硅酸钠对5083铝合金点蚀性能的影响研究

通过循环阳极极化曲线、电化学阻抗谱的测试以及浸泡腐蚀试验,研究了硅酸钠对5083铝合金在3.5%氯化钠溶液中的点蚀性能的影响。极化曲线结果表明,硅酸钠的加入使得5083铝合金在3.5%氯化钠溶液中的点蚀电位正移。通过EIS试验和浸泡腐蚀试验可进一步得出:体系中硅酸钠水解使得溶液中OH-浓度增加,铝合金表面钝化膜和Al2(SiO3)3沉淀膜增厚,从而较好地抑制了铝合金表面的点蚀,基体得到保护。

Effect of Sodium Silicate on the Pitting Corrosion of 5083 Aluminium Alloy

The effect of sodium silicate（Na2SiO3） on the piting corrosion of 5083 aluminium alloy in 3.5%NaCl solution was studied by using anodic cyclic polarization、electrochemical impedance spectra（EIS） and corrosion immersion test.The polarization curves showed that the pitting potential of 5083 aluminium alloy in 3.5%NaCl solution shifted positively with the accession of Na2SiO3.Through the EIS and the corrosion immersion test results we concluded showed that：the hydrolystate of sodium silicate in the system was OH-,which conduced to the increment of the passive films and the deposition of Al2（SiO3）3 on aluminium alloy,then the pitting corrosion was restrained,and the matrix was protected.