Abrasion- and Peel-Resistant Sol-Gel Coating on Aluminum and Method for Producing a Coating of This Type

Abstract

Provided herein is an aluminum surface having an abrasion- and peel-resistant sol-gel coating. To obtain the coating, the aluminum surface is treated with an aqueous, oxidizing solution, such that said surface provides a suitable base for the subsequent sol-gel coating.

1 . A method for providing a base for a directly following sol-gel coating on an aluminum surface with a natural oxide layer, comprising treating the aluminum surface with an aqueous oxidizing agent, selected from the group consisting of peroxides, persulfates, perchlorates and perborates, wherein a pH value of the aqueous oxidizing agent is in a range of 3 to 8, and wherein the oxidizing agent is used at a concentration of 5 to 50 g/l. 
     
     
         2 . The method according to  claim 1 , wherein the treatment with the aqueous oxidizing agent is carried out at ambient temperature for a period of at least 2 minutes. 
     
     
         3 . The method according to  claim 2 , wherein the ambient temperature is 15° C. to 25° C. 
     
     
         4 . The method according to  claim 1 , wherein the treatment with the aqueous oxidizing agent is carried out over a period of 5 to 10 minutes. 
     
     
         5 . (canceled) 
     
     
         6 . A method for producing an abrasion-resistant aluminum surface, comprising:
 a) pretreating an aluminum surface by the method according to  claim 1 :   b) rinsing the pretreated surface and then optionally drying the surface; and subsequently   c) applying a sol-gel coat and hardening the sol-gel coat.   
     
     
         7 . The method according to  claim 6 , wherein the sol-gel coating on the aluminum surface has a coat thickness of 0.5 to 5.0 μm. 
     
     
         8 . An aluminum surface with an abrasion- and peel-resistant sol-gel coating obtained according to a method according to  claim 6 .