T225NG钛合金在高温高压水质中的电化学行为

本文采用电化学测量方法测定了特殊换热器传热管用材料钛合金T225NG在高温高压不同氯离子浓度和不同溶解氧含量水质条件下的极化曲线,并探讨了钛合金T225NG在不同水质条件下的电化学行为和腐蚀机理.在本实验条件下钛合金T225NG的各阳极极化曲线没有出现活化区,但随着Cl-浓度和溶解O2浓度的增加,阳极极化曲线的维钝电流密度增大,钛合金的腐蚀增大.当Cl-＜0.005mg/L时,钛合金T225NG的阳极极化曲线只有一个电位区间氧化膜形成区A段;而当Cl-≥0.02mg/L时,各阳极极化曲线则存在两个电位区间A段和B段.

Electrochemical Behavior of T225NG Titanium Alloy in High Temperature and High Pressure Aqueous Solution

The polarization curves of T225NG Titanium Alloy in high temperature and high pressure aqueous solution with different concentrations of chlorine ion and dissolved oxygen have been measured by electrochemical method, and its electrochemical behavior and corrosion mechanism have been analyzed. The active regions of the anodic polarization curves of T225NG Titanium Alloy have not been found in the test condition. Passive current density and corrosion of T225NG Titanium Alloy increases when the concentration Cl^- and dissolved O2 becomes high. There is a formation of oxide film i.e. A region in the solution which Cl^- is below 0.005mg/L while there are formation of oxide film and release of Cl2 i.e. A and B regions in the solution which Cl^- is above 0.02mg/L for the polarization curves of T225NG Titanium Alloy.