title: Superhard tungsten tetraboride films prepared by pulsed laser deposition method.
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.
authors.affiliation: Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche (CNR), Via del Fosso del Cavaliere, 100-00133 Rome, Italy. giulietta.rau@ism.cnr.it
authors.forename: Julietta V
authors.initials: JV
authors.lastname: Rau
authors.forename: Alessandro
authors.initials: A
authors.lastname: Latini
authors.forename: Roberto
authors.initials: R
authors.lastname: Teghil
authors.forename: Angela
authors.initials: A
authors.lastname: De Bonis
authors.forename: Marco
authors.initials: M
authors.lastname: Fosca
authors.forename: Ruggero
authors.initials: R
authors.lastname: Caminiti
authors.forename: Valerio
authors.initials: V
authors.lastname: Rossi Albertini
mesh_terms: D001896:Boron Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D053844:Lasers, Solid-State; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D012822:Silicon Dioxide / Q000737:chemistry; D014414:Tungsten / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D001896:Boron Compounds; D012822:Silicon Dioxide; D014414:Tungsten