电参数调控TC4钛合金微弧氧化膜层耐蚀性的研究

Electrical Parameters to Regulate Corrosion Resistance of Micro-arc Oxidation Coating on TC4 Titanium Alloy

摘要:

采用极差分析法研究电参数（电压、脉冲频率、占空比和处理时间）对TC4钛合金微弧氧化膜层耐蚀性的共同影响，进而探寻影响膜层耐蚀性的电参数显著性关系和最佳因素水平组合。同时结合膜层形貌和物相组成进一步探讨电参数对膜层耐蚀性的影响机制并建立回归方程，以此来实现通过电参数对微弧氧化膜层耐蚀性的调控。结果表明：占空比对膜层电化学耐蚀性影响的显著性最高，其次是脉冲频率和电压，处理时间对其影响较小。占空比和脉冲频率通过改变燃弧放电时间和熄弧冷却时间来影响膜层结构和性能，增加电压、占空比、处理时间或降低脉冲频率可使电源输出功率增加，导致膜层厚度增加、微孔孔径增大、致密度降低，膜层中Al₂TiO₅的生成效率更高，电化学耐蚀性能随之降低。通过相关系数法检验可知：所建立回归方程的因变量与自变量之间具有高度相关性，可以为钛合金微弧氧化膜的性能调控提供理论支持和预测方法。

Abstract:

The combined effects of voltage, pulse frequency, duty cycle and processing time on the corrosion resistance of micro-arc oxidation coatings on TC4 titanium alloy were investigated using range analysis, with a subsequent objective of exploring the significance relationship of electrical parameters and their optimal combination. The influence mechanism of electrical parameters on the corrosion resistance of the coatings was explored by combining coating morphology and phase composition. A regression equation was established to facilitate regulation of the corrosion resistance of micro-arc oxidation coatings through manipulation of electrical parameters. The results show that the duty cycle exhibits the most significant influence on the electrochemical corrosion resistance of the coating, followed by pulse frequency and voltage, while the processing time shows a comparatively lesser effect. The duty cycle and pulse frequency influence both structure and performance characteristics of the coating by modulating arc ignition discharge duration and arc quenching cooling time. Increasing voltage, duty cycle and processing time, or decreasing pulse frequency can elevate the power supply output, which leads to an increase in coating thickness and pore size in microporous structures while reducing coating densification. Furthermore, this process promotes more efficient generation of Al₂TiO₅ in the coating; however, it ultimately results in diminished electrochemical corrosion resistance. The results of correlation coefficient testing indicate a strong relationship between the dependent and independent variables within the established regression equation. This finding provides theoretical support and predicting methods to regulate performance characteristics of titanium alloy micro-arc oxidation coatings.