Evaluation Methods Of Corrosion Resistance Of Positive Grid Alloys For Lead Acid Batteries

Research on corrosion resistance and corrosion mechanism of positive grid alloys for lead-acid batteries has always been an important direction.During the development of lead-acid battery industry,a variety of classic or modern metal corrosion analysis and evaluation methods have been depl oyed and great progress has been made in this field.Four polished lead alloy samples of the same size were subject to constant potential anodic corrosion tests at 60? and 35? and to step potential cyclic anodic corrosion at 35 ?.Weight loss measurement,metallographic analysis and SEM obserrvations were used to study the corrosion resistances of lead alloy samples.The results showed that corrosion products and corrosion resistance performance were different in constant potential and stepped potential anodic corrosion tests while stepped potential corrosion was able to shorten corrosion treatment period.In addition,another four corresponding blank lead alloy samples were made for polarization test and corrosion current density and corrosion potential were obtained through Tafel linear extrapolation.The constant potential analysis and nonelectrochemical method offered similar corrosion resistance conclusion.Different metal corrosion analysis methods were applied to study the corrosion resistance behavior of four different positivet lead alloys.The advanta ges and disadvantages of these analysis methods are as follows: electrochemical polarization test is effient but not able to observe sample apperance.Weight loss analysis is quantitative with high precision in quatity change but not able to obtain corrosi on morphology.Metallography is able to reflect corrosion morphology directly but doesn't have high precision in average corrosion rate.SEM is to observe microscopic morphology but it is difficult to analyze corrosion depth and average corrosion rate.Through the comparison and confirmation of different corrosion evaluation methods,the factors that influence corrosion incidence and the possible composition of corrosion products were clearly analyzed.The advantages,disadvantages,applicability and application scope of different analytical methods are clarified.The selection of corrosion analysis methods was then put forward for different lead alloys and different research aims.