Treating solution for preparing Al-Mo-Mn-Re quaternary composite passivation film on aluminum profile surface and its application method

Abstract

The invention discloses a treating solution for preparing a corrosion resistant Al-Mo-Mn-Re quaternary composite passivation film on an aluminum alloy surface and its application method. The passivation solution is characterized by being a passivation treatment solution which is used for preparing a passivation film on an aluminum alloy surface by utilizing a molybdate, a rare earth salt and a permanganate oxidant. Per liter of the treating solution consists of: 8g.L<-1>-25g.L<-1> of sodium molybdate (or ammonium molybdate), 5g.L<-1>-10g.L<-1> of potassium permanganate, 0.5g.L<-1>-3g.L<-1> of sodium fluoride (or potassium fluoride), 0.5g.L<-1>-5g.L<-1> of cerium nitrate (or ceric sulfate, lanthanum nitrate), 1g.L<-1>-5g.L<-1> of acetic acid, 0.5g.L<-1>-1g.L<-1> of sodium dodecyl benzene sulfonate (or OP-10) . The application method includes: (1) removing adhered dust and other dirt from the aluminum alloy; (2) then conducting pretreatment on the aluminum alloy surface; (3) using the treating solution for passivation treatment; and (4) carrying out water washing and drying. The treating solution of the invention has the advantages of fast film formation speed, simple process, uniform film, strong corrosion resistance, and less environmental pollution, etc.

Description

technical field [0001] The invention relates to an aluminum alloy surface treatment method, in particular to preparing an Al-Mo-Mn-Re quaternary 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 widely used in many fields such as automobiles, aerospace, architectural decoration, home appliances, instruments, computers, mobile phones, daily hardware, etc. It is the second largest metal structural material after steel. Due to the high chemical activity of aluminum and its alloys, damages such as pitting corrosion, crevice corrosion, stress corrosion and corrosion fatigue are very easy to occur, which cannot meet the use requirements in harsh environments. In order to improve the service life of aluminum alloys and meet the requirements of product appearance and decoration, aluminum alloy products must undergo surface treatment before use. ...

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 process of substituting chromium passivation film at home and abroad, such as titanium zirconate system, cobalt salt system and silica sol system, etc., these technologies still need to be improved in terms of corrosion resistance and treatment process, and the production efficiency is relatively low. Low, so these technologies can not completely replace the chromate system