A method for forming a trivalent chromium coating on an aluminum alloy substrate includes adding a chromium-containing solution to a vessel, immersing the aluminum alloy substrate in the chromium-containing solution, immersing a counter electrode in the chromium-containing solution, and applying an electrical potential bias to the aluminum alloy substrate with respect to its equilibrium potential to form a trivalent chromium coating on an outer surface of the aluminum alloy substrate. A method for forming a trivalent chromium coating on a metal substrate includes adding a chromium-containing solution to a vessel, immersing the metal substrate in the chromium-containing solution, immersing a counter electrode in the chromium-containing solution, and modulating an electrical potential difference between the metal substrate and the counter electrode to form a trivalent chromium coating on an outer surface of the metal substrate.