不锈钢电化学诱导表面退火的机理研究和处理工艺优化原则

采用XRD、循环伏安和硬度测试等方法研究了不锈钢中的电化学诱导表面退火(EISA)的机理及处理工艺。结果表明:阴极过程中的H+离子还原、H原子向钢内部的扩散和积聚,阳极过程中H原子重新氧化是EISA相变的决定性过程。-1.44 V(相对于饱和甘汞电极)的阴极电位可致H+离子还原,足以导致EISA相变。当阳极电位高于0.3 V(相对于饱和甘汞电极)时会形成过厚的钝化膜,阻止H原子的扩散,从而抑制EISA相变。长阴极/短阳极的处理方式可以提高EISA处理效率。只有在电脉冲处理过程中防止溶液中Fe2+/Fe3+反应发生才会发生EISA相变。

Mechanistic study and optimization principles of electrochemically induced surface annealing of stainless steel

The principles and mechanism of electrochemically induced surface annealing (EISA) have been studied using XRD, cyclic voltammetry and hardness tests. H+ ion reduction, and H atom penetration and accumulation in the steel during the cathodic part, together with H atom re- oxidization in the anodic part were found to be the critical steps in the EISA treatment. A cathodic potential of -1.44V (vs. SCE), which can reduce H+ ions, is low enough for EISA treatment. An anodic potential higher than 0.3V (vs. SCE) may cause too thick a passive film, which will obstruct the diffusion of H atoms and hinder the EISA phase transformation. A long-cathode/short-anode EISA treatment can improve the efficiency of the treatment. EISA phase transformation can only occur in a solution which does not give Fe2+/Fe3+ reaction during the treatment process.