Ti6Al4V钛合金渗碳层在HF中的腐蚀行为

2021-04-19 13:11:12 作者：李坤茂来源：材料研究学报分享至：

Ti6Al4V钛合金渗碳层在HF中的腐蚀行为

李坤茂, 刘静, 张晓燕, 李宏, 代燕

1. 贵州大学材料与冶金学院贵阳 550003

2. 贵州师范大学材料与建筑工程学院贵阳 550025

Corrosion Behavior of Carburized Ti6Al4V Ti-alloy in HF Solution

Li Kunmao, LIU Jing, ZHANG Xiaoyan, LI Hong, DAI Yan

1. College of Materials and Metallurgy, Guizhou University, Guiyang 550003, China

2. School of Materials and Architectural Engineering, Guizhou Normal University, Guiyang 550025, China

摘要

用真空感应渗碳方法对Ti6Al4V钛合金进行高速渗碳，研究了渗碳层在HF溶液中的腐蚀行为。对腐蚀前后渗碳层的相结构和形貌的分析发现：对Ti6Al4V钛合金高速渗碳后，在表面生成一层TiC和CTi0.42V1.58复合化合物相的渗碳层。因为表面有渗碳层，Ti6Al4V钛合金在浓度为0.2%的HF中？泡其腐蚀速率从4.65×10-10 g·m-2·h-1降低到3.3×10-10 g·m-2·h-1。电化学腐蚀测试结果表明，其自腐蚀电位从未渗碳时的-0.94 V升高到-0.68 V,腐蚀电流密度从4.10 mA·cm-2降至1.65 mA·cm-2,极化电阻从6.36 Ω·cm2增大到15.8 Ω·cm2,Rt从0.2 Ω·cm2增大到5.7 Ω·cm2。渗碳层具有n型半导体特性，未渗碳样品具有p型半导体特性。Ti6Al4V钛合金渗碳后，在腐蚀过程中电子转移的阻力增大，使耐蚀性提高。F-对Ti6Al4V钛合金渗碳层的腐蚀机理，主要是析氢腐蚀。

关键词：材料表面与界面 ; 渗碳 ; 感应加热 ; Ti6Al4V ; 组织 ; 腐蚀行为

Abstract

The rapid carburization of Ti6Al4V titanium alloy was carried out by vacuum induction carburizing method. The corrosion behavior of carburized Ti-alloy in HF solution was investigated. Results show that after rapid carburization a layer of TiC and CTi0.42V1.58 composite compound was formed on the surface of T-alloy, and in comparison with the blank Ti-alloy, the corrosion rate in 0.2% HF solution decreases from 4.65×10-10 g·m-2·h-1 to 3.3×10-10 g·m-2·h-1 for the carburized Ti-alloy. Correspondingly, the free-corrosion potential increased from -0.94 V to -0.68 V, the corrosion current density decreased from 4.10 mA·cm-2 to 1.65 mA·cm-2, the polarization resistance increases from 6.36 Ω·cm2 to 15.8 Ω·cm2 and Rt increases from 0.2 Ω·cm2 to 5.7 Ω·cm2. The corrosion product of carburized layer mainly exhibits n-type semiconductor characteristics, and that of the blank Ti-alloy exhibits p-type semiconductor characteristics. The corrosion mechanism of F- on the carburized layer of Ti6Al4V Ti-alloy is mainly hydrogen evolution corrosion.

Keywords： surface and interface ; carburizing ; induction heating ; Ti6Al4V ; microstructure ; corrosion behavior