阀金属表面微弧氧化放电机理研究进展

Research Progress on Discharge Mechanism of Micro-arc Oxidation on Valve Metal Surface

微弧氧化涂层是一种在碱性电解质溶液中,依靠金属-电解质界面发生的等离子体放电为驱动力,在各种阀金属(例如Mg、Al、Ti、Zr)表面原位形成粘附性能高的电化学涂层。在涂层的形成过程中,金属的表面特性会因等离子放电时产生的电化学反应而显著改变,从而在金属表面形成粘附性强的高硬度涂层。本文从介电击穿时的瞬态放电行为、气体逸出、阴极放电、柔性等离子放电四个方面综述MAO涂层的放电机理。

The micro-arc oxidation coating is one of the electrochemical coatings,which formed in an alkaline electrolyte solution,relying on the plasma discharge occurring at the metal-electrolyte interface as the driving force,in-situ inorganic coatings with high adhesion were formed on various valve metal surfaces(such as Mg,Al,Ti,Zr).During the formation of the coating,the surface characteristics of metal would be altered significantly by electrochemical reactions assisted by plasma discharges,resulting in the formation of hard,adhesive inorganic layer on the metal substrate.A couple of the discharge mechanisms including transient discharge mechanism at breakdown,gas evolution,cathodic discharge and soft plasma discharge were described.