Sealing process for an anodized aluminum-alloy surface

A sealing process, comprising:

• applying a first reactant to a substrate having a porous structure, the first reactant comprising at least one of a trivalent chromium precursor and a transition metal precursor;
• wherein the substrate is an anodized aluminum-alloy surface with a barrier oxide film;
• and
• applying a second reactant to the first reactant in the porous structure, where the second reactant comprises a rare earth element precursor and an alkaline earth element precursor;
• and
• reacting the first reactant with the second reactant to produce a physical barrier over the substrate;
• where the physical barrier seals the porous structure to form reservoirs that contain the trivalent chromium precursor.