 2.3 N. Meanwhile, the fracture surface of the sample exhibited a brittle characteristic.