Materials Literature
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Yttria is an interesting material for the production of high performance ceramic cores for Directionally Solidified investment casting. DS casting of superalloys of the last generation challenge conventional silica ceramic cores, because of the high temperatures and the long times involved. Compared to silica, yttria…
Alumina-mullite refractory tiles are used as liners in gas turbines for power production, for the thermal insulation of the combustion chambers. The typical microstructure is characterized by a coarse fraction, in order to increase porosity (and hence thermal insulation) and improve thermal shock resistance (by grain…
<span><span style="font-family: TimesNewRomanPSMT;">Liquid lithium lead (LiPb) eutectic is considered as one of the promising candidates of tritium breeder materials for fusion reactors. Series experiments on compatibility of LiPb with candidate <span style="font-family: TimesNewRomanPSMT;">structura…
In complex perovskite-type oxides which have been studied as cathode materials, the thermal expansion coefficient increases with the increase in the oxygen ionic conductivity. In the present study, with the aim to explain such a behavior, a research has been carried out from a chemical bond point of view. For oxides A…
Al2O3-YAG-ZrO2 composites have been produced by surface modification of a commercial nano-crystalline alumina powder with inorganic precursors of the desired second phases. The doped powders were calcined at various temperatures and for different times: as a function of the thermal treatment, zirconia directly crystal…
In the present study we focused on the nickelate system, which presents stable stripe order and allow a large domain of oxygen doping. More specifically, we studied the non-stoichiometric system La2NiO4 in which the oxygen excess tends to order. ESR technique has been used due to its sensibility to microscopic magne…
Zinc and copper pyrovanadates are promising materials for micro- and optoelectronics due to their negative coefficient of volume thermal expansion (NTE). Besides, solid solutions on the base of these compounds can be used to obtain grade materials with variable thermal coefficients. Thermal deformation of both Zn2V2O7…
The mechanical behaviour of ceramic refractories formulated in the MgO-CaO-SiO2- ZrO2 system is analysed in terms of the room temperature Young´s modulus, the modulus of rupture and the work of fracture at 25 and 1100°C. The materials have been designed taking into account the phase equilibrium relationships to obtain…
Three kinds of brittle fibers (SiC fiber, glass fiber, and carbon fiber) were tensioned to fracture at both quasi-static and dynamic loading rates. Scanning electron microscope observations of the morphology of the fracture surfaces show two distinct fracture modes for all three fibers. The mode of fracture changes wi…
In this work perovskite materials A2/3Cu3Ti4O12 (where A=Nd, Sm, Gd, Dy) were synthesized by conventional solid state reaction and sintered at 1000-1100°C. X-ray diffraction analysis confirmed single-phase composition of the investigated ceramics. Dielectric properties of the samples were investigated in the temperatu…
Sintering in two-steps has been applied with success for densification of nanometric and submicrometer ceramic powders without grain growth. In this work the applicability of two-step sintering as a means of suppressing the grain growth of submicrometer alumina is verified. Experiments, in which the grain growth and d…
In this paper we discuss the development of metamaterials containing ferromagnetic microwires which makes it possible to tune the electromagnetic response in the microwave frequency band. Metallic wire media are known to demonstrate very strong dispersion of the effective permittivity at GHz frequencies. At certain co…
The method of electrochemical extraction of oxygen from air employing a solid oxide electrolyte (SOE) is presented. The prototype of electrochemical oxygen generator (pump) for medical applications has been developed and fabricated. It is based on thin-walled tubular segments of YSZ electrolyte (170 μm) with LSM based…
5 at.% Mn-doped and undoped, 200 nm thick BaTiO3 thin films have been grown under different oxygen partial pressures by pulsed laser deposition on Pt/sapphire substrates. X-ray diffraction (XRD) measurements reveal the same polycrystalline single-phase perovskite structure for all the thin films despite the different…
Chromogenic materials are able to change their optical properties in response to external stimuli such as temperature (in thermochromic materials) and electrical charge insertion (in electrochromic materials). Below we review some recent advances for these types of materials. Specifically we first discuss the limitati…
Magnetoelectric(ME) coupling in multi-ferroic composite designed by using two material elements of Pb(Zr, Ti)O3 (PZT: 260μm) and magnetostrictive alloys(Galfenol based Fe-Ga-X(X=Al, Co), ferromagnetic shape memory Fe-Pd) was investigated. Output ME Voltage under the driving a.c.magnetic field Hac at f = 1 Hz in Fe81Ga…
The fabrication of MB2-SiC and MB2-MC-SiC (M=Zr, Hf, Ta) Ultra High Temperature Ceramics (UHTCs) is investigated in this work by combining Self-propagating High-temperature Synthesis (SHS) and Spark Plasma Sintering (SPS). Zr, Hf or Ta, B4C, Si, and graphite powders are first reacted by SHS to successfully form in-sit…
Ab initio density functional calculations were performed on a toroidal carbon C120 nanostructure with a single beryllium atom bonded to its outer surface. These calculations are based on DFT with the generalized gradient approximation PW91 (Perdew and Wang) as implemented in the Materials Studio v.4.3 code. The Dmol3…
Monodispersed plate-like CeO2 particles were successfully synthesized by a mild solution process followed by calcination in air at 400oC. During the solution processing, monodispersed orthorhombic single-crystal of plate-like Ce2(CO3)3.8H2O was obtained by using Ce(NO3)3.6H2O as cerium source, and NaHCO3 aqueous solut…
Metal hydrides have high hydrogen atom density, which is equivalent to that of liquid water. Fast neutrons are efficiently moderated by hydrogen in metal hydrides. Metal hydrides have been studied for their potential application as nuclear materials in fast reactors (FRs). Two types of the utilizations of metal hydrid…