建筑铝型材表面转化膜的制备及膜层组成分析

Preparation and Constituent of Conversion Film on Aluminum Profile Surface

以钼酸钠和十二烷基苯磺酸钠混合溶液为成膜试剂,在建筑用6061铝型材表面制备了无Cr复合转化膜,对复合转化膜层的成膜过程和组织结构进行了观察,并探讨了转化膜的形成机理。结果表明,随着成膜时间的延长,转化膜表面的显微小孔逐渐被均匀分布的微裂纹所覆盖,微裂纹宽度逐渐增加;复合转化膜层由非晶态氧化物和氢氧化物组成,主要为MoO3、MoO(OH)2、CeO2、Ce(OH)4、Ce(OH)3、MnO2、Al(OH)3、Al2O3以及可能存在的MoO2。

With sodium molybdate and sodium twelve mixed solution as the membrane forming agent, composite film with Cr-free on the 6061 aluminum surface was prepared, and the forming process and microstructure of the composite conversion film were investigated, meanwhile, the formation mechanism of the conversion film was described. The results show that, with increasing in the film formation time, micro-hole in the conversion film surface is covered gradually with uniformly distributed micro-crack, and the width of micro-crack is increased increasingly. Composite conversion coating consists of amorphous oxides and hydroxides, such as MoO3 ,MoO（OH）2 ,CeO2 ,Ce（OH）4 ,Ce（OH）3 ,MnO2 ,Al（OH）3Al2O3 and possible MOO2.