Mechanical properties of La2O3 doped diamond-like carbon films

Twelve La2O3 doped diamond-like carbon (DLC) nanofilms were deposited using unbalanced dual-magnetron sputtering. AFM, XRD, Raman spectroscopy, AES, XPS, TEM, contact surface profiler and nanoindenter were employed to investigate the structure and tribological properties of deposited films. The results show that the La2O3 doped DLC films are amorphous. La2O3 doping obviously decreases internal stress, and effectively increases the elastic modulus. This results from the dissolving and dissolution of La2O3 within the amorphous DLC matrix. Furthermore, the friction coefficient of the doped DLC films decreases, and adhesion strength increases. These are attributed to the lubrication function of La2O3 and the formation of transition layer at interface, respectively.