Synthesis, characterization, and properties of lead-based relaxor ferroelectrics

1996 ◽  
Vol 11 (5) ◽  
pp. 1210-1218 ◽  
Author(s):  
Michael M. A. Sekar ◽  
Arvind Halliyal ◽  
K. C. Patil
Keyword(s):  
Thermal Evolution ◽  
Combustion Process ◽  
Diffraction Method ◽  
Relaxor Ferroelectrics ◽  
X Ray Diffraction ◽  
Solution Combustion ◽  
X Ray ◽  
Metal Nitrates ◽  
Different Temperatures ◽  
Solution Combustion Process

Lead-based relaxor ferroelectrics such as Pb(Mg1/3Nb2/3)O3 (PMN), Pb(Zn1/3Nb2/3)O3 (PZN), and their solid solutions with BaTiO3 and PbTiO3 have been prepared by a solution combustion process which involves metal nitrates/oxalate and tetraformal trisazine (TFTA) at 350 °C. Thermal evolution of perovskite relaxors has been investigated at different temperatures of calcination using the powder x-ray diffraction method. Particles are fine and sinter-active at low temperature (1050 °C). Both particulate and dielectric properties are compared.

scholarly journals SÍNTESIS DE YAIO3 (YAP) POLICRISTALINO POR EL MÉTODO DE COMBUSTIÓN EN SOLUCIÓN

2018 ◽  
Vol 27 (1) ◽  
pp. 61
Author(s):  
A. Lazo ◽  
C. Paucarchuco ◽  
H. Loro
Keyword(s):  
Combustion Process ◽  
Orthorhombic Phase ◽  
Combustion Method ◽  
X Ray Diffraction ◽  
Solution Combustion ◽  
X Ray ◽  
Structure And Morphology ◽  
Palabras Clave ◽  
Diffraction Peaks ◽  
Ray Patterns

Se presenta el método de combustión en solución y su aplicación para la síntesis de YAlO3 (YAP), fueron usados como combustibles para la reacción de combustión y síntesis la urea y glicina, del YAP. Usando las técnicas de difracción de rayos X (XRD) por el método del polvo y microscopia electrónica de barrido (MEB) fueron analizadas la parte estructural y morfológica de las muestras obtenidas. Los difractogramas de Rayos X muestran una excelente correspondencia con lo reportado en la literatura para este material. Se suministran también los resultados de las muestras de material YAlxCrx‐1O3, dopado con Cr3+ con x = 0.001, 0.01, que exhiben picos de difracción dominantes debidos a la fase ortorrómbica de YAlO3 Palabras clave.- YAP, YAlO3, Combustion method. ABSTRACT The solution‐combustion process is presented, as well as its application to the synthesis of YAlO3 (YAP). Urea and glycine were used as fuel for the combustion reaction and synthesis of the YAP. The structure and morphology of the obtained sample were analyzed using the X‐ray diffraction (XRD) powder method and scanning electron microscopy (SEM). The X‐ray patterns showed an excellent agreement with data reported in the literature for this material. Results are also given for samples of YAlxCrx‐1O3 doped with Cr3+, with x = 0.001, 0.01, which showed dominant diffraction peaks due to the orthorhombic phase of YAlO3. Keywords.- YAP, YAlO3, combustion method.

Synthesis of Ultrafine Lu2Hf2O7/Tb Phosphor by Solution Combustion Process

2007 ◽  
Vol 336-338 ◽  
pp. 640-642 ◽  
Author(s):  
Yi Kun Liao ◽  
Dan Yu Jiang ◽  
Yun Peng Xu ◽  
Jian Lin Shi
Keyword(s):  
Amorphous Materials ◽  
Intermediate Phase ◽  
Combustion Process ◽  
Phase Evolution ◽  
X Ray Diffraction ◽  
Solution Combustion ◽  
Uniform Size ◽  
Solution Combustion Process ◽  
Xrd Techniques ◽  
Different Content

Ultrafine terbium-doped Lu2Hf2O7/Tb phosphor powders are prepared by a solution combustion process using glycine and urea as fuel. Phase evolution of the synthesized powder is determined by X-ray diffraction (XRD) techniques. Single-phase cubic Lu2Hf2O7/Tb crystalline powder is obtained by calcining the amorphous materials at 800oC and no intermediate phase is observed. Transmission electronic microscope (TEM) morphology shows that the resultant Lu2Hf2O7/Tb powders have uniform size and good homogeneity. The photoluminescence (PL) spectra of Tb3+ substituted for Lu3+ in Lu2Hf2O7 with different content has been measured on samples calcined at 1000oC.

scholarly journals Nanosized LaCo0.6Fe0.4O3 perovskites synthesized by citrate sol gel auto combustion method

2014 ◽  
Vol 8 (2) ◽  
pp. 87-92 ◽  
Author(s):  
Unikoth Megha ◽  
Karakat Shijina ◽  
George Varghese
Keyword(s):  
Sol Gel ◽  
Combustion Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dense Microstructure ◽  
Metal Nitrates ◽  
Average Grain Size ◽  
Auto Combustion ◽  
Different Temperatures ◽  
Lcr Meter

LaCo0.6Fe0.4O3 (LCFO) nanopowder was synthesized from constituent metal nitrates, citric acid and ethylene glycol by citrate sol gel autocombustion method and calcined at different temperatures. The powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX) and Fourier transform infrared spectra (FTIR), whereas dielectric properties were investigated with LCR-meter. The FTIR spectra, taken for the xerogel and the sample calcined at 1000?C, confirm that the organic groups were removed during calcination and oxide structure was formed. The XRD result shows that LCFO has rhombhohedral crystal structure with R-3C space group and forms single phase after calcination at 600?C. The activation energy of crystallite growth, determined from the Arrhenius plot, was 17?2 kJ/mol. Surface feature studies of the powders were obtained from SEM. At 1000?C, dense microstructure with wellshaped grain boundaries was obtained and the average grain size was around 400 nm. EDAX confirms the elemental composition. Finally, from the dielectric studies, it was found that the dielectric constant (?r) as well as dielectric loss tangent (tan ?) decreases with increase in frequency.

Oxidation of thiophene over copper-manganese mixed oxides

2009 ◽  
Vol 63 (2) ◽  
Author(s):  
Małgorzata Szynkowska ◽  
Aneta Węglińska ◽  
Elżbieta Wojciechowska ◽  
Tadeusz Paryjczak
Keyword(s):  
Noble Metals ◽  
Mixed Oxides ◽  
Diffraction Method ◽  
Catalytic Performance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Copper Manganese ◽  
Different Temperatures ◽  
Temperature Programmed ◽  
Lower Temperature

AbstractCommercial hopcalite calcined at different temperatures and hopcalite modified with noble metals (Pt, Pd, and Au) were studied in oxidation of thiophene. Surface and bulk properties of catalysts were studied using temperature-programmed reduction (TPRH2), X-ray diffraction method (XRD) and thermal analysis (TG-DTA-MS). It was shown that calcined samples displayed higher activity in comparison with commercial untreated hopcalite; however, a lower temperature of calcination was favourable. High temperature of thermal treatment induced an increase in the crystallinity and a decrease in the surface area of the samples, and, as a consequence, the loss of catalysts activity. Moreover, marked improvement in the catalytic performance of platinum and palladium modified catalysts in relation to base hopcalite was observed. The obtained results indicate that the higher activity of samples containing Pt and Pd was accompanied by better reducibility of the catalysts.

scholarly journals COXSIYTEZ NANOCOMPOSITE MANUFACTURE BY SOLUTION COMBUSTION PROCESS ASSISTED BY MICRO-WAVE

2020 ◽  
Vol 8 (10) ◽  
pp. 134-141
Author(s):  
Mauro Guilherme Ferreira Bezerra ◽  
◽  
Alice Sperandio Porto ◽  
Judes Gonçalves dos Santos ◽  
◽  
...  
Keyword(s):  
Single Phase ◽  
Combustion Process ◽  
Synthesis Process ◽  
X Ray Diffraction ◽  
Solution Combustion ◽  
X Ray ◽  
New Material ◽  
Two Stages ◽  
Constituent Elements ◽  
Stable Material

A possible formation of the nanocomposite based on silicon, cobalt and tellurium was produced by the combustion synthesis process in solution (SCS) assisted by microwave in two stages, combustion using a conventional microwave oven and purification by means of calcination at 650 ºC in a muffle furnace. The new material was developed in different oxidant-fuel relationships where it observed the effects on the evolution of the phase and morphology of the powders, the structural, morphological and thermal properties were investigated by the X-ray diffraction technique (XRD), energy dispersive X-ray spectroscopy (EDX) coupled to the scanning electron microscope (SEM) and TGA and DTG curves. Through the analysis it is possible to suggest the development of a new stable material in single phase, being isostructural to the Co8Te12O32 (ICDD-50702) of nanometric dimensions with interesting potentials due to the properties of the constituent elements.

LiNi0.5Mn1.5O4 Prepared by a Solution Combustion Synthesis at Different Temperatures

2011 ◽  
Vol 186 ◽  
pp. 3-6
Author(s):  
Gui Yang Liu ◽  
Jun Ming Guo ◽  
Bao Sen Wang
Keyword(s):  
Electrochemical Performance ◽  
Single Phase ◽  
Solution Combustion Synthesis ◽  
Combustion Method ◽  
X Ray Diffraction ◽  
Solution Combustion ◽  
Solution Combustion Method ◽  
X Ray ◽  
Different Temperatures ◽  
Micro Morphology

LiNi0.5Mn1.5O4 powders have been prepared by a solution combustion method at 300-800oC. X-ray diffraction (XRD) and scanning electric microscope (SEM) were used to determine the phase composition and micro morphology of the products. The results indicate that the products with single phase LiNi0.5Mn1.5O4 can be obtained at 400-600oC. The electrochemical performance was tested by a coin-type battery. The product prepared at 600oC has the best electrochemical performance. The maximum capacity of the product prepared at 600oC is 135mAh/g at the current density of 30mA/g, and after 30 cycles, the capacity fades little.

Nanocrystalline GdFeO3 via the gel-combustion process

2005 ◽  
Vol 20 (10) ◽  
pp. 2654-2659 ◽  
Author(s):  
S.V. Chavan ◽  
A.K. Tyagi
Keyword(s):  
Combustion Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molar Ratios ◽  
Metal Nitrates ◽  
Transmission Electron ◽  
Expansion Behavior ◽  
High Temperature Xrd ◽  
Gel Combustion ◽  
Crystallite Sizes

Nanocrystalline GdFeO3 powder was synthesized by a combustion technique, using glycine as the fuel and the corresponding metal nitrates as oxidants. Five different molar ratios of fuel-to-oxidant were chosen to study the effect of fuel content on the phase formation and the powder properties. The powders after calcination were characterized by x-ray diffraction (XRD) and crystallite sizes calculated by x-ray line broadening. The crystallite sizes for the phase pure products after calcination at 600 °C were in the range 40–65 nm. The transmission electron microscopy observations clearly highlight the pronounced crystallinity for the propellant chemistry samples. The nature of the agglomerates was investigated by light scattering studies. The lattice thermal expansion behavior was also studied by high-temperature XRD.

scholarly journals A Superhydrophobic, Antibacterial, and Durable Surface of Poplar Wood

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1885
Author(s):  
Xinyu Wu ◽  
Feng Yang ◽  
Jian Gan ◽  
Zhangqian Kong ◽  
Yan Wu
Keyword(s):  
Stearic Acid ◽  
Antibacterial Properties ◽  
Alkali Resistance ◽  
Poplar Wood ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Temperatures ◽  
Acid And Alkali Resistance ◽  
The Stability

The silver particles were grown in situ on the surface of wood by the silver mirror method and modified with stearic acid to acquire a surface with superhydrophobic and antibacterial properties. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray energy spectroscopy (XPS) were used to analyze the reaction mechanism of the modification process. Scanning electron microscopy (SEM) and contact angle tests were used to characterize the wettability and surface morphology. A coating with a micro rough structure was successfully constructed by the modification of stearic acid, which imparted superhydrophobicity and antibacterial activity to poplar wood. The stability tests were performed to discuss the stability of its hydrophobic performance. The results showed that it has good mechanical properties, acid and alkali resistance, and UV stability. The durability tests demonstrated that the coating has the function of water resistance and fouling resistance and can maintain the stability of its hydrophobic properties under different temperatures of heat treatment.

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