Design, processing and characterization of flexible hybrid coatings: A comparative evaluation

Visual appearance as well as mechanical and chemical resistance of a phenyl methyl silicone resin deposited on cylindrical aluminum substrates by dipping and spraying is investigated. The morphological features of the coatings were analyzed by contact gauge profiler and scanning electron microscopy. Scratch and wear endurance was tested by progressive load scratch and dry sliding linear reciprocating tribological tests. The chemical resistance was tested by contact tests during which the coatings were dipped in acid, solvent-based and surfactant-rich solutions. The machinability of the coated substrates was tested by three-point bending and tensile static tests. Performance of the phenyl methyl silicone resin was also evaluated by comparison with two organic coating systems based on epoxy and polyurethane resins, widely used in several industrial domains as for their outstanding properties of chemical insulation and ductility. The experimental findings highlight significant performances of silicone resins as for protective and decorative purposes. Yet, the characteristics of flexibility showed by pure organic materials remain unparalleled, thus making epoxy and/or polyurethane good choice as far as the machinability of the coated substrate is concerned.