Optimized Micro-Arc Oxidation Coating Thickness on ALZ Magnesium Lithium Alloy

Micro-arc oxidation (MAO) is known as a novel technique to use for the modifying the surface of valve metal, which improve mechanical and corrosion resistance properties. In this study, MAO coatings are fabricated on ALZ magnesium lithium alloy to protect the substrate from corrosion using environmentally friendly electrolytes under a high voltage power supply. The Taguchi method is used to identify the effects of current density, coating time and electrical frequency on the thickest coating uniformity. The optimum coating properties are characterized by coating thickness measurement, Scanning electron microscopy (SEM), Potentiodynamic polarization analysis. It was found that the processing time is the main factor affecting the thickest coating uniformity (tu). Coatings fabricated under optimum conditions are in close agreement with the predicted values of Taguchi analysis. The corrosion resistance of MAO coated on ALZ magnesium lithium alloy are greatly improved compare to the bare alloy in corrosive environments.

High-Field Growth of Semiconducting Anodic Oxide Films on Metal Surfaces for Photocatalytic Application

This work summarizes progresses achieved in the physical chemistry aspects of the growth of anodic oxides under high-field conditions for the synthesis of semiconducting thin solid films and their implementation as photocatalytic materials. We discuss the scope and mechanisms for anodic oxide growth, describing the development of kinetic models and the correlations between theory and kinetic data, leading to fundamental information to characterize the primary processes occurring during the anodization of valve metals under high fields. The main features related to the widely used self-assembly of nanostructures by valve metal anodization are highlighted and briefly discussed. This is followed by general considerations of heterogeneous photocatalysis on these functional materials, considering the kinetics of the heterogeneous catalytic processes involved and the overall photoelectrochemical performance. High control of the characteristics of the materials obtained with the method described, combined with the possibility of electrochemically assisting photocatalysis, allows application of this technology to the treatment of wastewaters, energy conversion, and related fields.