TC4钛合金在Na₃PO₄-NaF-CH₃COOH溶液体系中转化膜的制备及其性能研究

TC4 Titanium Alloy in the Na₃PO₄-NaF-CH₃COOHSolution Conversion Coating Preparation and Its Performance Study

摘要: 采用Na₃PO₄-NaF-CH₃COOH溶液体系对TC4钛合金进行表面转化膜处理。用SEM、EDS、XRD对转化膜表面形貌和组成进行分析，发现膜层主要由Na₃tiF₆相、TiO₂相和基体钛相等组成，结晶过程是膜层增重的主要原因。研究转化温度与时间对未酸洗及经过酸洗处理的TC4钛合金在Na₃PO₄-NaF-CH₃COOH溶液体系下的影响，发现在25℃、10 min的条件下，钛合金成膜效果最好，膜层呈浅灰色，而转化膜的制备亦是一个腐蚀与生长同时进行的过程。对TC4钛合金成膜前后的涂层附着力进行比对，结果显示经过磷酸盐–氟化物混合溶液处理的样品表面涂层附着力得到了较大的提升。

Abstract: Using the solution system of Na₃PO₄-NaF-CH₃COOH to conduct conversion coating surface treatment on TC4 titanium alloy, we analyze the surface shape and composition of conversion film by using SEM, EDS, XRD. Results show that the conversion film is mainly composed by Na3tiF6 phase, TiO₂ titanium phase and the matrix. The main reason for weight gain is the process of film crystallization. In Na₃PO₄-NaF-CH₃COOH solution system, we study the effect of translative temperature and time on the pickling and unpickling treatments of TC4 titanium alloy. We find that in the condition of 25˚C and 10 min, the process of titanium alloy film is best; and that the colour is light gray while the fabrication of the conversion film is a process of corrosion and growth. Comparing the coating adhesion force of the TC4 titanium alloy before and after filming, we find that the sample surface coating adhesion was greatly improved after fluoride phosphate mixed solution treatment.