Treating fluid and method for preparing vanadium-zirconium composite conversion coatings with self-repairing performance on aluminum alloy surfaces through same

The invention belongs to the technical field of chemical materials, and relates to a treating fluid and a method for preparing vanadium-zirconium composite conversion coatings with self-repairing performance on aluminum alloy surfaces through the same. The method includes the steps of firstly preparing the treating fluid containing fluorozirconate, metavanadate, sodium fluoride, nitrate, an accelerate and an additive; then putting an aluminum alloy after surface pretreatment into a working fluid made of the diluted treating fluid for 2min-10min; and finally subjecting the aluminum alloy to washing, drying and cooling to obtain the vanadium-zirconium composite conversion coatings. The preparation process is simple, heavy metals such as hexavalent chromium and nickel are not contained, the environment is friendly, the conversion coatings of the aluminum alloy after a conversion coating treatment are dense and high in binding force, metal ions in the conversion coatings can bond with base metal under a corrosion environment and provided with a certain self-repairing performance, and the treating technology of vanadium-zirconium conversion coatings can effectively replace chromate treatment on aluminum alloy surfaces.