The invention discloses a rare-earth modified Ti-Zr chemical
passivation solution for surface treatment of
aluminium profiles and a using method of the rare-earth modified Ti-Zr chemical
passivation solution. The rare-earth modified Ti-Zr chemical
passivation solution is characterized in that the passivation solution is a main salt for auxiliary film-formation, which takes rare-earth compounds as a Ti-Zr passivation treatment solution, and a passivation film is light yellow in appearance and has field judgement property on the quality of a formed film. A formula of the rare-earth modified Ti-Zr chemical passivation solution is as follows: each litre of solution contains 0.5g.L<-1>-10g.L<-1> of
potassium fluotitanate (
hexafluorotitanic acid), 0.5g.L<-1>-10g.L<-1> of
potassium fluozirconate (fluozirconic acid), 0.5g.L<-1>-5g.L<-1> of
cerium nitrate (
ceric sulfate and
ammonium ceric
nitrate), 2g.L<-1>-10g.L<-1> of
potassium nitrate, 0.5g.L<-1>-3g.L<-1> of
sodium fluoride (
potassium fluoride), 0.5g.L<-1>-1g.L<-1> of
sodium dodecyl
benzene sulfonate or OP-10, 0.2mL-5mL.L<-1> of
nitric acid and 1g.L<-1>-5g.L<-1> of
boric acid. The using method of the rare-earth modified Ti-Zr chemical passivation solution comprises the following steps of: (1) clearing
dirt, such as
dirt attached to an
aluminium alloy; (2) pretreating the surface of the
aluminium alloy; (3) carrying out passivating treatment on the surface of the
aluminium alloy by using the rare-earth modified Ti-Zr chemical passivation solution; and (4) washing the
aluminium alloy by using water and
drying the
aluminium alloy. The rare-earth modified Ti-Zr chemical passivation solution disclosed by the invention has the advantages of light yellow appearance, high film formation speed, simple process, uniformity in film layer, strong
corrosion resistance, low environment
pollution and the like.