热障涂层电磁/电容复合无损检测方法研究

Thermal barrier coatings play an important role in the improvement of aero engine thrust and thermal efficiency. Owing to the complex structure and various damage of thermal barrier coating system, the existing non-destructive testing methods are difficult to achieve comprehensive test of thermal barrier coating system. Aiming at the requirement of comprehensive testing and assessment for hot end components such as aero engine turbine blade thermal barrier coating system, an electromagnetic/capacitive compound testing method is proposed in this project. The main research contents include electromagnetic/capacitive compound testing mechanism of thermal barrier coating system, electromagnetic/capacitive sensor design and manufacturing, weak signal detection and processing, sensor calibration and error compensation, damage testing and assessment methods for thermal barrier coating system, etc. This study intends to break through some key technologies such as optimization design and manufacturing of flexible electromagnetic/ capacitive sensor with high sensitivity and resolution, information fusion of compound sensor array and inversion of physical properties of materials, to solve some key scientific problems such as electromagnetic/capacitive compound detection mechanism of thermal barrier coating system, accurate signal feature extraction under multi frequency excitation, and inversion of physical properties of thermal barrier coating system, develop flexible planar electromagnetic/capacitive sensor array samples and principle prototype of thermal barrier coating testing system, thus lay theoretical and technical foundation for the integrity, effectiveness and safety assessment of the hot end parts of equipments.

热障涂层对提高航空发动机的推力和热效率具有重要作用，但由于热障涂层系统结构复杂并且损伤类型多样，现有无损检测方法难以实现热障涂层系统的全面检测。本项目针对航空发动机涡轮叶片等热端部件热障涂层系统全面检测与评估的需求，提出一种电磁/电容复合检测方法，重点研究热障涂层系统电磁/电容复合检测机理、电磁/电容复合式传感器设计与制备、微弱信号检测与处理、传感器标定与误差补偿、热障涂层系统损伤检测与评估方法等内容，拟突破高灵敏度、高分辨率柔性电磁/电容传感器优化设计与制造、复合式传感器阵列信息融合、材料多物理属性反演等关键技术，解决热障涂层系统电磁/电容复合检测机理、多频激励下信号特征的高精度提取、热障涂层系统多物理属性反演等关键科学问题，研制平面阵列式柔性电磁/电容传感器样品和热障涂层检测系统原理样机，为装备热端部件的完整性、有效性和安全评估奠定理论和技术基础。

热障涂层对提高航空发动机的推力和热效率具有重要作用，但由于热障涂层系统结构复杂并且损伤类型多样，现有无损检测方法难以实现热障涂层系统的全面检测。本项目针对航空发动机涡轮叶片等热端部件热障涂层系统全面检测与评估的需求，提出了一种电磁/电容复合检测方法，重点研究了热障涂层系统电磁/电容复合检测机理、电磁/电容复合式传感器设计与制备、微弱信号检测与处理、传感器标定与误差补偿、热障涂层系统损伤检测与评估方法等内容，解决了以下关键科学问题：.（1）电磁/电容复合检测机理及传感器优化设计.分别对平面电磁传感器和平面电容传感器的检测机理进行了分析，根据电磁传感器适合检测导电材料、电容传感器适合检测非导电材料的特点，通过对传感器结构的进行优化设计，将电磁传感器和电容传感器集成到同一平面内，实现了电磁/电容复合检测，最大程度地实现两种方法的优势互补，有效地提高了传感器的检测灵敏度和空间分辨率，为检测信息的融合奠定了基础。.（2）复合式传感器的信号检测与特征提取.复合式传感器阵列具有涡流和电容两种工作模式，在检测过程中将同时产生不同性质的多路微弱信号，并且由于采用多频激励，检测信号动态变化范围大。本项目采用精密阻抗分析仪，实现了传感器阻抗和等效电容的精密测量；分别建立了平面电磁传感器和平面电容传感器的误差模型，完成了传感器标定和检测通道的高精度校准。.（3）材料多物理属性反演 . 本项目利用从电磁/电容复合式传感器阵列中提取到的检测信息，采用理论建模、网格搜索、信息融合、机器学习等方法，实现了热障涂层系统中陶瓷层厚度、介电常数、粘结层电导率等多个物理参数的反演。.项目实现的主要技术指标包括：.（1）.实现了发动机涡轮叶片热障涂层系统的缺陷检测，检测分辨率达到0.1 mm；.（2）.实现了涂层电导率和介电常数的检测，检测误差小于1 %；.（3）.实现了涂层厚度的检测，检测误差小于10 mm。