Surface characterization of (La1−x Sr x )MnO3 synthesized using a sol-gel process and solid-state reaction

1995 ◽  
Vol 14 (1) ◽  
pp. 12-14 ◽  
Author(s):  
H. Taguchi ◽  
D. Matsuda ◽  
M. Nagao ◽  
K. Tabata
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Surface Characterization ◽  
Sol Gel ◽  
Sol Gel Process

Preparation and Microwave-Absorption Property of SiO2-SiC-Based Composites

2010 ◽  
Vol 434-435 ◽  
pp. 231-234
Author(s):  
Li Guan ◽  
Bing Bing Fan ◽  
Ming Liang Li ◽  
He Jing Wen ◽  
Kai Li ◽  
...  
Keyword(s):  
Solid State ◽  
Microwave Absorption ◽  
Solid State Reaction ◽  
Sol Gel ◽  
Composite Particles ◽  
Network Analyzer ◽  
Epoxide Resin ◽  
Maximum Reflectivity ◽  
Sol Gel Process ◽  
Sic Composites

SiO2-SiC composite particles were prepared using a sol-gel process. BaTiO3 powders were synthesize through solid-state reaction. They were mixed as microwave absorbents with Fe3O4 powders to obtain the complex absorption. Epoxide resin (EP) was used as matrix and solidified with the mixtures. The techniques of DSC-TG, XRD were used to characterize the composite particles and the obtained compacts. A vector network analyzer was used to measure the reflectivity of the SiO2-SiC-based composites. The effects of the aborbents’ contents on the reflection of the microwave absorption materials were disscussed. It was found that SiO2-SiC composites could be prepared using sol-gel process and BaTiO3 powders could be synthesize through solid-state reaction. The results indicated that SiO2-SiC composite is contribute to absorb microwave, where SiO2-SiC: BaTiO3: Fe3O4 = 6:2:2 (vol %), the frequency region in which the maximum reflectivity is more than -10 dB is 5.4-7.6 GHz.

Synthesis of Pure Dicalcium Silicate Powder by the Pechini Method and Characterization of Hydrated Cement

2014 ◽  
Vol 787 ◽  
pp. 387-394 ◽  
Author(s):  
Yan Ni Tan ◽  
Yong Liu ◽  
Zhang Qing ◽  
Gurpreet Birdi ◽  
Liam M. Grover
Keyword(s):  
Solid State ◽  
Mass Loss ◽  
Solid State Reaction ◽  
Pechini Method ◽  
Sol Gel ◽  
Dicalcium Silicate ◽  
Hydrated Cement ◽  
Gel Method ◽  
Sol Gel Method

Calcium silicate (CS) is a main component of Portland cement and is responsible for the strength development. Recent research has shown that dicalcium silicate cement (CSC) is bioactive and is a potential candidate for bone replacement. Traditionally, dicalcium silicate powder is synthesized by a solid state reaction or a sol-gel method. The solid-state reaction, however, usually needs a higher temperature and a longer calcination time. Furthermore, the dicalcium silicate powder made by the sol-gel method is not pure, and contains a significant quantity of CaO which is harmful to the strength and biological properties of the CSC. The Pechini technique is an alternative, low temperature polymeric precursor route for synthesis of high purity powders. In this study, purer CS powder was synthesized via the Pechini method by calcination at 800°C for 3h. DSC-TGA, XRD, SEM were used for characterization of CS powder and the hydrated cement. The DSC-TGA curves showed that the main exothermic peak was at 479°C and the total mass loss was 79.2%. The XRD patterns of CSC after hydration for 7, 14, and 35 days illustrated that dicalcium silicate hydrate (Ca1.5SiO3.5·xH2O, C-S-H) was formed in the hardened CS paste. The XRD peaks on the diffraction pattern of the C-S-H of the day 35 sample were of greater intensity than those at day 7 and day 14. This demonstrates that the hydration speed was slow and complete hydration could take more than one month. Flake-like crystals were observed on scanning electron micrographs following hardening. The degradation study result showed that there was no mass loss of CSC after the samples were soaked into phosphate buffered saline (PBS) for 40 days. The silicon assay revealed that orthosilicic acid could be released from CSC after the samples were soaked in simulated body fluid (SBF). Silicon is known to be critical to skeletal mineralization. The existence of silicon may stimulate the proliferation of bone and activate cells to produce bone. Investigation of cell attachment confirmed that the MC-3T3 cells attached well to the surfaces of CSC after seeding.

COMPARATIVE STUDY OF Bi-2223/Ag SUPERCONDUCTORS DERIVED FROM PARTICLES SIZE OF STARTING MATERIALS

2007 ◽  
Vol 21 (18n19) ◽  
pp. 3246-3249 ◽  
Author(s):  
D. SÝKOROVÁ ◽  
O. SMRČKOVÁ ◽  
K. RUBEŠOVÁ ◽  
P. VAŠEK
Keyword(s):  
Solid State ◽  
Comparative Study ◽  
Temperature Dependence ◽  
Solid State Reaction ◽  
Sintering Temperature ◽  
Sol Gel ◽  
Sol Gel Process ◽  
Current Densities ◽  
Size Of Particles ◽  
Micrometer Size

Series of the samples with nominal compositions Bi 3.2 Pb 0.8 Sr 4 Ca 5 Cu 7 O x and Bi 3.2 Pb 0.8 Sr 4 Ca 5 Cu 7 O x / Ag (10 wt%) were prepared by the standard solid state reaction at the same calcination and sintering temperature and time. Three starting mixtures were used, carbonates, oxides and silver i) with nanoparticles, ii) with micrometer size of particles and iii) powder obtained by modified sol-gel process. The main phase in all samples was Bi -2223 and silver formed the separate phase. The sol-gel process was found to be effective way in term of porosity, bulk density and connectivity of the grains. The effect of the microstructure on the transport properties were described by the temperature dependence of resistivity and critical current densities.

The use of multinuclear solid state NMR for the characterization of siloxane-oxide hybrid nanocomposites

2004 ◽  
Vol 847 ◽  
Author(s):  
Christel Gervais ◽  
Beatriz Julián ◽  
Eloisa Cordoncillo ◽  
Purificación Escribano ◽  
Mark E. Smith ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Sol Gel ◽  
Hybrid Nanocomposites ◽  
Sol Gel Process ◽  
Hydrolysis And Condensation ◽  
Silicon Alkoxides ◽  
Different Types ◽  
Nmr Techniques

ABSTRACTThe objective of this paper is to review various solid state NMR techniques that have been, or can be used for the structural characterization of siloxane—oxide hybrid systems prepared by sol-gel process, and to discuss the type of information they provide, as well as their limitations. More precisely, this paper focuses on NMR techniques to probe and quantify the different types of oxo-bridges (M–O–M of oxide network, Si–O–Si of siloxane chains and Si–O–M siloxane–MxOy interface) in siloxane-oxide nanocomposites prepared through hydrolysis and condensation of organosilanes and M(OR)n alkoxides. In addition the influence of the functionality of the silicon alkoxides and the nature of the MxOy oxides on the extent of the Si-O-M interface will be examined.

Synthesis and characterization of CeO2·α-Fe2O3 and CeO2·Pr6O11 ceramic pigments through the solid state reaction and modified sol–gel method

2014 ◽  
Vol 106 ◽  
pp. 14-19 ◽  
Author(s):  
Renata Cristina Olegário ◽  
Eder Carlos Ferreira de Souza ◽  
José Flávio Marcelino Borges ◽  
João Batista Marimon da Cunha ◽  
André Vitor Chaves de Andrade ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Sol Gel ◽  
Synthesis And Characterization ◽  
Ceramic Pigments ◽  
Gel Method ◽  
Sol Gel Method

Fine Lithium Iron(II) Phospho-Olivine Prepared by Different Methods

2007 ◽  
Vol 336-338 ◽  
pp. 521-523
Author(s):  
Hong Gang Sun ◽  
Heng Liu ◽  
Wei Liu ◽  
Ya Lan Luan
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Sol Gel ◽  
Chemical Properties ◽  
Lithium Insertion ◽  
Reaction Conditions ◽  
Electroactive Materials ◽  
Sol Gel Process ◽  
Carbon Coated ◽  
Electrochemical Evaluation

The electroactive materials LiFePO4, Li0.98Mg0.01FePO4 and carbon-coated LiFePO4 were synthesized by an improved solid-state reaction and by a sol-gel process and characterized by XRD, SEM, and their electrochemical performance. The reaction conditions favor stabilization of the iron as Fe2+ as well as offering some control of the product morphology and particle size. Electrochemical evaluation of the products reveals a lithium insertion plateau around 3.4V vs Li. Excellent electro- chemical properties in terms of capacity, reversibility and cycling stability have been achieved for doped LiFePO4 synthesized by an improved solid-state reaction. The two methods all produced pure, fine and homogeneous particles.

Comparative study of solid-state reaction and sol-gel process for synthesis of Zr-doped Li0.5La0.5TiO3 solid electrolytes

Ionics ◽  
2016 ◽  
Vol 22 (11) ◽  
pp. 2151-2156 ◽  
Author(s):  
Ming’en Ling ◽  
Xiaohong Zhu ◽  
Yue Jiang ◽  
Jiliang Zhu
Keyword(s):  
Solid State ◽  
Comparative Study ◽  
Solid State Reaction ◽  
Solid Electrolytes ◽  
Sol Gel ◽  
Sol Gel Process

Preparation and characterization of organic-inorganic hybrid materials incorporating diphosphino moieties. Study of the accessibility of the phosphorus atoms included into the material

2000 ◽  
Vol 78 (11) ◽  
pp. 1519-1525 ◽  
Author(s):  
Jean-Philippe Bezombes ◽  
Claude Chuit ◽  
Robert JP Corriu ◽  
Catherine Reyé
Keyword(s):  
Solid State ◽  
Hybrid Materials ◽  
Sol Gel ◽  
Inorganic Hybrid ◽  
Sol Gel Process ◽  
Inorganic Network

The hydrolysis-polycondensation by the sol-gel process of the aromatic diphosphines (X3SiC6H4)2PC6H4P(C6H4SiX3)2, which are rigid molecules bearing four hydrolysable SiX3 groups (X = OiPr, H), leads to new organic-inorganic hybrid materials, characterized by solid state 13C, 29Si, and 31P NMR spectroscopies. The accessibility of the phosphorus centres incorporated into the xerogel obtained from the diphosphine with X = OiPr has been studied. All the phosphorus atoms reacted quantitatively with H2O2, S8, and CH3I but only 20% with the more bulky reagent W(CO)5·THF. This result is explained by the rigidity of the inorganic network resulting from the high number of hydrolysable Si-OiPr groups in the precursor.Key words : Diphosphines, sol-gel process, xerogels, solid 31P NMR.

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