镁合金表面改性技术现状研究

镁在自然界中含量丰富,在地壳金属元素中储量排名第三位,是最轻的金属结构材料之一.镁合金的密度为1.74 g/cm3,比强度高达134,兼具韧性好、减震性强、热容量低、压铸性能好以及切削加工性能优良等优点,在军工、航天航空以及汽车等领域上有广泛应用.由于镁的电负性极强,稳定性不好,易被腐蚀,因而需要对镁合金表面进行处理才能适应实际应用的要求.镁合金表面改性是改善镁及其合金耐蚀性、提高使用寿命、扩大应用领域的重要技术手段之一.综述了镁合金表面改性技术的研究现状,介绍了化学转化处理(化学氧化处理)、电镀和化学镀、阳极氧化和微弧氧化、激光表面处理、热喷涂以及有机涂层等方法 的原理、优点以及存在的问题,并简要介绍气相沉积、离子注入、达克罗涂层等表面改性技术,最后分析了镁合金表面改性的发展趋势,认为镁合金表面改性技术应朝着低污染、低成本、高效率、多技术复合的方向发展.

Development of Corrosion Surface Modification Technology for Magnesium Alloys

Magnesium and its alloys, which have abundant storage in nature, rank third among the whole list of metal elements in the earth crust. As one of the lightest metal structure materials, the density of magnesium alloy is 1. 74 g/ cm3, and the ratio of specific strength is up to 134, with good toughness, strong shock absorption, low heat capacity, good performance, excellent diecutting performance and so on, and therefore magnesium alloy has a wide range of applications in the military, aerospace and automotive and other fields for its characteristics, such as low density, high strength, specific rigidity, high damping ability, better casting property and so on. The preventive disposing on magnesium alloy''s surface is very important for improving its low corrosion resistance, prolonging its service life and expanding the application field. The principles, advantages and current existing problems of the surface treatment technology used for magnesium alloys were reviewed in detail, and the principle, advantages and existing problems of chemical conversion processing, electroless nickel plating, chemical plating, anodic oxidation, micro-arc oxidation, laser surface treatment, thermal spraying, and organic coating were introduced. The surface modification techniques including vapor deposition, ion implantation and Dacromet coatings were briefly introduced, finally the development trend of magnesium alloy surface modification was analyzed and it was proposed that magnesium alloy surface modification technology should develop towards low pollution, low cost, high efficiency, and multi-technology.