等离子喷涂ZrO_2复合涂层的热膨胀性能研究

Study on the thermal expansion properties of plasma spraying ZrO_2 composite coatings

研究了等离子喷涂方法制备Al/Ni-ZrO2系涂层的热膨胀性能,测试了各种ZrO2含量的复合涂层在不同温度范围下的线膨胀系数,发现当涂层陶瓷含量超过一定值,在高于700℃时发生反常热膨胀现象。分析了ZrO2相变和涂层金属氧化对膨胀的影响,提出了涂层内微裂纹的发展造成异常膨胀的机制,并建立了与之相适用的涂层微观结构模型。

The thermal expansion properties of Al/Ni-ZrO2 serials coatings by plasma spraying were studied, and the thermal expansion coefficients of composite coatings with diverse ZrO2 at different temperature were measured. The results show that coatings expand abnormally above 700 ℃ when the proportion of ceramic is more than a certain value. The effects of ZrO2 phase transformation and the metal oxide on expansion were analyzed, the mechanism of abnormal expansion due to inner tiny cracks＇propagation was put forward, and the related model of coating microstructure was established.