Improving the long time ablation resistance of thermal protective coating is the key index to promote the development of hypervelocity aerocrafts. In this work, the ablation behaviors of ZrB₂-MoSi₂ and ZrB₂-MoSi₂-WB composite coatings fabricated by vacuum plasma spray (VPS) were evaluated by plasma flame. The microstructure evolution induced by prolonged ablation was focused on and discussed in detail. The results shows that the addition of WB significantly improved the long-term ablation resistant performance of the ZrB₂-MoSi₂ coating, as characterized by integrated macrostructure, compact microstructure and decreased thickness of oxide layer. The function of WB was explained in detail based on microstructure observation and thermodynamic calculations, which would give some inspirations for the design of UHTCs.

提高热防护涂层的长期抗烧蚀性能是推动超高速飞行器发展的关键指标。在这项工作中，通过等离子火焰评估了真空等离子喷涂（VPS）制备的ZrB ₂ -MoSi ₂和ZrB ₂ -MoSi ₂ -WB复合涂层的烧蚀行为。重点关注和详细讨论了长时间烧蚀引起的微观结构演变。结果表明，WB的加入显着提高了ZrB ₂ -MoSi ₂的长期抗烧蚀性能涂层，其特点是整体宏观结构，致密的微观结构和减少的氧化层厚度。在微观结构观察和热力学计算的基础上，对WB的功能进行了详细解释，这将为UHTCs的设计提供一些启发。