al18b4o33w6061复合材料表面铈转化膜形成及耐蚀机理word格式论文.docx

电阻亦有影响，相比长时间成膜，短时间成膜试样耐蚀性更好。关键词：硼酸铝晶须；铝基复合材料；预处理；铈转化膜；腐蚀AbstractAlumina borate whisker-reinforced 6061 composite (Al18B4O33w/6061) have great superiority in applications where low density and high mechanical performance arerequired, such as in the motorcar and aerospace industry. However，corrosion is one ofthe most critical problems for the composites, which need to be solved before the application of composites in aggressive environment. Cerium-based conversion coatings (CeCC) have drawn more and more attention in anticorrosion area for over twenty years, as it is one of the most prospective replacements of carcinogenic chromium-based conversion coatings for its environmentally friendly property, low cost and easy operation. In most of the studies, CeCC were mainly deposited on aluminium alloys. Relatively, little is known about the CeCC on Al18B4O33w/6061.The formation mechanism and the corrosion mechanism of the CeCC was studiedon Al18B4O33w/6061. The effect of the HF pre-treatment and hydrothermal pre-treatment on the microstructure and corrosion behaviour of CeCC was studied. And the CeCC formation and corrosion process were studied by open circuit potential (OCP) and electrochemical noise (EN). The role of Alumina borate whisker played in the process of CeCC was clarified by comparing the matrix Al and its composites, and the formation mechanism was illustrated.The formation, growth and microstructure of the CeCC were strongly influenced by the HF pre-treatment, the pre-treatment could highly active the surface of the composite. The longer of the pre-treatment time was, the faster of the formation of the CeCC and the greater of the unevenness were. The results of the potentialdynamic polarization curve showed that the CeCC can improve the corrosion resistance obviously, the performance of the coating is depend on the microstructure of the coating. Electrochemical impedance (EIS) showed that a self-healing effect was observed on the coated composite with sm