植酸浓度对AZ31B镁合金植酸转化膜防腐性能的影响

摘要

在不同浓度的植酸溶液中制备了AZ31B镁合金植酸转化试样,并应用析氢实验及Tafel极化曲线测试其防腐性能,使用SEM,EDS,FTIR观察转化膜形貌、元素组成及官能团构成.结果表明:植酸溶液的浓度对植酸转化试样的防腐性能具有较大的影响,C=4.0g·L-1时所制备的转化试样具有最佳的防腐性能,电流密度较未处理试样降低了2个数量级.此外,植酸转化膜主要由Mg,Al,Zn,O,P等元素组成,并含有PO34-,HPO24-,OH-基团,转化膜存在一定的裂纹,且裂纹处仍有很薄的一层植酸转化膜.%The phytic acid conversion coatings on AZ31B magnesium alloy were formed in different phytic acid concentrations and the corrosion resistance of the conversion samples was studied by hydrogen evolution method and Tafel. The morphology, composition and functional groups were investigated by SEM, EDS and FTIR, respectively. The results indicate that the concentration of phytic acid has obvious influence on the corrosion resistance of the conversion samples, the conversion sample formed under C=4.0g · L-1 has the best corrosion resistance, the current density decreases about two orders than that of the untreated sample. The main elements of the coating are Mg, Al, Zn, O and P, the functional groups are PO43- , HPO42- and OH- . The conversion coating also has few cracks, and the thin coating is formed on the crack.