摘要
采用Mn2+/HCO-3水溶液为处理液,在AZ91D镁合金表面上制得了Mg6Al2(OH)16CO3·4H2O/MnCO3复合膜。通过扫描电镜(SEM)和X射线衍射(XRD)分析了膜层的表面形貌和成分,利用极化曲线和交流阻抗(EIS)、浸泡试验来评价该转化膜的耐蚀性。结果表明,NaOH溶液的滴加能有效促进碳酸锰的沉积,随着滴加速度的降低,膜层的沉积量逐渐增大,当滴加速度为每隔3 min滴加1 mL时,膜层最为均匀、完整,耐蚀性明显优于镁合金基体,试样的腐蚀速度为9.8×10-5A·cm-2,约为镁合金基体的1/30。
The Mg,Al-hydrotalcite/MnCO3 carbonate composite conversion film on AZ91D Mg alloy was developed in aqueous Mn2+/HCO3-solution.The surface morphology and the chemical composition of the conversion film were analyzed by scanning electron microscopy ( SEM) and X-ray diffraction ( XRD ) .The polarization curve, electrochemical impedance spectroscopy ( EIS ) and immersion corrosion test were carried out to evaluate the corrosion resistance of the conversion film on AZ91D.The results show that the MnCO3 deposition velocity is promoted by NaOH solution added, and with the decrease of dropping speed, the quantity of MnCO3 deposition increases.A uniform and continuous film forms on AZ91D when the dropping speed of NaOH solution is 1 mL per 3 min, which corrosion resistance is significantly better than that of the magnesium alloy substrate.The corrosion rate is 9.8 ×10-5 A· cm-2 which is approximately 1/30 that of Mg substrate.
出处
《金属热处理》
CAS
CSCD
北大核心
2014年第10期57-61,共5页
Heat Treatment of Metals
基金
江苏省高校自然科学研究项目(12KJB430007)
南京工程学院创新基金(CKJB201203)
江苏省大学生实践训练计划(201311276001)
关键词
镁合金
镁铝水滑石
碳酸锰
转化膜
耐蚀性
magnesium alloy
Mg,Al-hydrotalcite
MnCO3
conversion film
corrosion resistance
