Jianfeng Huang Wendong Yang Liyun Cao
材料科学技术（英文）
In order to improve the oxidation resistance of carbon/carbon (C/C) composites, a SiC/C-AlPO4 multi-layer coating was fabricated on the C/C composites by a simple and low-cost method. The internal SiC bonding layer was prepared by a two-step pack cementation process and the external C-AlPO4 coating was deposited by hydrothermal electrophoretic deposition process. Phase compositions and microstructures of the as-prepared multi-layer coating were characterized by X-ray diffraction (XRD), scaning electron microspocy (SEM) and energy dispersive spectrometer (EDS). Anti-oxidation properties, oxidation behavior and the failure behavior of the coated composites were investigated. The results indicate that the multi-layer coating exhibits obviously two-layer structure. The inner layer is composed of β-SiC, α-SiC phase with a scale of silicon phase. The outer layer is composed of cristobalite aluminum phosphate (C-AlPO4) crystallites. The SEM observation shows the good bonding between the inner and outer layers. The multi-layer coating displays an excellent oxidation resistance in air in the temperature range from 1573 to 1773 K, and the corresponding oxidation activation energy of the coated C/C composites is calculated to be 117.2 kJ/mol. The oxidation process is predominantly controlled by the diffusion of O2 through the C-AlPO4 coating. The failure of the multi-layer coating results from the generation of the microholes that may be left by the escape of the oxidation gases.
关键词:
Carbon/carbon composites
,
磷酸铝
,
水热电泳沉积
,
涂层
,
氧化
王博
,
黄剑锋
,
刘淼
,
曹丽云
,
吴建鹏
无机材料学报
doi:10.3724/SP.J.1077.2010.01291
采用水热电泳沉积法在SiC-C/C复合材料表面制备纳米碳化硅和二硅化钼的复相(SiCn-MoSi2)抗氧化涂层.分别采用XRD和SEM等测试手段对涂层的晶相组成和显微结构进行了表征. 主要研究了沉积电压对涂层显微结构及高温抗氧化性能的影响, 分析了涂层试样在1500℃下的静态氧化行为及热循环失效机理. 结果表明: 外涂层主要由MoSi2和β-SiC晶相组成. 当沉积电压为100~180V时, 外涂层的致密程度、厚度及抗氧化性能随着沉积电压的升高而提高. 沉积电压过高(220V)时, 复合涂层中出现裂纹等缺陷, 涂层的氧化保护能力相应减弱. 抗氧化性能测试表明复合涂层可在1500℃的静态空气中有效保护C/C复合材料346h, 失重率仅1.41wt%. 涂层的高温失效是由于涂层试样在热循环过程中产生了贯穿性裂纹导致的.
关键词:
C/C复合材料
,
multilayer coating
,
hydrothermal electrophoretic deposition
,
deposition voltage
