Superhard tungsten tetraboride films prepared by pulsed laser deposition method

ACS Appl Mater Interfaces. 2011 Sep;3(9):3738-43. doi: 10.1021/am200927q. Epub 2011 Sep 12.

Abstract

Attempts to synthesize and/or theoretically predict new superhard materials are the subject of an intense research activity. The trials to deposit them in the form of films have just began. WB(2) (77 wt % WB(2) and 23 wt % WB(4)) and WB(4) (65 wt % WB(4) and 35 wt % WB(2)) polycrystalline bulk samples were obtained in this work via electron beam synthesis technique and, subsequently, used as targets for films preparation by the pulsed laser deposition method. The targets were irradiated by a frequency-doubled Nd:glass laser with a pulse duration of 250 fs. The films grown on SiO(2) substrates at 600 °C were characterized by X-ray diffraction, scanning electron and atomic force microscopies, and Vickers microhardness technique. The deposited films are composed of WB(4). The intrinsic film hardness, calculated according to the "law-of-mixtures" model, lies in the superhardness region 42-50 GPa.

MeSH terms

  • Boron Compounds / chemical synthesis
  • Boron Compounds / chemistry*
  • Lasers, Solid-State*
  • Microscopy, Atomic Force
  • Microscopy, Electron, Scanning
  • Silicon Dioxide / chemistry
  • Tungsten / chemistry*
  • X-Ray Diffraction

Substances

  • Boron Compounds
  • Silicon Dioxide
  • Tungsten