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利用大气等离子喷涂制备了ZrO2涂层,采用扫描电子显微镜结合图像分析的方法对涂层的显微结构特征(总气孔率和大气率)进行了量化表征.同时利用扫描电子显微镜附带X射线扫描成像对涂层内部的微裂纹和大的分隔裂纹的三维分布进行了表征.据此建立了ZrO2涂层显微结构与热导率之间的关系.室温下,涂层N2的热导率较N1的低,因为涂层N2内气孔和微裂纹数较多;在1000℃,由于微裂纹的烧结作用导致热导率增大,所以涂层N2的热导率较N1反而高.高温下,涂层内由微裂纹汇聚而形成的大的分隔裂纹的存在则可以有效地抑制烧结,降低涂层的热导率.
The ZrO2 coating was prepared by atmospheric plasma spraying and the microstructure characteristics (total porosity and atmospheric rate) of the coating were characterized by scanning electron microscopy and image analysis.At the same time, scanning electron microscopy with X-ray imaging The three-dimensional distribution of micro-cracks and large separation cracks in the coating was characterized.Accordingly, the relationship between the microstructure and the thermal conductivity of the ZrO2 coating was established.Compared with N1 Because of the large number of pores and micro-cracks in the coating N2; the thermal conductivity of the coating N2 is higher than that of N1 at 1000 ° C due to the increase of the thermal conductivity due to the sintering of the micro-cracks. The existence of large separation cracks formed by the aggregation of microcracks in the layer can effectively suppress the sintering and reduce the thermal conductivity of the coating.