12007-35-1Relevant articles and documents
Bulk monolithic zirconium and tantalum diborides by reactive and non-reactive spark plasma sintering
Licheri, Roberta,Musa, Clara,Orrù, Roberto,Cao, Giacomo,Sciti, Diletta,Silvestroni, Laura
, p. 351 - 359 (2016)
Monolithic ZrB2 and TaB2 were produced starting from the precursors through Self-propagating High temperature Synthesis followed by Spark Plasma Sintering (SHS-SPS) and by means of Reactive Spark Plasma Sintering (RSPS). Both methods enabled to achieve almost fully dense ceramics with mean grain size typical of pure bulks. ZrB2 materials displayed significant differences in the final mean grain size of the products obtained by the two routes, while a satisfactory homogeneity was reached in both cases. This was confirmed by good mechanical strength values, about 400 MPa at room temperature, basically maintained up to 1200°C. On the other hand, TaB2 sintered materials were quite diverse, in particular TaB2/RSPS showed a dual distribution of mean grain size, along with an almost no residual porosity, whilst TaB2/SHS-SPS had more homogeneous grain size distribution and diffused trapped porosity which corrupted the mechanical and oxidation performances.
Superhard Tungsten Diboride-Based Solid Solutions
Pangilinan, Lisa E.,Turner, Christopher L.,Akopov, Georgiy,Anderson, Mackenzie,Mohammadi, Reza,Kaner, Richard B.
, p. 15305 - 15313 (2018)
Solid solutions of tungsten diboride (WB2) with increasing substitution of tungsten (W) by tantalum (Ta) and niobium (Nb) - ranging from 0 to 50 at. % on a metals basis - were synthesized through resistive arc melting. Samples were characterized using a combination of powder X-ray diffraction (PXRD) for phase identification, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy for elemental composition, Vickers microindentation for hardness measurements, and thermogravimetric analysis for thermal stability. The solubility limit was found to be less than 8 at. % for Nb and less than 10 at. % for Ta, as determined by PXRD. Vickers hardness (Hv) values were measured to be 40.3 ± 1.6 and 41.0 ± 1.2 GPa at 0.49 N for 6 at. % Nb and for 8 at. % Ta substitution, respectively. In addition, the hardest solid solution (W0.92Ta0.08B2) showed oxidation resistance up to ～570 °C, approximately 70 °C higher than that of tungsten carbide (WC). Although pure WB2 is known not to be superhard, these results demonstrate the formation of superhard solid solutions through the substitution of tungsten by small amounts of transition metals. This increase in hardness can be attributed to solid solution hardening.
A convenient inorganic solvent thermal route to nanocrystalline tantalum diboride
Ma, Jianhua,Du, Yihong
, p. 510 - 511 (2008)
Nanocrystalline TaB2 has been prepared via a simple inorganic solvent thermal route by the reaction of metallic magnesium powders with tantalum pentoxide and boric acid in an autoclave at 650°C. X-ray powder diffraction patterns indicate that the product was hexagonal tantalum diboride. Scanning electron microscopy images show that it consisted of particles with an average size of about 40 nm. The product was also studied by BET and TGA. Copyright
