Dielectric and optical characterizations of insulating coatings prepared by Micro-Arc Oxidation process on aluminum space parts

The optical and electrical properties of aluminum oxide layers for potential application in spacecrafts have been investigated. We have correlated the operational conditions of the Micro-Arc Oxidation (MAO) process to the structural features of the coatings and to the optical properties. Our results show that for appropriate electrolyte formulation the thermo-optical parameters of the coatings could fit the specification range for cold coatings used in space applications. Furthermore, the electrical properties of such coatings have been investigated by means of surface and volume conductivity measurements as well as dielectric spectroscopy. Results show that materials exhibiting the best thermo-optical properties are those having the higher electrical conductivity, with values appearing favorable regarding the targeted application.