Controllable Synthesis of Different Bismuth Ferrites by a PVA Modified Hydrothermal Method and Photocatalytic Characterization

2013 ◽  
Vol 1552 ◽  
pp. 35-41 ◽  
Author(s):  
Tong Tong ◽  
Dengren Jin ◽  
Jinrong Cheng
Keyword(s):  
Hydrothermal Method ◽  
Phase Evolution ◽  
Xrd Analysis ◽  
Processing Parameters ◽  
X Ray Diffraction ◽  
Light Region ◽  
Wide Range ◽  
The Individual ◽  
Degradation Effect ◽  
Modified Hydrothermal Method

ABSTRACTBismuth ferrites crystallites were synthesized by a polyvinyl alcohol (PVA) modified hydrothermal method. X-ray diffraction (XRD) analysis indicated that the pure phase of Bi25FeO40, BiFeO3 and Bi2Fe4O9 were synthesized with initial Bi/Fe ratio of 1:1 at the temperature of 200°C for 24 h, using NaOH concentration of 2, 5 and 10 M, respectively. With addition of PVA, the individual Bi-Fe oxides could be existed in a more wide range of processing parameters. The phase evolution of bismuth ferrites in the process of hydrothermal reactions was discussed. Moreover, photocatalytic properties of the bismuth ferrites crystallites were explored. The results showed that they possessed band gaps of about 2.0 eV and performed good degradation effect at visible light region.

Controllable phase evolution of bismuth ferrite oxides by an organic additive modified hydrothermal method

2015 ◽  
Vol 41 ◽  
pp. S106-S110 ◽  
Author(s):  
Tong Tong ◽  
Wenhui Cao ◽  
Han Zhang ◽  
Jianguo Chen ◽  
Dengren Jin ◽  
...  
Keyword(s):  
Hydrothermal Method ◽  
Bismuth Ferrite ◽  
Phase Evolution ◽  
Organic Additive ◽  
Modified Hydrothermal Method

Synthesis and luminescence properties of the red phosphor CaZrO3:Eu3+ for white light-emitting diode application

Open Physics ◽  
2011 ◽  
Vol 9 (4) ◽  
Author(s):  
Junli Huang ◽  
Liya Zhou ◽  
Yuwei Lan ◽  
Fuzhong Gong ◽  
Qunliang Li ◽  
...  
Keyword(s):  
White Light ◽  
Light Emitting Diode ◽  
Red Light ◽  
Average Diameter ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Solid State Method ◽  
Light Emitting ◽  
Near Ultraviolet ◽  
Light Region

AbstractEu3+-doped CaZrO3 phosphor with perovskite-type structure was synthesized by the high temperature solid-state method. The samples were characterized by X-ray diffraction, scanning electron microscopy, fluorescence spectrophotometer and UV-vis spectrophotometer, respectively. XRD analysis showed that the formation of CaZrO3 was at the calcinations temperature of 1400°C. The average diameter of CaZrO3 with 4 mol% doped-Eu3+ was 2µm. The PL spectra demonstrated that CaZrO3:Eu3+ phosphor could be excited effectively in the near ultraviolet light region (397 nm) and emitted strong red-emission lines at 616 nm corresponding to the forced electric dipole 5 D 0 → 7 F 2 transitions of Eu3+. Meanwhile, the light-emitting diode was fabricated with the Ca0.96ZrO3:Eu0.043+ phosphor, which can efficiently absorb ∼ 400 nm irradiation and emit red light. Therefore Ca0.96ZrO3:Eu0.043+ may have applications for a near ultraviolet InGaN chip-based white light-emitting diode.

Synthesis, Structural and Dielectric Properties of Pure and Ni Substituted Bismuth Ferrite

2014 ◽  
Vol 938 ◽  
pp. 140-144 ◽  
Author(s):  
S. Blessi ◽  
S. Vijayalakshmi ◽  
S. Pauline
Keyword(s):  
Dielectric Properties ◽  
Hydrothermal Method ◽  
Bismuth Ferrite ◽  
Synthesis Method ◽  
Cost Effective ◽  
Xrd Analysis ◽  
Practical Application ◽  
X Ray ◽  
Wide Range ◽  
Good Agreement

Multiferroics have been known as materials exhibiting both ferroelectric and ferromagnetic properties in same phase, they have interesting physical properties as well as possibility of practical application in some new memories, spintronics and sensor devices. The present work reports the fabrication of pure and Nickel substituted Bismuth Ferrite by simple hydrothermal method at 180oC for 11 hours. The structural study was carried out using X-ray powder diffraction (XRD), and the Dielectric properties were investigated over a wide range of frequency and temperature. The image of SEM is in good agreement with the XRD analysis. The synthesis method is simple and cost effective. KEYWORDS: Multiferroics; Dielectric loss; Hydrothermal method; XRD.

TiO2 Nanoparticles Synthesized with Ti(SO4)2 as Precursor via the Hydrothermal Method and their Optical Absorption Properties

2017 ◽  
Vol 727 ◽  
pp. 280-283
Author(s):  
Xiao Ming Fu
Keyword(s):  
Hydrothermal Method ◽  
Ph Value ◽  
Blue Shift ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Absorption Properties ◽  
Tem Analysis ◽  
Visible Absorption ◽  
Transmission Electron ◽  
20 Nm

Anatase TiO2 particles of about 20 nm in the diameter were successfully synthesized with Ti (SO4)2 as titanium source and stronger ammonia water as precipitant at 240°C for 48 h with pH=5 using the hydrothermal method. The samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and ultraviolet-visible absorption spectroscopy (UV-VIS). XRD analysis showed that the phase of the samples was anatase TiO2. TEM analysis confirmed that TiO2 particles of about 50 nm in the diameter were obtained when the pH value was 0.12. With the increasement of the pH value, the size of as-prepared TiO2 particles became remarkably fine. However, with the further increase of the pH value, the size of TiO2 particles was not obvious. TiO2 particles of about 20 nm in the diameter were obtained when the pH value was 5. And UV-VIS results showed that the size of anatase TiO2 nanoparticles, which became small, was propitious to the blue shift of their absorption peak.

Micro Arc Oxidation of AZ91 Mg Alloy for Improved Corrosion Resistance

2011 ◽  
Vol 312-315 ◽  
pp. 877-881 ◽  
Author(s):  
H.G. Yavuz ◽  
M. Gunyuz ◽  
Isa Metin Ozkara ◽  
Murat Baydogan ◽  
Huseyin Cimenoglu
Keyword(s):  
Corrosion Resistance ◽  
Surface Topography ◽  
Xrd Analysis ◽  
Processing Parameters ◽  
Mg Alloy ◽  
X Ray Diffraction ◽  
Corrosive Solution ◽  
Weight Losses ◽  
Before And After ◽  
Micro Arc Oxidation

AZ91 Mg alloy was subjected to the micro arc oxidation process by using different processing parameters. Following oxidation, surface topography and qualitative phase analysis were made by tabletop digital microscopy and X-ray diffraction (XRD) analysis. In order to evaluate the relative corrosion resistance of the samples that were oxidized in different parameters, the samples were immersed in a corrosive solution for 6 days and the weight losses before and after the corrosion tests were compared. Relative corrosion resistance of the samples was evaluated on the basis of surface topography.

Effect of SiO2 Solid Loading and Sintering Temperatures on the Physical Properties of SiO2-NiO Foam

2018 ◽  
Vol 791 ◽  
pp. 37-44
Author(s):  
Rizamarhaiza Muda ◽  
M. Azham Azmi ◽  
Shahruddin Mahzan ◽  
Hatem Mostafa Elwalwal ◽  
Sufizar Ahmad ◽  
...  
Keyword(s):  
Sintering Temperature ◽  
Porous Ceramic ◽  
Catalyst Support ◽  
Xrd Analysis ◽  
Solid Loading ◽  
X Ray Diffraction ◽  
Replication Method ◽  
Wide Range ◽  
Porosity Percentage ◽  
Interconnected Pores

Porous ceramic is a type of material that has highly open and partially interconnected pores. It has a wide range of applications which include catalyst support, electrical conductivity, refractory insulation of furnaces, filtration, adsorption, and separation. There are many conventional methods for producing silica foam including direct forming, steam heating, freeze casting and the polymeric sponge method which is also known as the replication method. In this study, SiO2-NiO foam was fabricated using 25wt. %, 30wt % and 35wt.% of SiO2and 5wt.% of NiO under different sintering temperatures (850 °C and 1050 °C)viareplication method. The morphologies of SiO2-NiO foams were observed using Scanning Electron Microscopy (SEM) while the identification of the different phases of foam was analysed using X-Ray Diffraction (XRD). The XRD analysis indicated that there were only SiO2and NiO present and no additional phases were detected after sintering. The effects of sintering temperature (850 °C, 1050 °C) and SiO2solid loading on properties such as apparent porosity, bulk density and shrinkage were investigated. It was found that when the solid loading of SiO2and sintering temperature increased, the density of SiO2-NiO foams increased in the range of 0.6373 g/cm3to 0.8165 g/cm3. On the other hand, the porosity percentage obtained increased from 78.51 % to 81.63 %. The density and porosity analyses showed that the density of foam increases when the porosity of SiO2-NiO foam decreases. However, the shrinkage after sintering ranged between 3.5081cm to 6.9975 cm at 850C ̊ and 7.3618 cm to 8.3704 cm at 1050 °C respectively. Thus, this proves that SiO2-NiO foam can be successfully fabricated through the replication method.

Variations of structure and composition in magnesium incorporated hydroxyapatite/β-tricalcium phosphate

2006 ◽  
Vol 21 (2) ◽  
pp. 428-436 ◽  
Author(s):  
Hyun-Seung Ryu ◽  
Kug Sun Hong ◽  
Jung-Kun Lee ◽  
Deug Joong Kim
Keyword(s):  
Phase Transition ◽  
Tricalcium Phosphate ◽  
Phase Evolution ◽  
Processing Parameters ◽  
Solubility Limit ◽  
Mode Analysis ◽  
X Ray Diffraction ◽  
Mg Addition ◽  
Tcp Phase ◽  
Mg Content

The phase evolution of magnesium incorporated hydroxyapatite/β-tricalcium phosphate (HA/β-TCP) ceramics of high purity prepared by solid-state reaction was investigated with the aid of x-ray diffraction and infrared spectroscopy (IR) in transmittance mode analysis. The dependence of the microstructure on the phase evolution of biphasic ceramics during natural sintering was also investigated as a function of Mg content. When sintered at 1100 °C, Mg is preferentially incorporated into the β-TCP phase rather than the HA phase. This Mg incorporation into the β-TCP effectively suppresses the phase transition from β- to α-TCP. With increasing sintering temperature, the solubility limit of the Mg in the β-TCP decreases and Mg starts to be either incorporated into the HA phase or segregated as free MgO. The decreased Mg content in the β-TCP facilitates the phase transition from β- into α-TCP, at 1300 °C or higher. Different processing methods on Mg addition show that the retarded phase transition from β- to α-TCP is the inherent property of Mg-doped HA/TCP. The variations in processing parameters mainly affect the microstructure instead of the phase evolution, leading to highly densified HA/β-TCP ceramics.

scholarly journals Role of Disordered Precursor in L10 Phase Formation in FePt-Based Nanocomposite Magnet

2021 ◽  
Vol 7 (11) ◽  
pp. 149
Author(s):  
Alina Daniela Crisan ◽  
Ioan Dan ◽  
Ovidiu Crisan
Keyword(s):  
Permanent Magnets ◽  
Magnetic Measurements ◽  
Phase Evolution ◽  
Annealed Sample ◽  
X Ray Diffraction ◽  
Soft Magnetic ◽  
Spectra Analysis ◽  
Annealing Temperatures ◽  
Wide Range

In order to prove the usefulness of having a structurally disordered precursor to the formation of FePt L10 phase and to facilitate the co-existence of exchange coupled hard and soft magnetic phases with optimized magnetic properties in various conditions of annealing, a Fe-Pt-Zr-B melt spun alloy has been synthesized and detailed structural and magnetic investigations have been undertaken to probe its phase evolution during annealing. The dynamics of formation of the hard magnetic L10 phase during the gradual disorder–order phase transformation has been monitored by using a complex combination of X-ray diffraction methods and 57Fe Mössbauer spectroscopy methods, over a wide range of annealing temperatures. Multiple phases co-existing in the annealed sample microstructures, observed in XRD, have been reconfirmed by the Mössbauer spectra analysis and, moreover, accurate quantitative data have been acquired in what concerns the relative abundance of each of the observed crystalline phases in every stage of annealing. It is shown that the formation of the hard magnetic phase, emerging from the chemically disordered precursor, is gradual and occurs via complex mechanisms, involving the presence of a disordered Fe-Zr-B-rich intergranular region which contributes to an increase in the abundance of the L10 phase for higher annealing temperatures. Magnetic measurements have confirmed the good performances of these alloys in terms of coercivity and remanence. These results contribute to the development of these alloys as the next generation of rare earth, free permanent magnets.

Phase Evolution and Physical Properties of (1-x)BZT-xBFN Ceramic System

2008 ◽  
Vol 55-57 ◽  
pp. 53-56 ◽  
Author(s):  
H. Maimon ◽  
Sukum Eitssayeam ◽  
Uraiwan Intatha ◽  
Tawee Tunkasiri ◽  
G. Satittada
Keyword(s):  
Physical Properties ◽  
Physical And Mechanical Properties ◽  
Phase Evolution ◽  
Xrd Analysis ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Ceramic System ◽  
Solid State Reaction Technique ◽  
Temperature Changes ◽  
X Ray

Phase evolution and physical properties of (1-x)BZT–xBFN ceramic system were investigated to find the optimum condition for electronic applications. (1-x)BZT–xBFN powders were prepared by solid state reaction technique varying x from 0.2 to 0.8 and various sintering temperatures from 1350 °C to 1450 °C. Phase formation was investigated by X-ray diffraction technique. The XRD analysis demonstrated that with increasing BFN content in (1−x)BZT–xBFN, the structural change occurred from the tetragonal to the cubic phase at room temperature. Changes in the physical and mechanical properties were then related to this structural transformation depending on the BFN content.

scholarly journals Relaxor Phase Evolution of (Bi0.5Na0.5-xKx)TiO3 Ceramics due to K Ion Substitution and Their Corresponding Electrical Properties

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 455 ◽  
Author(s):  
Sam Yeon Cho ◽  
Eun-Young Kim ◽  
Sun Yong Kim ◽  
Thuy Linh Pham ◽  
Jin Kyu Han ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Phase Evolution ◽  
Xrd Analysis ◽  
Solid State Reaction Method ◽  
Tetragonal Structure ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Structural And Electrical Properties ◽  
Ion Substitution

We synthesized lead-free piezoelectric (Bi0.5Na0.5-xKx)TiO3 (BNKT) ceramics using a conventional solid-state reaction method. We have investigated the structural and electrical properties of the materials with x = 0.05 to 0.40. The X-ray diffraction (XRD) analysis suggests that the BNKT ceramics show the transition from rhombohedral to tetragonal structure. The ratio of the tetragonal structure increased continuously in accordance with the increasing composition of x. The sample of x = 0.10 showed a similar ratio between the tetragonal and rhombohedral structures. Frequency-dependent dielectric measurements showed a sort of relaxor properties emerged with increasing x composition, this effect may be interpreted in terms of the formation of polar nano-regions (PNRs) in samples. The value of remnant polarization (Pr) decreases rapidly as x increases beyond the point of x = 0.10 from 25.3 μC/cm2 to 5.9 μC/cm2. On the contrary, as for inverse piezoelectric coefficient (d33*), a higher value of d33* (336 pm/V) at x = 0.10, was observed when compared with x = 0.05 (d33* = 51 pm/V). These results can be explained by the formation of PNRs and their variations with the external applied field. We here propose a possible mechanism showing the effects of dipolar defects, which can be resulted from the K ion substitution on (Bi,Na)TiO3 (BNT) ceramics.

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