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High-temperature properties of ZrB2–HfB2 and ZrB2–HfB2–SiC solid solutions
Physicochemical Mechanics of MaterialsSolid (ZrxHf1–х)B2 and (ZrxHf1–х)B2–15 vol.% SiC composites were obtained by hot pressing. It was shown that the formation of homogeneous solid solution occurs at an equimolar ratio. The coreshell structure was formed in composite with 25 and 75 at.% HfB2.
D. V. Vedel +4 more
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A model for the oxidation of ZrB2, HfB2 and TiB2
Acta Materialia, 2007Abstract A mechanistic model that interprets the oxidation behavior of the diborides of Zr, Hf and Ti in the temperature range of ∼1000–1800 °C was formulated. Available thermodynamic data and literature data for vapor pressures and diffusivities were used to evaluate the model.
T.A. Parthasarathy +3 more
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The high-temperature hardness of ZrB2 and HfB2
Journal of the Less Common Metals, 1974Abstract The variation of hardness with temperature has been investigated for ZrB2 and HfB2 in the temperature range 25–550°C, using a high temperature microscope equipped with a microhardness tester. A plot of log hardness versus temperature displays straight-line behaviour. Hardness anisotropy is demonstrated for both diborides.
Lars Bsenko, Torsten Lundström
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Thermal Expansion of Micro- and Nanocrystalline HfB2
High Temperature, 2019Hafnium diboride nano- and microcrystals are studied by high-temperature X-ray diffraction in the temperature range of 300–1500 K. HfB2 nanocrystals are found to have a greater thermal expansion coefficient than HfB2 microcrystals. The thermal expansion of HfB2 is found to be anisotropic with respect to the unit cell axes.
D. Yu. Kovalev +7 more
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Combustion synthesis of HfB2-Al composites
Metallurgical and Materials Transactions B, 1998Combustion synthesis (SHS) of HfB2-Al composite materials with a wide range of HfB2-to-Al ratios corresponding to either metal (Al) or ceramic (HfB2) matrix was carried out with the emphasis on 60 and 70 vol pct Al. The effects of composition and green density of pellets on the combustion characteristics were studied.
H. C. Yi +3 more
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Thermodynamic Calculation of HfB2 Volatility Diagram
Journal of Phase Equilibria and Diffusion, 2011The thermodynamics of the oxidation of HfB2 at temperatures of 1000, 1500, 2000, and 2500 K have been studied using volatility diagrams. Both the equilibrium oxygen partial pressure ( $$ P_{{{\text{O}}_{2} }} $$ ) for the HfB2(s) to HfO2(s) plus B2O3(l) and the ...
Hui Li +3 more
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Materials Chemistry and Physics, 2019
Abstract Ternary ZrB2–SiC-HfB2 composites with different amount of 4, 8 and 12 vol% HfB2 were consolidated at 1800 °C, 9 min and 30 MPa SPS conditions. Microstructural evaluations were done by scanning electron microscopic (SEM). Densification was measured by Arashmidous method. Fracture toughness was determined by crack length measurement.
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Abstract Ternary ZrB2–SiC-HfB2 composites with different amount of 4, 8 and 12 vol% HfB2 were consolidated at 1800 °C, 9 min and 30 MPa SPS conditions. Microstructural evaluations were done by scanning electron microscopic (SEM). Densification was measured by Arashmidous method. Fracture toughness was determined by crack length measurement.
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Oxidation behaviour of a pressureless sintered HfB2–MoSi2 composite
Journal of the European Ceramic Society, 2009The thermal stability of a 80 vol% HfB2+ 20 vol% MoSi2 composite is tested under oxidizing environment. Oxidation tests are carried out in flowing synthetic air in a TG equipment from 1000 to 1400°C with exposure time of 30 hours. At temperatures 1200°C the silica resulting from oxidation of molybdenum disilicide seals the sample surface, preventing ...
Diletta Sciti +2 more
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Synthesis of submicrometer HfB2 powder and its densification
Materials Letters, 2012Abstract This work reported submicrometric HfB 2 powder synthesis by a new borothermal reduction route using HfO 2 and boron as raw materials. The particle size of HfB 2 powders by conventional borothermal reduction was ~ 2.1 μm. HfB 2 particle coarsening mainly depended on the presence of B 2 O 3 product.
Wei-Ming Guo +2 more
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Characterization of Hafnium Diboride, HfB2 (0001), by XPS
Surface Science Spectra, 2000X-ray photoelectron spectra of a clean, well-ordered HfB2 (0001) single crystal surface are reported. A survey spectrum covering a binding energy range of 0 to 1000 eV is shown, which reveals the presence of minor amounts of oxygen and zirconium. Spectra over narrower binding energy ranges are also shown for the Hf 4f, B 1s, and Hf 4s/O 1s regions.
C. L. Perkins +3 more
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