钢基表面热浸镀55%Al-Zn-1.6Si合金镀层物相特征及腐蚀行为

Study on the Phase Characteristics and Corrosion Behavior of 55%Al-Zn-1.6Si Alloy Coating on the Steel Substrate

采用OM、SEM、EDS、XRD等分析技术研究了镀层锌花特征、成分、相组成及厚度测量;采用辉光放电光谱仪（GDOES）研究沿镀层厚度方向上各元素的含量变化规律;通过盐雾试验对镀层进行腐蚀测试,并探讨镀层在腐蚀过程中的组织演变规律。结果表明：镀层表面锌花呈现树枝叶晶网格状、碎点状、六角星型3种形态,不同形态锌花成分相差无异;镀层整体厚度为17~18μm,外镀层为11~13μm,金属化合物层4~5μm;外镀层相组成除Al、Zn线条外,还有微量的FeAl3相、α-Fe-Al-Si等,且Al、Zn含量之和维持在96%以上;越靠近金属化合物层时,其Al、Zn含量越少,而Fe元素含量逐渐上升,抵达钢基体含量为100%。在中性盐雾试验144h周期内,镀55%Al-Zn-1.6Si合金镀层表现出了优异的耐腐蚀能力。

In order to research morphology, chemical composition, phase and thickness of coating, the OM, SEM, EDS, XRD was studied. The thickness of coating and element distribution along the thickness was measured by the GDOES. The corrosion corrosion and the morphology evolution of coating was tested by salt spray testing. The results show that three shape is consisted on the coating and the composition of different shape zinc flower on the surface coating is similar. The thickness of coating is about 17-18μm. The out coating is about 11-13 μm The intermetallic compound coating （IMC） is about 4-5μm. The out coating not only has phase of Al, Zn, also has FeA13, α- Fe-Al-Si in the out coating. The gross of A1, Zn is maintain in the 96% above. The distribution of Al, Zn is reduced, and Fe is improve which closing to the intermetallic compound （IMC）. The coating of 55%Al-Zn-1.6Si alloy is excel lent performance in 144 h after salt fog test.