超声辅助镁合金水滑石/铈盐复合膜的耐蚀性

Corrosion Resistance of Hydrotalcite/Cerium Composite Film on Magnesium Alloy by Ultrasonic Assistance

采用超声辅助工艺在AZ91D镁合金表面制备水滑石/铈盐复合转化膜,研究了超声辅助时间对复合膜质量及耐蚀性的影响。研究表明:复合膜主要成分为镁铝水滑石和氧化铈。随处理时间的延长,氧化铈对水滑石膜的封闭效果先提高后下降。当处理时间为30 min时,CeO_2沉积物填充于水滑石膜裂纹处,封闭效果最好,复合膜的腐蚀电流密度为2.60×10^(-6)A·cm^(-2),约为基体的1/50,约为单一水滑石膜试样的1/30。

Mg-Al hydrotalcite and cerium-based composite conversion film was prepared on the surface of AZ91 D magnesium alloy by ultrasonic assistance process. The influence of ultrasonic assisted time on the integrity and corrosion resistance of the film was also investigated. The results show that the main components of the composite film are Mg-Al hydrotalcite（HT） and cerium oxide（CeO2）. With the increase of treating time, the sealing effect of CeO2 for hydrotalcite film firstly increases and then decreases. The effectiveness of sealing treatment reaches optimum when cerium dioxide fills the cracks of the HT coating after being treated for 30 min. And then, the corrosion current density of the composite film is 2.60×10^-6A·cm^-2, which is approximately 1/50 of that of Mg substrate and 1/30 of that of HT coating sample, respectively.