Abstract:A new ternary Zr x Cu y C z phase is observed in the reactively infiltrated ZrC/W composite. The X-ray diffraction and transmission electron microscopy analyses reveal that the Zr x Cu y C z phase has a same rocksalt structure as ZrC, but possesses sixfold long-period structure with lattice constant of 2.88 ± 0.07 nm. This finding indicates the existence of Zr x Cu y C z compound, which expands the ternary carbides and nitrides permutation space.
“…Materials with different amounts of Zr should be fabricated and the dependencies of the physical characteristics of the materials versus the amount of Zr should be investigated, to verify the optimum composition. The present work is a preliminary study on the C–Cu–Zr alloys [33], and further studies are needed to optimise the compositions and fabrication process to obtain the suitable carbon composite materials with high thermal conductivities. Figure 5 Schematic illustration of thermal conduction for C/Cu(Zr) composite materials.…”
Carbon (C)/copper (Cu)-based materials with high thermal conductivity and good stability at high temperatures were developed by adding a small amount of zirconium, which has a low enthalpy of alloy formation with C and Cu. The felt-type C/C composites, which were impregnated by Cu and zirconium, provided 1.4 times higher thermal conductivity at 1300 K than that of the original carbon materials. Microstructural analysis showed that the increase of thermal conductivity is due to the formation of zirconium compounds at the C/Cu interface. These carbon-based materials could be one of the candidate materials for the plasma-facing components of the fusion devices.
“…Materials with different amounts of Zr should be fabricated and the dependencies of the physical characteristics of the materials versus the amount of Zr should be investigated, to verify the optimum composition. The present work is a preliminary study on the C–Cu–Zr alloys [33], and further studies are needed to optimise the compositions and fabrication process to obtain the suitable carbon composite materials with high thermal conductivities. Figure 5 Schematic illustration of thermal conduction for C/Cu(Zr) composite materials.…”
Carbon (C)/copper (Cu)-based materials with high thermal conductivity and good stability at high temperatures were developed by adding a small amount of zirconium, which has a low enthalpy of alloy formation with C and Cu. The felt-type C/C composites, which were impregnated by Cu and zirconium, provided 1.4 times higher thermal conductivity at 1300 K than that of the original carbon materials. Microstructural analysis showed that the increase of thermal conductivity is due to the formation of zirconium compounds at the C/Cu interface. These carbon-based materials could be one of the candidate materials for the plasma-facing components of the fusion devices.
“…3,33 The peak at 449 cm −1 indicates A 2u vibration of octahedral FeO 6 bonds and other two peaks indicate E 1u vibration of FeO 4 tetrahedral. 34,35 Moreover, the peaks at 449 and 601 cm −1 are intense whereas the peak at 552 cm −1 is similar to a small notch. Similar behavior was observed by Durmus et al for barium hexaferrite.…”
In this paper, strontium hexaferrite nanoparticles were synthesized by the sol-gel auto-combustion method. Effect of annealing temperature on crystal structure, morphology and magnetic properties of nanoparticles was investigated by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). Also, the thermal decomposition of as-synthesized powdered samples has been studied by thermogravimetric analysis (TGA). The XRD patterns confirmed the formation of single phase M -type hexagonal crystal structure for powders annealed above 950 • C, whereas the presence of hematite (α-Fe 2 O 3 ) as secondary phase was also observed for sample annealed at 900 • C. Furthermore, the crystallinity along with the crystallite size were augmented with annealing temperature. Comparison of the FT-IR spectra of the samples before and after annealing treatment showed the existence of metal-oxygen stretching modes after annealing. The thermogravimetric analysis confirmed the thermal decomposition of as-burnt powders happened in three-stage degradation process. The TEM images showed the nanoparticles like hexagonal-shaped platelets as the size of nanoparticles increases by increasing the annealing temperature. With increasing annealing temperature, the magnetic saturation and the coercivity were increased to the maximum value of 74.26 emu/g and 5.67 kOe for sample annealed at 1000 • C and then decreased. ‡ Corresponding author. 1550190-1 Int. J. Mod. Phys. B Downloaded from www.worldscientific.com by FLINDERS UNIVERSITY LIBRARY on 10/02/15. For personal use only. E. Roohani et al.
“…NBT particles with plate-like morphology are preferred templates for fabricating textured NBT-based ceramics. 13,14 Although the TMC method has been used to prepare NBT templates transformed from NBIT 9 precursors or from Bi 4 Ti 3 O 12 precursors, 11 the factors that affect the synthesis are not mentioned explicitly. In this work, TMC synthesis of plate-like NBT crystals is described.…”
Na0.5Bi0.5TiO3 (NBT) platelets with high aspect ratio were synthesized from Na0.5Bi4.5Ti4O15 (NBIT) precursors via a topochemical microcrystal conversion in molten salt conditions. The effect of the synthesis parameters, such as the molten salt system, synthesis temperature, and the molar ratio of Na2CO3 and NBIT, was investigated. The results showed that NaCl–KCl molten salt environment and excess Na2CO3 played a positive role in the synthesis, square‐shaped NBT was obtained at 950°C in NaCl–KCl molten salt and a TiO2‐free environment, and it was a suitable template candidate to achieve NBT‐based textured ceramics using the reactive template grain growth (RTGG) method.
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