摘要
热镀铝锌硅镀层钢板(GL钢板)发生变形时,镀层中裂纹数量和大小对其耐蚀性有重要影响。对GL钢板进行单向拉伸,采用动电位极化法和电化学阻抗谱测试了GL钢板不同拉伸变形量时在3.5%NaCl溶液中的电化学腐蚀行为,采用扫描电镜观察了不同变形量时GL镀层电化学腐蚀前后的表面形貌。结果表明:GL钢板变形到一定程度,镀层便产生裂纹,裂纹随变形量的增加而变多、变大、变深;GL镀层的腐蚀优先在裂纹内发生,随变形量的增加,腐蚀的深度和面积逐渐增大,当变形量为20%时,镀层表面的裂纹扩展至镀层/钢基体界面,造成钢基体裸露,镀层耐蚀性大幅降低。
Galvalume( GL) steel sheet was drawn. The electrochemical corrosion behavior of as-drawn GL steel sheet with different degrees of drawing in 3. 5% NaCl was evaluated by potentiodynamic polarization method and electrochemical impedance spectroscopic method. The surface morphologies of the galvalume coatings on GL steel sheets with different degrees of drawing,before and after electrochemical corrosion,were observed with a scanning electron microscope. Results indicated that,at a certain degree of drawing deformation,cracks emerged in the galvalume coatings of the GL steel sheets,and the cracks tended to rise in amount,size and color with increasing deformation. Besides,corrosion of the galvalume coatings preferentially occured inside the cracks,and the corroded depth and area tended to gradually rise with elevating degree of deformation. Particularly,at a deformation degree of 20%,the cracks on the surface of the galvalume coatings were propagated to the coating-steel interface,thereby causing exposure of the GL steel as well as significant decrease of the corrosion resistance of the galvalume coating.
出处
《材料保护》
CAS
CSCD
北大核心
2013年第11期13-16,5,共4页
Materials Protection
基金
国家自然科学基金(51071052)
国家"十二五"科技支撑项目(2012BAJ13B03)资助
关键词
单向拉伸变形
耐蚀性
裂纹
GL钢板
镀层
drawing deformation
galvalume steel sheet
galvalume coating
corrosion resistance
crack
