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Hafnium carbide (HfC) is the most refractory compound known to mankind. A catalyst‐assisted chemical vapor deposition method has been applied to synthesize contaminant‐layer‐free single ...
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Four different absorber materials are inserted in the same capsule: hafnium carbide, hafnium carbide with a molybdenum silicide additive, samarium hafnate, and europium hafnate. The two capsules are planned for irradiation in the flux trap of the High Flux Isotope Reactor at two different neutron fluence levels and with a target specimen ...
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The elastic properties of zirconium carbide are anisotropic, since they change depending on the crystallographic direction [hkl] ... Hafnium carbide (HfC) and tantalum carbide (TaC), as potential ultra-high temperature ceramics (UHTCs), have attracted widespread attention due to their unique physical and chemical properties. ...
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Tungsten carbide was the least stable and it transformed into W 2 C upon annealing whereas NbC decomposed after similar exposure. Hafnium carbide and ZrC were found to be the most stable and possessed the highest emissivity (0.9) among the carbides investigated. The experimental observation was examined in terms of …
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Tantalum carbide (TaC) and hafnium carbide (HfC) are of particular interest due to their high melting temperatures (>4000 K) which are the highest reported among all known inorganic materials 1,2 ...
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In order to gain insight into the effect of elevated temperature on the mechanical performance of zirconium carbide (ZrC) and hafnium carbide (HfC), their temperature-dependent elastic constants have been systematically studied. For both ZrC and HfC, isoentropic (C_ {11}) gradually decreases with the increase in temperature, …
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In terms of regular compounds rather than alloys, hafnium carbide has the highest melting point, of any compound consisting of just two elements, at just under 3,990 0 C. Moving …
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Hafnium carbide (HfC) is a potential candidate of ultrahigh-temperature ceramics (UHTCs) and has attracted significantly widespread interest in recent years. Here, we have synthesized high-purity HfC samples with NaCl-type structure by using a high-pressure solid–solid reaction. The structural stability, equation of state, plastic …
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Hafnium carbide powder (99.9% purity, 5 μm) and carbon fiber (Umatex UMT-49) were used as starting materials. Mixing fibers of a length of 10–15 mm and the powder was carried out in a ball mill in the presence of polyvinyl alcohol for 30 min at a rate of 150 rpm. The slurry ob-tained was then dried and hot pressed at 1800°C, under a
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Credit: NASA. Researchers have discovered that tantalum carbide and hafnium carbide materials can withstand scorching temperatures of nearly 4000 degrees Celsius. In particular, the team from ...
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In this work, a novel carbon fiber reinforced hafnium carbide matrix composite (Cf/HfC) is fabricated, and its potential serving as TPS material is studied inside an inductively coupled plasma ...
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Hafnium carbide | HfC or CHf | CID 16212551 - structure, chemical names, physical and chemical properties, classification, patents, literature, biological activities, …
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Hafnium carbide (HfC) is the most refractory compound known to mankind. ... electron microscope images and electron diffraction patterns show that most of the nanowires grew in the <100> direction. Morphological and compositional analyses confirmed that the nanowire growth followed the vapor-liquid-solid mechanism. Field ion …
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Introduction Nanostructured materials have a lot of important applications in various fields because of their unique properties. 1–3 Hafnium is known as the "little brother" of titanium and zirconium. Its dioxide (HfO 2) is a material with a number of technologically attractive properties such as high melting point (2758 °C), high dielectric constant (≈30), high …
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Hafnium carbide (HfC), one of transition-metal carbides with face-centered cubic (fcc) structure, has ultra-high melting pointing (3928 °C), high hardness (Vickers …
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Therefore, the lattice constants a, b, and c in the three directions of the constructed supercell are generally not less than 10 Å for each crystal. The BZ integration was performed using a 2 × 2 × 2 k-point mesh. ... Both zirconium carbide (ZrC) and hafnium carbide (HfC) have the same cubic crystal structure (NaCl-type, space group: ...
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72 Hf 178.480000000 Hafnium. See more Hafnium products. Hafnium (atomic symbol: Hf, atomic number: 72) is a Block D, Group 4, Period 6 element with an atomic weight of 178.49. The number of electrons in each of Hafnium's shells is 2, 8, 18, 32, 10, 2 and its electron configuration is [Xe] 4f 14 5d 2 6s 2.
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Hafnium carbide has a melting temperature of 3900°C, so it is among binary carbides with the highest melting temperature. The C/C–HfC composite with a hybrid matrix consisting …
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Product identifier Hafnium carbide powder Other means of identification SDS number 1KG Materion Code 1KG CAS number 1 ... (1/2 mile) in all directions; also consider initial evacuation for 800 meters (1/2 mile) in all directions. ALWAYS stay away from tanks engulfed in flame. Use water spray to cool unopened containers. Withdraw ...
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Carbides ZrC, HfC and TaC have a face-centered a cubic lattice [9]. Hafnium carbide has excep-tional resistance to high temperature oxidation, on its surface forms a stable oxide of hafnium (HfO. 2), which serves as a barrier to oxygen diffusion into the bulk material, protecting it from further oxida-tion [10, 11].
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Single-crystalline hafnium carbide (HfC) nanowires were synthesized by a Ni-catalyst-assisted chemical vapor deposition (CVD) method at 1025 °C below the eutectic temperature (TE).
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where T is temperature, K, and x is the value of index in HfC 1−x formula (Eqs. ()–() were recommended for the range of temperatures from 1200 to 2500 K).The thermodynamic functions of stoichiometric hafnium carbide are tabulated by Turchanin et al. [58, 59] in the range of 0–3000 K, by Schick [] in the range of 0–3900 K and by Barin …
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Single-crystalline hafnium carbide (HfC) nanowires were synthesized by a Ni-catalyst-assisted chemical vapor deposition (CVD) ... Most of the nanowires are grown along 〈112〉 crystal direction and the cluster/column interfaces at the wire tips parallel to the {011} crystal planes with a lower function. ...
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Hafnium carbide nanocrystal chains for field emitters. Single-crystal HfC nanocrystal chains were obtained by a catalytic CVD method. The chains with many faceted octahedral nanocrystals grow along a [0 0 1] direction. The chains have diameters of tens of nm to 500 nm and lengths of a few μm.
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Hafnium Carbide (HfC) is the most refractory binary compound known to man. Density, melting point and electrical resistivity data are provided.
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Entirely aqueous solution-gel route for the preparation of zirconium carbide, hafnium carbide and their ternary carbide powders Ceramics – Silikáty 60 (3) 248-253 (2016) 249 carbide precursors were concerned, the metal source was comprised of zirconium and hafnium salts in the molar ratios 0.5Hf:0.5Zr and 0.9Hf:0.1Zr and the other
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The team predicted 10 phases of hafnium-tantalum carbide that differ in the relative proportion of the two metals in the resulting material and synthesized them all using the unique experimental ...
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For example, hafnium carbide begins to oxidize at about 800 °C [7] with the formation of a HfO 2 layer on the sample surface, which cracks and breaks its integrity as a diffusion barrier, thereby facilitating the penetration of oxygen and accelerating oxidation. However, with the temperature rise to 1600–1800 °C, the formed oxide layers are ...
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After sintering of the MHC green powder compact, phases like hafnium oxide particles (HfO 2, monoclinic, ∼Ø5-10 μm), molybdenum carbide layers at the grain boundaries (Mo 2 C, hexagonal (hex), ∼1–3 μm thick) and large plate-like hafnium carbides (HfC, face centered cubic (fcc), ∼Ø1 μm diameter and ∼50–80 nm thick) can be ...
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Among them, hafnium carbide is of particular interest owing to its high melting point (3900 °C) and application in harsh environments where remarkable chemical resistance is required [21]. However, densification of this high-temperature carbide is challenging as it requires very high temperatures and a large amount of energy owing to …
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