Preparation And Properties Of The Silane Film Treatment On Galvanized Sheet

The organic silane passivation technology can improve the corrosion resistance ofgalvanized sheet, which is the important research for protection the galvanized sheet.A new preparation method of silica solution for passivating galvanized sheet wasdeveloped by using3-glycidoxylpropyltrimethoxy silane.The influence factors ofhydrolysis and condensation of silanes were investigated which were important to thecorrosion resistance of silane film.It had proved that the silane film had a good protectioneffect through brine immersion test and electrochemical experiments.The galvanized sheet was passivated by the KH-560silane solution. The optimumconditions of silane film formation were established by corrosion resistance experiment,silane amount is5ml, solvent pH value is3.5, methanol/water ratio is15:85, hydrolysistemperature is40℃, the static time is48h; silane film deposition process: deposit time is10s, curing temperature is120℃, curing time is30min, The CuSO4titration test couldachieve64s, the corrosin rate is1.11g/(m2·d) by salt immersion testA kind of new passivation on the galvanized sheet was formed by KH-560complexedwith cerium nitrate or titanium acid butyl ester. It had proved that the corrosion resistanceof composite membrane was better than onefold film. The CuSO4titration test ofsilane/cerium nitrate could achieve85s which was better than chromate. The CuSO4titration test of silane KH-560/cerium nitrate/TBOT ternary composite membrane couldachieve136s which is better than binary composite membrane.It had proved that the silane film could be formed on galvanized sheet by the SEM.The silane solution and silane filme were characterized by IR, the result indicated that:silane can hydrolysis; silane molecules can formed dense reticular structure on galvanizedsheet which had played an important role on preservative. The silane film had a good antic-corrosive performance in3.5wt%NaCl by electrochemical experiments. The additive ofcomposite membrane have inhibit anodic reaction on galvanized sheet. The corrosion rateof galvanized sheet have been reduced by the corrosion resistance of silane film proved.