等离子喷涂热障涂层材料弹性模量与硬度的压痕测试分析

Investigations of Elastic Modulus and Hardness of Air Plasma Sprayed Thermal Barrier Coatings by Nanoindentation Method

采用纳米压痕法,研究了经高温热循环处理后的等离子喷涂热障涂层材料弹性模量和硬度的抛物线式演变规律,并采用Weibull统计分析方法对纳米压痕测试数据进行了处理和分析,提高了实验数据的可靠性。结果表明,经过高温热循环处理之后,不同位置处的热障涂层弹性模量和硬度都呈现出明显的各向异性分布。随着热循环次数的增加,涂层表面和截面上的弹性模量和硬度都随之增大,当达到一定次数之后,两者的数值变化趋于平缓。涂层截面处的弹性模量和硬度都大于涂层表面处的数值。最后结合热循环处理前后热障涂层材料微观结构的变化观察,简单讨论了其弹性模量和硬度演变的原因。

The parabolic evolutions of elastic modulus and hardness of air plasma sprayed thermal barrier coatings under thermal cycles were studied by nanoindentation method.The experimental data were analyzed by Weibull statistical method to minimize the measurement scatter.The results indicated that elastic modulus and hardness in the interface region of the coating display anisotropic distribution.They increase with thermal cycling and then gradually keep a constant after some thermal cycles.The values of elastic modulus and hardness in the cross-sectional coating are larger than that in the coating surface region.The reason was discussed with the aid of the scanning electronic microscope observations.