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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。
The hydrotalcite / cerium salt composite conversion coating was prepared on the surface of AZ91D magnesium alloy by ultrasonic assisted technique. The effect of ultrasonic assisted time on the quality and corrosion resistance of composite film was studied. The results show that the main components of composite films are MgAl2O4 and cerium oxide. With the extension of treatment time, the sealing effect of cerium oxide on hydrotalcite membrane first increased and then decreased. When the treatment time is 30 min, the CeO 2 deposit fills the cracks in the hydrotalcite membrane, and the sealing effect is the best. The corrosion current density of the composite membrane is 2.60 × 10 -6 A · cm -2, The matrix of 1/50, about a single hydrotalcite film sample 1/30.