镀后冷却速度对铝锌镀层表面凝固行为的影响  

Effects of cooling process on solidification behavior of Al-Zn alloy coating

作　　者：丁志龙[1,2] 张杰[1] 张启富[1] DING Zhilong;ZHANG Jie;ZHANG Qifu(National Engineering Laboratory of Advanced Coating Technology for Metals,Central Iron and Steel Research Institute,Beijing 100081,China;Research Institute,Baoshan Iron and Steel Co.Ltd.,Nanjing 210039,China)

机构地区：[1]钢铁研究总院先进金属材料涂镀国家工程实验室,北京100081 [2]宝山钢铁股份有限公司中央研究院,江苏南京210039

出　　处：《兵器材料科学与工程》2023年第5期1-6,共6页Ordnance Material Science and Engineering

基　　金：国家重点研发计划课题。

摘　　要：为研究镀后冷却速度对铝锌镀层锌花尺寸、表面及截面形貌与结构等凝固行为的影响,探讨锌花形成及凝固机制,用热浸镀模拟试验机模拟不同镀后冷却速度下的铝锌镀层(55%Al-43.4%Zn-1.6%Si)(质量分数,下同),采用扫描电子显微镜(SEM)及能谱仪(EDS)观察镀层表面和截面的微观形貌及元素分布。结果表明:随镀后冷却速度增大,铝锌镀层组织细化,镀层表面锌花尺寸明显减小,二次枝晶间距缩小,金属间化合物层厚度降低,表面缩孔尺寸变小。随冷却速度提高,凝固形核方式由单一的钢基镀层界面形核转变为钢基镀层界面和镀层表面同时形核,富Al固溶体相形核率提高导致镀层表面锌花尺寸变小。stract In order to study the effect of cooling rate on solidification behavior of Al⁃Zn alloy coated steel including the size of spangle,surface morphology and microstructure,and discuss the formation mechanism of spangle solidification,the experiment of Al⁃Zn coating(55%Al⁃43.4%Zn⁃1.6%Si)with different cooling conditions was simulated by hot⁃dip simulation unit.Scanning electron microscope(SEM)and energy dispersive spectroscopy(EDS)were used to investigate the mirostructure and element distribution of coating layers.The results show that increasing cooling rate can refine the microstructure of Al⁃Zn coating and reduce the spangle size.Increasing cooling rate can also decrease the secondary dendrite arm spacing and reduce the thickness of intermetallic compound layer and reduce the size of surface shrinkage hole.Increasing cooling rate can change the nucleation mode.It changes from IMC nucleation to simultaneous nucleation of IMC and coating surface.The increase of nucleation rate of aluminum rich phase leads to smaller spangle on the Al⁃Zn coating.

关 键 词：铝锌镀层 凝固 冷却速度 锌花 

分 类 号：TG174.443[金属学及工艺—金属表面处理]