Study on Recovery of Electrical Degradation of ZnO Varistors

2007 ◽  
Vol 350 ◽  
pp. 209-212 ◽  
Author(s):  
Hiroshi Yoshida ◽  
Masayuki Takada ◽  
Shinzo Yoshikado
Keyword(s):  
Crystal Structure ◽  
Optimum Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxygen Ions ◽  
Electrical Degradation ◽  
Long Time ◽  
Zno Varistors ◽  
The Relationship ◽  
Scanning Electron

The relationship between the crystal structure of Bi2O3 and the recovery of the electrical degradation of ZnO varistors was investigated. The evaluation methods used were analysis of the voltage-current (V-I) characteristics, scanning electron microscopy (SEM), energy-dispersion X-ray spectroscopy (EDX), and X-ray diffraction (XRD) measurements. The electrical degradation was estimated by the nonlinearity of the V-I characteristics. A marked recovery of the nonlinearity of the V-I characteristics was observed for a sample having the crystal structure of δ-type Bi2O3. It is speculated that the electrical degradation is markedly recovered for optimum conditions of both the amount and the crystal structure of the added Bi2O3, because, for samples sintered for a long time, the recovery speed is shorter than that for samples sintered for a shorter time. During long-time sintering, the amount of Bi2O3 decreased because of evaporation. No change of the crystal structure of Bi2O3 was observed upon repeated the electrical degradation and the recovery. It is suggested that another mechanism apart from the diffusion of oxygen ions through the grain boundaries of ZnO particles contributes to the electrical degradation and recovery of the nonlinearity of V-I characteristics.

Effect of SnO2 Addition on Electrical Degradation of ZnO Varistors

2007 ◽  
Vol 350 ◽  
pp. 213-216 ◽  
Author(s):  
Masayuki Takada ◽  
Shinzo Yoshikado
Keyword(s):  
Grain Boundary ◽  
Integral Intensity ◽  
Local Maximum ◽  
Diffraction Peak ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxygen Ions ◽  
Xrd Diffraction ◽  
Electrical Degradation ◽  
Zno Varistors

The effects of SnO2 addition on the electrical degradation characteristics of Bi2O3-MnO2-Co3O4 -added ZnO varistors were investigated by field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and voltage-current (V-I) characteristics. The ZnO grain size was made uniform by the addition of SnO2 or Sb2O3. The nonlinearity index α of the V-I characteristic for Bi-Mn-Co-SnO2-added samples was approximately 50 and the varistor voltage was 120~140V/mm. The value of α after the electrical degradation showed a local maximum at approximately 0.1mol% added SnO2 and then showed a local minimum at approximately 0.5mol%, similar to the relative integral intensity of the XRD diffraction peak for the (004) plane for a small amount of SnO2 added. It is suggested that the diffusion of oxygen ions through the grain boundary is affected by the change in crystal orientation of ZnO grains at the grain boundary induced by the addition of a small amount of SnO2.

X-ray powder diffraction data of LaNi0.5Ti0.45Co0.05O3, LaNi0.45Co0.05Ti0.5O3, and LaNi0.5Ti0.5O3 perovskites

2021 ◽  
pp. 1-6
Author(s):  
Mariana M. V. M. Souza ◽  
Alex Maza ◽  
Pablo V. Tuza
Keyword(s):  
Crystal Structure ◽  
Rietveld Method ◽  
Pechini Method ◽  
Powder Diffraction Data ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Modified Pechini Method ◽  
Scanning Electron

In the present work, LaNi0.5Ti0.45Co0.05O3, LaNi0.45Co0.05Ti0.5O3, and LaNi0.5Ti0.5O3 perovskites were synthesized by the modified Pechini method. These materials were characterized using X-ray fluorescence, scanning electron microscopy, and powder X-ray diffraction coupled to the Rietveld method. The crystal structure of these materials is orthorhombic, with space group Pbnm (No 62). The unit-cell parameters are a = 5.535(5) Å, b = 5.527(3) Å, c = 7.819(7) Å, V = 239.2(3) Å3, for the LaNi0.5Ti0.45Co0.05O3, a = 5.538(6) Å, b = 5.528(4) Å, c = 7.825(10) Å, V = 239.5(4) Å3, for the LaNi0.45Co0.05Ti0.5O3, and a = 5.540(2) Å, b = 5.5334(15) Å, c = 7.834(3) Å, V = 240.2(1) Å3, for the LaNi0.5Ti0.5O3.

Study on the Properties of Doped La in BaBi4Ti4O15 Ceramic

2007 ◽  
Vol 26-28 ◽  
pp. 243-246
Author(s):  
Xing Hua Yang ◽  
Jin Liang Huang ◽  
Xiao Wang ◽  
Chun Wei Cui
Keyword(s):  
Crystal Structure ◽  
Grain Size ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Sintering Temperature ◽  
Solid Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lanthanum Content ◽  
Scanning Electron

BaBi4-xLaxTi4O15 (BBLT) ceramics were prepared by conventional solid phase sintering ceramics processing technology. The crystal structure and the microstructure were detected by X-ray diffraction (XRD) and scanning electron microscope (SEM). The XRD analyses show that La3+ ions doping did not change the crystal structure of BBT ceramics. The sintering temperature increased from 1120°C to 1150°C with increasing Lanthanum content from 0 to 0.5, but it widened the sintering temperature range from 20°C to 50°C and refined the grain size of the BBT ceramic. Additionally, polarization treatment was performed and finally piezoelectric property was measured. As a result, the piezoelectric constant d33 of the 0.1at.% doped BBLT ceramics reached its highest value about 22pc/N at polarizing electric field of 8kV/mm and polarizing temperature of 120°C for 30min.

High-performance electrical properties of La-based perovskite ceramics for the functional phase of thick film resistors

2020 ◽  
Author(s):  
Yongcheng Lu ◽  
Yuanxun Li ◽  
Daming Chen ◽  
Rui Peng ◽  
Qinghui Yang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electrical Properties ◽  
Thick Film ◽  
High Performance ◽  
Composite Ceramics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Alternative Material ◽  
Perovskite Ceramics ◽  
Scanning Electron

Abstract In order to explore an economical functional phase alternative material for thick film resistors, the crystal structure, microstructure, and electrical properties of (1-x)LSCN + xLCNZ (x = 0.0–1.0) composite ceramics were studied through solid-state reaction experiments. The composite ceramics were characterized by x–ray diffraction, scanning electron microscopy, energy dispersive x–ray spectroscopy, and DC four–probe method. Results suggested that the main phases of LSCN and LCNZ were formed, along with a small part of impurity phases. The addition of LCNZ to LSCN decreased the electrical conductivity and changed the TCR from positive to negative. Zero TCR could be achieved around 0.6 < x < 0.8 and relatively low absolute TCR values could be obtained for the samples of 0.4 ≤ x ≤ 0.8. The ceramic of 0.6LSCN + 0.4LCNZ showed the optimal performances of conductivity = 1923 S/cm, TCR = 379.54 ppm/℃, and relative density = 95.05%.

Nanocrystalline Barium Zirconium Titanate Synthesized by the Sonochemical Process

2013 ◽  
Vol 802 ◽  
pp. 119-123
Author(s):  
Supamas Wirunchit ◽  
Rangson Muanghlua ◽  
Supamas Wirunchit ◽  
Wanwilai Vittayakorn ◽  
Naratip Vittayakorn
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Reaction Time ◽  
Single Phase ◽  
Zirconium Titanate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Large Particles ◽  
Barium Zirconium Titanate ◽  
Scanning Electron

Nanocrystalline barium zirconium titanate, BaZr0.4Ti0.6O3, was synthesized successfully via the sonochemical process. The effects of reaction time on the precipitation of Ba(Zr,Ti)O3 particles were investigated briefly. The crystal structure as well as molecular vibrations and morphology were investigated. X-ray diffraction indicated that the powders exhibited a single phase perovskite structure, without the presence of pyrochlore or unwanted phases at the reaction time of 60 min. Nanocrystals were formed before being oriented and aggregated into large particles in aqueous solution under ultrasonic irradiation. A scanning electron microscopy (SEM) photograph showed the BZT powder as spherical in shape with uniform nanosized features.

scholarly journals Phase Equilibria in the Nb-Rich Region of Al-Nb-Sn at 900 and 1200 °C

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2759 ◽  
Author(s):  
Ioannis Papadimitriou ◽  
Claire Utton ◽  
Panos Tsakiropoulos
Keyword(s):  
Crystal Structure ◽  
Phase Equilibria ◽  
Ternary Phase ◽  
X Ray Diffraction ◽  
High Solubility ◽  
Rich Region ◽  
X Ray ◽  
Heat Treated ◽  
Aero Engine ◽  
Scanning Electron

The Al-Nb-Sn phase diagram was studied experimentally in the Nb-rich region to provide important phase equilibria information for alloy design of Nb-silicide based materials for aero engine applications. Three alloys were produced: Nb-17Al-17Sn, Nb-33Al-13Sn and Nb-16Al-20Sn (at.%). As-cast and heat-treated alloys (900 and 1200 °C) were analysed using XRD (X-ray diffraction) and SEM/EDS (scanning electron microscopy/ electron dispersive x-ray spectroscopy). Tin showed a high solubility in Nb2Al, reaching up to 21 at.% in the Sn-rich areas, substituting for Al atoms. Tin and Al also substituted for each other in the A15 phases (Nb3Al and Nb3Sn). Tin showed limited solubility in NbAl3, not exceeding 3.6 at.% as it substituted Al atoms. The solubility of Al in NbSn2 varied from 4.8 to 6.8 at.%. A ternary phase, Nb5Sn2Al with the tI32 W5Si3 crystal structure, was found to be stable. This phase was observed in the 900 °C heat-treated samples, but not in the 1200 °C heated samples.

The Effect of Water Content on the Formation of TiO2 Nanotubes in Ethylene Glycol

2010 ◽  
Vol 173 ◽  
pp. 102-105 ◽  
Author(s):  
Khairul Arifah Saharudin ◽  
Srimala Sreekantan
Keyword(s):  
Crystal Structure ◽  
Aspect Ratio ◽  
Ethylene Glycol ◽  
Water Content ◽  
Anatase Phase ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Degradation Of Methyl Orange ◽  
Scanning Electron

In this paper, anodization of Ti foil was carried out in ethylene glycol (EG) containing 5 wt% NH4F solution and 0 to 1.5 wt% of water at 50 V for 60 min. The pH of the bath was kept constant at ~pH7. The crystal structure was studied by X-Ray Diffraction (XRD) analysis, and the morphology was observed via field emission scanning electron microscopy (FESEM). TiO2 nanotube with aspect ratio of 100 was obtained in EG containing less than 1wt % water. The nanotubes wall was very smooth. Increasing the water content > 1wt % results in short nanotubes of approximately 6.2μm with aspect ratio of 62. As anodized, nanotubes were amorphous and annealed at 400 °C promote 100 % anatase phase. Photocatalytic activity of the nanotubes produced at different water content was also evaluated by the degradation of methyl orange and the detail of the observation was discussed thoroughly in this paper.

Preparation and Properties of RE/Novel Polyamide Composite Fibers

2012 ◽  
Vol 627 ◽  
pp. 839-843 ◽  
Author(s):  
Bin Wang ◽  
Qing Xiu Jia ◽  
Guo Liang Zhao
Keyword(s):  
Lanthanide Complexes ◽  
Melt Spinning ◽  
Fluorescence Spectra ◽  
Composite Fibers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Doping Technique ◽  
The Relationship ◽  
Rare Earth Content ◽  
Scanning Electron

Eu(TTA)3phen of Lanthanide complexes was synthesized, and the biobased aliphatic copolyamides (novel PA) were synthesized by condensing the biobased diacids and diamines. The luminescent europium composite fibers, Eu (TTA)3phen/bio-PA,were prepared by doping technique, and by using melt spinning method, we obtained Eu (TTA)3phen/novel PA composite fibers. The phase structure and the relationship between the fluorescence intensity of composite materials with added rare earth content were characterized by scanning electron microscopy, fluorescence spectra and X-ray diffraction.

Effect of Annealing on Electrical Degradation Characteristics of ZnO Varistors

2008 ◽  
Vol 388 ◽  
pp. 7-10 ◽  
Author(s):  
Masayuki Takada ◽  
Shinzo Yoshikado
Keyword(s):  
Grain Boundaries ◽  
Diffraction Peak ◽  
Full Width ◽  
Half Maximum ◽  
X Ray Diffraction ◽  
X Ray ◽  
Annealing Conditions ◽  
Electrical Degradation ◽  
Zno Varistors ◽  
Triple Points

The effects of the thermally annealing of Bi-Mn-Co-Sb2O3-added ZnO varistors on their electrical degradation were investigated. For the samples with 0.01mol% Sb2O3added and without Sb2O3, no marked difference in the non linearity index of the voltage-current (V-I) characteristics was observed upon electrical degradation for the annealed and nonannealed samples. Upon increasing the amount of Sb2O3 added, the values of  increased after electrical degradation for the annealed samples. Moreover, the value of  after electrical degradation was proportional to the full width at half maximum (FWHM) of the X-ray diffraction peak for Zn2.33Sb0.67O4-type spinel particles under various annealing conditions. The added Sb2O3 did not dissolve in the ZnO grains but became segregated at grain boundaries. Therefore, it is speculated that the increase in the FWHM for the spinel particles is due to the increase in the numbers of fine spinel particles at grain boundaries and triple points.

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