晶须层间强化的抗冲蚀涂层的制备及其机理研究

The low erosion resistance of plasma sprayed ceramic coatings is caused by the large non-bonded interfaces between lamella. A new method is proposed to adjust the non-bonded interfaces in this work, between which whiskers arranged directionally under an applied electric field during spraying. It is expected whiskers bridge and rivet with lamella neighboring the interface. Correspondingly, the erosion resistance of coatings can be improved. The effect of key factors, such as the parameters of applied electrical field and spraying etc on directional arrangement of whiskers will be clarified. The bonding mechanism of interface-phase (between whisker and coating) will be confirmed after the in-situ whisker pullout test under the observation of SEM, coupled with the analysis by Digital Speckle Correlation System. Furthermore, the erosion resistance of coatings is correlated with the coating microstructure, including the parameters of interface-phase. The whole process of mechanical response of coatings will be investigated. In the end the physical nature will be revealed for the improvement of erosion resistance. The findings not only open a new way to increase the erosion resistance of coatings, and improve the reliability and stability of corresponding components, but also provide new ideas for the design and preparation of coatings.

针对等离子喷涂涂层的层间存在大面积未结合区域，造成涂层冲蚀性能差的问题，本项目提出在喷涂过程中辅助外加电场作用，形成晶须在涂层层间定向排布的调控涂层结构的新方法-与层间间隙的相邻粒子形成铆接、在涂层层间形成桥接，从而预期可实现涂层冲蚀性能的大幅度提高。从动力学角度研究外加电场作用下晶须的定向排布问题，研究关键因素对晶须排布的影响规律；进行电镜下的原位纤维拔出试验，配合数字散斑系统，确定界面相的结合机理，建立界面相的微观结构与涂层冲蚀性能的有效关联，表征新型涂层结构与冲蚀性能的关系；计及界面相的不同结合方式，结合涂层结构的有限元模型，研究颗粒冲蚀作用下涂层系统的全过程力学响应，揭示冲蚀性能提高的物理本质。研究结果不仅可开辟增强涂层性能的新途径，并提高冲蚀环境下设备的可靠性与稳定性，而且为涂层的设计和制备提供新思路。

针对等离子喷涂涂层的层间结合有限，从而造成涂层的抗冲蚀性能、磨损与腐蚀性能差等问题，本项目以外加高压静电场为牵引，诱导掺杂在粉末中的细长晶须发生偏转，进而在涂层层间形成铆接作用。在几年的研究中，设计并搭建了高压静电场，从动力学角度研究了晶须、单个粒子、涂层中的晶须等在电场作用下的偏转行为。探索涂层中的固有缺陷对涂层的性能的影响规律，建立涂层结构、冲蚀性能、冲蚀参量的有效关联，揭示冲蚀性能提高的物理本质，为涂层设计与制备提供新思路。