García-Pérez, María✉; Fernández-Silva, Samuel David; Roman, Claudia; Lazar, Liliana; Mozo, Juan Daniel; Delgado, Miguel Ángel; García-Morales, Moisés
This work investigated the use of anodic aluminum oxide (AAO) coatings as dielectric platforms to enable electrically tunable lubrication. One of the main challenges in electro-responsive lubrication is the risk of electrical short-circuiting when metal surfaces act as electrodes. In this context, AAO coatings were explored as a means to allow the application of an electric field across a lubricated contact while restricting electrical conduction.
AAO coatings were obtained on aluminum alloy substrates through hard anodizing under different processing times, leading to coatings with varying thicknesses and associated dielectric breakdown voltages. Their electro-tribological response was evaluated under lubricated sliding tests using an electro-responsive lubricant consisting of a 6 wt% dispersion of Cloisite 15A in castor oil.
The results showed that a minimum coating thickness was required to sustain an effective electric field across the lubricated contact. Once this condition was fulfilled, the application of the electric field produced noticeable changes in friction and wear behavior.
These findings demonstrate that AAO coatings can go beyond their conventional role as protective layers, offering a promising approach for the development of smart lubrication systems.
