Abstract: Ozone was used as oxidizing accelerant in phosphating of metallic aluminium based on its strong oxidizing property and environmental friendliness.The best mix ratio of  phosphating solution components was confirmed by SEM and polarization as follows:ρ（Zn²⁺）=5.0 g/L，ρ(PO^3-₄)=20 g/L,ρ(F^-)=1.5 g/L,ρ(ammonium molybdate)=1.0 g/L,ρ(ozone)=0.5~0.9 mg/L,and pH was at 3.5~3.7.Under above conditions,the phosphating film was prepared while adding ozone-ammonium molybdate compound accelerant.Main ingredient of the prepared phosphating film was Zn₃(PO₄)₂•₄H₂O,in which a small amount of zinc was contained and the film weight could reach 4.95 g/m².Polarization curve of phosphating film was measured in NaCl solution with the mass fraction of 3%.Its corrosion potential had a positive shift comparing with that of the phosphating films formed under other conditions and the corrosion current density was only 3.0 μA/cm².Thus showed it had a good corrosion resistance.

Key words: ozone；phosphating；ammonium molybdate, compound accelerant