ECO-FRIENDLY CHROME-FREE FILM COMPOSITION FOR GALVANISED SHEETS

摘要

The present invention relates to an eco-friendly chrome-free film composition for galvanised sheets. Said composition comprises 2-5g/L of titanium ion, 20-40g/L of phosphate ion, 5-10g/L of calcium ion, 5-10g/L of nitrate ion, 5-10g/L of silicon ion, and 5-10g/L of polyvinyl alcohol in distilled water. Said composition is characterised in that it can be applied as a film post-processing solution onto both electrolytic and hot-dipped galvanised steel sheets in all existing facilities; despite being chrome-free, it achieves corrosion resistance equal to or greater than hexavalent chromium chromate; it does not produce soot when welded; and it produces an elegant and finger print-resistant finish.