Microwave-hydrothermal processing for synthesis of electroceramic powders

1993 ◽  
Vol 8 (12) ◽  
pp. 3176-3183 ◽  
Author(s):  
Sridhar Komarneni ◽  
Q. Li ◽  
Karin M. Stefansson ◽  
Rustum Roy
Keyword(s):  
Chemical Analysis ◽  
Processing Technique ◽  
Hydrothermal Processing ◽  
Ceramic Powders ◽  
Inorganic Solids ◽  
Microwave Hydrothermal

Microwave-hydrothermal processing has so far been used only to dissolve inorganic solids for chemical analysis. We report herein the use of microwave-hydrothermal processing to synthesize various ceramic powders in binary and polynary systems. We describe the synthesis of some electroceramic powders such as BaTiO3, SrTiO3, Sr0.5Ba0.5TiO3, PbTiO3, BaZrO3, SrZrO3, Pb(Zr0.52Ti0.48)O3, and pyrochlore phases with the Pb(Mg1/3Nb2/3)O3 and Pb(Zn1/3Nb2/3)O3 compositions by this novel microwave-hydrothermal processing technique.

Microwave-hydrothermal processing of metal powders

1995 ◽  
Vol 10 (7) ◽  
pp. 1687-1692 ◽  
Author(s):  
Sridhar Komarneni ◽  
Rajyalakshmi Pidugu ◽  
Qing Hua Li ◽  
Rustum Roy
Keyword(s):  
Ethylene Glycol ◽  
Metal Powder ◽  
Metal Salts ◽  
Hydrothermal Processing ◽  
Metal Powders ◽  
Ceramic Powders ◽  
Powder Synthesis ◽  
Microwave Hydrothermal ◽  
Order Of Magnitude ◽  
Kinetics Of

Novel microwave-hydrothermal processing has been developed by us recently for the synthesis of a wide variety of ceramic powders. Herein, we report the use of microwave-hydrothermal processing to synthesize several metal powders such as Cu, Ni, Co, and Ag by reducing their corresponding metal salts or hydroxides with ethylene glycol. Metal powders have been produced extremely rapidly a (few minutes) by microwave catalysis. The kinetics of metal powder synthesis have been increased by at least an order of magnitude by microwave-hydrothermal processing compared to the conventional refluxing process in ethylene glycol at about 195 °C.

ChemInform Abstract: Microwave-Hydrothermal Processing of BiFeO3 and CsAl2PO6.

ChemInform ◽  
2010 ◽  
Vol 27 (40) ◽  
pp. no-no
Author(s):  
S. KOMARNENI ◽  
V. C. MENON ◽  
Q. H. LI ◽  
R. ROY ◽  
F. AINGER
Keyword(s):  
Hydrothermal Processing ◽  
Microwave Hydrothermal

Processing of Porous Zirconium Tungstate and Their Thermomechanical Properties

2014 ◽  
Author(s):  
Mingang Wang ◽  
Truong Do ◽  
Patrick Kwon
Keyword(s):  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Processing Technique ◽  
Thermomechanical Properties ◽  
Processing Route ◽  
Full Density ◽  
Ceramic Powders ◽  
Zirconium Tungstate ◽  
Spherical Graphite ◽  
New Processing

This paper explores a new processing method to fabricate porous zirconium tungstate (ZrW2O8 or ZT) with the porosity content up to 40% in volume. The method uses spherical graphite powders that are mechanically stable, allowing us to compact with ceramic powders in dry condition. Thus, the ceramic powders mixed with spherical graphite powders can be compacted and sintered to a near full density. During sintering, the graphite powders burn out without damaging the powder compact due to their inherent near-zero thermal expansion. The processing route discussed in this paper is applicable to all oxide ceramics where the sintering can take place in air and above 700°C to dissociate the graphite. In this paper, we have applied this processing technique to fabricate porous ZrW2O8. Many porous ZrW2O8 with a range of porosity levels were fabricated and tested for their theromomechanical properties including elastic modulus (E) and coefficient of thermal expansion (CTE). The experimentally determined properties were compared with the predictions based on the micromechanical Mori-Tanaka scheme.

Microwave–hydrothermal processing for synthesis of layered and network phosphates

1994 ◽  
Vol 4 (12) ◽  
pp. 1903-1906 ◽  
Author(s):  
Sridhar Komarneni ◽  
Qing Hua Li ◽  
Rustum Roy
Keyword(s):  
Hydrothermal Processing ◽  
Microwave Hydrothermal

Effect of Dispersant on Preparation of Barium Strontium Titanate Nanopowders by Microwave Hydrothermal Processing

2016 ◽  
Vol 852 ◽  
pp. 362-368
Author(s):  
Jie Chen ◽  
Ming Chao Che ◽  
Feng Yan
Keyword(s):  
Polyethylene Glycol ◽  
Strontium Titanate ◽  
Barium Strontium Titanate ◽  
Raw Materials ◽  
Strontium Nitrate ◽  
Hydrothermal Processing ◽  
Dispersive Effect ◽  
Microwave Hydrothermal ◽  
Barium Strontium ◽  
Polyethylene Glycol 6000

Through the microwave-hydrothermal processing at 70 °C in 10 min, barium strontium titanate (BST) nanopowders are prepared by using butyl-titanate, barium nitrate and strontium nitrate as raw materials. Two kinds of dispersants namely polyethylene glycol 6000 and OP-10 are added, respectively. The dispersant mechanism and dosage on the crystal phase and microstructure are studied by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM). The results show that the dispersive effect of OP-10 is better than the polyethylene glycol 6000. The long chain of OP-10 can be used to disperse nanopowders through a space steric hindrance mechanism, well-dispersed BST nanopowders are obtained when mass percent ratio of dispersant (OP-10) is 5%.

Microwave-hydrothermal synthesis of ceramic powders

1992 ◽  
Vol 27 (12) ◽  
pp. 1393-1405 ◽  
Author(s):  
Sridhar Komarneni ◽  
Rustum Roy ◽  
Q.H. Li
Keyword(s):  
Hydrothermal Synthesis ◽  
Ceramic Powders ◽  
Microwave Hydrothermal

Microwave-Hydrothermal Synthesis of Transition Metal Tungstates with Nanosized Particles

2012 ◽  
Vol 194 ◽  
pp. 209-212 ◽  
Author(s):  
Kisla P.F. Siqueira ◽  
Anderson Dias
Keyword(s):  
Raman Spectroscopy ◽  
Structural Changes ◽  
Single Phase ◽  
Amorphous Matrix ◽  
Nanosized Particles ◽  
Hydrothermal Processing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Hydrothermal ◽  
Metal Tungstates

Microwave-hydrothermal processing was employed to synthesize Mn and Co tungstates under environmentally friendly conditions. X-ray diffraction showed that crystalline, single-phase materials were produced. Incipient crystallized compounds were also obtained in some conditions, as verified by TEM. For these samples, nanostructured regions could be observed inside the amorphous matrix. Sintered solid-solutions of Mn1-xCoxWO4 compounds were produced to investigate the morphological and structural changes in the resulted ceramic. Raman spectroscopy was used to obtain a reliable set of spectra containing all the Raman-active bands predicted by group-theory calculations.

Effect of Microwave-Hydrothermal Synthesis on Tin (II) Oxide Properties

2015 ◽  
Vol 1085 ◽  
pp. 187-191
Author(s):  
Аlina A. Pichugina ◽  
Svetlana A. Kuznetsova
Keyword(s):  
Photocatalytic Activity ◽  
Hydrothermal Synthesis ◽  
Methyl Orange ◽  
Surface Morphology ◽  
Photocatalytic Degradation ◽  
Pore Volume ◽  
Hydrothermal Processing ◽  
Sorption Activity ◽  
Microwave Hydrothermal ◽  
Degradation Of Methyl Orange

The article demonstrates how time and speed of pressure growth in the course of microwave-hydrothermal processing affect surface morphology and photocatalytic activity of tin (II) oxide. The experiment proved that the materials’ pore size and pore volume influenced their sorption activity and the speed of photocatalytic degradation of methyl orange.

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