VGE 特性对 TA4 等离子体电化学抛光过程中的等离子体电化学反应路径的影响
刘力允¹ ,刘进伟¹
（1.四川大学机械工程学院，四川 成都 610065）
[摘要]
在钛合金的等离子体电化学抛光（Plasma Electrochemical Polishing，PEP）过程中，气态包络（Vapor-Gaseous Envelope，VGE）的形态特征与等离子体电化学反应路径之间的关联尚不明确，制约了该技术的进一步优化与应用。
研究在2% NaF + 2% NH₄Cl的中性抛光液中进行，单次抛光时间为1 min，调节抛光液初始温度（40-80℃，间隔10℃），促使TA4合金表面形成不同特征的VGE。通过分析不同VGE下的PEP反应产物，阐明了VGE特征与等离子体电化学反应路径之间的关联。
实验发现，随着溶液初始温度的升高，VGE依次呈现三种典型状态：“波动-薄” VGE、“稳定-薄” VGE、“波动-厚” VGE。在不同的VGE特征下进行的PEP过程，表面主导反应路径发生显著变化：在“波动-薄” VGE下，氟化与氧化的竞争达到平衡，主要生成TiOF₂；在“稳定-薄” VGE下，氧化反应成为主导反应，主要生成TiO₂；在“波动-厚” VGE下，电化学驱动的氟化反应占据优势，主要生成TiF₄。在“稳定-薄” VGE下对TA4进行6min抛光，可将粗糙度由 325.7 nm 降低到47.5 nm。
研究阐明了气态包络的形态特征与等离子体电化学反应路径的关系，为实现钛合金表面的原子级抛光提供了重要的理论依据与工艺指导。
[关键词] 等离子体电化学抛光；钛合金；气态包络特征；等离子体电化学反应路径

The influence of VGE characteristics on the plasma-electrochemical reaction pathways in plasma electrochemical polishing of TA4
Liyun Liu¹, Jinwei Liu¹
(1. College of Mechanical Engineering, Sichuan University, Chengdu 610065, Sichuan, China) 
Abstract:
The connection between vapor-gaseous envelope (VGE) characteristics and plasma-electrochemical reaction pathways in plasma electrochemical polishing (PEP) of titanium alloys remains unclear, which hinders the further optimization and application of this technology.
In this study, a neutral solution of 2% NaF + 2% NH₄Cl was used as the polishing solution, with a single polishing time of 1 min. By controlling the solution's initial temperature (40-80 ℃, step size 10 ℃), different VGE characteristics were constructed. The reaction pathway of the TA4 in PEP was elucidated by analyzing surface reaction products under varying VGE characteristics.
The VGE displays three primary states as the solution's initial temperature rises: “shaky-thin” VGE, “stable-thin” VGE, and “shaky-thick” VGE. In the PEP processes with different VGE characteristics, the dominant reaction pathways on the surface changed significantly. In the “shaky-thin” VGE, TiOF₂ becomes the main reaction product due to the balance between F and O. In the “stable-thin” VGE, TiO₂ becomes the main reaction product due to the oxidation reaction becoming the dominant reaction. In the “shaky-thick” VGE, TiF₄ becomes the main reaction product owing to electrochemically driven fluorination.
This study clarified the relationship between the VGE characteristics and the plasma electrochemical reaction pathway, providing essential theoretical guidance for achieving atomic-level precision in polishing titanium alloy surfaces.
Keywords: Plasma electrochemical polishing; Titanium alloy; Vapor gaseous envelope characteristic; Plasma-electrochemical reaction pathway

等离子体电化学抛光；钛合金；气态包络特征；等离子体电化学反应路径