Rare-earth modified Ti-Zr chemical passivation solution for surface treatment of aluminium profiles and using method of rare-earth modified Ti-Zr chemical passivation solution

Abstract

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.

Description

technical field [0001] The invention relates to an aluminum alloy surface treatment method, in particular to preparing a rare earth modified Ti-Zr composite passivation film with good corrosion resistance on the aluminum alloy surface by using a non-chromium passivation treatment liquid. Background technique [0002] Aluminum alloy is the second largest metal structural material after steel, and is widely used in many fields such as automobiles, aerospace, architectural decoration, home appliances, instruments, computers, mobile phones, and daily hardware. Aluminum alloy products must undergo surface treatment before use. Among them, chemical passivation treatment has the advantages of little impact on the fatigue performance of the base material, convenient operation, low cost, high production efficiency, and wide application range. It is the most widely used surface treatment technology. one. The aluminum alloy is coated after passivation treatment, which can greatly impr...

AI Technical Summary

Problems solved by technology

At present, the chemical passivation process of aluminum alloys generally adopts the chromate method, which has been widely used in aluminum materials in industries such as aviation, aerospace, automobiles, home appliances, construction and decoration, but the hexavalent chromium compound contained in its process formula is a It is a kind of toxic chemical, improper disposal will not only cause great pollution to the environment but also seriously endanger human health

Because of this, chromate has been listed as extremely poisonous by the relevant environmental protection departments of many countries. In 2000, the European Parliament passed the ELVs law to stipulate that the amount of hexavalent chromium used for the surface protection treatment of each car should not exceed 2g. The European Union’s ROHS Explicit restrictions include Cr 6+ The use of six components in electrical and electronic equipment, it is foreseeable that the application of chromate in industry will be subject to increasingly strict restrictions

Although a lot of research has been done on the chromium-substituting passivation film process at home and abroad, the titanium-zirconium system is the earliest chromium-free treatment system developed, and most of the current industrial production uses this treatment solution containing titanium (zirconium) fluorine complexes. However, its passivation film is colorless, which brings certain difficulties to industrial operation, and the overall performance needs to be improved, so these technologies cannot completely replace the chromate system.