Hybrid sol–gel coating on Al

New coating materials providing mechanical and chemical resistance to corrosion were developed for protection of metal surfaces. An aluminum plate surface was coated with polyurethane and epoxy based resins which were previously modified with ceramic powders, such as Al₂O₃, SiO₂, or SiC. Effects of the type and particle size of ceramic powder, organic matrix, co-reactants, the dispersant type and mixing rate on the coating material were investigated. Coated metal surface was subjected to taber-abrasion, adhesion and corrosion tests. Surface properties and thermal resistance of the coating materials were characterized by scanning electron microscopy (SEM) and thermogravimetric and differential thermal analysis (TG/DTA). Results revealed that polyurethane based coatings, whether contain ceramic powder or not, seems to be more advantageous than epoxy based one, besides surface modified ceramic powders provide excellent properties to the coatings.