Enhanced the dielectric relaxation characteristics of BaTiO3 ceramic doped by BiFeO3 and synthesized by the microwave sintering method

2020 ◽  
Vol 250 ◽  
pp. 123034 ◽  
Author(s):  
Tao Fan ◽  
Cong Ji ◽  
Gang Chen ◽  
Wei Cai ◽  
Rongli Gao ◽  
...  
Keyword(s):  
Dielectric Relaxation ◽  
Microwave Sintering ◽  
Batio3 Ceramic ◽  
Sintering Method ◽  
Relaxation Characteristics

Permittivity Relaxation Variation for Additive Doping in Cobalt Ferrite at High Frequencies

2019 ◽  
Vol 201 (1) ◽  
pp. 155-162
Author(s):  
S. Bharadwaj ◽  
Suman Kumar Burnwal ◽  
Subimal Deb ◽  
S. Ragini ◽  
S. R. Murthy
Keyword(s):  
Dielectric Relaxation ◽  
Cobalt Ferrite ◽  
Microwave Sintering ◽  
Least Square ◽  
High Frequencies ◽  
Microwave Hydrothermal ◽  
Least Square Fit ◽  
C 30 ◽  
Linear Least Square ◽  
Sintering Method

We present a comparative study of the variation in dielectric relaxation for the additives SiO2, TiO2 and ZrO2 in cobalt ferrite. CoFe2O4 was prepared using microwave hydrothermal system and sintered at 900 °C/30 min using microwave sintering method. Real and imaginary parts of permittivity were measured in the frequency range of 1 MHz to 1.8 GHz for these samples. A shift in the dielectric relaxation towards higher frequencies for doped samples is observed as expected in percolating systems. A non-linear least square fit of the electron oscillator model is used to parameterize absorption in the samples.

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.

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.

Dynamic mechanical and dielectric relaxation characteristics of microcellular rubber composites

2008 ◽  
Vol 19 (9) ◽  
pp. 1311-1322 ◽  
Author(s):  
S. P. Mahapatra ◽  
V. Sridhar ◽  
D. K. Tripathy ◽  
J. K. Kim ◽  
H. Kwak
Keyword(s):  
Dielectric Relaxation ◽  
Rubber Composites ◽  
Dynamic Mechanical ◽  
Relaxation Characteristics

Considerations for BaTiO3Ceramics with High Piezoelectric Properties Fabricated by Microwave Sintering Method

2008 ◽  
Vol 47 (11) ◽  
pp. 8468-8471 ◽  
Author(s):  
Hirofumi Takahashi ◽  
Yoshiki Numamoto ◽  
Junji Tani ◽  
Sadahiro Tsurekawa
Keyword(s):  
Piezoelectric Properties ◽  
Microwave Sintering ◽  
Sintering Method

Double Inhibitory Actions on WC Grains of Microwave Sintered WC-12wt%Co-VC Alloy

2015 ◽  
Vol 816 ◽  
pp. 715-721 ◽  
Author(s):  
Rui Bao ◽  
Jian Hong Yi ◽  
Jia Min Zhang ◽  
Yi Chun Liu ◽  
Feng Xian Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Positive Impact ◽  
Rupture Strength ◽  
Microwave Sintering ◽  
Inhibitory Effects ◽  
Microwave Exposure ◽  
Microstructure Observation ◽  
Average Grain Size ◽  
Bulk Alloys ◽  
Sintering Method

It is well known that grain-refinement has a positive impact on the mechanical properties of WC-Co cemented carbide. The effect of VC inhibitor and microwave on density, microstructure and mechanical properties of the sintered WC–12wt%Co alloy was investigated in the present study. The ball milled WC-12wt%Co-xVC composites were compressed and fabricated by using microwave sintering method. The experimental results indicate that the microwave sintering cycle was significantly shorter to that of vacuum processing, and the density of bulk alloys increased with VC inhibitor contents and microwave sintering temperatures. Moreover, the microstructure observation of the sintered samples suggests that VC inhibitor had prominent inhibitory action on WC grains in microwave exposure, and the WC average grain size of alloy with 0.7wt%VC inhibitor was 0.43μm when the sintering temperature reached 1420°C. It is also evident that WC-12wt% alloys with an appropriate proportion of VC inhibitor exhibited higher hardness (92.1HRA) and better transverse rupture strength (2380MPa). And finally the mechanism of inhibitory effects on WC grains under microwave irradiation was discussed.

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