Study on anti-ablation properties of HfB2-TaSi2 coatings prepared by atmospheric plasma spraying

• Published in: Journal of alloys and compounds 2024-09, Vol.999, p.175069, Article 175069
• Main Authors: He, Siyuan, Liu, Yanbo, Ma, Zhuang, Zhu, Shizhen, Liu, Ling, Mu, GuangYi, Li, YingLu
• Format: Article
• Language: English
• Subjects: Anti-ablation coatings; Atmospherics plasma spray; Carbon fiber reinforced carbon substrate; Oxyacetylene flame; Ultra-high temperature ceramics
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2024.175069

To improve the oxidation resistance of HfB2-based coatings in high-temperature environments, HfB2-TaSi2 coatings with different TaSi2 additions have been developed by using atmospheric plasma spraying technique(APS). The oxidation resistance of the coating was studied with oxyacetylene at 1750 °C. The results confirmed that the glass-phase SiO2 layer formed by the coating ablation after adding TaSi2 plays a role in sealing the pores. Meanwhile, Ta2O5 formed upon the oxidation of TaSi2 increased the viscosity of the SiO2 glass phase, which leads to a certain self-healing ability of the oxide layer. In addition, Ta2O5 reacts with HfO2 to produce Hf6Ta2O17 with excellent phase stability, which forms a dense equiaxed crystal band and has a strong oxygen inhibition ability. The HfB2 coating containing 20 vol% TaSi2 has the best oxidation resistance with a mass ablation rate of 4.85×10−4 g/s. These results indicate that TaSi2 modified HfB2 coating has good ablative resistance, and provides effective ablative protection for carbon fiber reinforced carbon substrate. •HfB2-SiC-TaSi2 coatings were prepared by APS.•HfB2-SiC-TaSi2 coating has better ablation resistance than HfB2-SiC coating.•SiO2-Ta2O5 as a sealing phase healed the pores.