Application of nano-aluminum sol in aluminum anodization

The small particles in the Boehmite sol enter the pores of the anodic oxide film, and the large particles formed by the small particles are covered on the surface layer of the oxide film. After the hole is sealed, the oxide film is dried to remove the water in the oxide film, and a sol-gel film with strong corrosion resistance is formed on the surface layer of the oxide film. Therefore, the acid resistance of Boehmite sol sealing film containing sol-gel film is better.

(1) Sealing process parameters

Temperature: Room temperature is fine

Soaking time: 30min

Closed PH: 4-4.5

The drying temperature after aluminum sol closure: 80℃

Drying time after aluminum sol closure: 8h

(2) Sealing effect

Compared with boiling water sealing, normal temperature nickel fluoride sealing, medium temperature nickel acetate sealing, alkaline earth metal salt sealing, organic acid sealing, zirconium-titanium sealing, rare earth sealing, bichromate sealing, Boehmite sol sealing is not only green, low cost, but also has the best corrosion resistance to acid and alkali, and its hardness after sealing is also better. The discoloration time of the drop test solution of the anodic oxide film closed by Boehmite sol can reach 33min, and the weight loss rate of acid leaching is lower than 30㎎/d㎡. Both of these properties meet the requirements of industrial production. On the whole, the performance of Boehmite sol sealing film is good in all aspects, which has the prospect of further development and research.