Oxidation and erosion resistance of multi-layer SiC nanowires reinforced SiC coating prepared by CVD on C/C composites in static and aerodynamic oxidation environments
Oxidation and erosion resistance of multi-layer SiC nanowires reinforced SiC coating prepared by CVD on C/C composites in static and aerodynamic oxidation environments
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DOI：
10.1016/j.ceramint.2018.06.005
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发表时间：
2018-10
影响因子：
5.2
通讯作者：
Xinfa Qiang;Hejun Li;Yunfan Liu;N. Zhang;Xin Li;Song Tian;Yuan Cong
中科院分区：
文献类型：
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作者：
Xinfa Qiang;Hejun Li;Yunfan Liu;N. Zhang;Xin Li;Song Tian;Yuan Cong
采用三种化学气相沉积（CVD）工艺在C/C复合材料表面原位制备了多层SiC纳米线增强SiC（SiCnws-SiC）涂层。利用SEM、TEM和XRD对第一层SiCnws-SiC涂层和涂层上制备的纳米线的微观结构和相组成进行了分析。在第一层SiCnws-SiC涂层上，直径约50 nm，长度约几十μ m的竹节状SiC纳米线呈直线状、无规取向、网状分布。生长方向为[111]，生长机制为VS。多层SiCnws-SiC涂层有三层：第一层的厚度约为400 µm，外两层约为200 µm。每一层都有一个夹层结构。在电炉和高温风洞中研究了SiCnws-SiC多层涂层的等温氧化和冲蚀性能。结果表明，SiCnws-SiC多层涂层C/C复合材料在1773 K静态空气中氧化361 h后的失重率仅为1.8%。此外，在风洞中在1873 K下腐蚀130小时后，涂覆的样品由于在夹紧位置（即80 mm）处的涂层断裂而失效。涂层C/C复合材料在氧化热冲击过程中由于涂层中穿透裂纹的形成而发生了失重。最大弯曲力矩和较大的夹紧力导致涂层断裂，导致基体强烈氧化，试样失效。
A multi-layer SiC nanowires reinforced SiC (SiCnws-SiC) coating was prepared in-situ on carbon/carbon (C/C) composites by three chemical vapor deposition (CVD) processes. The microstructure and phase composition of the nanowires fabricated on the first-layer SiCnws-SiC coating and the coatings were examined by SEM, TEM, and XRD. The bamboo-like SiC nanowires with a 50 nm diameter and a length of several tens of micrometers are straight, randomly orientated and distributed like a net on the first-layer SiCnws-SiC coating. The growth direction is [111], and the growth mechanism is VS. The multi-layer SiCnws-SiC coating has three layers: the thickness of the first-layer is roughly 400 µm, and the outer two layers are about 200 µm. Each layer has a sandwich structure. The isothermal oxidation and erosion resistance of the multi-layer SiCnws-SiC coating were investigated in an electrical furnace and a high temperature wind tunnel. The results indicated that the weight loss of the multi-layer SiCnws-SiC coated C/C composites was only 1.8% after oxidation in static air at 1773 K for 361 h. Further, the coated sample failed due to fracture of the coating at the clamping position (i.e. 80 mm) after erosion at 1873 K for 130 h in the wind tunnel. The weight loss of the coated C/C composites occurred due to the formation of penetrating cracks in the coating during the oxidation thermal shock. The maximum bending moment and the larger clamping force caused the coating fracture and resulted in intense oxidation of the substrate and the failure of the specimen.