钽在无水乙醇中的腐蚀

采用动电位极化、循环伏安、交流阻抗和扫描电镜等技术研究了钽在四乙基氯化铵（TEA）乙醇溶液中的腐蚀行为．在循环伏安曲线的扫描初期，电极表面因存在一薄层氧化物膜而使得电流密度缓慢增加．后来钝化膜因受到氯离子的攻击而被击穿，即点蚀．扫描电镜图很好地显示出蚀孔的生长过程．点蚀电位随着TEA浓度的增加而下降，随着水含量的增加而上升．在所研究的温度范围内，电化学反应的活化能为36kJ／mol．所有电极电位下的交流阻抗图谱都包含两个时间常数，钝化膜电阻和电荷传递电阻均随电极电位的增加而下降．

Corrosion Study on Tantalum in Anhydrous Ethanol

The corrosion behavior of tantalum in tetraethyl ammonium chloride （TEA） ethanol solutions was investigated using potentiodynamic polarization, cyclic voltammetry, and impedance techniques along with scanning electron microscopy （SEM）. At the early stage of scanning, the current density in the cyclic voltammetry curves very slowly increased because of the presence of a thin oxide film on the electrode surface. Pitting corrosion then occurred as a result of the passivity breakdown caused by the aggressive attack of the Cl^- anions. SEM images showed the growth process of the pits on the electrode surface. The pitting potential decreased with the increase in TEA concentration but increased with the increase in water concentration. The apparent activation energy of the electrochemical reaction was 36 kJ/mol. The impedance spectra exhibited two time constants for all the potentials. Both the passive layer resistance and the charge transfer resistance decreased with the increase in the potential.