N+-implantation induced enhanced adhesion of amorphous-sic films deposited on stainless-steel

Amorphous a-SiC films were deposited by rf magnetron sputtering on stainless steel and N+ implantations were performed at room temperature over a fluence range of 1X10(16)-1X10(17) ions/cm2 at 30 and 160 keV Chemical characterization of the a-SiC/steel interface and compositional depth profiles were obtained by Auger electron spectroscopy. Adhesion properties of the films were examined using a scratch tester in conjunction with scanning electron microscopy. A strong adhesion enhancement (about a factor of eight) along with an improvement of the fracture toughness were observed in the implanted a-SiC/steel specimens. The key mechanisms envisaged to explain the enhanced adhesion is mainly related to the new chemical bondings, involving C and N in Si-(N,C)-Cr complexes formation at the a-SiC/steel interface.