Effect of Sintering Temperature on Nanostructured Multiferroic BiFeO3 Ceramics

2012 ◽  
Vol 510-511 ◽  
pp. 348-355 ◽  
Author(s):  
M.Y. Shami ◽  
M.S. Awan ◽  
M. Anis-ur-Rehman
Keyword(s):  
Sintering Temperature ◽  
Volumetric Strain ◽  
Precipitation Method ◽  
Ferromagnetic Behavior ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Electrical And Magnetic Properties ◽  
Multiferroic Bifeo ◽  
Different Temperatures ◽  
Co Precipitation

Nanostructured multiferroic BiFeO3(BFO) powders were synthesized by using the co-precipitation method. Calcination of acquired powder was carried out at 400°C for 3h. Uniaxially pressed pellets were sintered at 500°C, 600°C, 700°C and 800°C for 2 hours in air. These samples were characterized for structural, thermal, electrical and magnetic properties. X-ray diffraction (XRD) confirmed the amorphous nature of the as driven powder and phase purity of the calcined BFO sample. The crystallite size varied with the sintering temperature from 52 to 70 nm. Sintering above 500°C induced impure phases due to oxygen vacancies and volumetric strain in crystal structure. Ferroelectric to paraelectric transition temperature TC~815°C was verified by the differential scanning calorimetry (DSC). Surface morphology and grain growth was observed using scanning electron microscopy (SEM). Electrical ac measurements were performed in the frequency range from 20 Hz to 3 MHz at room temperature. For a particular sample, capacitance decreased and susceptance increased with the increase of applied frequency signal. These parameters were increased with the increase of sintering temperature. Vibrating sample magnetometer (VSM) revealed the diverse weak ferromagnetic behavior for the samples sintered at different temperatures. Maximum coercivity (Hc~119.2 Oe) and maximum remnant magnetization (MR~2.1x10-3emu/g) were obtained for the sample sintered at 700°C for 2hr.

Characterization of Al2(WO4)3 Synthesized by Co-Precipitation Method

2014 ◽  
Vol 798-799 ◽  
pp. 85-89 ◽  
Author(s):  
E.S.G. Junior ◽  
P.M . Jardim
Keyword(s):  
Precipitation Method ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Tem Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Co Precipitation ◽  
Alpha Alumina

Al2(WO4)3was synthesized by co-precipitation using Na2WO4and Al (NO3)3as precursors. After drying the precipitate, it was calcined at different temperatures between 500°C and 800°C. The crystallization and degradation temperatures of the samples were evaluated by means of Differential Scanning Calorimetry (DSC), Thermogravimetry (TG) and X-Ray Diffraction (XRD). It was observed that the crystallization starts at around 600°C, however Transmission Electron Microscopy (TEM) analysis showed that at this temperature the sample is partially amorphous. The degradation of the material starts at around 1200°C and at 1400°C the tungsten oxide has almost completely evaporated and the material is transformed mainly in alpha-alumina.

Synthesis Mechanism and Microstructure Characterization of BaIn2O4

2011 ◽  
Vol 347-353 ◽  
pp. 1342-1347 ◽  
Author(s):  
Ping Ren ◽  
Li Cheng Zhou ◽  
Jun Xi Zhang ◽  
Hong Yun
Keyword(s):  
Sintering Temperature ◽  
Precipitation Method ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Synthesis Mechanism ◽  
X Ray ◽  
Grain Sizes ◽  
Co Precipitation

The synthesis mechanism and microstructures of BaIn2O4 particles were analyzed by simultaneous thermogravimetry - differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), and scanning electron microscope (SEM). Firstly, In(OH)3 and BaCO3 precursors were prepared by the co-precipitation method. Next, during the sintering process In(OH)3 initially decomposed into In2O3 and water, and then BaCO3 reacted with In2O3 to synthesize Ba4In6O13. Finally, Ba4In6O13 and In2O3 further reacted to form BaIn2O4. The obtained BaIn2O4 particles were in monoclinic structure and exhibited high crystal quality. The grains were tightly bound together and their boundaries became blurry. The grain sizes increased with increasing the sintering temperature.

The Influence of Calcination Temperature on Quantitative Phase of Hematite from Iron Stone Tanah Laut

2015 ◽  
Vol 1112 ◽  
pp. 489-492
Author(s):  
Ali Mufid ◽  
M. Zainuri
Keyword(s):  
Particle Size ◽  
Calcination Temperature ◽  
Thermo Gravimetric Analysis ◽  
Precipitation Method ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Particle Size Analyzer ◽  
Co Precipitation

This research aims to form particles of hematite (α-Fe2O3) with a basis of mineral iron ore Fe3O4 from Tanah Laut. Magnetite Fe3O4 was synthesized using co-precipitation method. Further characterization using X-ray fluorescence (XRF) to obtain the percentage of the elements, obtained an iron content of 98.51%. Then characterized using thermo-gravimetric analysis and differential scanning calorimetry (TGA-DSC) to determine the calcination temperature, that at a temperature of 445 °C mass decreased by 0.369% due to increase in temperature. Further Characterization of X-ray diffraction (XRD) to determine the phases formed at the calcination temperature variation of 400 °C, 445 °C, 500 °C and 600 °C with a holding time of 5 hours to form a single phase α-Fe2O3 hematite. Testing with a particle size analyzer (PSA) to determine the particle size distribution, where test results indicate that the α-Fe2O3 phase of each having a particle size of 269.7 nm, 332.2 nm, 357.9 nm, 412.2 nm. The best quantity is shown at a temperature of 500 °C to form the hematite phase. This result is used as the calcination procedure to obtain a source of Fe ions in the manufacture of Lithium Ferro Phosphate.

A Comparative Study on the Morphology and Magnetic Properties of Barium and Strontium Hexaferrite Nanoparticles Synthesized by Co-Precipitation Method

2009 ◽  
Vol 67 ◽  
pp. 203-208 ◽  
Author(s):  
Sachin Tyagi ◽  
Ramesh Chandra Agarwala ◽  
Vijaya Agarwala
Keyword(s):  
Ultrafine Particles ◽  
Barium Hexaferrite ◽  
Nitrogen Atmosphere ◽  
Precipitation Method ◽  
Strontium Hexaferrite ◽  
X Ray Diffraction ◽  
Heat Treated ◽  
Different Temperatures ◽  
Co Precipitation ◽  
Decomposition Behaviour

Nanocrystalline strontium hexaferrite (SrFe12O19) and barium hexaferrite (BaFe12O19) powders were synthesized by co-precipitation method. The ‘as synthesized’ powders were heat treated (HT) at different temperatures ranging from 800 to 1200°C at a heating rate of 30°C /min in nitrogen atmosphere. Decomposition behaviour and the phases associated therein are investigated by thermal analysis (DTA/DTG/TG) and X-ray diffraction (XRD). Formations of ultrafine particles have been confirmed through field emission scanning electron microscop (FESEM). The superparamagnetic behavior of both, barium and strontium hexaferrite is confirmed by vibrating sample magnetometer (VSM). The increase in saturation magnetization from 1.94 to 31.05 emu/gm in case of barium hexaferrite and from 2.44 to 43.38 emu/gm for strontium hexaferrite is observed with HT temperatures. The changes in coercivity and remanence with HT temperatures for both the ferrites are analysed.

Effect of Sintering Temperature on Structural, Electrical and Dielectric Parameters of Mn-Zn Nano Ferrites

2012 ◽  
Vol 510-511 ◽  
pp. 163-170 ◽  
Author(s):  
Humaira Anwar ◽  
Ashari Maqsood
Keyword(s):  
Sintering Temperature ◽  
Small Polaron ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Dielectric Parameters ◽  
Zn Ferrite ◽  
Dta Analysis ◽  
Frequency Relaxation ◽  
Co Precipitation ◽  
Frequency Curves

Mn-Zn ferrite powders (Mn0.5Zn0.5Fe2O4) were prepared by the chemical co-precipitation method. The effect of sintering temperature on the crystalline phase formation and dielectric properties were investigated by X-ray diffraction and impedance analyzer respectively. The TGA/DTA analysis was carried out to know decomposition mechanism. Ferrites decomposed to Fe3O4 above 873 K sintering temperature. Crystallite size increased with increasing sintering temperature between 7-13 nm. The resistivity decreased with increase in temperature showing semiconducting like behaviour. Activation energy was in the range of 0.70 to 0.77eV for these samples. Dielectric constant decreased with increasing frequency. Relaxation peak occurred for loss tangent versus frequency curves. The ac conductivity explained using small polaron tunnelling (SPT) model.

Synthesis of LiFePO4 Cathode Materials by a Chemical Method

2011 ◽  
Vol 197-198 ◽  
pp. 1049-1052
Author(s):  
Yuan Sun ◽  
Xiu Juan Zhao ◽  
Guo Jun Li ◽  
Rui Ming Ren
Keyword(s):  
Chemical Method ◽  
Single Phase ◽  
Raw Materials ◽  
Thermo Gravimetric Analysis ◽  
Precipitation Method ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Thermo Gravimetric ◽  
Co Precipitation

The olivine-type LiFePO4powder was prepared by a chemical method using the synthesized FePO41.78H2O, LiOH, citric acid and PEG as raw materials. The synthesized FePO41.78H2O precursor powder was obtained by co-precipitation method. LiFePO4powder was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermo-gravimetric analysis (TGA)/differential scanning calorimetry (DSC). The results showed that the calcined LiFePO4was in a single phase when fabricated by using the synthesized FePO41.78H2O powder at pH of 3.5 in argon atmosphere.

Y3Al5O12 Nanocrystallites Prepared from a Novel Crystalline Precursor

2011 ◽  
Vol 306-307 ◽  
pp. 1142-1147 ◽  
Author(s):  
Rong Jiang Han ◽  
Dan Gao ◽  
Ke Zheng Chen
Keyword(s):  
Precipitation Method ◽  
Test Results ◽  
X Ray Diffraction ◽  
Electronic Microscopy ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Air Atmosphere ◽  
Thermal Gravimetry ◽  
Measured Weight ◽  
Co Precipitation

A novel crystalline precursor for preparing Y3Al5O12 (YAG) nanocrystallite was synthesized via a co-precipitation method using (NH4)2CO3 solution as the precipitator. The precursor was characterized by means of powder X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), thermal gravimetry (TG), differential thermal gravimetry (DTG) and differential scanning calorimetry (DSC), respectively. The empirical chemical formula of the crystalline precursor can be expressed as 5[(NH4)2Al6(CO3)3(OH)14]×9[Y2(CO3)3×3H2O] according to the test results. The measured weight loss of 46.7% of the precursor without consideration of the absorbed water is in accord with the calculated value of 47.5% according to the above empirical formula. The phase-pure YAG nanocrystallites were obtained by calcining the above precursors at 900°C for 2 hours in air atmosphere. Transmission electronic microscopy (TEM) result showed that the particle size of YAG nanocrystallites is 40-80 nm. The mechanism of themal decomposition of the crystalline precursor was also presented.

scholarly journals Zinc Titanate Nanopowders. Synthesis and Characterization

2021 ◽  
Author(s):  
M Gabal ◽  
Y.M. Al Angari
Keyword(s):  
Nitrogen Adsorption ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Zinc Titanate ◽  
Low Dielectric ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Precursor Decomposition ◽  
Co Precipitation ◽  
Adsorption Desorption

Abstract Zinc titanates nanopowders viz.; Zn2TiO4, ZnTi3O8 and ZnTiO3 were synthesized through the thermal decomposition course of ZnC2O4.2H2O-TiO2 precursor (1:1 mole ratio), prepared via a new co-precipitation method up to 900oC. Thermogravimetric measurement (TG) was utilized to characterize the precursor decomposition while X-ray diffraction (XRD), Fourier transform infra-red (FT-IR) were used to characterize the decomposition products as well as the phase transitions at different temperatures. XRD revealed the starting of titanates formation at 700oC via detecting Zn2TiO4 along with ZnO and TiO2 (anatase) diffraction peaks. By increasing the calcination temperature to 800oC, the ZnO content vanished with the appearing of Zn2Ti3O8 besides ZnTi2O4 and impurities of TiO2 (anatase). Finally at 900oC, the Zn2Ti3O8 content was decomposed into ZnTiO3. Nitrogen adsorption-desorption isotherm of the calcined precursor at 900oC indicated low specific surface area of 7.1 m2 g-1 in accordance with the agglomeration nature estimated via transmission electron microscopy (TEM) study. The conductivity measurements showed semiconducting behavior of the prepared titanates with ferroelectric transition in the range 200-308oC.The obtained low dielectric value suggests the uses of present titanates as a co-fired ceramic or resonator ceramics.

Modified Synthesis Temperature of Ba3 Co1.7 Ni0.1 Cu0.1 Mn0.1 Fe24 O41 Z-Type Ferrite Nanoparticles Prepared by Co-Precipitation Method

2013 ◽  
Vol 829 ◽  
pp. 737-741 ◽  
Author(s):  
Mohammad Javad Pourhosseini Asl ◽  
Ali Ghasemi ◽  
Gholam Reza Gordani
Keyword(s):  
Low Temperature ◽  
Synthesis Temperature ◽  
Precipitation Method ◽  
Diffraction Field ◽  
X Ray Diffraction ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis ◽  
Optimum Synthesis ◽  
Different Temperatures ◽  
Co Precipitation

In this study, the low temperature synthesis of barium-Z type hexaferrite nanoparticles was considered. In this manner, the Z-type hexaferrite with the chemical composition of Ba3 Co1.7 Ni0.1 Cu0.1 Mn0.1 Fe24 O41 was synthesized at different temperatures of 900, 1000 and 1100 0C for 3hr. An X-Ray diffraction, field emission scanning electron microscopy (FE-SEM) and a vibrating sample magnetometer (VSM) analysis were carried out to investigate structural and magnetic properties of samples. XRD results showed that the Z-type ferrite phase was formed in all samples. However, At the low temperature synthesis (T=900 0C), the Ba2Me2Fe12O22 and BaFe2O4 phases were also detected. FE-SEM micrographs showed that with increasing the synthesis temperature, the particle size was increased. It was found that the saturation of magnetization was slightly increased from 54 to 55. 5emugr with an increase in synthesis temperature from 900 to 11000C, while the coercivity increased initially from 670 Oe to 860 Oe and then decreased to 488 Oe. The results also indicated that the temperature of 10000C was the optimum synthesis temperature of Ba-Z type hexaferrite nanoparticles, which was much lower than that of Z-type hexaferrite produced by previous researchers.

Microstructures, Electrical and Magnetic Properties of Zn Doped Co Nanoferrites

2012 ◽  
Vol 510-511 ◽  
pp. 221-226 ◽  
Author(s):  
M. Akram ◽  
M. Anis-ur-Rehman ◽  
M. Mubeen ◽  
M. Ali
Keyword(s):  
Magnetic Properties ◽  
Electrical Transport ◽  
Room Temperature ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Electrical Transport Properties ◽  
X Ray ◽  
Electrical And Magnetic Properties ◽  
Crystallite Sizes ◽  
Co Precipitation

Non toxicity, bio compatibility and nanometer sizes regime which is comparable to the size of a cell, makes nanocrystalline Co ferrites particles very proficient. In the present research Zn doped cobalt ferrites were prepared by the chemical co-precipitation method and characterized by X-ray diffraction (XRD) at room temperature for structural analysis. X-ray diffraction patterns confirmed the FCC spinel structure of synthesized particles. Crystallite sizes were calculated from the most intense peak (311) using the Debye-Scherrer formula. The obtained crystallite sizes were in nanometer range for all the samples synthesized at reaction temperature of 70°C. Then samples were sintered at 550°C for 2 hours, characterized again by X-ray diffraction at room temperature. The crystallite sizes and lattice constants for all the samples were calculated again from the data obtained by XRD. DC electrical resistivity and AC electrical transport properties were analyzed. The magnetic properties such as coercivity (Hc) and remanence (Mr) of Co1-xZnxFe2O4for x = 0.0, 0.2, 0.4 were measured at room temperature by vibrating sample magnetometer. Coercivity and remanence were found maximum with minimum value of Zn in Co1-xZnxFe2O4.Observed structural and conduction properties of synthesized nanomaterials were correlated.

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