空蚀对镍基Inconel600合金钝化膜电化学性能影响

The influence of cavitation erosion on the electrochemical bahavior of the passive film on nickel-based alloy Inconel 600 in NaCl solution and water was investigated using electrochemical work station and rotating disk equipment, the point defect densities, flat-band potential, Femi energy and the electric field were acquired by measuring the EIS, Mott-Schottky and the photon electron current response of the passive film after cavitation erosion or during cavitation process. The mechanism of the cavitation effect on the microstructures of the passive film and cavitation region was obtained by XPS, AES, AFM and SEM. On the basement of energy band theory, electrochemistry and surface technology, the relationship of electrochemical behaviour and cavitation erosion was discussed, the influence of film formation and chloride ions on the cavitation erosion of Inconel 600 alloy was also detected. According to the above results, the corresponded energy band of the passive film which having anti-cavitation erosion can be found, and then the design criteria of the novel nickel-based alloy which had anti-cavitation erosion can be acquired.

利用电化学工作站和旋转圆盘研究镍基合金Inconel600在氯化钠溶液和自来水介质中空蚀对其表面钝化膜电化学性能影响，通过空蚀前后和空蚀过程中钝化膜电化学阻抗谱(EIS)、Mott-Schottky曲线以及光电流响应曲线等测试获得膜内点缺陷浓度、平带电位、费米能级以及膜内电场强度等有关物理参数的变化规律；借助于X射线光电子能谱(XPS)、俄歇能谱(AES)、原子力显微镜(AFM)、扫描电镜(SEM)等分析手段获得空蚀对钝化膜微观结构和空蚀区域的微观形貌的影响机理。利用半导体表面能带理论、电化学理论以及表面分析结果分析Inconel600合金表面钝化膜电化学性能与其空蚀行为间的相互关联性。同时研究成膜条件和氯离子等外界因素对Inconel600合金空蚀性能影响，找到抗空蚀镍基合金钝化膜所对应的能带结构，利用能带结构与基体成份间的对应关系为抗空蚀镍基合金研制提供设计准则。

本项目以螺旋桨、管道以及阀门等过流部件的空蚀现象为研究背景，通过研究空蚀过程中Inconel600合金钝化膜电化学性能的变化来获取空蚀对钝化膜的半导体参数的影响机理，并利用钝化膜半导体参数可通过合金化以及热处理等手段进行调节的规律可以找到抗空蚀镍基合金钝化膜所对应的能带结构，利用能带结构与基体成份间的对应关系为抗空蚀镍基合金研制提供设计准则。通过该项目的进行可以得到随着钝化膜内载流子浓度的减小、钝化膜平带电位的正移以及钝化膜厚度的增加，基体的抗空蚀能力显著增强。通过调控钝化膜能带结构实现对基体抗空蚀能力调控的原理在于钝化膜的能带在液体介质中由于膜和液体的化学势或费米能级的不同而造成钝化膜能带在膜/液体界面处发生弯曲现象，弯曲的结果使得膜表面会吸附一层负电荷，且膜的平带电位越正所带负电荷越多。而在实际的液体介质中含有大量的微颗粒，且微气泡和微颗粒均带有负电性，这样一来，当微气泡或携带微颗粒的微气泡高速趋近基体表面时会受到同性电荷强烈的排斥作用，进而减缓其对基体的打击作用。通过该项目的研究可以丰富空蚀发生机理且为新型抗空蚀镍基合金的研制提供设计准则。