Atomic Layer Deposition of Thin Film Oxides on Magnesium Alloys to Inhibit Corrosion
Abstract
Magnesium alloys are integrated into many performance consumer products because of their high strength to weight ratio; however, one of the major engineering hurdles of magnesium alloys is their susceptibility to corrosion in harsh environments, which limits their use in several applications. To overcome this limitation, we hypothesize that coating magnesium alloys with thin films of different chemistries via atomic layer deposition (ALD) will inhibit the effects of corrosion. While chemical and physical vapor deposition techniques have been used to coat Mg alloys, little work has been done using ALD. ALD is a thin film growth technique that uses cyclic self-limiting chemical reactions to deposit conformal, pinhole-free films in a layer-by-layer fashion. Using ALD, amorphous aluminum oxide (alumina, Al2O3) and titanium dioxide (titania, TiO2) coatings were applied to magnesium alloy (AZ-31) substrates in an attempt to inhibit corrosion. The oxide coatings and their impact on corrosion resistance were characterized using atomic force microscopy, electrochemical impedance spectroscopy, linear polarization measurements, and mechanical testing.
Atomic Layer Deposition of Thin Film Oxides on Magnesium Alloys to Inhibit Corrosion
Magnesium alloys are integrated into many performance consumer products because of their high strength to weight ratio; however, one of the major engineering hurdles of magnesium alloys is their susceptibility to corrosion in harsh environments, which limits their use in several applications. To overcome this limitation, we hypothesize that coating magnesium alloys with thin films of different chemistries via atomic layer deposition (ALD) will inhibit the effects of corrosion. While chemical and physical vapor deposition techniques have been used to coat Mg alloys, little work has been done using ALD. ALD is a thin film growth technique that uses cyclic self-limiting chemical reactions to deposit conformal, pinhole-free films in a layer-by-layer fashion. Using ALD, amorphous aluminum oxide (alumina, Al2O3) and titanium dioxide (titania, TiO2) coatings were applied to magnesium alloy (AZ-31) substrates in an attempt to inhibit corrosion. The oxide coatings and their impact on corrosion resistance were characterized using atomic force microscopy, electrochemical impedance spectroscopy, linear polarization measurements, and mechanical testing.