原位生成周期性层片结构镀层及其在NaCl溶液中的腐蚀形貌  

Periodic Layered Structure Coating Formed In-situ and Its Corrosion Morphology in NaCl Solution

作　　者：张先满[1] 李星涛 季坤鹏 陈再雨 罗洪峰[1] ZHANG Xianman;LI Xingtao;JI Kunpeng;CHEN Zaiyu;LUO Hongfeng(School of Mechanical and Electrical Engineering,Hainan University,Haikou 570228,China)

机构地区：[1]海南大学机电工程学院,海口570228

出　　处：《材料导报》2024年第12期162-168,共7页Materials Reports

基　　金：海南省自然科学基金(420RC522,521RC503,517076);国家自然科学基金(42066003,51701053)。

摘　　要：金属在海洋氯离子环境中极易发生腐蚀,并造成巨大的经济损失。通过制备新型Fe-Cr-B铸钢,采用热浸镀铝-扩散热处理原位生成含有周期性层片结构(PLSs)的镀层,并利用扫描电子显微镜(SEM)、电子探针X射线显微分析仪(EPMA)等手段研究了该镀层的组织结构及其在3.5%(质量分数)NaCl溶液中的腐蚀行为。结果表明,该铸钢的显微组织主要由粗大的初生(Cr,Fe)_(2)B及α-Fe组成;热浸镀铝时在(Cr,Fe)_(2)B/Al界面上生成由FeAl3和Cr-Al-B相组成的PLSs,在α-Fe/Al界面上生成FeAl3;扩散热处理使得反应层增厚,且PLSs在反应层中大量生成;相比FeAl3,镀层中的PLSs在腐蚀过程中充当阳极优先腐蚀,并表现出腐蚀各向异性,尤其是其中的Cr-Al-B相可明显阻挡氯离子腐蚀,使得PLSs通过延长腐蚀路径进而提高镀层的耐氯离子腐蚀性能。Metals corrode easily in marine environments containing chloride ions,thus causing considerable economic losses.A novel Fe-Cr-B cast steel was prepared,and the periodic layered structures(PLSs)coating was formed in-situ by hot-dip aluminizing and thermal diffusion treatment of the Fe-Cr-B cast steel.The microstructure and corrosion behavior of the coating in a 3.5wt%NaCl solution were studied using SEM and EPMA.The results showed that the cast steel microstructure was mainly composed of coarse primary(Cr,Fe)_(2)B andα-Fe.During hot-dip aluminizing,the PLSs composed of FeAl 3and Cr-Al-B phase formed at the(Cr,Fe)_(2)B/Al interface.While,FeAl 3 formed at theα-Fe/Al interface.The thermal diffusion treatment thickened the reaction layer,in which the PLSs were formed in large quantities.Compared with FeAl 3,the PLSs in the coating acted as the anode in the corrosion process and exhibited corrosion anisotropy.This study demonstrates that the Cr-Al-B phase in PLSs can significantly block chloride ion corrosion,so that the PLSs improve the chloride-ion corrosion resistance of the coating by prolonging the corrosion path.

关 键 词：Fe-Cr-B铸钢 热浸镀铝 扩散热处理 周期性层片结构(PLSs) 氯离子 

分 类 号：TB37[一般工业技术—材料科学与工程]