Abstract To improve the ablation resistance of HfC coating for carbon/carbon (C/C) composites, various fractions of HfC nanowires were incorporated into the HfC coating by chemical vapor deposition (CVD). Effects of HfC nanowire amount on the microstructure and ablation resistance of the CVD-HfC coating were investigated. Results indicated that the HfC nanowire layer became thicker and denser with the deposition time extending. HfC nanowires could inhibit the formation of cracks and interlaminar gaps in the HfC coating. With the increase of HfC nanowire amount, the HfC coating became thicker, while its porosity and roughness firstly decreased and then increased. Ablation tests indicated that the incorporation of HfC nanowires could effectively improve the ablation resistance of the HfC coating, which could be ascribed to the decreasing surface temperature of the coated samples and the effective alleviation of cracking and delamination of the coating during ablation. The HfC coating with HfC nanowires deposited for 1 h exhibited better ablation resistance owing to its compact microstructure, and its mass and linear ablation rates were only 0.41 mg/s and − 1.53 µm/s after ablation for 120 s.

中文翻译：

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HfC纳米线用量对CVD-HfC涂层微观结构和耐烧蚀性的影响

摘要 为了提高碳/碳 (C/C) 复合材料的 HfC 涂层的耐烧蚀性，通过化学气相沉积 (CVD) 将不同分数的 HfC 纳米线掺入 HfC 涂层中。研究了 HfC 纳米线用量对 CVD-HfC 涂层微观结构和耐烧蚀性的影响。结果表明，随着沉积时间的延长，HfC 纳米线层变得更厚和更致密。HfC 纳米线可以抑制 HfC 涂层中裂纹和层间间隙的形成。随着HfC纳米线数量的增加，HfC涂层变厚，孔隙率和粗糙度先降低后增加。烧蚀试验表明，掺入 HfC 纳米线可以有效提高 HfC 涂层的抗烧蚀性，这可能归因于涂层样品表面温度的降低和烧蚀过程中涂层开裂和分层的有效缓解。具有沉积 1 小时 HfC 纳米线的 HfC 涂层由于其紧凑的微观结构表现出更好的耐烧蚀性，并且在烧蚀 120 秒后其质量和线性烧蚀速率仅为 0.41 mg/s 和 - 1.53 µm/s。