中温NaCl-水蒸气协同作用下铁的腐蚀机理

The Mechanism of Electrochemical Testing Method under Synergistic Effect of NaCl and Water Vapor at 600℃

应用电偶电流测试法研究在中温固态NaCl盐膜-水蒸气协同作用下,纯铁的腐蚀电化学反应机理.交流阻抗(EIS)法和SEM测试表明,阻抗谱能有效地表征材料表面氧化膜的存在以及反应过程氧化物的变化趋势,其中金属的氧化层电阻与腐蚀速率之间有较好的对应关系.

The existence of electrochemical reaction during the corrosion process of pure Fe under a deposit of solid NaCl in water vapor at above 400 ℃ had been detected by measuring the corrosion current using doublelayer electrode. In EIS measurement, only one capacitive loop was obtained on the pure metals and this gave the information of oxide layer on them. The electrochemical impedance spectroscopy （EIS） and scanning-electron microscopy （SEM） results testified that there is a good relationship between the resistance of oxide layer Rox and the corresion reaction rate for pure metals with different oxidation times. The electrochemical technique is an effective method for studying corrosion performance at high temperature.