预制膜对铝合金微弧氧化陶瓷层生长过程的影响

在磷酸盐体系电解液中,利用微弧氧化技术,分别对有、无高温氧化预制膜的铝合金进行表面陶瓷化处理,研究了预制膜对陶瓷层生长的影响规律.结果表明:高温氧化预制膜有利于提高陶瓷层的生长速率,降低起弧电压;陶瓷层的生长先是以初期形成的陶瓷颗粒为核心呈线状扩展,然后多条线接合呈网状,最后蔓延成面;陶瓷层生长的初期以高温氧化预制膜熔化生成为主,到后期,则是以铝合金基体熔化生成为主,此时预制膜对陶瓷层生长过程的影响较小,但由预制膜生成的陶瓷对陶瓷层生长的影响较大.

Effect of Prefab Film on Growth of Micro-arc Oxidation Coating on Aluminum Alloy

Ceramic coatings were formed by micro-arc oxidation in a phosphate electrolyte solution on aluminium alloy with and without a high temperature oxidation prefab film respectively.The effect of prefab films on the micro-arc oxidation coatings was studied.The results show that the high temperature oxidation prefab film is conducive to decrease of the arc starting voltage of the micro-arc oxidation and increase rate of the growth of micro-arc oxidation coatings;The growth process of the micro-arc oxidation ceramic coatings contains the formation of grain type of melted lumps,the expansion of the lumps in line along the sample surface,the formation of many network areas with a number of linear materials and the development of network areas into a continuous layer.In the process of MAO,the growth of ceramic coating mainly relies on the melting of high temperature oxidation film in the initial stage,and the melting of aluminium alloy matrix in the later stage.Compared with the later stage,the high temperature oxidation film makes greater effect on the initial stage,but the ceramic coating formed in the initial stage plays an important role on the growth of ceramic coating in the later stage.