采用熔体处理和金属助镀相结合的新工艺在Q235钢表面先预镀一层锌后再进行热浸镀Al-43%Zn-1.6%Si合金;用光学显微镜、扫描电子显微镜和能谱仪分析了镀层的形貌以及相组成,并对热浸镀钢板的耐腐蚀性能和力学性能进行了研究.结果表明:采用新工艺热浸镀Al-43%Zn-1.6%Si合金镀层的厚度达到50 μm;镀层组织为树枝晶,合金层中含有Al-Zn-Si-Fe四元相;镀后钢板在中性NaCl溶液中的耐腐蚀性能优良,腐蚀速率为1.7×10-2 mg·cm-2·h-1;热浸镀使钢材的塑性提高;得到了无漏镀、呈银色、性能良好的热浸镀钢板.

Al-43%Zn-1.6%Si alloy on the Q235 steel surface which was pre-coated Zn was hot-diped by a new process of melt treatment and metal assistant plating.The morphology and phase composition of the coating were analyzed by means of optical microscope,scanning electron microscope and energy dispersive spectroscope.The corrosion resistance and mechanical properties of the hot-diped plate were investigated.The results show that the thickness of the Al-43%Zn-1.6%Si alloy coating prepared with the new hot-diped process was about 50 μm.The microstructure of the coating was dendrite,and the alloy coating was composed of Al-Zn-Si-Fe quaternary phase.The plate had good corrosion resistance in NaCl solution,whose corrosion rate was 1.7×10-2 mg·cm-2·h-1.After hot-diped,the plasticity of the steel increased,and a silverly witheout any bare spots plate with good performance was obtained.