铝合金阳极氧化方法及成膜机理的研究进展

Research Progress of Anodic Oxidation Methods and Film Formation Mechanism of Aluminium Alloys

对铝合金阳极氧化的发展现状及趋势进行了总结和展望。首先,介绍了阳极氧化工艺的类型,并着重阐述了最常用的酸性阳极氧化以及碱性阳极氧化的特点。随后,概括了阳极氧化膜生长机理的研究进展,包括氧化膜的生长过程及提出的相关理论。此外,对碱性阳极氧化的研究现状进行了归纳,并简要介绍了其与酸性阳极氧化在氧化膜结构特点及生长机理方面的异同。最后,针对当前阳极氧化技术存在的问题和面临的挑战,对其未来的发展趋势做了展望,并指出了阳极氧化技术的发展方向。

Aluminium and aluminium alloys are widely used in many fields such as aerospace,automotive and transportation,construction and electronics owing to their low density,non-polluting and easy recycling,good electrical conductivity,corrosion resistance and ductility.However,surface treatment is often necessary for aluminum alloys to meet the application requirements due to their high activity and service in the complex and harsh environments.At present,the surface treatments which can be used for aluminum alloys include chemical conversion,anodic oxidation,micro-arc oxidation,electroplating,electroless plating,vapor deposition,thermal spraying,laser cladding,etc.Among them,anodic oxidation,as an efficient surface treatments,can significantly improve the performance of aluminum alloys,which has gained widespread attention and has become one of the most commonly used surface treatments for aluminum alloys.With the development of social economy,the application of aluminum alloys continues to expand,which makes more and more diversity for the required performance of anodic film.However,there are still some deficiencies in the current commonly used anodic oxidation process,and the film growth mechanism is not comprehensively understood.The work aims to summarize the research progress of anodic oxidation of aluminum alloy and propose the development trends.Firstly,the types of anodic oxidation processes are introduced and the characteristics of the most commonly used acid anodic oxidation as well as alkaline anodic oxidation are emphasized.Among them,acidic anodic oxidation is widely studied and applied due to the advantages of low cost,high production efficiency and simple operation.Acidic anodic oxidation includes sulfuric acid,oxalic acid,chromic acid,hydroxyethyl phosphoric acid,mixed acid,hard anodic oxidation,porcelain anodic oxidation,spark discharge anodic oxidation and other types according to the electrolyte and electrical parameters,each with its own characteristics,widely used in various fields.Then,the research progress of the growth mechanism of anodic oxide film,including the growth process of oxide film and the related theories are presented.The focus is also placed on the current investigation of the relevant mechanisms under alkaline conditions and a detailed description of the preparation of four different types of oxide films under different pH phosphate conditions is provided.Although some progress has been made in the research of alkaline anodizing,the structure formation mechanism of the oxide film is still unclear,and the research on the application of the process still needs to be strengthened.Therefore,an in-depth study of alkaline anodizing technology is of great significance for expanding the application range of anodizing.In the future,alkaline anodic oxidation research should focus on those materials for which acid anodic oxidation is not applicable,and concentrate on exploring and optimizing the process conditions to overcome the large structural differences between alkaline anodic oxidation films and traditional acid anodic oxidation films.In addition,the growth mechanism of alkaline anodic oxidation film should also be the focus of research.Through in-depth exploration,it is expected to grasp this technology more comprehensively,so as to promote its wide application in the industrial field.