摘要
锌铝镁镀层钢板作为重要的耐蚀材料,在使用过程中需要进行各种加工变形,研究变形量对镀层形貌及耐蚀性能的影响至关重要.本文以镀层重量为275 g/m2的Zn-1.6%Al-1.4%Mg镀层钢板为研究对象,进行10%、20%的拉伸应变,扫描电镜(SEM)和金相(OM)观察镀层形貌显示裂纹宽度和密度随着拉伸应变量的增长而升高,10%应变试样裂纹宽度为9.5 μm,而20%应变时裂纹宽度达到15.4 μm,两者均有部分裂纹贯穿镀层达到基板,含有MgZn2相更多的二元共晶相成为裂纹的起源.电化学试验和中性盐雾试验表明,随应变量增大,镀层腐蚀电流增大,腐蚀失重加大,盐雾试验出红锈时间缩短.裂纹加速了腐蚀初期电化学反应进程.
Abstract
The Zn-Al-Mg coating steels are important materials for the corrosion protection of steel sheets.However,the Zn-Al-Mg coatings should undergo various deformations in use,so it is very important to study the effect of deformation on the crack and corrosion resistance of coatings.In this work,the effect of 10%and 20%tensile deformation on the Zn-1.6%Al-1.4%Mg alloy coatings with coating weight of 275 g/m2 was studied.Scanning electron microscopy(SEM)and optical microscope(OM)were utilized to observe the crack of the coatings.The crack width of 10%strain specimen was 9.5 μm and that of 20%strain specimen reached 15.4 μm,and both of them have some cracks through the coating to the substrate.Binary eutectic phases containing more MgZn2 became the origin of the crack.The electrochemical test and neutral salt spray test show that with the increase of strain,the corrosion current and corrosion weight loss of the coating increased,but the red rust time was shortened.The crack accelerates the electrochemical reaction during the initial corrosion.
基金项目
河北省自然科学基金资助项目(E2021318006)
NETL
NSTL
万方数据