(陕西理工学院 材料科学与工程学院，汉中 723001)
摘 要: 采用X射线衍射仪、扫描电子显微镜、能谱仪、透射电子显微镜、全浸腐蚀及中性盐雾腐蚀试验等方法，对比研究Zn-0.5Al-1.5Mg、Zn-2Al-1.5Mg和Zn-2Al-1.5Mg-0.3Si(质量分数，%)合金镀层的组织与性能，探讨Al和Si对热浸Zn-Al-Mg合金镀层组织和耐腐蚀性能的影响。结果表明：三合金镀层的组成相是Zn相、Al相和MgZn2相；Zn-0.5Al-1.5Mg合金镀层由块状富Zn相和晶界Zn+MgZn2二元共晶组织组成，Zn-2Al-1.5Mg合金镀层由块状富Zn相和晶界Zn+Al+MgZn2三元共晶组织组成，Zn-2Al-1.5Mg-0.3Si合金镀层由块状富Zn相、晶界Zn+Al+MgZn2三元共晶组织和针状相Mg2Si组成；Al、Mg和Si主要分布在晶界，Al和Si有细化镀层晶粒作用，添加Si能提高Zn-Al-Mg合金镀层的耐腐蚀性能。
关键字: Zn-Al-Mg合金；Zn-Al-Mg-Si合金；热浸镀；镀层组织；耐腐蚀性能
（School of Materials Science and Engineering, Shaanxi University of Technology, Hanzhong 723001, China）
Abstract:The microstructure and properties of Zn-0.5Al-1.5Mg, Zn-2Al-1.5Mg and Zn-2Al-1.5Mg-0.3Si (mass fraction, %) alloy coatings were comparatively studied, and the effects of Al and Si on the microstructure and the corrosion resistance of hot dipping Zn-Al-Mg alloy coatings were investigated by X-ray diffraction, scanning electron microscope, energy dispersive spectrometer, transmission electron microscope, full immersion corrosion and neutral salt spray test. The results show that the composition phases of three alloy coatings are Zn, Al and MgZn2 phases. Zn-0.5Al-1.5Mg alloy coating is composed of bulk Zn-rich phase and Zn+MgZn2 eutectic structure at the grain boundary, Zn-2Al-1.5Mg alloy coating is composed of bulk Zn-rich phase and Zn+Al+MgZn2 eutectic structure at the grain boundary, Zn-2Al-1.5Mg-0.3Si alloy coating is composed of bulk Zn-rich phase, Zn+Al+MgZn2 eutectic structure at the grain boundary and acicular Mg2Si. The Al, Mg and Si distribute mainly at the grain boundary. The Al and Si possess the functions of refining the grain size. The corrosion resistance can be enhanced by the addition of Si in Zn-Al-Mg alloy coating.
Key words: Zn-Al-Mg alloy; Zn-Al-Mg-Si alloy; hot-dipping; coating microstructure; corrosion resistance
