氧离子导体陶瓷薄膜压阻式高温应力传感性能与机制研究

Stress sensors are being widely used in modern industries nowadays but those suitable for high temperature applications (such as in aerospace, airplanes, flue gas filtration and so on) are still not sophisticated enough. The key solution to this issue is to develop stress sensing materials with outstanding piezoresistive performance (i.e. the resistance changes swiftly with the applied stress) and excellent stability at high temperatures (above 600°C). Oxygen ion conductive ceramics are excellent high-temperature conductors. Their crystal structures and the oxygen ion transportation and thus the resistances can be significantly changed by stress. Therefore, it is possible to develop stress-sensitive materials with high performance at high temperature based on oxygen ion conductors. In this project, we will prepare heterostructured multilayers of doped-zirconia/amorphous alumina which are supported by flexible substrates. The crystal structures, mechanical and electrical performances of the thin films will be tuned by the hetero-phase interfacial interaction, through which the controllable preparation of high-performance stress-sensitive thin films will be realized. Cyclic loading-unloading will be applied to the thin film, and the mechanism for the stress-induced crystal distortion and the influence on the oxygen ion conduction will be studied using in-situ Raman spectroscopic and in-situ electrical tests. The quantitative relationship between crystal strain, Raman shift, and the resistance at high temperature, as well as the mechanism for the high-temperature piezoresistive sensing behaviors will be established. Furthermore, array-type stress sensors will be fabricated and the influence of interfacial stress transfer on the stress sensing mechanism will be studied. The stress-sensitive thin films of oxygen-ion conductive ceramics prepared in this project would possibly become an important base material for the next-generation high-temperature stress sensors.

应力传感器在现代工业生产中已获得广泛应用，但适于高温环境（如航空航天、高温烟气过滤等领域）的传感器仍然不成熟。开发在高温（>600°C）下稳定且具有高灵敏压阻效应（电阻随应力改变迅速变化）的应力传感材料是解决问题的关键。氧离子导体陶瓷是一种优异的高温导体材料，且应力可显著改变其晶格结构和氧离子传导并调控电阻大小，因此有望开发基于氧离子导体的高性能高温力敏材料。本项目拟制备柔性衬底支撑的掺杂氧化锆/非晶氧化铝多层异质薄膜，通过异质界面作用调控薄膜的微观结构、力学与压阻性能，实现高性能力敏薄膜的可控制备；对薄膜作加载-卸载循环，结合原位拉曼和原位电学测试研究外力诱导晶格畸变机制及其对氧离子传导的影响，建立应变-频移-电阻定量关系，阐明高温应力响应机理。进一步制备阵列式应力传感器，研究界面应力传递对力传感微观机制的影响。本项目拟制备的力敏感氧离子导体膜有望成为下一代高温应力传感器的重要基础材料。

氧离子导体材料已被广泛用于高温领域，且应力可显著改变其晶格结构和氧离子传导能力，进而调控电阻大小，有望应用于高温应力传感领域。本项目采用射频磁控溅射方法制备了无择优取向Ce0.8Sm0.2O2-δ/Al2O3（SDC/AO）多层膜电解质，其400 ºC电导率相对于YSZ块体提高2个数量级。结合微加工工艺，将沉积在柔性人造云母衬底上的SDC/AO薄膜成功制作了微型高温应力传感器。发现异质界面调控择优取向和非择优取向的多晶多层薄膜界面微观结构作用不同，因而对电学性能的调控呈现相反界面效应：无择优取向的SDC/AO多层膜的异相界面区域晶体结构缺陷增加，结构高度无序，有利于加速氧离子传导，界面电导率相对于非界面电导率提高将近100倍，产生正面界面效应；强（111）织构的SDC/AO多层膜的异相界面区域比非界面区域晶粒取向无规则性强，晶界对氧离子传导阻碍作用更高，产生负面界面效应。建立了结合拉曼和电学测试研究氧离子导体薄膜压阻性能的测试方法，建立了应变-频移-电阻关系，阐明界面应力传递对力传感微观机制的影响，实现了高温（600-800°C）下灵敏度高且稳定的应力传感。