Thermal Conductivity of the ZrO2 Based Composite Coatings Prepared by Gas Tunnel Type Atmospheric Plasma Spraying
Thermal Conductivity of the ZrO2 Based Composite Coatings Prepared by Gas Tunnel Type Atmospheric Plasma Spraying
复制标题
气体隧道式常压等离子喷涂ZrO2基复合涂层的导热性能
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
A. Kobayashi
中科院分区：
文献类型：
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作者：
Jialiang Zhang;A. Kobayashi
采用等离子喷涂法制备的zro2基热障涂层，为了提高其抗氧离子性能，经常加入Al2O3等添加剂进行改性。采用气隧道式等离子喷涂技术，制备了氧化锆基复合涂层，其等离子体温度比传统电弧等离子喷涂技术高，稳定性比传统电弧等离子喷涂技术好。由于等离子体的稳定性，在保持喷涂参数不变的情况下，涂层的微观结构参数如厚度、氧化铝混合比和孔隙率等都能得到很好的再现。本研究制备了一组厚度几乎相同但成分比例不同的涂层样品。采用扫描电子显微镜（SEM）和光学显微镜（OM）对涂层的表面和截面形貌进行了观察。通过SEM照片测量涂层厚度，评估氧化铝含量比，通过光学照片的图像分析获得涂层孔隙率（横截面上的孔隙率分布和平均孔隙率）。采用显微维氏硬度计测量涂层硬度，采用平行热板间稳定热流原理测量涂层导热系数。结果表明：氧化铝的加入提高了涂层的硬度，降低了涂层的孔隙率，但没有降低涂层的热阻。
ZrO 2 based thermal barrier coatings prepared using plasma spraying are frequently modified by mixing some kinds of additives such Al2O3, in order to improve their oxygen ion resistance. Using gas tunnel type plasma spraying, characterized by higher plasma temperature and better stability than traditional arc plasma spraying, zirconia based composite coatings with various mixing ratios of alumina were used to generate graded-functional microstructures. Because of the plasma stability, the coating micro-structural parameters such as the thickness, mixing ratio of alumina and porosity were well reproduced by keeping the spraying parameter constant. A group of coating samples was prepared in this research to be almost the same thickness but different composition ratios. The surface and cross-sectional morphologies of the coatings were examined by SEM (Scanning Electron Microscope) and OM (Optical Microscopy). The coating thickness was measured and the alumina content ratio was assessed from the SEM photos, while the coating porosity (the porosity profile over the cross-section and the average porosity) was obtained from the image analysis of the optical photos. The coating hardness was measured with a micro Vicker hardness tester and the thermal conductivity was measured based on the principle of steady heat flux between two parallel hot plates. The results showed that the addition of alumina increased the coating hardness and lowered the coating porosity, while not reducing the thermal resistance of the coating layers.