温度对AZ31B镁合金植酸转化膜性能的影响  

Influence of Conversion Fluid Temperature on Corrosion Resistance of Phytic Acid Conversion Coating of AZ31B Magnesium Alloy

作　　者：高焕方[1,2] 张胜涛[1] 李军[2] 刘益风[2] 牛英男[2] 

机构地区：[1]重庆大学化学与化工学院,重庆400030 [2]重庆理工大学化学化工学院,重庆400050

出　　处：《材料保护》2011年第9期35-37,43,共4页Materials Protection

基　　金：重庆自然科学基金(2008BB4062)资助

摘　　要：为了探讨转化温度对镁合金防腐蚀性能的影响,应用析氢试验、Tafel分析法及SEM,EDS,FTIR研究了不同植酸液温度所形成的转化膜的防腐蚀性能及表面微观形貌、元素组成及官能团构成。结果表明转化温度对镁合金植酸转化膜的防腐蚀性能有较大的影响:在较低范围内,转化膜的防腐蚀性能随着温度的升高而增加,转化温度为40℃时,转化膜防腐蚀性能最佳,此后随着温度的进一步提高,转化膜的防腐蚀性能随之下降。镁合金植酸转化膜为较薄的致密内层及具有一定裂纹的外层所组成,主要成分Mg,Al,Zn,C,O,P等元素,并含有PO43-,HPO24-及OH-基团。Phytic acid conversion coatings were prepared on the surface of AZ31B magnesium alloy at different temperature of the conversion fluid.The corrosion resistance of as-prepared conversion coatings was evaluated based on hydrogen evolution test and Tafel test.The morphology,elemental composition and chemical feature of the conversion coatings were analyzed by means of scanning electron microscopy,energy dispersive spectrometry and Fourier transform infrared spectrometry.Results indicate that the temperature of phytic acid conversion fluid has obvious influence on the corrosion resistance of the conversion coatings.At relatively low temperature of the conversion fluid,the corrosion resistance of as-prepared conversion coatings increased with increasing conversion fluid temperature,and the conversion coating obtained from the conversion fluid of 40 ℃ possessed the best corrosion resistance.When the conversion fluid temperature was above 40 ℃,the corrosion resistance of conversion coatings declined with further increase of temperature.The phytic acid conversion coating on Mg alloy surface consisted of a thin and compact inner layer plus an outer layer containing some cracks,and was mainly composed of Mg,Al,Zn,C,O,P as well as functional groups including PO3-4,HPO2-4 and OH-.

关 键 词：转化膜 植酸 转化温度 镁合金 防腐蚀性能 

分 类 号：TG174.4[金属学及工艺—金属表面处理]