RCC复合材料涂层厚度的涡流法测量技术研究

发布时间：2018-06-26 03:51

本文选题：涡流法 + 碳纤维复合材料　；参考：《南昌航空大学》2015年硕士论文

【摘要】：碳纤维增强碳基(RCC)复合材料作为先进的材料已被广泛用于制作航空航天关键零部件,这类材料常常工作于超高温的环境中,为了防止其被氧化烧蚀,需要在复合材料的表面镀一层抗氧化的碳化硅涂层,涂层厚度范围约为40~200μm。抗氧化涂层的厚度直接影响零部件的稳定性,对于确保航空航天器的正常工作具有重要意义,利用涡流检测法是测量此类薄抗氧化涂层厚度最为有效的手段之一。本文首先从理论出发,表述了涡流法检测及测厚的理论基础,根据所研究的碳纤维复合材料基体与涂层的特性,结合有限元仿真,分析了涡流提离效应、基体材料电导率不均匀性、涂层材料电导率不均匀性与涂层厚度变化对涡流检测信号的影响,分析结果表明通过选择合适的检测参数,涡流法可以用于复合材料的涂层厚度测量。然后,在理论分析的基础上选用合适的涡流检测仪和研制相匹配的专用涡流测厚探头,利用涡流检测仪和测厚探头开展碳纤维复合材料试块涂层厚度的测量试验研究,测量确定涡流检测设备的最佳检测参数,探究设备检测分辨能力的大小和检测灵敏度,确定测量范围,通过多项式拟合分析涡流检测信号与覆盖层厚度之间的定量关系,同时测量带有不同厚度涂层的复合材料试块,得出其当量厚度值,并对测量结果进行数据处理与分析,评价试块表面的涂层厚度分布状况。最后,利用扫描电子显微镜观察分析试块剖面的微观形貌,测量涂层厚度,开展基体材料的不均匀性测量试验,探究涡流法测量的精度。通过理论分析和试验研究结果表明,利用涡流检测仪和专用涡流测厚探头可以实现RCC复合材料表面Si C涂层厚度的有效测量与评价,为此类材料涂层厚度的测量提供了一种可靠的解决方法。
[Abstract]:Carbon fiber reinforced carbon matrix (RCC) composites, as advanced materials, have been widely used in the manufacture of key aerospace components. These materials often work in ultra-high temperature environments to prevent them from being oxidized and ablated. An oxidation resistant silicon carbide coating needs to be deposited on the surface of the composite material. The thickness of the coating is about 40 ~ 200 渭 m. The thickness of anti-oxidation coating directly affects the stability of parts and it is important to ensure the normal operation of aerospace spacecraft. Eddy current detection method is one of the most effective means to measure the thickness of such thin anti-oxidation coating. In this paper, the theoretical basis of eddy current measurement and thickness measurement is described. Based on the characteristics of matrix and coating of carbon fiber composites studied in this paper, combined with finite element simulation, the eddy current lift effect is analyzed. The influence of the conductivity inhomogeneity of the substrate material, the conductivity inhomogeneity of the coating material and the thickness of the coating on the eddy current testing signal is analyzed. The results show that the appropriate detection parameters are selected. Eddy current method can be used to measure the coating thickness of composite materials. Then, on the basis of theoretical analysis, a suitable eddy current detector and a matching special eddy current thickness detector are selected, and the thickness measurement of carbon fiber composite specimen coating is carried out by means of eddy current detector and thickness detector. The measurement determines the best detection parameters of eddy current testing equipment, probes into the detection resolution and sensitivity of the equipment, determines the measurement range, and analyzes the quantitative relationship between the eddy current detection signal and the thickness of the overburden by polynomial fitting. At the same time, the thickness of composite material with different thickness coatings was measured, the equivalent thickness value was obtained, and the measured results were processed and analyzed to evaluate the distribution of coating thickness on the surface of the sample. Finally, scanning electron microscope (SEM) was used to observe and analyze the microscopic morphology of the sample section, to measure the thickness of the coating, to test the nonuniformity of the substrate material, and to explore the accuracy of the eddy current method. The theoretical analysis and experimental results show that the thickness of sic coating on RCC composite can be effectively measured and evaluated by using eddy current detector and special eddy current thickness detector. It provides a reliable solution for measuring the coating thickness of this kind of material.
【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG115.28

【共引文献】