摘要
采用两步法在Q235钢表面制备Al-Cr梯度复合涂层.首先通过电镀法在Q235钢表面制备Cr涂层,再通过热浸镀法制备Al涂层.研究助镀剂、热浸温度和热浸时间对涂层的影响,采用OM、SEM、EDS、XRD、显微硬度仪等测试手段,分析了涂层的显微形貌、厚度、硬度及组成,并通过全浸泡实验对涂层耐蚀性能进行了研究.结果表明:采用助镀剂10%NH4Cl+27%ZnCl2制备的涂层表面平整均匀,组织致密,未出现剥落、漏镀等缺陷.随着热浸温度升高和热浸时间的延长,涂层的显微结构和厚度均发生改变.涂层由“三层结构”(Al层、Al-Cr合金层、Al-Cr-Fe合金层)转变为“两层结构”(Al层、Al-Cr-Fe合金层).涂层中Al层的厚度随热浸温度的升高而减小,而合金层的厚度则呈现上升的趋势.随着热浸时间的延长,Al层和合金层的厚度均有所增加.Al-Cr梯度复合涂层试样的耐蚀性优于未涂覆试样和热浸镀铝试样,且腐蚀速率约为未涂覆试样的1/5.
A two-step method was used to prepare an Al-Cr gradient composite coating on the surface of Q235 steel.First,Cr coating was prepared on the surface of Q235 steel by electroplating,and then Al coating was prepared by hot dip plating.The effects of plating auxiliary,hot dip temperature and time on the coating were studied.The microstructure,thickness,hardness and composition of the coating were analyzed by OM,SEM,EDS,XRD and microhardness test .The corrosion resistance of the coating was evaluated by a full immersion test.The results show that the surface of the coating prepared by 10% NH 4Cl+27%ZnCl 2 is flat and uniform.The structure is compact and no defects such as spalling and leakage plating appear.The microstructure and thickness of the coating change under different hot dip process.A three-layer structure (Al layer,Al-Cr alloy layer,Al-Cr-Fe alloy layer) of the coating is converted into a two-layer structure (Al layer,Al-Cr-Fe alloy layer) by.The thickness of the Al layer in the coating decreases with the increase of hot dip temperature,while the thickness of the alloy layer shows an increasing trend.As the hot dip time is extended,the thickness of both the Al layer and the alloy layer is increased.The Al-Cr gradient composite coating has better salt water corrosion resistance than the uncoated steel sheet and the hot-dip aluminum-plated steel sheet,and the corrosion rate is about 1/5 of that of the uncoated sample.
作者
杨璞
魏森森
赵雪妮
王瑶
陈雪岩
张伟刚
刘庆瑶
郑佳梅
桂珍珍
YANG Pu;WEI Sen-sen;ZHAO Xue-ni;WANG Yao;CHEN Xue-yan;ZHANG Wei-gang;LIU Qing-yao;ZHENG Jia-mei;GUI Zhen-zhen(Collegeof Mechanicaland Electrical Engineering,Shaanxi University of Science & Technology,Xi'an 710021,China)
出处
《陕西科技大学学报》
CAS
2019年第4期101-106,113,共7页
Journal of Shaanxi University of Science & Technology
基金
国家自然科学基金项目(51772179,51072107)
陕西省科技厅重点研发计划项目(2018GY-168)
陕西省科技厅自然科学基金项目(2014JM6233)
凝固技术国家重点实验室开放课题(SKLSP201823)
陕西省大学生创新创业训练计划项目(201810708022)
关键词
电镀法
热浸镀法
Al-Cr梯度复合涂层
显微组织
耐蚀性
electroplating method
hot dip coating method
Al-Cr gradient composite coating
micro-structure
corrosion resistance
