Microstructure and thermal stability of TaSi2 coating fabricated by vacuum plasma spray

• Published in: Surface & coatings technology 2015-10, Vol.279, p.1-8
• Main Authors: Niu, Yaran, Huang, Liping, Zhai, Cuihong, Zeng, Yi, Zheng, Xuebin, Ding, Chuanxian
• Format: Article
• Language: English
• Subjects: Coating; Microstructure; Oxidation; Oxidation tests; Sprayers; Sprays; TaSi2 coating; Thermal stability; Transmission electron microscopy; Vacuum plasma spray
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2015.08.025

This work was aimed at reporting a new method for fabrication of TaSi2 coating. In this research, vacuum plasma spray (VPS) process was applied to fabricate TaSi2 coating. The chemical composition and microstructure of the coating was characterized by SEM, XRD, TEM and EDS. Its thermal stability was evaluated by TG-DTA and oxidation tests at 500°C–1000°C. The results showed that the TaSi2 coating was composed of hexagonal TaSi2 phase and presented dense lamellar microstructure combining defects, such as pores, interfaces and oxygen impurity. There was a sharp weight increase in TG curve at range of 800°C–1000°C with an exothermic phenomenon. The coating exhibited excellent thermal stability at 500°C up to 50h in atmospheric environment. Obvious oxidation was observed at 800°C. The TaSi2 coating was completely oxidized and fragmented into pieces after oxidation at 900°C for 1h. The oxidation mechanism was also discussed. •TaSi2 coating fabricated by vacuum plasma spray technique was reported.•The microstructure of TaSi2 coating was characterized in detail.•The thermal stability was evaluated by TG-DTA and oxidation tests.•TaSi2 coating had exellent thermal stability at 500°C up to 50h. Obvious oxidation was observed after oxidation at 800°C for 1h.