Mechanical properties of pulsed laser deposited nanocrystalline SiC films

The mechanical properties of nanocrystalline SiC thin films grown on (100) Si at a substrate temperature of 1000 °C under a CH4 atmosphere using the pulsed laser deposition (PLD) technique were investigated. Nanoindentation results showed that films exhibited hardness values around 36 GPa and Young modulus values around 250 GPa. Scratch tests found that films were adherent to the substrate, with critical load values similar to those recorded for other hard coatings deposited on significantly softer Si substrates. Wear tests performed at a temperature of 900 °C showed that films exhibited friction coefficients and wear rates very similar to those measured at room temperature, due to the presence of C-C bonds as evidenced by X-ray photoelectron spectroscopy investigations. These results recommend such coatings for demanding high temperature applications such as nuclear fuel encapsulation.