Results 151 to 160 of about 951 (206)
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Mechanical properties of HfB2 whiskers
Journal of Superhard Materials, 2013Nanoindentation has been used to study mechanical behavior of HfB2 whiskers 10–20μm in diameter in a directionally reinforced ceramics. For comparison a bulk (0001) HfB2 single crystal 5 mm in diameter has been tested. For both the samples a pop-in due to the nucleation of dislocations in a previously dislocation-free region under the indent has been ...
S N Dub, P I Loboda, I Bogomol
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Ablation Tests of Hot-Pressed Ultrahigh-Temperature HfB2 and HfB2–SiC Ceramic
Journal of Superhard MaterialsT A Prikhna, V E Moshchil, Prikhna T O
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The resistance to oxidation of an HfB2–SiC composite
Journal of the European Ceramic Society, 2005The oxidation resistance of an hot-pressed HfB2-SiC composite was studied through non-isothermal and isothermal treatments at temperatures up to 1600°C in air. The most severe oxidation conditions consisted of repeated heating-cooling cycles at 1600°C for up to 80 min of exposure. A thermogravimetric test for over 20 h at 1450°C provided evidence that,
Frederic Monteverde, Alida Bellosi
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Wetting and joining of HfB2 and Ta with Ni
WETTING and JOINING of HfB2 and Ta with Ni, 2010the wetting behavior of Ni on a HfB2/Ta assembly was examined in vacuum using dense HfB2 (99.5% purity) produced, without sintering aids, by HP-HT at 7 GPa. The real-time imaging by a high resolution digital camera and precise temperature control demonstrated solid-state Ni/HfB2 interaction resulòting in metal contact melting at 1300°C. Ongoing heating,
N Sobczak +7 more
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The electron Fermi surface of HfB2
AIP Conference Proceedings, 1991The de Haas‐van Alphen (dHvA) effect of HfB2 has been studied using a field modulation technique. Single crystal samples for the dHvA measurements were grown by a floating zone technique of rf heating. Observed dHvA oscillations in the (1010), (1120), and (0001) planes have frequencies of the order of 102 T.
T. Tanaka, Y. Ishizawa
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Interaction in the LaB6-HfB2 system
Soviet Powder Metallurgy and Metal Ceramics, 1984The data of metallographic and x-ray diffraction analyses, determination of the melting point, and measurement of the microhardness of individual phases served as the basis for constructing the phase diagram of the quasibinary eutectic type LaB6-HfB2 system with a eutectic composition of 70% LaB6 30% HfB2 and teut= 2750°K.
S. S. Ordan'yan +3 more
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Wetting and interfacial phenomena in Ni–HfB2 systems
Acta Materialia, 2009The wettability and reactivity between polycrystalline hot-pressed HfB2 and liquid Ni, Ni-Ti and Ni-B alloys have been investigated by the sessile drop method up to 1520°C. Independently of the sintering aids (B4C, HfSi2),high-temperature interactions led to the formation of a bimodal interface profile, due to the competition between the strong ...
A Passerone +4 more
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The behavior of HfB2 under neutron irradiation
Nuclear Science and Techniques/Hewuli, 2016Due to the interesting properties of hafnium diboride (HfB2) as a ceramic, it has drawn considerable attention from several researchers. To understand the radiation properties of HfB2 that may be used in the nuclear industry, the interaction of this composite under neutron irradiation was studied.
Mohammad Mehdi Nasseri
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Why HfB2 is not Superconductor
Journal of Superconductivity and Novel Magnetism, 2014The phonon spectra, electron-phonon Eliashberg function, and T c of the hafnium diboride were investigated from the first principles using the full potential linear muffin-tin orbital method. The calculations of the dynamic matrix were carried out within the framework of the linear response theory.
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Journal of Alloys and Compounds, 2018
Abstract Carbon nanotubes (CNTs) were synthesized over a Ni/Y2O3/HfB2 catalyst by chemical vapor deposition of methane at temperatures ranging from 800 °C to 1200 °C. Results of X-ray diffraction, scanning electron microcopy, transmission electron microcopy, and Raman spectroscopy indicated that 1100 °C was the most suitable synthesis temperature for
Hua Jin +4 more
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Abstract Carbon nanotubes (CNTs) were synthesized over a Ni/Y2O3/HfB2 catalyst by chemical vapor deposition of methane at temperatures ranging from 800 °C to 1200 °C. Results of X-ray diffraction, scanning electron microcopy, transmission electron microcopy, and Raman spectroscopy indicated that 1100 °C was the most suitable synthesis temperature for
Hua Jin +4 more
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