Hydrophilic and antimicrobial low-silica-zeolite LTA and high-silica-zeolite MFI hybrid coatings on aluminum alloys

A hydrophilic and antimicrobial two-layer zeolite composite coating was formed on aluminum alloys. The base layer is a high-silica-zeolite (HSZ) MFI coating formed directly on the aluminum alloy by in situ crystallization. The top layer is a crystalline zeolite hybrid coating of low-silica-zeolite (LSZ) LTA (zeolite A, or ZA) crystals imbedded within a HSZ-MFI matrix and is formed by a seeded growth method. The two-layer composite coatings are demonstrated by using ASTM D 3359B-02 method to have excellent adhesion to the aluminum alloy substrates. The hybrid layer is hydrophilic with contact angles below 5° and when they are silver-ion exchanged the hybrid coating is highly antimicrobial.