Nanostructured superhard films as typical nanomaterials

The advantages of the use of film samples for nanomaterials science studies are characterized. In particular, nanograined structures are readily obtained in film samples, whereas they are difficult to obtain in bulk samples. The properties of superhard multilayer nitride films, including the deformation of TiN and TiB2 films during indentation, the effect of an additional external magnetic field on the (TiB2-B4C) films' nanostructure and microhardness, as well as galvanomagnetic properties of TiN films are described and discussed in detail. It was found that generally the microhardness of multilayer nitride films increased with the number of layers, except if the two layers mutually dissolved. A microhardness of 78 GPa was achieved in 180 layer TiN/NbN films. TiB2 films had an inhomogencous step-like deformation pattern under indentation, in contrast to TiN films, which had a homogeneous deformation pattern, probably due to a slip along columnar grain boundaries. Application of an additional external magnetic field during magnetron sputter deposition increased hardness and smoothness of both crystalline and amorphous (TiB2-B4C) films. Decreasing the grain size of TiN films decreased the electron mobility while maintaining the carrier density. The oxygen and carbon distribution can be considered as random in TiN films with the grain size interval of 10-30 tim. (c) 2006 Elsevier B.V. All rights reserved.