سال انتشار: ۱۳۸۵

محل انتشار: یازدهمین کنگره ملی مهندسی شیمی ایران

تعداد صفحات: ۶

نویسنده(ها):

Khoshvaght – Master of Science from Sharif University of Technology, Tehran, Iran
Hosseini – Assistant of professor of Tabriz University, Tabriz, Iran
Arshadi – professor of chemistry of Sharif University of Technology, Tehran, Iran

چکیده:

The changes in crystal structure, grain size and corrosion resistance that occur in zinc phosphate coatings on sheet steel substrates when calcium ions are incorporated in a zincphosphating formulation are reported. Stable samples of phosphating formulations with and without calcium salts were prepared and the structure and corrosion resistance of the phosphate coatings were determined using X-ray diffraction (XRD) technique, scanning electron microscopy and ASTM salt spray test. XRD shows that the incorporation of calcium changes the structure of phosphate coatings from essentially phosphophylite-hopeite to schlozite-paraschlozite with considerable reduction in grain size (from 150 to 3 mm) and a substantial improvement in compactness as evidenced by scanning electron micrographs (secondary emission). The corresponding increase in corrosion resistance has been demonstrated by sale spray tests on painted phosphated panels.