摘要
用失重法、线性电位扫描、恒流放电、电化学阻抗谱等方法研究了AZ31镁合金在中性MgSO4溶液中的电化学性能及有机添加剂十二烷基苯磺酸钠(SDBS)对AZ31镁合金的缓蚀作用。结果表明,少量的SDBS能使AZ31镁合金的开路电位和活化电位正移,极化电阻增大,电极表面氢气的析出受到抑制,大电流放电性能得到改善。SDBS的缓蚀效果与其使用量之间成"反S"型的变化关系。SDBS浓度小于0.1mmol/L时,其缓蚀作用随SDBS的增加而增强;在0.1～0.2mmol/L的范围内,缓蚀作用则随SDBS的增加而降低;之后又随SDBS的增加而增强。有机缓蚀剂吸附理论可以解释这种变化规律,而驰豫过程阻抗值和电荷传递电阻受SDBS影响的不同步是这一规律的深层原因。AZ31镁合金在50mA/cm2电流密度下的恒流放电效率大于73%,具有作为金属燃料电池负极材料的实际价值。
The electrochemical properties of AZ31 alloy in MgSO4 solution and the inhibiting ability of sodium dodecyl benzene sulfonate （SDBS） to the alloy were investigated by weight-loss measurement, linear sweep voltammetry （LSV）, chronopotentiometry and electrochemical impedance spectroscopy （EIS）. The results show that a small quantity of SDBS could make the open circuit and active potential more positive, polar resistance bigger, the bubbling of hydrogen on the surface of electrode was restrained, resulting in the performance of discharge at high current density was improved. In studied concentration range of SDBS, there was an ＂anti-S＂ shape rule between the concentration and the inhibiting ability to AZ31 alloy. When the concentration was less than 0.1 mmol/L, the inhibiting ability gradually enhanced; when between 0.1.-0.2 mmol/L, the inhibiting ability reduced; when more than 0.2 mmol/L, the ability increased again. The phenomenon could be attributed to the nonsynchronous change between the resistance of relaxation process of adsorbed species on the electrode surface and the resistance of charge transfer. The current efficiency of discharge at 50 mA/cm^2 was bigger than 73%, which implied the actual utilization of AZ31 alloy in metal fuel cells.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2007年第12期2244-2247,共4页
Rare Metal Materials and Engineering
关键词
AZ31镁合金
负极材料
缓蚀
十二烷基苯磺酸钠
AZ31 magnesium alloy
negative material
inhibiting
sodium dodecyl benzene sulfonate
