NaCl盐膜对CuCr合金高温腐蚀行为的影响

EFFECT OF NaCl DEPOSIT ON THE CORROSION BEHAVIOR OF CuCr ALLOY AT 700℃～900℃

用金相、X射线衍射(XRD)、扫描电镜/能谱(SEM/EDX)及热重分析法研究了NaCl盐膜对CuCr合金在700℃～900℃下的腐蚀行为的影响.结果表明:CuCr合金在NaCl盐膜下比在单独空气中发生更严重的腐蚀,其腐蚀产物疏松且易剥落,Cr相较Cu易腐蚀,且在腐蚀区以下的合金基体中有贫铬现象.讨论了在该环境下变形对CuCr合金腐蚀的影响及NaCl加速CuCr合金腐蚀作用的机制.

A simulated galvanostatic occluded cell was used to investigate the effect of cathodic polarization on chemical and electrochemical states inside occluded cell （OC） of localized corrosion for cast iron in alkaline solution. It has been found that as the cathodic current passes through the cell, the pH value of the OC solution rises with prolonging of time and rising of current density; the rate of Cl^- migrating out from the OC also rises with prolonging of time and rising of current density. Because of Cl^- migrating out from OC and OH^- immigrating into OC, the localized corrosion was retarded. Passing cathodic polarization in alkaline solution can make Cl^- migrating more quickly, it is more efficiency than the cast iron dipping in alkaline solution（no cathodic polariza tion）.