中文摘要：

运用扫描电子显微镜/能谱仪、X射线衍射、盐雾实验、电极化曲线等手段,研究冷却速度和Si对Zn-5Al-0.1RE合金组织及耐蚀性能的影响.结果表明,Zn-5Al-0.1RE-x Si合金由先析出的η-Zn和η-Zn＋α-Al共晶组织组成,前者均匀分布在相邻的η-Zn＋α-Al共晶胞的边界上.降低冷却速度和Si的加入,均使Zn-5Al-0.1RE-x Si合金单位面积的晶粒增大,晶界减少,合金耐蚀性能提高.Zn-5Al-0.1RE-x Si合金耐蚀性能的差异与合金凝固组织及合金腐蚀产物中Zn_5（OH）_8Cl_2·H_2O和Zn O的相对量有关.

英文摘要：

The effects of cooling rate and Si on the microstructure and corrosion property of the Zn-5 Al-0. 1 RE alloy were studied by scanning electron microscopy-energy dispersive spectrometry, X-ray diffraction, neutral salt spray test and polarization curves. The results show that Zn-5Al-0. 1RE-xSi alloys are composed of primary η-Zn phase and η-Zn ＋ α-Al eutectic structure, and the former is uniformly distributed on the adjacent η-Zn ＋ α-Al entectic cells. The reduction of cooling rate and the addition of Si make the grain size increase and the boundary area per unit alloy area decrease; at the same time, the corrosion resistance is improved. The corrosion resistance of the Zn-5Al-0. 1 RE-xSi alloys is dependent on their solidification structure and the relative amount of corrosion products including Zn5 （OH） 8 Cl2· H20 and ZnO.