Creation of super hard coatings with excellent oxidation resistance made from ubiquitous elements

We prepared composite films consisting of nitride and oxide in order to obtain new protective coatings having super high hardness and excellent oxidationresistance, which were made from ubiquitous elements. The new nanocomposite coatings consisting of AlN and oxide （SiOx or AlxOy) were deposited with the differential pumping co-sputtering system. The indentation hardness of AlN and the oxide were 24GPa and 11~ 13GPa, respectively. Regardless of the lower hardness of single phase films, the AlN/SiOx or AlN/AxOy nanocomposite coatings showed an increase of ~50% in indentation hardness from that of the AlN film and achieved a maximum hardness of 34 GPa by co-deposition of oxide and nitride. The indentation hardness of some composite coatings barely changed when the coating samples were annealed at 800 ℃×1 hour in air