Method for aluminum electroless deposition

A method for coating a substrate with an anodized aluminum oxide layer, comprising:

• activating the surface of the substrate to be coated by applying a coating of a catalyst metal;
• preparing a mixture of urea (NH2CONH2) and anhydrous aluminum chloride (AlCl3) wherein a molar ratio of AlCl3:NH2CONH2 is greater than 1:1 to obtain a Lewis acid room temperature ionic liquid (RTIL);
• dissolving a hydride reducing agent in an aprotic anhydrous solvent to obtain a hydride solution;
• mixing the hydride solution and the AlCl3:NH2CONH2 RTIL to obtain an electroless Al solution;
• exposing the activated surface of the substrate to the electroless Al solution;
• and
• removing the electroless Al solution from the substrate surface to obtain an electroless aluminum plated substrate;
• submerging the electroless aluminum plated substrate in an electrolytic solution;
• applying an anode current to the aluminum coat to form an aluminum oxide coat comprising a barrier layer;
• and
• treating the aluminum oxide layer to form pores in the aluminum oxide structure.