摘要
The phosphated hot-dip galvanized(HDG) sheets were post-sealed with sodium molybdate solution to improve the corrosion resistance of phosphate coatings. The morphology,chemical composition and corrosion resistance of the coatings were investigated using scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),Tafel polarization measurements and neutral salt spray(NSS) tests,and were compared with those of the single coatings. The results show that post-sealing the phosphated HDG steel with molybdate solution,the pores among the zinc phosphate crystals are sealed with molybdate films containing Zn,P,O and Mo,and the continuous composite coatings are formed. The suppression of both the anodic and the cathodic processes of zinc corrosion on the samples are enhanced significantly. The synergistic corrosion protection effect of the single phosphate coatings and molybdate films for zinc is evident. The corrosion resistance of the composite coatings increases with phosphating time up to 300 s.
The phosphated hot-dip galvanized (HDG) sheets were post-sealed with sodium molybdate solution to improve the corrosion resistance of phosphate coatings. The morphology, chemical composition and corrosion resistance of the coatings were investigated using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Tafel polarization measurements and neutral salt spray (NSS) tests, and were compared with those of the single coatings. The results show that post-sealing the phosphated HDG steel with molyhdate solution, the pores among the zinc phosphate crystals are sealed with molybdate films containing Zn, P, O and Mo, and the continuous composite coatings are formed. The suppression of both the anodic and the cathodic processes of zinc corrosion on the samples are enhanced significantly. The synergistic corrosion protection effect of the single phosphate coatings and molybdate films for zinc is evident. The corrosion resistance of the composite coatings increases with phosphating time up to 300 s.
出处
《中国有色金属学会会刊:英文版》
CSCD
2007年第A01期198-203,共6页
Transactions of Nonferrous Metals Society of China
基金
Project(07BS405) supported by the Excellent Talents Foundation of Huaqiao Univeristy, China
关键词
镀锌钢材
磷酸盐
微观结构
腐蚀测试
钼酸盐
galvanized steel
phosphate coatings
molybdate
corrosion resistance
polarization curve