One kind of phosphating treatment agent used for treating the surface of corroded zinc plated steel sheet was studied.The
optimal formulae gained from orthogonal test and single factor test are as follows:200 mL/L phosphoric acid,60 mL/L ethanol,3.0 mL/L OP-10,1.0 g/L zinc oxide,1.5 g/L chelating agent,2.5 g/L nickel nitrate,(2.5 g/L) manganese nitrate,1.0 g/L sodium chlorate,(2.0 g/L) sodium fluoride.The
phosphating solution can translate the corrosion layer into preventive film directly and the zinc layer can be phosphated simultaneously.The phosphating film gained from the solution can resist cupric sulfate spot test for 2～3 min and dipping test in the NaCl solution of more than(15 h).The adhesion is ≤1.There are no bubbling,falling off and corrosion on the coating.Coating weight is as follows: rusted steel sheet 14～24 g/m~2 and hot-dip zinc plated sheet 5～8 g/m~2.In-room test of the in-rack panel showed no rust for six months.This phosphating solution is suitable for steel material,corroded zinc plated steel substrate and
zinc plated steel material.