scholarly journals Impedance and Electrical Modulus Study of Microwave-Sintered Ceramic

ISRN Ceramics ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
V. Senthil ◽  
T. Badapanda ◽  
A. Chandra Bose ◽  
S. Panigrahi
Keyword(s):  
Microwave Sintering ◽  
Fatigue Property ◽  
Activation Energies ◽  
Nyquist Plot ◽  
Sintered Pellet ◽  
X Ray Diffraction ◽  
Sintered Ceramic ◽  
Solid State Route ◽  
Conventional Sintering ◽  
Single Arc

Bismuth layered structure SrBi2Ta2O9 ceramic is prepared by the microwave sintering technique via solid state route at 1100°C for 30 mins. X-ray diffraction analysis is used to analyze the phase purity, which identifies the orthorhombic structure with A21am space group. The fracture surface of the sintered pellet is visualized by scanning electron microscopy. Impedance spectroscopy is used to analyze the sample behavior as a function of frequency and temperature. Impedance and modulus study reveals the temperature-dependent non-Debye type relaxation phenomenon. The Nyquist plot shows a single arc representing the grain effect in the material, and the conductivity increases with increase in temperature. The Nyquist plot is fitted with an equivalent circuit, and the simulated parameters are well agreed with the calculated parameters. Arrhenius plot shows two different activation energies at below and above 300°C which identifies the phase transition of SrBi2Ta2O9 ceramic. The fatigue property is explained by the basis of activation energies, which shows that SBT sintered by microwave technique is more fatigue resistant than conventional sintering.

Dielectric and Conductivity Study of SrBi2Ta2O9 Ceramic by Microwave Sintering Technique

2012 ◽  
Vol 584 ◽  
pp. 169-172
Author(s):  
Venkatesan Senthil ◽  
Tanmaya Badapanda ◽  
Simanchalo Panigrahi
Keyword(s):  
Microwave Sintering ◽  
Fatigue Property ◽  
Orthorhombic Phase ◽  
Negative Temperature ◽  
Dielectric Study ◽  
Sintered Pellet ◽  
X Ray Diffraction ◽  
Phase Transition Behavior ◽  
Solid State Route ◽  
Diffusive Phase Transition

Bismuth layered structure SrBi2Ta2O9ceramic is prepared by the microwave sintering technique via solid state route at 1100°C. X-ray diffraction analysis is used to analyze the phase purity and identifies the orthorhombic phase with A21am space group. The fracture surface morphology of the sintered pellet is visualized by scanning electron microscopy. Diffusive phase transition behavior is existed in the temperature dependence dielectric study at Tc= 305°C. The electrical ac and dc conductivity study shows the negative temperature coefficient of resistance behavior. Activation energy from the Arrhenius plot is studied to discuss the fatigue property.

Microwave Sintering of YSZ Electrolyte Materials for SOFC

2008 ◽  
Vol 368-372 ◽  
pp. 238-240 ◽  
Author(s):  
Xi Tang Wang ◽  
Girish M. Kale
Keyword(s):  
Microwave Sintering ◽  
X Ray Diffraction ◽  
Final Phase ◽  
X Ray ◽  
Microwave Furnace ◽  
Scanning Electron Microcopy ◽  
Conventional Sintering ◽  
Y2o3 Content ◽  
Ysz Electrolyte ◽  
Considerable Enhancement

Microwave sintering behaviors of four different compositions of YSZ electrolyte materials were investigated. The samples were sintered in 2.45GHz microwave furnace. For comparison, conventional sintering was performed at 1821K.The densities of sintered samples showed considerable enhancement in the densification process under the influence of microwave fields. The samples with lower Y2O3 content are easy to sinter. The influence of the composition and sintering methods on the final phase composition and microstructure were investigated by X-ray diffraction and scanning electron microcopy. Finer and more uniform microstructures were observed in the microwave sintered samples comparing to the conventionally sintered samples.

Formation of Tricalcium Silicate Prepared by Electric and Microwave Sintering

2010 ◽  
Vol 148-149 ◽  
pp. 1119-1123
Author(s):  
Kai Ke ◽  
Bao Guo Ma ◽  
Xiao Liang Wang ◽  
Xiang Guo Li
Keyword(s):  
Heating Temperature ◽  
Microwave Sintering ◽  
Electric Heating ◽  
Tricalcium Silicate ◽  
Experimental Results ◽  
X Ray Diffraction ◽  
X Ray ◽  
Conventional Sintering ◽  
Sintering Method

A microwave sintering method was used to prepare C3S from Ca(OH)2, SiO2 and MexOy. f-CaO assay, X-ray diffraction and SEM were used to characterize the sintered samples.The results indicated that ion oxides played a very important role in C3S formation in conventional sintering, the use of MexOy as an additive was so effective in promoting C3S formation. The experimental results showed that samples were heated at an electric heating temperature(1500°C) and then further sintered with microwave for 30~60 min, tricalcium silicate could be formed with kilogram step. The new burning technique can greatly increase the forming speed of tricalcium silicate, MnO2, CuO and Ni2O3 could enhance the microwave sintering.

scholarly journals Ag+, Cu2+ and Zn2+ doped hydroxyapatite/tricalcium phosphate bioceramics: Influence of doping and sintering technique on mechanical properties

2018 ◽  
Vol 12 (3) ◽  
pp. 268-276 ◽  
Author(s):  
Zeljko Radovanovic ◽  
Ðordje Veljovic ◽  
Lidija Radovanovic ◽  
Ilmars Zalite ◽  
Eriks Palcevskis ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Tricalcium Phosphate ◽  
Microwave Sintering ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydroxyapatite Ceramics ◽  
Average Grain Size ◽  
Conventional Sintering ◽  
Scanning Electron

Green hydroxyapatite ceramics were obtained by cold uniaxial and isostatic pressing of hydrothermally synthesized powders, pure hydroxyapatite and hydroxyapatite doped with Ag+, Cu2+ and Zn2+ ions. The ceramics were conventionally and microwave sintered and analyzed by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, X-ray diffraction analysis, and energy-dispersive X-ray spectroscopy. The effect of doping on the mechanical properties of the obtained hydroxyapatite/tricalcium phosphate ceramics was examined by comparing their average grain size, porosity and values of the hardness and fracture toughness. The results showed that doping with Cu2+ ions caused the lowest porosity of the ceramics and the highest values of hardness and fracture toughness. The ceramics obtained from hydroxyapatite doped with Ag+ and Zn2+ ions exhibited worse mechanical properties due to the higher porosity even in the case of microwave sintering, which provide denser ceramics than conventional sintering.

Estimates for Diffusion Barriers and Atomic Potentials in Mgo: Cndo/2 Calculations for the Study of Microwave Effects in Sintering

1990 ◽  
Vol 189 ◽  
Author(s):  
L. Skala ◽  
V.M. Kenkre ◽  
M.W. Weiser ◽  
J.D. Katz
Keyword(s):  
Microwave Sintering ◽  
Activation Energies ◽  
Diffusion Barriers ◽  
Electron Densities ◽  
Self Consistent ◽  
Interstitial Atoms ◽  
Microwave Effects

ABSTRACTAs part of a program of investigation of microwave sintering, self-consistent CNDO/2 calculations are presented for diffusion barriers and potentials for the motion of interstitial atoms and vacancies in MgO. Clusters of 30 atoms are used in the calculations. Activation energies, diffusion barriers, shape of the potentials and electron densities are obtained.

Effect of Green Microstructure and Processing Variables on the Microwave Sintering of Alumina

1990 ◽  
Vol 189 ◽  
Author(s):  
Arindam Dé ◽  
Iftikhar Ahmad ◽  
E. Dow Whitney ◽  
David E. Clark
Keyword(s):  
Particle Size ◽  
Microwave Sintering ◽  
Heating Rates ◽  
Hybrid Heating ◽  
Processing Variables ◽  
Conventional Sintering ◽  
Rapid Sintering ◽  
Temperature Time ◽  
Fast Firing

ABSTRACTThe concept of 'hybrid heating with microwave (MW) energy at 2.45 GHZ.'for ultra rapid sintering of alumina is being introduced. This technique is a combination of MW - materual interaction as well as conventional radiant/conduction mechanisms, and facilitates the attainment of perhaps, the highest possible heating rates in a multimode MW cavity at 2.45 GJZz. (1500ºC in 120 sees.). Rapid sintering of pure.undoped alumina with this novel techniQue culminates in uniform, homogeneous microstructures and mechanical property enhancements vis-a-vis conventional fast firing.The role of green microstructure (particle size) on MW(hybrid) heating and processing variables (temperature, time) on the MW (hybrid) heating phenomena vs. conventional fast firing were investigated. Hybrid heated samples showed accelerated densification with comparable grain sizes when compared with the conventionally fast fired samples. The effectof particle size on the microwave (hybrid) heating phenomena was found to be analogous to conventional sintering.

scholarly journals Dielectric relaxation and modulus spectroscopy analysis of (Na0.47 K0.47 Li0.06) NbO3 ceramics

2017 ◽  
Vol 07 (03) ◽  
pp. 1750020 ◽  
Author(s):  
Md Kashif Shamim ◽  
Seema Sharma ◽  
Sangeeta Sinha ◽  
Eqra Nasreen
Keyword(s):  
Dielectric Relaxation ◽  
Spectroscopic Analysis ◽  
Microwave Sintering ◽  
Complex Impedance ◽  
Tungsten Bronze ◽  
Negative Temperature ◽  
Nyquist Plot ◽  
Orthorhombic Symmetry ◽  
Modulus Spectroscopy ◽  
C Complex

We have investigated the structure, dielectric and electrical properties of lead-free polycrystalline (Na[Formula: see text] K[Formula: see text] Li[Formula: see text]) NbO3 ceramics as a function of temperature and frequency in order to understand the intrinsic contribution of grain/bulk and grain boundary effects toward the dielectric response as well as the electrical conduction mechanism in the samples fabricated by microwave sintering method. X-ray diffraction analysis exhibits perovskite structure with orthorhombic symmetry, which is well supported by the Raman spectroscopic analysis. A minor secondary impurity phase of tungsten bronze structure was observed for samples sintered at 1050[Formula: see text]C, which gets weaker for samples sintered at 1150[Formula: see text]C. Dielectric permittivity was enhanced by 50%, although there was a reduction in the dielectric loss by about 50% at Curie temperature (450[Formula: see text]C) for samples sintered at 1150[Formula: see text]C. Complex impedance spectroscopic analysis indicated non-Debye-type dielectric relaxation present in the samples, and this phenomenon followed thermally activated process related to hopping mechanism. Nyquist plot showed the negative temperature coefficient of resistance, characteristic of the samples.

The Effect of Microwave Sintering Time to PM Aluminum Alloys

2015 ◽  
Vol 754-755 ◽  
pp. 240-244
Author(s):  
M.N. Derman ◽  
Syaza Nabilla Mohd Suhaimi ◽  
Zuraidawani Che Daud
Keyword(s):  
Microwave Sintering ◽  
Microwave Oven ◽  
Solid Particles ◽  
Binding Reaction ◽  
Aluminium Powder ◽  
Sintering Time ◽  
Conventional Sintering ◽  
Rapid Sintering ◽  
Powder Particles ◽  
Solid Liquid

Microwave sintering is new sintering technology method to produce Al alloys. The advantages of this method because of very short sintering time and less production cost compare to conventional sintering. However, the main problems in microwave sintering are required to be controlled sintering time due to rapid sintering mechanism. Therefore the effect of microwave sintering time to PM Aluminium will be studied. The compacted and sintered aluminium powder is placed in a microwave oven at a different period of 5 minutes, 10 minutes, 15 minutes and 20 minutes. Compression of 150 MPa is applied on aluminium powder to form pellets. Palette is shaped to 1cm in diameter and weighs 1g. SiC is placed together with aluminium samples in the microwave for the purpose of absorbing electromagnetic energy and is converted to heat. Results of different period sintering of aluminium pallet production altered physical properties of each sample. For a rapid sintering time, aluminium pallet does not show any binding reaction between powder particles. Whereas, for long microwave sintering period, solid particles phase change into solid-liquid phase caused by the movement and the formation of bonds between particles. Hence, this will be affecting the mechanical properties of the sample material.

Study on Structural Properties of Gallium and Titanium Doped Zinc Oxide Films Deposited by Magnetron Sputtering

2014 ◽  
Vol 908 ◽  
pp. 124-128 ◽  
Author(s):  
S.B. Chen ◽  
Z.Y. Zhong
Keyword(s):  
Thin Films ◽  
Zinc Oxide ◽  
Magnetron Sputtering ◽  
Crystal Structures ◽  
X Ray Diffraction ◽  
Hexagonal Crystal ◽  
Working Pressure ◽  
Sintered Ceramic ◽  
Glass Substrates ◽  
Zinc Oxide Films

Thin films of transparent conducting gallium and titanium doped zinc oxide (GTZO) were prepared on glass substrates by magnetron sputtering technique using a sintered ceramic target. The microstructural properties of the deposited thin films were characterized with X-ray diffraction (XRD). The results demonstrated that the polycrystalline GTZO thin films consist of the hexagonal crystal structures with c-axis as the preferred growth orientation normal to the substrate, and that the working pressure significantly affects the crystal structures of the thin films. The GTZO thin film deposited at the working pressure of 0.4 Pa has the best crystallinity, the largest grain size and the lowest stress.

scholarly journals Study of Microstructural, Electrical and Dielectric Properties of La0.9Pb0.1MnO3 and La0.8Y0.1Pb0.1MnO3 Ceramics

2019 ◽  
pp. 33-44 ◽  
Keyword(s):  
Transition Temperature ◽  
Frequency Dispersion ◽  
Insulator Transition ◽  
X Ray Diffraction ◽  
Phonon Modes ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Solid State Route ◽  
Distorted Structure ◽  
Lower Temperature

The present work studies the microstructural and electrical properties of La0.9Pb0.1MnO3 and La0.8Y0.1Pb0.1MnO3 ceramics synthesized by solid-state route method. Microstructure and elemental analysis of both samples were carried out by field emission scanning electron microscope (FESEM) and energy dispersive spectroscopy (EDS) method, respectively. Phase analysis by X-ray diffraction (XRD) indicated formation of single phase distorted structure. The XRD data were further analyzed by Rietveld refinement technique. Raman analysis reveals that Y atom substitutes La site into the LPMO with shifting of phonon modes. The temperature variation of resistivity of undoped and Y-doped La0.9Pb0.1MnO3 samples have been investigated. The electrical resistivity as a function of temperature showed that all samples undergo an metal-insulator (M-I) transition having a peak at transition temperature TMI. Y-doping increases the resistivity and the metal-insulator transition temperature (TMI) shifts to lower temperature. The temperature-dependent resistivity for temperatures less than metal-insulator transition is explained in terms the quadratic temperature dependence and for T > TMI, thermally activated conduction (TAC) is appropriate. Variation of frequency dispersion in permittivity and loss pattern due to La-site substitution in LPMO was observed in the dielectric response curve.

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