铅锑合金负极极耳腐蚀的研究

Corrosion of the Pb-Sb negative lugs in H2SO4 solution

采用观察金相、电子探针、化学分析和线性电位扫描等方法探讨了铅锑合金负极极耳在铅酸蓄电池中发生腐蚀的原因.结果表明,由于合金在浇铸过程中各部分冷却速度不同等因素,使得合金不同部位的结晶形态等有所不同,这种现象在铅合金质量较大的极耳上表现尤为明显,极耳中央部位的结晶较边缘的杂乱、松散,并有比较严重的锑的表面偏析现象.这种晶体组织结构上的明显差异,导致中央部位的腐蚀速度显著增大,严重时会出现极耳中心穿孔的现象.另外,电极在充放电过程中板栅上硫酸盐层下的基底的氧化腐蚀,是腐蚀过程深向内部的重要原因.

The corrosion problem of the Pb-Sb negative lugs of lead acid battery has been investigated by means of metallographic method,electron macroprobe,chemical analysis and electroche mical techniques. The results show that the metallographic texture of the alloy and the distribution of Sb in the alloy play an important role in the corrosion process. The crystallites in the middle part of the negative lug exhibit greater disorder and have less size than those in the edge part. The content of Sb in the 0. 05mm surface layer of the middle part is 10% higher than that in the edge part. The corrosion rate of the middle part of the lug is greater than that of the edge part during charge-discharge cycling. The non-uniform distribution of Sb and the surface sedimentation of Sb accelerate the corrosion of the central part of the lug.