Combustion Synthesis of Sr-Substituted LaCo0.4Fe0.6O3 Powders

1992 ◽  
Vol 271 ◽  
Author(s):  
J. J. Kingsley ◽  
L. A. Chick ◽  
G. W. Coffey ◽  
D. E. McCready ◽  
L. R. Pederson
Keyword(s):  
Solid State ◽  
Metal Oxides ◽  
Mixed Oxides ◽  
Electronic Conductivity ◽  
Solid State Reactions ◽  
Bet Surface Area ◽  
Metal Nitrates ◽  
Subsequent Calcination ◽  
Multi Phase ◽  
Sorption Characteristics

ABSTRACTSr-substituted perovskite LaCo0.4Fe0.6O3 is known to have excellent mixed ionic and electronic conductivity and increased O2 sorption characteristics. These perovskites are usually prepared by lengthy solid-state reactions of the component oxides at temperatures near 1150°C, and often produce inhomogeneous, multi-phase powders. Presently, it has been prepared by the calcination of combustion-derived fine mixed oxides at 850°C in 6 hrs. Combustion reactions are carried out using precursor solutions containing the corresponding metal nitrates (oxidizers) and glycine (fuel) at 250°C. The metal oxides produced by this process and subsequent calcination were characterized by XRD, TEM and BET surface area analysis.

Vanadium Pentoxide Gels from Liquid Crystals to Lithium Batteries

1994 ◽  
Vol 369 ◽  
Author(s):  
J. Livage ◽  
N. Baffier ◽  
J.P. Pereira-Ramos ◽  
P. Davidson
Keyword(s):  
Vanadium Pentoxide ◽  
Lithium Batteries ◽  
Mixed Oxides ◽  
Electronic Conductivity ◽  
Specific Capacity ◽  
Solid State Reactions ◽  
Polymerization Process ◽  
Display Devices ◽  
Oriented Films ◽  
Vanadic Acid

AbstractVanadium pentoxide gels V205.nH20 are formed via the condensation of vanadic acid in aqueous solutions. They exhibit both ionic and electronic conductivity and could therefore be used as cathode materials in lithium batteries or electrochromic display devices. The polymerization process leads to ribbon-like vanadium pentoxide particles. In a given range of concentration, sols and gels exhibit a homogeneous lyotropic nematic phase in which the ribbons align in the same direction. Ordered fluid phases are thus obtained leading to oriented films when deposited onto flat substrates. Moreover, mixed oxides MxV205 (M = Na+, K+,Ba2+, Al3+, Fe3+,Fe3+,...) exhibiting some preferred orientation are obtained via ion exchange.These compounds exhibit improved lectrochemical properties (specific capacity, cycling properties) compared to usual mixed oxides prepared via solid state reactions.

Modeling of Multi-Phase Solid State Reactions-Case of IMC Growth

2012 ◽  
Vol 323-325 ◽  
pp. 127-132
Author(s):  
M. Pawełkiewicz ◽  
Marek Danielewski ◽  
Jolanta Janczak-Rusch ◽  
Bartek Wierzba
Keyword(s):  
Solid State ◽  
Joint Strength ◽  
Void Formation ◽  
Solid State Reactions ◽  
Reactive Diffusion ◽  
Metallurgical Bond ◽  
Multi Phase ◽  
Reaction Processes ◽  
Different Time Scales ◽  
Simultaneous Growth

The formation of intermetallic compounds (IMC) at the solder-substrate interface is required to initiate the metallurgical bond. However, rapid growth of IMCs may degrade joint strength through i) the increased presence of a low toughness phase, ii) the consumption of the solderable surface (void formation) and iii) generation of primary and secondary stresses. Knowledge of mass transport and reaction processes during joint formation and service life are essential for solder system design. The mathematical description of inter-and reactive diffusion in open system presented here is based on Darken method (bi-velocity), involving the different molar volumes in the system and Wagner boundary conditions. It combines the interdiffusion, reactive diffusion and the effective flux constraints to couple processes occurring at different time scales. The rCADiff software serves as a tool to simulate simultaneous growth of the two Cu-Sn IMCs.

Nanocasted Synthesis of Mesoporous Metal Oxides and Mixed Oxides from Mesoporous Cubic (Ia3d) Vinylsilica

2008 ◽  
Vol 8 (11) ◽  
pp. 5652-5658 ◽  
Author(s):  
Yangang Wang ◽  
Yanqin Wang ◽  
Xiaohui Liu ◽  
Yun Guo ◽  
Yanglong Guo ◽  
...  
Keyword(s):  
Metal Oxides ◽  
Mixed Oxides ◽  
Catalytic Properties ◽  
Bet Surface Area ◽  
High Catalytic Activity ◽  
Complete Oxidation ◽  
Functionalized Silica ◽  
Ordered Structures ◽  
Mesoporous Metal Oxides ◽  
Mesoporous Metal

Mesoporous metal oxides and mixed oxides, such as NiO, CeO2, Cr2O3, Fe2O3, Mn2O3, NiFe2O4 and CexZr1−xO2 (x = 0.8 and 0.6) have been synthesized by nanocasting from mesoporous cubic (Ia3d) vinyl-functionalized silica (vinylsilica). Their structural properties were characterized by XRD, TEM, N2-sorption and Raman spectra. Thus-prepared mesoporous materials possess a high BET surface area (110–190 m2g−1), high pore volume (0.25–0.40 cm3g−1) and relatively ordered structures. The catalytic properties of Cr2O3 were tested in the oxidation of toluene. The mesoporous Cr2O3 exhibits unusually high catalytic activity in the complete oxidation of toluene as compared with commercial Cr2O3.

Ceramic colors

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Gerhard Pfaff
Keyword(s):  
High Temperature ◽  
Solid State ◽  
Metal Oxides ◽  
Colloidal Particles ◽  
Solid State Reactions ◽  
Mixed Metal Oxides ◽  
Bone China ◽  
Application Systems ◽  
Ceramic Color ◽  
Gold Silver

Abstract Ceramic colors or stains consist mainly of pigments, glaze or body, and opacifiers. They are used for the decoration of porcelain, earthenware bone china and other ceramics. Glazes and enamels are the main application systems for ceramic colors. Pigments are the color giving components in the composition of a ceramic color. High temperature and chemical stability as well as high tinting strength are characteristics of stains. Technically important ceramic colors are cadmium sulfide and sulfoselenides (occluded in zircon), metals such as gold, silver, platinum, and copper (as colloidal particles), metal oxides (α-Fe2O3, Cr2O3, CuO, Co3O4/CoO, MnO2/Mn2O3, and NiO/Ni2O3), mixed metal oxides and silicates, zirconia-based and zircon-based compositions. Ceramic colors are often produced using solid state reactions.

The effect of combined diffusion and kinetic transport barriers on multi-phase solid state reactions with a vapour reactant

1996 ◽  
Vol 31 (22) ◽  
pp. 5865-5871 ◽  
Author(s):  
W. B. Hillig ◽  
S. Adjerid ◽  
J. E. Flaherty ◽  
J. B. Hudson
Keyword(s):  
Solid State ◽  
Solid State Reactions ◽  
Transport Barriers ◽  
Multi Phase

Thin Films of Ionic Conductors by Laser Ablation

1998 ◽  
Vol 548 ◽  
Author(s):  
M. Morcrette ◽  
P. Barboux ◽  
J. Perrière ◽  
A. Laurent ◽  
J. P. Boilot ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Solid State ◽  
Transition Metal ◽  
Metal Oxides ◽  
Electrochemical Sensors ◽  
Rutherford Backscattering Spectrometry ◽  
Lithium Concentration ◽  
Solid State Reactions ◽  
Ionic Conductors ◽  
Thermodynamical Equilibrium

ABSTRACTFilms of insertion compounds and solid state electrolytes have been synthesized in order to study their applications in the domain of electrochemical ion and gas sensors. Laser ablation was used to deposit lithium metal oxides (LiMO2 where M is a transition metal Co or Mn).The chemical composition in the films has been studied by Rutherford Backscattering spectrometry and nuclear reactions analysis in the case of the light elements (O, Li). For lithium transition metal oxides (LiMO2), the oxygen and lithium contents are determined by a thermodynamical equilibrium between the films and the partial pressures in the chamber. In these cases, laser ablation allows the synthesis of crystalline structures with a large range of oxygen non stoichiometry as compared to solid state reactions. They lead to interesting electrical properties. Using the appropriate temperatures and oxygen pressures, films with the correct stoichiometry could be obtained as polycrystalline onto Si or Si/Pt substrates whereas they exhibit high texturing and epitaxial growth onto MgO or MgO/Pt.The films of LiMn2O4 and LiCoO2 have been used as electrochemical sensors for the measurement of the lithium concentration in solutions. They show a very rapid and selective response.

Sign in / Sign up

Export Citation Format

Share Document