航空发动机叶片热障涂层厚度的无损定量评估

Quantitative Non-destructive Evaluation of Thermal Barrier Coatings of Aero-engine Blades

目前用来提高航空发动机涡轮叶片的耐高温及抗腐蚀性能的热障涂层易出现过薄或脱落的情况,针对涡轮叶片的微米级热障涂层,集中探究其厚度的有效无损定量评估方法,采用高频涡流检测,配合涡流检测正逆问题求解模型进行求解。通过建立涡流检测阻抗信号-陶瓷层厚度与粘接层厚度的解析方程组,结合逆运算算法和试验拾取的线圈阻抗信号,联立求解陶瓷层厚度与粘接层厚度的预测值,继而计算2层厚度之和。为了验证计算结果的正确性,利用扫描电镜来测量样本热障涂层的真实厚度,结果显示该方法能够对涡轮叶片热障涂层厚度实现高效定量评估,评估精度可达90%以上。

The turbine blade is one apply the thermal barrier coating of the crucial components in advanced aero-engines. It is of importance to （TBC） to the turbine blade in a bid to enhance its high temperature re- sistance and corrosion resistance performance. However, defects involving wall-thinning and delamination considerably decrease the protective effect of in-service TBC, which significantly influence the safety of turbine blades and aero-engines. This paper intensively investigates the technique for quantitative NDE of TBC which is subject to wall-thinning defects in micrometers. It has been found that high-frequency eddy current technique in conjunction with the inverse model is applicable and effective for NDE of TBC. The esermal ermal tional results, by scanning electron microscope （SEM） to measure the true thickness of sample barrier coatings. The results show that this method can achieve efficient quantitative assessment of barrier coating of turbine blades with accuracy over 90%.