Analysis on Film Forming Mechanism of Chromium-Free Passivation Agent for Aluminum Alloy Wheel Hub

Abstract

In order to study the film forming mechanism of chromium-free passivation film for aluminum alloy wheel hub， the film-forming effect and mechanism of chromium-free chemical conversion film on aluminum alloy automobile wheel hub were studied by electrochemical method combined with X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM).Results showed that during the formation of chemical conversion film， organics， zirconium and oxygen compounds would grow competitively.At the initial stage of film formation，inorganic zirconium and oxygen compounds had faster reaction and film forming rate.With the extension of film forming time， silane and resin，organic components， slowly formed chemical bonds to form a film， forming an inorganic/organic complete continuum， thus playing a better corrosion resistance coordination role.

Keywords

• aluminum alloy|chromium-free passivation|fluorozirconic acid|resin|corrosion inhibition