47 Result(s)
within
P. Duran
Polymer Sciences
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Article
Titanium local environment and electrical conductivity of TiO2-doped stabilized tetragonal zirconia
Solid state reactions in the ZrO2-Y2O3-TiO2system have been studied and the solid solubility limit of TiO2 in yttria stabilized tetragonal zirconia Y-TZP has been stablished. Structural characterization was carri...
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Article
Preparation of nanometric titanium hydrous oxide particles by vapour phase hydrolysis of titanium tetrabutoxide
Spherical titanium nanoparticles in the range of 60 to 500 nm have been obtained by a vapour-phase hydrolysis procedure using titanium tetrabutoxide as raw material. In this work, different parameters such as ...
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Article
Phase transition and electrical conductivity in the system YMnO3-CaMnO3
Solid solution formation between the ferroelectric hexagonal compound YMnO3 and the semiconducting perovskite compound CaMnO3 has been studied in the Y-rich region of the pseudobinary system. The materials were p...
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Article
Nanostructured and near defect-free ceramics by low-temperature pressureless sintering of nanosized Y-TZP powders
Nanosized (∼6 nm) Y-TZP (3 mol% Y2O3) powders have been produced by chemical co-precipitation (Y-inorganic + Zr-organic precursors) and thorough isopropanol-washing step, after calcining in air at 450 °C. The nan...
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Article
Seeding effects on crystallization of air-calcined Y-TZP amorphous precursors
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Article
Characterization and sintering behaviour of submicrometre titanium dioxide spherical particles obtained by gas-phase hydrolysis of titanium tetrabutoxide
Spherical fine (∼0.7 μm) titania powders were prepared by vapour-phase hydrolysis of a titanium tetrabutoxide/butanol solution. Powder X-ray diffraction showed that as-prepared powders were amorphous and cryst...
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Article
Ceramic–electrode interaction in PZT and PNN–PZT multilayer piezoelectric ceramics with AG/PD 70/30 inner electrode
Pb(Zr0.53Ti0.47)O3(PZT) and PbNi1/3Nb2/3O3-PZT (PNN–PZT) multilayers with Ag/Pd 70/30 inner electrodes have been studied from the point of view of the ceramic–electrode interaction. PZT multilayers have shown ...
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Article
Improving sintering behaviour of BaTiO3 by small do** additions
The dielectric properties of BaTiO3 ceramics are associated with its microstructure, which depends on the stoichiometric ratio, dopant nature, and ceramic processing. Optimum densification at low temperatures to ...
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Article
Preparation and sintering behaviour of submicronic Bi4Ti3O12 powders
Submicronic powders of Bi4Ti3O12 with different morphologies were prepared by both the oxalate coprecipitation and the conventional mixing oxides methods. Compacts of the two calcined powders were sintered at 850...
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Article
Low temperature fully densified nanostructured Y TZP ceramics
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Article
Improvement of thermal stability and fracture toughness of Ti-TZP ceramics by small ceria additions
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Article
Characterization of Pb(Zr, Ti)O3 thin films obtained by MOD
Pb(Zr, Ti)O3 thin films were deposited by dip-coating on polycrystalline alumina substrates by using an MOD method. The thickness and homogeneity of the films were measured as a function of dip rates and solution...
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Article
Processing and microstructure of porous and dense PZT thick films on Al2O3
The processing of porous PZT thick-film ceramics on Al2O3 has been studied. The films were screen-printed from a thixotropic ink of PZT with a 58% solids content. The thick films were sintered between 1000 and 11...
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Article
Phosphor-doped BaTiO3: Microstructure development and dielectric properties
The phosphor cation retards BaTiO3 formation during the first reaction stage, and favours Ba2TiO4 formation. As a consequence, the end of the reaction is only accomplished at 1150 °C. The average particle size of...
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Article
High Tc superconductor polymer composites based on YBa2Cu3O7−x
This work reports on the study of the microstructure and electrical properties (conduction and superconduction) of YBa2Cu3O7−x (Y) and polypropylene (PP) composites. For the purpose of enhancing and improving the...
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Article
Preparation and properties evaluation of zirconiabased/Al2O3 composites as electrolytes for solid oxide fuel cell systems
The powder morphology and particle size of both mixtures of ultrafine yttria-doped zirconia (3 to 8 mol% Y2O3) and aluminium hydroxide (0 to 20 wt% Al2O3), and zirconia/yttria/alumina coprecipitated powders were ...
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Article
Preparation and properties evaluation of zirconia-based/Al2O3 composites electrolytes for solid oxide fuel cell systems
The compaction behaviour of ultrafine yttria-doped zirconia powders (6–8 nm) without and with alumina additions (0 to 20 wt%) has been studied. From the pore size distribution and using isothermal and nonisoth...
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Article
Preparation and properties evaluation of zirconia-based/Al2O3 composites as electrolytes for solid oxide fuel cell systems
Yttria-doped zirconia powders containing 3 to 8 mol% Y2O3 and 0 to 20 wt% Al2O3 were prepared by both mixing commercial oxides and a coprecipitation method, and the mechanical and electrical properties have been ...
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Article
Perovskite phase formation in the PbMg1/3Nb2/3 O3-PbZrO3-PbTiO3 system by the columbite route
The reaction mechanism of PbMg1/3Nb2/3O3-PbZrO3-PbTiO3 (PMN-PZT) perovskite phase prepared by the columbite route has been studied in the temperature range from 600 to 800 °C. The effects of heating and cooling r...
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Article
Microstructure and properties of K2O doped superconducting YBa2Cu3O7−x
K doped YBa2Cu2Ox powders have been obtained by incorporating K2CO3 to previously coprecipitated amorphous hydroxide mixtures. Synthesis was performed at 900‡C and an orthorhombic 1 2 3 phase was the final produc...
