A5026953474- Advancements in Solid Oxide Fuel Cells
- Electronic and Structural Properties of Oxides
- Ferroelectric and Piezoelectric Materials
- Fuel Cells and Related Materials
- Microwave Dielectric Ceramics Synthesis
- Magnetic and transport properties of perovskites and related materials
- Electrocatalysts for Energy Conversion
- Dielectric properties of ceramics
- Catalysis and Oxidation Reactions
- Catalytic Processes in Materials Science
- Multiferroics and related materials
- Acoustic Wave Resonator Technologies
- Advanced ceramic materials synthesis
- Analytical Chemistry and Sensors
- Semiconductor materials and devices
- Chemical Looping and Thermochemical Processes
- Electrophoretic Deposition in Materials Science
- Gas Sensing Nanomaterials and Sensors
- Particle accelerators and beam dynamics
- Physics of Superconductivity and Magnetism
- Metal and Thin Film Mechanics
- Advanced battery technologies research
- Photorefractive and Nonlinear Optics
- Force Microscopy Techniques and Applications
- Innovative Microfluidic and Catalytic Techniques Innovation
National Research Council
2009-2024
Institute of Condensed Matter Chemistry and Technologies for Energy
2016-2024
Istituto Nazionale di Fisica Nucleare, Sezione di Genova
1993-2018
Consorzio Roma Ricerche
2018
Institute for Energetics and Interphases
2006-2016
National Academies of Sciences, Engineering, and Medicine
2003-2013
University of Genoa
1996-2008
National Interuniversity Consortium of Materials Science and Technology
2008
École Nationale Supérieure des Mines de Paris
2008
Centre des Matériaux
2008
A progressive reduction of tetragonal distortion, heat transition, Curie temperature, and relative dielectric constant has been observed on dense ${\mathrm{BaTiO}}_{3}$ ceramics with grain size decreasing from 1200 to $50\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$. The correlations between size, extent ferroelectric properties strongly support the existence an intrinsic effect. From experimental trends critical for disappearance ferroelectricity evaluated be...
Theoretical models for small ferroelectric particles predict a progressive decrease of the Curie temperature, spontaneous lattice strain, and polarization until critical size corresponding to transition cubic phase disappearance ferroelectricity is reached. In contrast, behavior nanocrystalline $\mathrm{Ba}\mathrm{Ti}{\mathrm{O}}_{3}$ ceramics with grain $\ensuremath{\approx}30\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ dominated by extrinsic effects related boundaries which mask expected...
The results of an atomistic simulation study on the incorporation ions first series transition metals (Cr 3+ , Cr 4+ Fe 2+ Co Ni and ), Y lanthanide (Er Gd Tb Pr La ) in BaTiO 3 lattice are presented discussed. prefer to substitute at titanium site with oxygen‐vacancy compensation. For iron cobalt, oxidation from divalent trivalent state during is favored. Nickel chromium preferentially incorporated valence 3+, respectively. Formation stable defect pairs different types defects predicted for...
Dense BaTiO3 ceramics with 50 nm average grain size obtained by spark plasma sintering were investigated. The dielectric data show a broad ferro–para phase transition maximum permittivity of at 390 K and 1 kHz. local ferroelectric switching behaviour was investigated piezoresponse force microscopy. Typical piezoelectric hysteresis loops recorded different positions the sample. present results provide experimental evidence for polarization scale, indicating that critical disappearance in...
A systematic kinetic investigation on the chemical synthesis of BaTiO3 particles from aqueous solutions BaCl2 and TiCl4 at T < 100 °C pH 14 has been performed. Initially, a viscous suspension Ti-rich gel phase is obtained room temperature. Later, formation induced by heating above 70 gradually converted to crystalline perovskite. The isothermal kinetics evolution crystal size particle during course reaction are significantly influenced temperature, concentration, barium-to-titanium ratio...
Abstract The synthesis of powders with controlled shape and narrow particle size distributions is still a major challenge for many industries. A continuous Segmented Flow Tubular Reactor (SFTR) has been developed to overcome homogeneity scale‐up problems encountered when using batch reactors. Supersaturation created by mixing the co‐reactants in micromixer inducing precipitation; suspension then segmented into identical micro‐volumes non‐miscible fluid sent through tube. These are more...
Cubic SrTiO3 particles are obtained by precipitation from an aqueous gel suspension. The suspension is prepared hydrolyzing a TiOCl2 solution with NaOH and adding SrCl2. addition of citric acid leads to spherical particles. particle size can be tailored in the range 80−1400 nm varying temperature concentration. A careful control synthesis conditions essential for producing narrow distribution. results HRTEM ED investigations provide strong evidence that oriented aggregation small (4−5 nm)...
The incorporation of Er 3+ into BaTiO 3 ceramics was investigated on samples containing 0.25, 0.5, 1, 2, 8, and 10 at.% dopant, after sintering at 1350–1550°C in air. For concentrations ≤1 at.%, dense large‐grained with low room‐temperature resistivity (10 2 –10 Ω·cm) were obtained. observed properties are largely independent stoichiometry. Simultaneous substitution both cation sites, higher preference for the Ba site, is proposed. behavior heavily doped depends When Ba/Ti < electrical...
A rigorous kinetic model for the solution precipitation and hydrothermal synthesis of BaTiO3 particles is proposed. Three elementary processes are considered: primary nucleation, secondary diffusion-controlled growth. Secondary nucleation accounts acceleration formation kinetics after an initial slow crystallization stage with a polycrystalline substructure. The time evolution yield, crystal size, particle size represented by means discretized mass population balance equations. system...
Well‐defined and stoichiometric spherical particles of BaTiO 3 narrow size distribution were produced at 82° 92°3C by precipitation from chloride solutions in a strong alkaline environment. The the can be tailored range ≅10 to 70–80 nm increasing barium concentration ≅0.07 0.7 mol/L. are composed tight aggregates resulting assembly several nanocrystals. nanocrystals decreases 200–300 30–40 reactant concentration. At low (≤0.07 mol/L 82°3C, ≤0.06 92°3C), formation is strongly slowed down...
The coating of BaTiO3 particles with a different perovskite and the subsequent consolidation to dense ceramics retaining radial composition gradient within single grains are presented discussed. A shell SrTiO3 or BaZrO3 was directly grown on surface spherical templates suspended in aqueous solution by means precipitation process making use inorganic precursors. overall particle size can be tailored over wide range. Densification resulting core−shell realized using spark plasma sintering...