TWO-STAGE PRE-TREATMENT OF ALUMINUM COMPRISING PICKLING AND PASSIVATION

摘要

A method for anti-corrosion treatment of components produced from aluminium, comprising a pre-treatment stage and subsequent painting. The pre-treatment stage includes steps of pickling and passivation wherein passivation of the components includes contacting them with an acidic, aqueous composition based on water-soluble compounds of the elements Zr and/or Ti. The pickling and passivation are coordinated with each other so that a re-dosing of active components of the passivation solution can occur in substantial parts from the pickling solution.

主权项

1. A method for anti-corrosion treatment of components at least partly produced from aluminum, comprising a pre-treatment stage and subsequent painting stage, wherein steps in the pre-treatment stage comprise:
a. contacting an aluminum component with an aqueous pickling solution that has a pH value of 1 to 3, a free acid content in points of at least 8 and a total fluoride content of at least 40 mmol/l; and b. contacting the component from step a) with an aqueous passivation solution that has a pH value of 1 to 3, a free acid content in points of below 8 and a total fluoride content of less than 60 mmol/l but at least 5 mmol/l, and also contains less than 10 mmol/l but at least 0.1 mmol/l of water-soluble compounds of the elements Zr and/or Ti for each respective element, whereby after the component is brought into contact with the pickling solution and before it is brought into contact with the passivation solution, no rinsing or drying step takes place.