采用光学显微镜、电化学测试、SEM等方法研究了Zn-4Al,Zn-5Al和Zn-6Al热浸镀锌合金的显微组织和耐蚀性.结果表明,Zn-4Al合金由Zn-Al层片状共晶组织和大量的初生β-Zn相枝晶组成,Zn-5Al合金为Zn-Al共晶组织加少量的初生β-Zn相组成,Zn-6Al合金为初生的块状α-Al相和Zn-Al共晶组织组成,块状α-Al相周围的共晶组织多为颗粒状.Zn-5Al合金的自腐蚀电流密度Jcorr最小,极化电阻Rp最大,合金表现出最好的耐腐蚀性.Zn-4Al和Zn-5Al合金是由初生的β-Zn相被优先选择腐蚀,Zr-6Al合金是由块状的α-A1相周围的共晶组织被优先选择腐蚀.%The microstructure and corrosion performance of Zn-4A1, Zn-5A1 and Zn-6A1 galvanized alloys were analyzed by optical microscopy, electrochemical tests, scanning electron microscopy and so on. The results show that the microstructure of Zn-4A1 alloy was composed of lamellar Zn-Al eutectic and lots of primary β-Zn phase. The microstructure of Zn-5A1 alloy was Zn-Al eutectic and a little primary β-Zn phase. Besides Zn-Al eutectic, a few massive α-Al primary phase was discovered in Zn-6A1 alloy, and the Zn-Al eutectic around primary α-Al phase was mostly granular. The electrochemical tests show that the corrosion current density Joorr of Zn-5A1 alloy was the least, and the electrode polarization resistance Rp of Zn-5A1 alloy was the largest, so the corrosion performance of Zn-5A1 alloy was the best. The corrosion of Zn-4A1 and Zn-5A1 alloy occurred preferentially at the primary β-Zn phase, and the corrosion of Zn-6A1 alloy occurred preferentially at Zn-Al eutectic around primary α-Al phase.
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