To improve the oxidation resistance of carbon/carbon (C/C) composites at mid and high temperature, a gradient composite coating was designed and prepared on SiC-coated C/C composites by in situ formed-SiO₂ densifying the porous SiC-ZrSi₂ pre-coating. SiO₂ gradient distribution was conducive to inhibiting the cracking of the coating. A dual-layer structure with the outer dense layer and the inner microporous layer was formed in the coating during densifying. The dense layer had excellent oxygen diffusion resistance and the microporous layer alleviated CTE mismatch between SiC inner coating and dense layer. Moreover, ZrSiO₄ particles inhibited crack propagation and stabilized SiO₂ glass. Therefore, the coating can protect the C/C composites from oxidation at 1473 K, 1573 K and 1773 K for 810 h, 815 h and 901 h, respectively. The coated samples underwent 30 thermal cycles between room temperature and 1773 K without mass loss, exhibiting good thermal shock resistance.

为提高碳/碳(C/C)复合材料的中高温抗氧化性，通过原位形成-SiO ₂致密化多孔SiC-ZrSi，在SiC包覆的C/C复合材料上设计并制备了梯度复合涂层。₂预涂。SiO ₂梯度分布有利于抑制涂层的开裂。在致密化过程中，涂层中形成了具有外致密层和内微孔层的双层结构。致密层具有优异的抗氧扩散性，微孔层减轻了 SiC 内涂层和致密层之间的 CTE 失配。此外，ZrSiO ₄颗粒抑制裂纹扩展并稳定SiO ₂玻璃。因此，涂层可以分别保护 C/C 复合材料在 1473 K、1573 K 和 1773 K 下氧化 810 h、815 h 和 901 h。涂层样品在室温和 1773 K 之间经历了 30 次热循环，没有质量损失，表现出良好的抗热震性。