Effect of inorganic constituent on nanomechanical and tribological properties of polymer, quasi-ceramic and hybrid coatings

This study investigates the variations in nanomechanical properties of coatings made of a pristine polymeric backbone and those containing silicone segments. Four different coatings with varying degrees of inorganic segments were prepared and analyzed. The four coatings were 1) a pure epoxy polymer coating, 2) a hybrid coating consisting of epoxy and silicone, 3) a ceramer coating consisting of organo-silicone and 4) a quasi-ceramic coating consisting of specialty silicone composition. The molecular bonding characteristics of the coatings were characterized with FTIR spectroscopy. The coatings were also tested using nanoindentation and nanoscratch methods to investigate mechanical and tribological properties. The scratched surface was investigated using scanning electron microscopy and atomic force microscopy. The hybrid coating displayed superior nanomechanical properties compared to the pure polymer coating, and the coating containing high silicone levels displayed better hardness. Atomic force microscopy showed that the epoxy-based polymer coating consisted of a smooth surface that was compressed when scratched using a nanoindenter. The hybrid coating had rough surface that was damaged and partially recovered after the scratch test. The ceramer and quasi-ceramic coatings displayed brittle failure.