Bonding strength, thermal shock and oxidation resistance of interlocking (Zr,Hf)C-SiC/SiC double-layer coating for C/C composites
Bonding strength, thermal shock and oxidation resistance of interlocking (Zr,Hf)C-SiC/SiC double-layer coating for C/C composites
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DOI：
10.1016/j.surfcoat.2017.02.072
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发表时间：
2017-04
影响因子：
5.4
通讯作者：
L. Zhuang;Q. Fu
中科院分区：
文献类型：
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作者：
L. Zhuang;Q. Fu
为了缓解CTEs（热膨胀系数）的失配，提高C/C复合材料表面超高温陶瓷涂层与内部SiC涂层之间的结合强度，采用包埋胶结的方法在C/C复合材料表面设计并制备了具有互锁结构的双层（Zr,Hf）C-SiC/SiC涂层。研究了涂层的显微组织、结合强度、热冲击性能和抗氧化性能。结果表明，粗粒微孔si基内涂层的构建有利于外层超高温碳化物涂层材料的渗透，从而实现超高温碳化物在整个涂层中的梯度分布。结合强度和热冲击试验表明，由于界面之字形的存在，内层与外层的结合强度显著提高。在1500°C空气中暴露220 h后，涂层试样的质量损失仅为2 mg·cm−2，这是由于cte失配的缓解和界面结合强度的提高。
In order to alleviate the mismatch of CTEs (coefficient of thermal expansions) and increase the bonding strength between the outer UHTCs (ultra-high temperature ceramics) coating and the inner SiC coating on C/C composites, a double-layer (Zr,Hf)C-SiC/SiC coating with interlocking structure was designed and prepared on C/C composites by pack cementation. The microstructure, bonding strength, thermal shock, and oxidation resistance of the coating were studied. The results showed that the construction of a coarse inner Si-based coating with microholes was beneficial for the outer UHTCs coating materials infiltrating into it, and thus realized a gradient distribution of UHTCs in the whole coating. The bonding strength and the thermal shock tests revealed that the adhesion strength between the inner layer and the outer layer was significantly increased owing to the zigzagged interface. After exposure to 1500 °C for 220 h in air, the coated specimens only had a mass loss of 2 mg·cm−2, which was attributed to the alleviation of the mismatch of CTEs and the better interface bonding strength.