Abstract: The inventive two-step process operates at low temperature, without any toxic heavy metals, to provide excellent sealing on anodized aluminum substrates, especially those aluminum substrates comprising silicon. The first step of the process seals the anodized surface and the second step passivates the anodized surface. The process allows for corrosion resistance in anodized aluminum and anodized aluminum alloys to be achieved that is comparable to traditional nickel based sealants, without the toxicity of nickel. The process additionally does not require any excessive temperatures, as required by hot water sealing processes. The composition used for the sealing step comprises soluble lithium ions, fluoride ions, and preferably, a complexing agent comprising phosphines, phosphonates and/or polymers of acrylic acid. The composition used for the passivation step comprises metal ions and preferably a complexing agent comprising phosphines, phosphonates and/or polymers of acrylic acid.

Abstract: The inventive two-step process operates at low temperature, without any toxic heavy metals, to provide excellent sealing on anodized aluminum substrates, especially those aluminum substrates comprising silicon. The first step of the process seals the anodized surface and the second step passivates the anodized surface. The process allows for corrosion resistance in anodized aluminum and anodized aluminum alloys to be achieved that is comparable to traditional nickel based sealants, without the toxicity of nickel. The process additionally does not require any excessive temperatures, as required by hot water sealing processes. The composition used for the sealing step comprises soluble lithium ions, fluoride ions, and preferably, a complexing agent comprising phosphines, phosphonates and/or polymers of acrylic acid. The composition used for the passivation step comprises metal ions and preferably a complexing agent comprising phosphines, phosphonates and/or polymers of acrylic acid.

Abstract: A method of preparing an aluminum or aluminum alloy substrate to accept an adherent coating thereon is provided. The method includes the steps of degreasing the substrate, deoxidizing the substrate, and providing a prepaint conversion coating on the degreased and deoxidized substrate. The prepaint conversion coating composition comprises i) a source of fluoride ions; ii) a source of zirconium ions; iii) an acrylic resin; and iv) an optical brightener and forms a colorless, chromium-free conversion coating on the aluminum substrate that can be observed by exposing the treated substrate to UV light.

Abstract: A method of preparing an aluminum or aluminum alloy substrate to accept an adherent coating thereon is provided. The method includes the steps of degreasing the substrate, deoxidizing the substrate, and providing a prepaint conversion coating on the degreased and deoxidized substrate. The prepaint conversion coating composition comprises i) a source of fluoride ions; ii) a source of zirconium ions; iii) an acrylic resin; and iv) an optical brightener and forms a colorless, chromium-free conversion coating on the aluminum substrate that can be observed by exposing the treated substrate to UV light.