镁合金表面冷喷涂层防护研究进展

Protection for Cold Sprayed Coatings on Magnesium Alloy

镁合金作为最轻质的金属结构材料,由于其密度低和比强度高等优良的物理和力学性能,在航空、航天、汽车以及电子等领域引起广泛关注。然而,镁合金化学性质活泼、耐腐蚀和耐磨损性差等缺点严重制约其进一步应用。近些年发展起来的冷喷涂技术,在固态下制备涂层,涂层致密且与基体结合良好,因此可为镁合金表面防护提供一种新的有效方法。主要综述了镁合金表面冷喷涂耐腐蚀涂层(纯铝、铝合金和复合材料涂层)和耐磨损涂层(合金和复合材料涂层),论述了影响冷喷涂层耐腐蚀、耐磨损以及其他力学性能(硬度和涂层/基体结合强度)的主要因素,包括杂质元素含量、合金种类以及复合材料涂层中陶瓷颗粒含量、尺寸和形貌等。对比了几种常用表面处理技术制备的纯铝涂层的耐腐蚀性能,并阐述了冷喷涂技术在镁合金表面防护方面的优势。此外,还分析了热处理对冷喷涂纯铝和复合材料涂层耐蚀性的影响。最后提出了目前冷喷涂技术在镁合金防护方面的局限性以及发展难题,对未来研究趋势进行了展望。

As the lightest structural metallic material, magnesium alloy has been widely applied in aeronautics, astronautics, automotive and electronic fields due to excellent physical and mechanical properties such as low density and high strength to weight ratio. However, the further use of magnesium alloys is restricted by inherent limitations such as high chemical reactivity, and poor wear and corrosion resistance. The cold spray method developed in recent years can be used to prepare coatings with high density and adhesion strength to substrate in solid state, so it can provide a new effective method for magnesium alloy protection. Cold-sprayed corrosion protection coatings（pure Al, Al alloy and composite coatings） and wear resistant coatings（alloy and composite coatings） on magnesium alloys are summarized in this work. Main factors（including content of impurity element, type of alloy and amount, size and morphology of ceramic particles in composite coating） affecting cold sprayed corrosion resistance, wear resistance and other mechanical properties（hardness and coating/substrate adhesion strength） are discussed. The corrosion resistance of pure Al coatings produced by several normal surface treatment techniques is contrasted and then the advantage of cold sprayed technique for magnesium alloy protection is set forth. Finally the limitations and development difficulty of cold sprayed technique in magnesium alloy protection are put forward and the future research trends are also presented.