Effects of Sintering Temperature on Microstructure and Properties in TiO2 Varistor Ceramics

2010 ◽  
Vol 105-106 ◽  
pp. 324-328 ◽  
Author(s):  
Ji Kang Yan ◽  
Guo You Gan ◽  
Jing Hong Du ◽  
Jia Lin Sun
Keyword(s):  
Dielectric Constant ◽  
Electrical Properties ◽  
Solid Solubility ◽  
Sintering Temperature ◽  
Relative Dielectric Constant ◽  
Chemical Compositions ◽  
Barrier Structure ◽  
Tio2 Sample ◽  
Linear Coefficient ◽  
Microstructure And Properties

The effects of sintering temperature on microstructure, micro-composition, barrier structure and electrical properties of TiO2 varistors ceramics were investigated. The microstructures and chemical compositions of grains in TiO2 ceramics were measured by SEM and EDS. Based on the thermo electronic emission theory, Grain boundaries barrier structure was calculated by analyzing electrical properties of samples. The sample sintered at 1350°C exhibits better microstructure and properties. The grains size of the TiO2 sample sintered at 1350°C is about 15m, and other electrical properties are as follows: solid solubility of donor doping Nb5+ cation solute in TiO2 grains of 1.49mol%, barriers height of 0.28ev, barriers width of 48nm, varistor voltages of 5.25V/mm, non-linear coefficient of 4.2 and relative dielectric constant of 1.1×104.

Sintering and Electrical Properties of Tungsten Doped Pb(Zr0.95Ti0.05)O3 Ferroelectric Ceramics

2011 ◽  
Vol 687 ◽  
pp. 380-384
Author(s):  
Jun Xia Wang ◽  
Xu Lan Zhen ◽  
Shi Yuan Yang ◽  
Jin Wang ◽  
Ke Tang
Keyword(s):  
Dielectric Constant ◽  
Electrical Properties ◽  
Sintering Temperature ◽  
Relative Dielectric Constant ◽  
Pulsed Power ◽  
Ferroelectric Ceramics ◽  
Ferroelectric Hysteresis Loop ◽  
Power Devices ◽  
Maximum Value ◽  
Ferroelectric Hysteresis

The effect of WO3 additions on the sintering ability and electrical properties of Pb(Zr0.95Ti0.05)O3 ferroelectric ceramics (PZT 95/5) was investigated. Pure and W-doped PZT 95/5 ceramics were prepared by the usual ceramic technique from raw oxides. The bulk density, microstructure, electrical properties of ceramics as a function of WO3 content were characterized. The results showed that the WO3 addition was benefit for the sintering densification of PZT, and the ceramics with 2.0 mol% WO3 addition exhibited the maximum value for the density (7.8 g/cm3) at a sintering temperature of 1250 °C. Moreover, piezoelectric constant (d33), relative dielectric constant (εr), dielectric loss (tanδ) and ferroelectric hysteresis loop of PZT 95/5 ceramics at the sintering temperature of 1250 °C all altered regularly with the change of WO3 doping level, whose optimum values were all obtained by doping 2.0 mol% WO3. The best values obtained for these parameters were: d33 = 65 pC/N, εr =314, tanδ = 0.028, Pr = 24.80 µC/cm2 and Ec = 1890 V/mm, respectively. These results show that tungsten doped Pb(Zr0.95Ti0.05)O3 ferroelectric ceramics can be hopefully used for the pulsed power devices.

Donor Solid Solubility and Microstructure of Nb-Doped TiO2 Ceramic Varistor

2012 ◽  
Vol 512-515 ◽  
pp. 1273-1276
Author(s):  
Rui Jiao Jia ◽  
Ji Kang Yan ◽  
Guo You Gan ◽  
Jing Hong Du ◽  
Jian Hong Yi
Keyword(s):  
Solid Solubility ◽  
Sintering Temperature ◽  
Chemical Compositions ◽  
Varistor Ceramic ◽  
Microstructure And Properties ◽  
Ceramic Varistor

In this paper, the effect of sintering temperature on microstructure and donor solid solubility of Nb-doped TiO2 varistor ceramic is investigated. SEM and EDXS were carried out to study the microstructure and chemical compositions of TiO2 grain. The results show that the TiO2 sample sintered at 1350°C have better microstructure and properties. The grains size of the TiO2 sample is about 15μm and solid solubility of donor Nb 5+ cation solute in TiO2 grains is 1.49mol%.

Effect Of Moisture On The Physical Properties Of Polyimide Films

1991 ◽  
Vol 227 ◽  
Author(s):  
Rajeevi Subramanian ◽  
Michael T. Pottiger ◽  
Jacqueline H. Morris ◽  
Joseph P. Curilla
Keyword(s):  
Dielectric Constant ◽  
Steady State ◽  
Electrical Properties ◽  
Relative Humidity ◽  
Quartz Crystal ◽  
Moisture Absorption ◽  
Relative Dielectric Constant ◽  
Moisture Uptake ◽  
Polyimide Films ◽  
Effect Of Moisture

ABSTRACTMoisture absorption and its effect on electrical properties were measured for several polyimides. A Quartz Crystal Microbalance (QCM) was used to investigate the moisture absorption in BPDA/PPD, PMDA/ODA, and BTDA//ODA/MPD polyimides. The steady-state moisture uptake in polyimides as a function of relative humidity (RH) was determined by exposing film samples to successively higher RH values ranging from 10 to 85% at 25°C. The isothermal moisture absorption as a function of percent RH was found to be nearly linear for all of the polyimides studied. The effect of moisture on the electrical properties of a BPDA/PPD polyimide was also investigated. The relative dielectric constant at 25 °C was found to be a linear function of the moisture absorbed.

Study on Microstructure and Properties of BTBY Piezoelectric Ceramics with High Curie Temperature

2010 ◽  
Vol 156-157 ◽  
pp. 1541-1544
Author(s):  
Bo Li ◽  
Feng Gao ◽  
Liang Liang Liu ◽  
Bei Xu
Keyword(s):  
Dielectric Constant ◽  
Grain Size ◽  
Electrical Properties ◽  
Dielectric Loss ◽  
Curie Temperature ◽  
Grain Morphology ◽  
High Curie Temperature ◽  
Microstructure And Properties ◽  
New Phase ◽  
Dielectric Relaxor

(1-x)(0.6BIT-0.4BT)-xBiYbO3(BTBY) ceramics with high Curie temperature were prepared by the conventional processing. The effect of BiYbO3 content on the microstructure and electrical properties was investigated. The results show that the main phase of BTBY ceramics is BIT-BT, and a new phase BaBi4Ti4O15 (BBT) appeared. The grain morphology of BTPY ceramics are platelike and the grain size was significantly increased with increasing content of BiYbO3 .Tc of all the BTBY samples are above 440 . The BTBY ceramics show obvious dielectric relaxor characteristic. The dispersion factor γ, the dielectric constant εr, and the dielectric loss tanδ decreased with increasing the content of BiYbO3. When the content of BiYbO3 is 0.06, the optimal properties of BTBY ceramics are obtained, Tc is 457 , εr is 165, tanδ is 0.0223 and d33 is 10 pC·N-1.

Electrical Properties of Modified BNT Based Lead-Free Ceramics

2016 ◽  
Vol 872 ◽  
pp. 87-91
Author(s):  
Supalak Manotham ◽  
Tawee Tunkasiri ◽  
Pharatree Jaita ◽  
Pichitchai Butnoi ◽  
Denis Russell Sweatman ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Solid State ◽  
Electrical Properties ◽  
Sintering Temperature ◽  
Ferroelectric Properties ◽  
Lead Free ◽  
Second Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lead Free Ceramics

The properties of modified Bi0.5Na0.5TiO3 (BNT) based lead-free ceramics were investigated. The BNT-based ceramics were prepared by a solid-state mixed oxide method Phase formation was determined by X-ray diffraction technique (XRD). The X-ray diffraction analysis of the ceramics suggested that all samples exhibited a perovskite structure without second phase. The value of dielectric constant increased with increasing in sintering temperature. Moreover, high sintering temperatures could improve ferroelectric properties of BNT base lead-free ceramics.

Nonlinear Electrical Properties of (Sc, Ta) Doped TiO2 Varistor Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 289-292 ◽  
Author(s):  
Wen Bin Su ◽  
Jin Feng Wang ◽  
Hong Cun Chen ◽  
Guo Zhong Zang ◽  
Peng Qi ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Electrical Properties ◽  
Crystal Lattice ◽  
Nonlinear Coefficient ◽  
Relative Dielectric Constant ◽  
Donor Concentration ◽  
Varistor Ceramic ◽  
Electrical Field ◽  
Schottky Type ◽  
Zno Varistors

The nonlinear electrical properties of TiO2-based varistor doped with 0.25mol% Ta2O5 and different contents of Sc2O3 were investigated. It was found that the TiO2 varistor ceramic doped with 0.10mol% Sc2O3 exhibited an optimal nonlinear coefficient of 7.8, a breakdown electrical field of 16.0V/mm, and relative dielectric constant of 1.27 × 105 (measured at 1 kHz). In order to analyze the effect of Sc2O3 on TiO2 varistors, studies were made on the capacitance versus voltage characteristics. A Schottky-type barrier, which is assumed as the origin of varistor behavior, was inferred from the C-V measurement. The barrier height and donor concentration were obtained as 0.41eV and 1.21 × 1026cm-3, respectively, for sample doped with 0.10mol% Sc2O3. Analogized to the ZnO varistors, the formation mechanism of Schottky-type barrier was discussed in this paper by the theory of defect in crystal lattice.

Synthesis of Pr6O11 Doped Zinc Varistors by High-Energy Milling

2010 ◽  
Vol 105-106 ◽  
pp. 314-316
Author(s):  
Guo Quan Qi ◽  
Jian Feng Zhu ◽  
Hai Bo Mao ◽  
Yang Wu ◽  
Hai Bo Yang ◽  
...  
Keyword(s):  
Grain Size ◽  
Electrical Properties ◽  
Milling Time ◽  
Sintering Temperature ◽  
Raw Materials ◽  
High Energy ◽  
Linear Coefficient ◽  
High Energy Milling ◽  
Zno Varistors ◽  
Doped Zno

High voltage zinc varistors was synthesized by high energy milling with Pr6O11 doped ZnO-Bi2O3 system as raw materials. The effects of milling time and sintering temperature on the electrical properties were investigated. The results show that high-energy milling decreases the sintering temperature of the ZnO varistors. The material derived from high-energy milling exhibit high density and good electrical properties at the sintering temperature from 1080 to 1180°C. The samples sintered at 1100 °C have average crystalline grain size of about 5 µm with the optimum values of electrical properties, gradient voltage V1mA is 371 V/mm, leakage current IL is 0.62 µA, non linear coefficient α is 60.

Effects of He/H2 Plasma Treatment on Properties of SiCOH Films Deposited with the 1,1,1,3,5,7,7,7- Octamethyl-3,5-Bis(Trimethylsiloxy) Tetrasiloxane Precursor

2020 ◽  
Vol 20 (11) ◽  
pp. 6706-6712
Author(s):  
Yoonsoo Park ◽  
Hyuna Lim ◽  
Sungyool Kwon ◽  
Younghyun Kim ◽  
Wonjin Ban ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Plasma Treatment ◽  
Inductively Coupled Plasma ◽  
Chemical Vapor ◽  
Relative Dielectric Constant ◽  
Chemical Compositions ◽  
Cage Structure ◽  
Inductively Coupled ◽  
Low Dielectric ◽  
Semiconductor Chips

Low-dielectric-constant SiCOH films fabricated using plasma enhanced chemical vapor deposition (PECVD) are widely used as inter-metallic dielectric (IMD) layers in interconnects of semiconductor chips. In this work, SiCOH films were deposited with 1,1,1,3,5,7,7,7-octamethyl-3,5-bis(trimethylsiloxy)tetrasiloxane (OMBTSTS), and plasma treatment was performed by an inductively coupled plasma (ICP) system with mixture of He and H2. The values of relative dielectric constant (k) of the as-deposited SiCOH films ranged from 2.64 to 4.19. The He/H2 plasma treatment led to a reduction of the k values of the SiCOH films from 2.64–4.19 to 2.07–3.94. To investigate the impacts of the He/H2 plasma treatment on the SiCOH films, the chemical compositions and structures of the as-deposited and treated the SiCOH films were compared by Fourier transform infrared spectroscopy. The experimental results indicate that the k value of the SiCOH films was decreased, there was a proportional increase in pore-related Si–O–Si structure, which is commonly called the cage structure with lager angle than 144°, after He/H2 plasma treatment. The He/H2 plasma treatment was considered to have reduced the k value by forming pores that could be represented by the cage structure. On the other hand, the leakage current density of the SiCOH films was slightly degraded by He/H2 plasma treatment, however, this was tolerable for IMD application. Concludingly the He/H2 plasma treated SiCOH film has the lowest relative dielectric constant (k~2.08) when the most highly hydrocarbon removal and cage structure formation increased.

Synthesis of Pr6O11 Doped ZnO-Based Varistors by Pyrogenic Decomposition of Nitrate

2011 ◽  
Vol 675-677 ◽  
pp. 179-182
Author(s):  
Jian Feng Zhu ◽  
Guo Quan Qi ◽  
Hai Bo Mao ◽  
Hai Bo Yang ◽  
Fen Wang
Keyword(s):  
Grain Size ◽  
Electrical Properties ◽  
Leakage Current ◽  
Sintering Temperature ◽  
Linear Coefficient ◽  
Average Grain Size ◽  
Non Linear ◽  
Different Temperatures ◽  
Zno Powders ◽  
Doped Zno

Pr6O11 doped ZnO-based varistor powders were prepared by a method of pyrogenic decomposition nitrate, which were together with ZnO powders, made into rounded mass and sintered at different temperatures. The effects of sintering temperatures on the composition, microstructure and electrical properties of Pr6O11 doped ZnO-based varistors were investigated. The results show that the optimum sintering temperature is at 1150 °C with 6 μm ZnO average grain size and the samples possess the advantageous electrical properties: varistor voltage of about 480 V/mm, non linear coefficient reaching 44 and leakage current of 0.7 μA.

Effect of TiO2 Nano Powder on the Microstructure and Electrical Properties of TiO2 Capacitor-Varistor Ceramics

2011 ◽  
Vol 341-342 ◽  
pp. 94-97
Author(s):  
Tian Guo Wang ◽  
Qun Qin ◽  
Wen Jun Zhang
Keyword(s):  
Dielectric Constant ◽  
Electrical Properties ◽  
Breakdown Voltage ◽  
Nonlinear Coefficient ◽  
Relative Dielectric Constant ◽  
Optimal Composition ◽  
Low Loss ◽  
Nano Powder

The influence of TiO2 nano powder on the electrical properties and microstructure of TiO2 ceramics was studied. The results showed that nano additive reduces the size of TiO2 grain. The results also showed that the breakdown voltage and nonlinear constant of the samples were improved and the dielectric constant was reduced by doping nano-titania. An optimal composition dopant with 6 mol% nano-titania exhibited a low breakdown voltage of 11.3 V/mm, a nonlinear coefficient of 5.5, an ultrahigh relative dielectric constant of 7.11×104 and relatively low loss of 0.28.

Sign in / Sign up

Export Citation Format

Share Document