Electrodeposition of cerium-based coatings for corrosion protection of aluminum alloys

A process for enhancing the corrosion resistance of an aluminum-containing component comprising:

• immersing an aluminum-containing cathode and an oxygen-evolving anode in an electrolyte comprising water, solvent, cerium ions, and an oxidizing agent selected from the group consisting of hydrogen peroxide, ozone, hypochlorite, nitric acid and mixtures thereof;
• and
• passing an electrical current through the electrolyte to facilitate cathodic precipitation under conditions characterized by a current density of from about 1 amp/ft.sup.2 to about 50 amps/ft.sup.2 to deposit a cerium-based coating onto the aluminum-containing cathode, said coating having a thickness of at least about 0.1 microns and a continuous surface area of at least about 15 in.sup.2.

A process for enhancing the corrosion resistance of an aluminum-containing component comprising:

• immersing an aluminum-containing cathode and an oxygen-evolving anode in an electrolyte having an initial pH in the range of from about 1 to about 1.5 comprising water, solvent, and cerium ions;
• and
• passing an electrical current through the electrolyte by applying electrical current having a current density of from about 1 amp/ft.sup.2 to about 50 amps/ft.sup.2 to the anode to deposit a cerium-based coating onto the aluminum-containing cathode, said coating having a thickness of at least about 0.1 microns and a continuous surface area of at least about 15 in.sup.2.

A process for enhancing the corrosion resistance of an aluminum-containing component comprising:

• immersing an aluminum-containing cathode and an oxygen-evolving anode in an electrolyte having an initial pH of from about 1.2 to about 1.3, the electrolyte comprising from about 30% by volume to about 60% by volume alcohol, an initial hydrogen peroxide concentration of from about 1% to about 4% by volume, an initial cerium ion concentration of from about 0.01 to about 0.05 moles per liter, and water;
• and
• passing an electrical current through the electrolyte by applying electrical current having a current density of between about 5 amp/ft.sup.2 and about 15 amps/ft.sup.2 to the anode to deposit a cerium-based coating onto the aluminum-containing cathode, said coating having a thickness of from about 0.1 microns to about 1.0 microns and a continuous surface area of at least about 15 in.sup.2.

An electrolyte for use in depositing a cerium-based coating onto a substrate, the electrolyte having a pH of from about 1.0 to about 1.5 and comprising from about 30% to about 60% by volume alcohol, from about 1% to about 4% by volume hydrogen peroxide, from about 0.01 to about 0.3 moles per liter cerium ions, and water.

A process for enhancing the corrosion resistance of an aluminum-containing component comprising:

• immersing an aluminum-containing cathode and an oxygen-evolving anode in an electrolyte having an initial pH in the range of from about 1 to about 1.5 comprising water, solvent, and cerium ions;
• and
• passing an electrical current through the electrolyte to facilitate cathodic precipitation under conditions characterized by a current density of from about 1 amp/ft.sup.2 to about 50 amps/ft.sup.2 to deposit a cerium-based coating onto the aluminum-containing cathode, said coating having a thickness of at least about 0.1 microns.

A process for enhancing the corrosion resistance of an aluminum-containing component comprising:

• immersing an aluminum-containing cathode and an oxygen-evolving anode in an electrolyte having an initial pH of from about 1.2 to about 1.3, the electrolyte comprising from about 30% by volume to about 60% by volume solvent, an initial hydrogen peroxide concentration of from about 1% to about 4% by volume, an initial cerium ion concentration of from about 0.01 to about 0.05 moles per liter, and water;
• and
• passing an electrical current through the electrolyte to facilitate cathodic precipitation under conditions characterized by a current density of between about 5 amp/ft.sup.2 and about 15 amps/ft.sup.2 to deposit a cerium-based coating onto the aluminum-containing cathode, said coating having a thickness of from about 0.1 microns to about 1.0 microns.