Corrosion Resistance And Electrochemical Properties Of PbCaSnAlCeAg Grid Alloy

At present,the most commonly used grid alloy in lead-acid batteries is lead-calcium alloy and nevertheless compounds formed on the surface of the alloy during its working is the main reason for excessive growth and fracture failure of the grid alloy.Aimed at this problem,this paper deals with the corrosion resistance,electrochemical properties and related microstructure of surface corrosion layer of PbCaSnAlCeAg alloy in cast-natural aged,solid solution-natural aged,cast-natural aged-cured treatment and solid solution-natural aged-cured treatment state respectively,using the corrosion rate of alloys,electrochemical methods,SEM and XRD analysis,taking PbCaSnAl alloy as counterpart.The results showed that the primary corrosion mode of the cast-natural aged alloys was intergranular corrosion.The grain size was reduced,the corrosion rate decreased and the surface corrosion layer was uniform and compact after adding Ce and Ag.The corrosion potential of PbCaSnAlCeAg alloy rose 10 mV,the oxygen evolution potential increased 31mV and the impedance of Pb（Ⅱ）film decreased 3275Ω·cm^-2.Compared with the cast-natural aged alloys,the grain size of alloys became larger after solid solution-natural aging treatment.The Pb₃Ca precipitated in the alloys accelerated the intergranular corrosion,the oxygen evolution reaction of the alloys intensified and the conductivity of Pb（Ⅱ）film decreased.These phenomena were more obvious in PbCaSnAl alloy than in PbCaSnAlCeAg alloy due to Ce and Ag addition,which can refine grain and inhibit the diffusion of Ca.After curing treatment of cast-natural aged alloys,the grain size of two alloys grew up slightly.This resulted in a decrease in the corrosion resistance and electrochemical properties of the alloys,but the effect in PbCaSnAlCeAg alloy was not distinct.For two solid solution-natural aged-cured treatment alloys,the corrosion product PbSO₄ on PbCaSnAl alloy peeled off earlier during the corrosion process than that on PbCaSnAlCeAg alloy,as the corrosion layer of PbSO₄ on PbCaSnAlCeAg alloy was denser.The study confirmed that the corrosion resistance and electrochemical properties of PbCaSnAlCeAg alloy were better than those of PbCaSnAl alloy under the same treatment and test conditions.