工况条件下锌基合金表面张力测定及极化曲线分析

Surface tension measurement and polarization curves analysis of zinc-based alloys under operational conditions

从锌液本身的物理性能着手,通过引进焦利秤测量微小力的原理,利用吊片法测定热浸镀锌中锌液及其合金在420～480℃的表面张力,确定微量铝的加入,使由锌铝组成的理想稀溶液的自由能降低,引起锌液的表面张力下降,进而使锌液的化学位降低。并通过电化学实验测定了纯Zn及Zn-0.2%Al的极化曲线,证实了由表面张力降低所引起的锌液化学位的降低对提高镀锌层的耐腐蚀性能起很大的作用。

Based on the physical properties of molten zinc and the principle of determi- ning micro forces with Joly balanceidentical accuracy measuremen, the plate-hanging method was adopted to measure the surface tension of zinc-based alloys in hot dip galvanizing temperatures from 420 ℃ to 480 ℃. The micro-addition of aluminum resulted in the decrease of the free energy of Zn-Al alloys, which led to the reduction of surface tension of molten zinc as well as its chemical potential. The polarization curves of Zn and Zn-0. 2 %0Al were determined by carrying out electrochemical test. It is confirmed that the decrease of chemical potential of molten zinc caused by the reduction of surface tension, plays an important role in improving the corrosion resistance performance of zinc coating.