利用EBSD技术研究690合金在高温高压水环境中腐蚀行为

Research on corrosion behavior of 690 alloy in high temperature and high pressure water environment using EBSD technology

摘要:

采用扫描Kelvin探针（SKP）和电子背散射衍射（EBSD）技术结合高温高压浸泡实验研究了两种不同变形量的690合金的C型环样品在浸泡后的电化学行为。结果表明：690合金在高温高压浸泡实验中生成Fe、Ni、Cr的腐蚀产物；EBSD检测统计分析得25%变形量的690合金样品Σ3晶界所占比例比50%变形量的690合金样品所占比例多10%，均有轻微不同种类的织构；扫描Kelvin探针测得浸泡后Ekp都有明显的升高，25%变形量的690合金C型环样品Ekp升高到-3.5 mV，而50%变形量的690合金C型环样品Ekp升高到-29.2 mV，说明25%变形量的690合金表面生成的腐蚀产物膜保护性能更好。

Abstract:

Scanning Kelvin probe (SKP) and electron backscatter diffraction（EBSD）testing techniques, combined with high temperature and pressure immersion test were used to investigate the electrochemical corrosion behavior of C-type ring made by 690 alloy with different degrees of deformation. The results show that the corrosion products on the 690 alloy are composed of oxide particles which are rich in Fe、Ni and Cr. EBSD test statistics analysis shows that the proportion of Σ3 grain boundaries in 690 alloy with 25% deformation is 10% more than that of 690 alloy with 50% deformation, and both kinds of 690 alloy have mild but different texture. The SKP measurement results display that Ekp of C-type ring samples after immersion has a significant rise, reaching -3.5mV for 690 alloy with 25% deformation and -29.2mV for 690 alloy with 50% deformation respectively, which also indicates the corrosion products film on 690 alloy with 25% deformation plays a better protective role as it results in a higher Ekp (26mV higher than that of 690 alloy with 50% deformation).