Study on the Strength of the Plasma Sprayed Ceramic Coating After Thermal Cycle Test

本研究的目的是研究等离子喷涂氧化铝涂层经过热循环试验后的强度。(1)利用弹性力学理论和边界元方法，对热喷涂过程中的热应力应变进行了分析，并进行了热循环试验。当试件由厚度为涂层厚度的4倍、长度和宽度为涂层厚度的8倍的涂层组成时，热循环试验时的热应力与现场喷涂的涂层的热应力相同。(2)对沉积在不锈钢衬底上的等离子喷涂氧化铝涂层进行了热循环试验。氧化铝涂层的热循环次数受涂层边缘形状的影响。(3)通过数值模拟，阐明了主要参数(陶瓷涂层与基材的线膨胀系数之差、两种材料的杨氏S模数之比)对热循环试验后J积分的影响。

The purpose of this study is to investigate the strength of the plasma sprayed alumina coating after thermal cycle test. A summary of the obtained results are as follows:(1) An analysis connected with the thermal stress and strain during thermal spraying and thermal cycle test are performed usaing the theory of elasticity and a boundary element method. If the test specimen are composed of the substrate with thethickness being 4 times, and the length and the width being 8 times as large as a thickness of sprayed coating, the thermal stress during thermal cycle test are the same as that of sprayed substrate in working field.(2) The thermal cycle test of plasma sprayed alumina coating which are deposited on the stainless substrate are carried out. The number of thermal cycle to failure of alumina coating are affected by the edge shape of coating.(3) The effect of dominant parameters ( the difference of the coefficient of linear thermal expansion between the ceramic coating and the substrate, the ratio of Young s modulus of both materials) on the J integral after thermal cycle test are clarified by numerical simulation.