scholarly journals Phase Formation and Morphological Features of Calcium Copper Titanate by Modified Solid State Process

2019 ◽  
Vol 16 (1) ◽  
pp. 37-42 ◽  
Author(s):  
ASHNARAYAN SAH ◽  
SOUMYA MUKHERJEE ◽  
MOHAMMED SHAHNAWAZ ◽  
SATH BANERJEE
Keyword(s):  
Chemical Activation ◽  
Morphological Features ◽  
Molar Ratio ◽  
Synthesis Process ◽  
Fixed Temperature ◽  
Chemical Route ◽  
State Process ◽  
Calcium Copper Titanate ◽  
Giant Dielectric ◽  
Size Growth

Perovskite calcium copper titanate posses giant dielectric constant making it a suitable candidate for possible applications in microelectronic components, advanced transistors, energy storage capacitors. Generally, this grade of material is synthesized by the chemical route to improving homogeneity, controlled size growth for enhanced properties. In the present research, a simple synthesis process was adopted using precursors of high purity oxides like Calcium carbonate, titania, Copper oxide without any use of complicated synthesis routes and costly chemical precursors. The molar ratio of oxides used was about 1:3:4 with mechano-chemical activation in an agate mortar for 20, 25 and 30 hours respectively in dry condition. After milling, powders obtained were made to undergo annealing at a fixed temperature of 900°C for 26 hours soaking period. Phase analysis was carried to determine the phase along with crystallite size calculation. Bonding information of the synthesized sample was analyzed to obtain the M-O coordination and vibration-stretching analysis of the bonds. Morphological features were also noted using FESEM (Field Emission Scanning Electron Microscopy) for understanding grains and granular boundaries. Both FTIR (Fourier Transform Infra-Red Spectroscopy) and XRD (X-Ray Diffractogram) analyses confirm the compound formation in terms of molecular structure responsible to obtain the proper phase.

scholarly journals Phase Development of Barium Bismuth Titanate by Modified Solid State Route

2020 ◽  
Vol 17 (2) ◽  
pp. 129-135
Author(s):  
Soumya Mukherjee ◽  
Mohammed Shahnawaz ◽  
Sathi Banerjee
Keyword(s):  
Solid State ◽  
Surface Engineering ◽  
Bismuth Titanate ◽  
Molar Ratio ◽  
Fixed Temperature ◽  
Spectra Analysis ◽  
Solid State Route ◽  
State Process ◽  
Phase Development ◽  
Barium Bismuth

Barium bismuth titanate materials are noted for ferroelectric behavior, competitor to lead based relaxor dielectrics and even for coating having wear resistance, toughness for improving surface engineering applications. In the present context, a modified solid state process aided by agate-mortar activation for milling is carried in compare to mechanochemical milling, melt-quench method to generate the complex ceramic structure. Molar ratio of BaO:Bi2O3:TiO2 1:2:4 ratio have been taken with fixed soaking temperature to develop the material. Activation milling period is varied for 20 hours, 25 hours and 30 hours while soaking period descends in the order 10 hours, 8 hours and 6 hours keeping fixed temperature of about 700°C. XRD confirms the presence of peaks for all cases. Crystallite size is estimated by Scherrers formula with proper planes of index corresponding to JCPDS data. FTIR confirmed the phases developed by XRD while indicating the proper M-O bond formation from analysis in the required spectral range. EDX spectra analysis given the presence of required elements present in the sample.

Electrospun nanofibrous membranes of cellulose acetate containing hydroxyapatite co-doped with Ag/Fe: morphological features, antibacterial and degradation of methylene blue from aqueous solutions

2021 ◽  
Author(s):  
Ahmed Esmail Shalan ◽  
M. Afifi ◽  
M.M. El-Desoky ◽  
M.k Ahmed
Keyword(s):  
Methylene Blue ◽  
Aqueous Solutions ◽  
Cellulose Acetate ◽  
Morphological Features ◽  
Molar Ratio ◽  
Electrospinning Technique ◽  
Nanofiber Membranes ◽  
Nanofibrous Membranes ◽  
Co Doped

Cellulose acetate nanofiber membranes containing hydroxyapatite co-doped with Ag/Fe were efficaciously attained through the electrospinning technique. Different molar ratio compositions of hydroxyapatite co-doped with Ag/Fe in the structure of the...

Effect of the Synthesis Method on the Properties of Ultrafine YAG Powder

2018 ◽  
Vol 281 ◽  
pp. 40-45
Author(s):  
Jie Guang Song ◽  
Lin Chen ◽  
Cai Liang Pang ◽  
Jia Zhang ◽  
Xian Zhong Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Calcination Temperature ◽  
Hydrothermal Reaction ◽  
Synthesis Method ◽  
Particle Morphology ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Synthesis Process ◽  
Powder Materials ◽  
Co Precipitation

YAG materials has a number of unique properties, the application is very extensive. In this paper, the superfine YAG powder materials were prepared by co-precipitation method and hydrothermal precipitation method. The influence of synthesis process on the morphology of the powder was investigated. The results showed that the precursor powder prepared via the co-precipitation method is mainly from amorphous to crystalline transition with the increasing calcination temperature, the precursor agglomeration is more serious, In the process of increasing the calcination temperature, the dispersibility of the roasted powder is greatly improved, which is favorable for the growth of the crystal grains, so that the particle size of the powder is gradually increased, the YAG precursor prepared by the co-precipitation method is transformed into YAG crystals, the phase transition occurs mainly between 900 and 1100°C. When the molar ratio of salt to alkali is Y3+: OH-=1: 8 via the hydrothermal reaction, the YAG particles with homogeneous morphology can be obtained. When the molar ratio of salt and alkali is increased continuously, the morphology of YAG particles is not obviously changed. The co-precipitation method is easy to control the particle size, the hydrothermal method is easy to control the particle morphology.

Nanosized Hydroxyapatite Powder Synthesized from Eggshell and Phosphoric Acid

2007 ◽  
Vol 7 (11) ◽  
pp. 4061-4064 ◽  
Author(s):  
Sang-Jin Lee ◽  
Young-Soo Yoon ◽  
Myung-Hyun Lee ◽  
Nam-Sik Oh
Keyword(s):  
Phosphoric Acid ◽  
Heating Temperature ◽  
Average Particle Size ◽  
Stoichiometric Composition ◽  
Synthesis Process ◽  
Average Particle ◽  
Mixing Ratio ◽  
Powder Synthesis ◽  
Chemical Route ◽  
Milling Method

The present research describes synthesis of highly sinterable, nano-sized hydroxyapatite (HAp) powders using a wet chemical route with recycled eggshell and phosphoric acid as calcium and phosphorous sources. The raw eggshell was easily turned to CaO by the calcining process, and phosphoric acid was mixed with the calcined eggshell by the wet, ball-milling method. The crystalline development and microstructures of the synthesized powders and sintered samples were examined by X-ray diffractometry and scanning electron microscopy, respectively. The observed phases on the powder synthesis process were dependent on the mixing ratio (wt%) of the calcined eggshell to phosphoric acid and the heating temperature. The ball-milled, nano-sized HAp powder, which has an average particle size of 70 nm, was fully densified at 1300 °C for 1h. The Ca/P ratio for stoichiometric composition of HAp was controlled by adjustment of the mixing ratio.

Zirconium Titanate: Synthesis and Processing of Fine Powders Prepared by Chemical Route

2006 ◽  
Vol 530-531 ◽  
pp. 683-688 ◽  
Author(s):  
Valter Ussui ◽  
Dolores Ribeiro Ricci Lazar ◽  
Nelson Batista de Lima ◽  
Ana Helena A. Bressiani ◽  
José Octavio A. Pascoal
Keyword(s):  
Metal Salt ◽  
Ceramic Powder ◽  
Ammonium Hydroxide ◽  
Molar Ratio ◽  
Precipitation Process ◽  
Zirconium Titanate ◽  
X Ray Diffraction ◽  
Chemical Route ◽  
Synthesis And Processing ◽  
Cylindrical Samples

A process for synthesis of fine zirconium titanate powders by chemical route is described. Zirconium/titanium molar ratio was varied from 0.67 to 1.5 and the powders produced were analyzed. The precipitation process comprises the mixture of zirconium and titanium metal salt solutions to ammonium hydroxide solution, followed by washing of the precipitate, calcination and grinding to result in zirconium titanate. The ceramic powder is then uniaxially pressed as cylindrical samples and sintered at 1400°C for 5 hours. The microstructure of fractured and thermally etched ceramic was observed by scanning electron microscopy, and crystal phase identifications were done by X-ray diffraction. At least two different zirconium titanate phases, ZrTiO4 and Zr5Ti7O24, were identified. Ceramic hardness was measured by Vickers indentation.

scholarly journals A STATISTICAL APPROACH FOR OPTIMIZING THE HIGH YIELD GREEN PRODUCTION OF THE FLAVOR ESTER BUTYL BUTYRATE

2017 ◽  
Vol 79 (7) ◽  
Author(s):  
Ida Nurhazwani Abd Rahman ◽  
Fatin Myra Abd Manan ◽  
Nur Haziqah Che Marzuki ◽  
Naji A. Mahat ◽  
Nursyafreena Attan ◽  
...  
Keyword(s):  
Molar Ratio ◽  
High Yield ◽  
Esterification Reaction ◽  
Reaction Parameters ◽  
Chemical Route ◽  
Butyl Butyrate ◽  
Novozyme 435 ◽  
Yield Production ◽  
Green Production ◽  
Percentage Conversion

Being the prevailing approach for producing esters such as butyl butyrate, the use of chemical route has been linked to numerous disadvantages. Hence, a green alternative method for higher yield production of butyl butyrate by esterification reaction utilizing Novozyme 435 as biocatalysts in a solvent-less system may prove useful. Such approach can be further improved by optimizing the relevant reaction parameters using the Response Surface Methodology by the Box-Benkhen Design attempted in this present study. The reaction parameters evaluated were: substrate molar ratio, time and temperature, and the response of each parameter was measured as percentage conversion yield. Using the Design Expert 7.1.6 optimization functions, the two sets of optimum conditions selected viz. [i] molar ratio butyric acid:butanol 1:3.93, 9.93 h at 56.09°C and [ii] molar ratio butyric acid:butanol 1:3.35, 9.79 h at 53.90°C had afforded the highest yield of butyl butyrate i.e. 99.62% and 99.55%, respectively. The ester product obtained from the reaction were confirmed as butyl butyrate by FTIR and GC. Therefore, the results substantiated the applicability of the RSM prediction technique as well as efficacy of Novozyme 435 as biocatalysts in the high yield solvent-less synthesis of butyl butyrate, adhering to the philosophy of Green Chemistry.

Cement Bonded Sol-Gel TiO2 Powder Photocatalysis for Phenol Removal

2015 ◽  
Vol 776 ◽  
pp. 271-276 ◽  
Author(s):  
Nor Hafizah ◽  
Iis Sopyan
Keyword(s):  
Anatase Phase ◽  
Sol Gel ◽  
Phenol Degradation ◽  
Xrd Analysis ◽  
Hydrolysis Rate ◽  
Molar Ratio ◽  
Synthesis Process ◽  
Phenol Removal ◽  
Titanium Tetraisopropoxide ◽  
Degussa P25

Photocatalysis has been proven effective in controlling various environmental problems originated by pollutions both in liquid and gaseous phases. Titanium dioxide (TiO2) is well known the most practical photocatalyst as it has high photocatalytic efficiency, low band gap energy, and no toxicity. Various chemical methods have been tried to produce TiO2 photocatalyst powder with high activity. In this study, sol-gel method has been employed to produce nanosized TiO2 photocatalyst particles and its physical properties and photocatalytic activity in phenol degradation test were compared with the commercial TiO2 powder, Degussa P25. The synthesis process was carried out through hydrolysis of titanium tetraisopropoxide (TPT) and methanol where the molar ratio of water to TPT was monitored to control the hydrolysis rate. From X-Ray Diffraction (XRD) analysis, the sol-gel TiO2 powder obtained was fully in anatase structure with high crystallinity. Scanning Electron Microscope (SEM) measurement showed that the powder was in nanoto sub-micron size, spherical in shape, and tightly agglomerated. Thermal analysis confirmed that sol-gel derived amorphous TiO2 powder transformed to anatase phase after 400°C calcination. The test on photocatalytic performance conducted using aqueous solution of phenol as the representative of water pollutant examined in this study showed that the sol-gel TiO2 powder is more efficient in degrading phenol compared to one of the most active photocatalysts commercially available, Degussa P25.

scholarly journals Effect of temperature on o-cresol methylation in a fluidized bed of commercial iron-chromium catalyst TZC-3/1

2013 ◽  
Vol 15 (3) ◽  
pp. 100-102 ◽  
Author(s):  
Gabriela Berkowicz ◽  
Witold Żukowski ◽  
Jerzy Baron
Keyword(s):  
Fluidized Bed ◽  
Effect Of Temperature ◽  
Molar Ratio ◽  
Synthesis Process ◽  
Maximum Efficiency ◽  
Chromium Catalyst ◽  
On Line ◽  
Commercial Iron ◽  
By Products ◽  
Iron Chromium

Abstract The paper presents the results of the synthesis of 2,6-dimetyhlphenol (26DMP) from o-cresol. The target compound is an important substrate for polymer chemistry. Due to a large amount of o-cresol which is generated as a by-product, during the synthesis of 2,6-dimethylphenol from phenol, the methylation of o-cresol to 2,6-dimethylphenol should be examined as a separate process. The alkylation of o-cresol was carried out in a fluidized bed of commercial iron-chromium catalyst TZC-3/1. Undesirable decomposition of methyl alcohol on the catalyst generates a number of environmentally dangerous by-products such as methane, carbon dioxide, carbon monoxide. The effect of temperature on the yield of the synthesis was investigated. The synthesis process was monitored on-line in the temperature range 310-380°C, completely covering the maximum efficiency of the process. Online analysis of the process by FTIR spectroscopy gave information about products of both methylation of o-cresol and pyrolysis of methanol. The maximum 85% yield of desired 2,6-dimethylphenol with more than 85% conversion of o-cresol was achieved at 340°C, at 1:6 molar ratio of o-cresol:methanol

Synthesis of Al-Doped Lithium Manganese Oxide from Al2O3-Li2CO3-MnO2 Ternary System

2011 ◽  
Vol 415-417 ◽  
pp. 1721-1724
Author(s):  
Xin Yan Sun ◽  
Gang He ◽  
Jian He Hong ◽  
Ming Zhong He ◽  
Hai Feng Li
Keyword(s):  
Ternary System ◽  
Electrochemical Performance ◽  
Ternary Phase Diagram ◽  
Raw Materials ◽  
Ternary Eutectic ◽  
Basic Knowledge ◽  
Molar Ratio ◽  
Synthesis Process ◽  
Composition Optimization ◽  
Process Composition

Al-doped LiMn2O4 was synthesized by γ-Al2O3, which has not toxic gas decomposed in the synthesis process. Composition optimization of was carried out in view of the basic knowledge of ternary phase diagram to find the best composition of raw materials in Al2O3-Li2CO3-MnO2 ternary system. The results showed that the Al2O3-Li2O-Mn2O3 ternary eutectic molten compound with single spinel structure and good electrochemical performance could be formed at temperature of 800°C and the molar ratio of the starting materials in the range of n(Al2O3)=0~3.3 mol%, n(Li2CO3)=18~22 mol%, n(MnO2)=75~82 mol%. The Al2O3-Li2O-Mn2O3 ternary eutectic compound with the molar ratio of the starting materials of n(Al2O3):n(Li2CO3):n(MnO2) at 0.02:0.5:1.96, showed the best electrochemical performance among all studied samples.

FORMATION MECHANISM OF BaFe12O19 NANOPARTICLES PROCESSED VIA WET CHEMICAL ROUTE USING MIXED SOLVENT

2011 ◽  
Vol 10 (04n05) ◽  
pp. 1083-1086 ◽  
Author(s):  
A. ATAIE ◽  
M. MONTAZERI-POUR
Keyword(s):  
Volume Ratio ◽  
Barium Hexaferrite ◽  
Ethanol Solution ◽  
Molar Ratio ◽  
Chemical Route ◽  
Crystalline Phases ◽  
Amorphous Phases ◽  
Sem Micrograph ◽  
Mean Size ◽  
Co Precipitation

Nanosize particles of barium hexaferrite were prepared by co-precipitation route using solution of iron and barium chlorides with a Fe+3/Ba+2 molar ratio of 11. Water and a mixture of water/ethanol with volume ratio of 1:3 were used as solvents. Co-precipitated powders were calcined at various temperatures. XRD results showed that single phase barium hexaferrite forms at 900°C for sample synthesized in aqueous solution and its formation is resulted from the reaction between mainly crystalline phases, while this temperature decreased to 700°C for sample synthesized in water/ethanol solution and the formation of barium hexaferrite consists of reactions between amorphous phases with crystalline phases. SEM micrographs of the calcined samples at 800°C indicated that the morphology of particles was affected by the type of solvent. Nano size particles of barium hexaferrite with mean particle size of almost 80 nm were observed in the SEM micrograph of sample synthesized in water/ethanol solution after calcination at 800°C. Barium hexaferrite crystallites with mean size of 35 nm, which was approximately consistent with size obtained from XRD line broadening technique, could be seen in TEM image of this sample after calcination at 700°C.

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