scholarly journals Densification Behavior, Microstructure, and Property of ZnO with Multi-Oxides Glass Addition at Different Sintering Temperatures

2020 ◽  
Author(s):  
Boen Houng ◽  
Wei-Chueh Chien ◽  
Chen-Kai Sun
Keyword(s):  
Dielectric Constant ◽  
Zinc Oxide ◽  
Sintering Temperature ◽  
Dielectric Constants ◽  
Densification Behavior ◽  
Sintering Aid ◽  
Glass Addition ◽  
Dense Microstructure ◽  
Different Temperatures ◽  
Lcr Meter

Zinc Oxide (ZnO) mixed with various amount of glasses were sintered at different temperatures. The densification behavior of zinc oxide with glass addition and its microstructure and dielectric constant sintered from 900° to 1200°C have been investigated. A unique glass composition contained GeO2, MoO3, and V2O5 (GMV) was designed to act as the sintering aid to enhance the densification and to adjust the dielectric constant of ZnO. The effect of sintering temperature on the densification behavior and dielectrics properties of ZnO was investigated by dilatometer, x-ray diffractometer, scanning electron microscopy and LCR meter.  The glass additive formed a thin continuous liquid phase and rearranged ZnO particles into a dense microstructure at relatively low temperature. The dielectric constants of glass added ZnO ceramics were found to vary with the glass concentration and sintering temperature.

Effect of Sintering Temperature on Dielectric Properties of CaCu3Ti4O12 Ceramics Prepared by Mechanochemical Process

2014 ◽  
Vol 974 ◽  
pp. 157-161
Author(s):  
Masturah Mohamed ◽  
Mahesh Talari ◽  
Mohd Salleh Mohd Deni ◽  
Azlan Zakaria
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Sintering Temperature ◽  
Processing Conditions ◽  
Dielectric Measurements ◽  
Frequency Range ◽  
Grain Sizes ◽  
Barrier Capacitance ◽  
Different Temperatures ◽  
Increasing Temperature

CaCu3Ti4O12(CCTO) is well known to have colossal dielectric constant in the range of 105.It is widely accepted that this phenomenon may be attributed to internal layer barrier capacitance (IBLC) model. The dielectric properties of CCTO were reported to be strongly dependent on the processing conditions and grain size. In this work, CCTO samples with different grain sizes were produced by varying sintering temperature in order to investigate IBLC effect on dielectric properties of CCTO. The samples were sintered at four different temperatures, (T=1100°C, 1050°C, 1000°C and 950°C). Dielectric measurements were carried out for the samples in the frequency range of 102– 106Hz using impedance spectrometer. Electron micrographs showed that increasing temperature promoted the grain growth of CCTO while sintering. The internal crystalline defects are seen to play major role by increasing the grain conductivity in dipole formation and increased the dielectric constant of the samples.

Sintering AlN Ceramics Below 1500°C with MgO-CaO-Al2O3-SiO2 Glass Addition

2007 ◽  
Vol 336-338 ◽  
pp. 1868-1871 ◽  
Author(s):  
Cheng Fu Yang ◽  
Chien Min Cheng ◽  
Ho Hua Chung ◽  
Chao Chin Chan
Keyword(s):  
Sintering Temperature ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Dielectric Characteristics ◽  
Sintering Aid ◽  
Glass Addition ◽  
X Ray ◽  
Crystal Phases ◽  
Diffraction Patterns ◽  
Scanning Electron

5~15 wt% MgO-CaO-Al2O3-SiO2 (MCAS, fabricated by sol-gel method) glass is used as the sintering aid of AlN ceramics. The sintering is proceeded from 1350oC~1550oC, scanning electron microscope is used to observe the sintered morphologies and X-ray diffraction pattern are used to confirm the crystal structures. From the SEM observations, as 10wt% and 15wt% MCAS is added, AlN ceramics can be densified at 1500oC and 1450oC, which are much lower than the before studies were. From the X-ray diffraction patterns, the crystal phases of MCAS-AlN ceramics are AlN, Al2O3, and cordierite phases. In this study, the dielectric characteristics of MCAS-AlN ceramics are also developed as a function of MCAS content and sintering temperature.

Effect of Y2O3 on the Sintering, Mechanical and Dielectric Properties of Mullite/h-BN Composites

2016 ◽  
Vol 848 ◽  
pp. 28-31
Author(s):  
Han Jin ◽  
Yong Feng Li ◽  
Zhong Qi Shi ◽  
Hong Yan Xia ◽  
Guan Jun Qiao
Keyword(s):  
Fracture Toughness ◽  
Dielectric Constant ◽  
Phase Composition ◽  
High Temperature ◽  
Dielectric Properties ◽  
Liquid Phase ◽  
Flexural Strength ◽  
Sintering Temperature ◽  
Pressureless Sintering ◽  
Different Temperatures

Mullite/10 wt. %h-BN composites with 5 wt. % Y2O3 additive were fabricated by pressureless sintering at different temperatures. The densification, phase composition, microstructure, mechanical and dielectric properties of the mullite/h-BN composites were investigated. With the addition of Y2O3, the sintering temperature of the mullite/h-BN composites declined, while the density, mechanical and dielectric properties all increased. The addition of Y2O3 promoted the formation of liquid phase at high temperature, which accelerated the densification. Besides, Y2O3 particles which were located at the grain boundaries inhibited the grain growth of mullite matrix. For the mullite/h-BN composites with Y2O3 additive, the appropriate sintering temperature was about 1600°C. The relative density, flexural strength, fracture toughness and dielectric constant of the Y2O3 doped mullite/h-BN composite sintered at 1600 °C reached 82%, 135 MPa, 2.3 MPa·m1/2 and 4.9, respectively.

EFFECTS OF V2O5 ADDITION ON MICROWAVE DIELECTRIC PROPERTIES OF 16CaO-9Li2O-12Sm2O3-63TiO2 CERAMICS

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1021-1027
Author(s):  
YONGJUN GU ◽  
JINLIANG HUANG ◽  
DAOMING SUN ◽  
QIAN LI ◽  
XIAO WANG ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Mixed Oxides ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Dielectric Constants ◽  
Sintering Aid ◽  
Microwave Dielectric

Effects of V 2 O 5 addition on the microwave dielectric properties of 16 CaO -9 Li 2 O -12 Sm 2 O 3-63 TiO 2 (abbreviated CLST) ceramics prepared by conventional mixed oxides method were investigated as a function of V 2 O 5 content and sintering temperature. All the specimens were sintered between 1100°C and 1250°C. The sintering temperature of the CLST ceramics was lowered by 100°C with V 2 O 5 addition. With the changing content of V 2 O 5, the dielectric constants lie between 88.6 and 108.2, while the Q × f values are between 3275 and 6573 GHz. Especially, the specimens doped by 0.75 wt% V 2 O 5 sintered at 1200°C and 1250°C for 3 h show good microwave dielectric properties with Kr =100.4-108.2, Q × f >4500 GHz , and TCF=7-8 ppm/°C. Obviously, V 2 O 5 could be used as a suitable sintering aid that could improve densification and microwave dielectric properties of the CLST ceramics.

scholarly journals On the direct determination of the electrostatic moments of molecules

1929 ◽  
Vol 124 (795) ◽  
pp. 689-698 ◽  
Keyword(s):  
Dielectric Constant ◽  
Direct Determination ◽  
Negative Temperature ◽  
Dielectric Constants ◽  
Temperature Coefficients ◽  
Different Temperatures

According to Faraday's ideas, the specific inductive capacity of a substance is due to the polarisation of the molecules as wholes. This is the basis of the old Clausius-Mosotti theory of dielectrics, on which it is shown first that the polarisation P is proportional to the polarising field, i. e. , P = k E, k being the dielectric constant, and second that δ being the density of the dielectric, k - 2/ k + 2 ·1/δ = constant. Now it is known that some substances have large negative temperature coefficients for their dielectric constants which cannot thus be accounted for. To provide for this Debye proposed the theory that the molecules were permanently polarised and that they were systematically orientated in the field. This leads to the equation k - 2/ k + 2 = a T -1 + b T -2 , to represent the change of specific inductive capacity with temperature. This theory has been developed by Gans and others, and a number of measurements have been made by Smyth and others, who have found the molecular moments of many substances by measuring the dielectric constants at different temperatures.

The Microwave Characteristics of Glass-Ba2Ti9O20 Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 262-264
Author(s):  
Hui Xing Lin ◽  
Xiang Yu Zhao ◽  
Ai Min Yang ◽  
Hua Xin Li ◽  
Wei Chen ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Crystalline Phases ◽  
Sintering Aid ◽  
Microwave Dielectric ◽  
Different Temperatures ◽  
Microwave Characteristics

In this study, 2BaO-3B2O3 (BB) glass was used as a sintering aid to lower the sintering temperature of Ba2Ti9O20 ceramics. Microwave Characteristics of the BB-added Ba2Ti9O20 ceramics sintered at different temperatures were investigated. The crystalline phases of BB-Ba2Ti9O20 ceramics are Ba2Ti9O20, BaTi(BO3)2 and TiO2. Good microwave dielectric properties (εr = 26, Q*f = 28770GHz and τf = 14.6ppm/oC) were obtained by sintering the BB-added Ba2Ti9O20 ceramics at 1040oC for 2 h.

Structural and Dielectric Properties of Zn1-xMoxO Nanoparticles

2020 ◽  
Vol 13 (2) ◽  
pp. 165-170
Keyword(s):  
Zinc Oxide ◽  
Dielectric Properties ◽  
Ac Conductivity ◽  
Hexagonal Wurtzite Structure ◽  
Dielectric Constants ◽  
Precipitation Method ◽  
Dielectric Parameters ◽  
Mo Doping ◽  
Lcr Meter ◽  
Co Precipitation

Abstract: In this work, samples of zinc oxide nanoparticles doped by molybdenum (Zn1-xMoxO with 0 ≤ x ≤ 0.1) were prepared by using the wet co-precipitation method. The characterization of the prepared samples was carried out by means of X-ray powder diffraction (XRD). The samples reserved their hexagonal wurtzite structure with Mo doping and showed a decrease in the crystallite size up to x = 0.04 followed by a further increase. On the other hand, dielectric measurements were performed using an LCR meter. The effect of frequency and temperature on the dielectric properties such as the real and imaginary parts of dielectric constant (ε^' and ε'', respectively), dielectric loss (tanδ) and ac-conductivity (σ_ac) of Mo-doped zinc oxide samples, was studied in the frequency range (100 Hz - 1 MHz) and at temperatures (300 - 773 K). The values of room temperature dielectric parameters were found to be strongly dependent on the Mo-doping. However, the increase in temperature caused an enhancement in the values of the dielectric parameters, particularly at 773 K. Keywords: Zinc oxide, XRD, Dielectric constants, Ac-conductivity.

scholarly journals Sintering Behaviors, Microstructure, and Microwave Dielectric Properties of CaTiO3–LaAlO3 Ceramics Using CuO/B2O3 Additions

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4187 ◽  
Author(s):  
Min-Hang Weng ◽  
Chihng-Tsung Liauh ◽  
Shueei-Muh Lin ◽  
Hung-Hsiang Wang ◽  
Ru-Yuan Yang
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Liquid Phase ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Liquid Phase Sintering ◽  
Sintering Aids ◽  
Sintering Aid ◽  
Microwave Dielectric ◽  
Quality Factor Q

The effect of CuO/B2O3 additions on the sintering behaviors, microstructures, and microwave dielectric properties of 0.95LaAlO3–0.05CaTiO3 ceramics is investigated. It is found that the sintering temperatures are lowered efficiently from 1600 °C to 1350 °C, as 1 wt % CuO, 1 wt % B2O3, and 0.5 wt % CuO +0.5 wt % B2O3 are used as the sintering aids due to the appearance of the liquid phase sintering. The microwave dielectric properties of 0.95LaAlO3–0.05CaTiO3 ceramics with the sintering aid additions are strongly related to the densification and the microstructure of the sintered ceramics. At the sintering temperature of 1300 °C, the 0.95LaAlO3–0.05CaTiO3 ceramic with 0.5 wt % CuO + 0.5 wt % B2O3 addition shows the best dielectric properties, including a dielectric constant (εr) of 21, approximate quality factor (Q × f) of 22,500 GHz, and a temperature coefficient of the resonant frequency (τf) of −3 ppm/°C.

Preparation of SiNOf/BN High Temperature Wave-Transparent Composites by Precursor Infiltration and Pyrolysis Method

2012 ◽  
Vol 508 ◽  
pp. 11-16 ◽  
Author(s):  
Feng Cao ◽  
Zhen Yu Fang ◽  
Fei Chen ◽  
Chang Rui Zhang ◽  
Qiang Shen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Pyrolysis Temperature ◽  
Temperature Wave ◽  
Densification Behavior ◽  
Pyrolysis Method ◽  
Dielectric Loss Angle ◽  
Different Temperatures ◽  
Transparent Composites

Sino Fibers Reinforced BN Wave-Transparent Composites (SiNOf/BN) Were Fabricated through Precursor Infiltration and Pyrolysis (PIP) Method Using Borazine as Precursor. The Effect of Pyrolysis Temperature on the Densification Behavior, Microstructures, Mechanical Properties and Dielectric Properties of the Composites Was Investigated. The Results Suggest that with the Increase of the Pyrolysis Temperature from 800 °C to 1000 °C, the Density, Mechanical Properties and Dielectric Constant of the Composites Are Increased, but the Infiltration Efficiency Varies Little. At the Pyrolysis Temperature of 1000 °C, the Density of SiNOf/BN Composites is 1.84 g∙cm-3 and the Flexural Strength and Elastic Modulus Are 148.2 MPa and 26.2 GPa Respectively. The Dielectric Properties, Including Dielectric Constant of 3-4 and Dielectric Loss Angle Tangent of below 7×10-3, Obtained at Three Different Temperatures Are Excellent for the SiNOf/BN Composites Applied as Wave-Transparent Materials.

Electrical Properties of Hot Press Sintered NASICON Ceramics

2007 ◽  
Vol 334-335 ◽  
pp. 149-152 ◽  
Author(s):  
Dong Mei Zhu ◽  
Zhang Long Xie ◽  
Fa Luo ◽  
Wan Cheng Zhou
Keyword(s):  
Ionic Conductivity ◽  
Electrical Properties ◽  
Crystal Size ◽  
Sintering Temperature ◽  
Dielectric Constants ◽  
Hot Press ◽  
Frequency Increase ◽  
Different Temperatures ◽  
Higher Temperature ◽  
Hot Press Process

Sodium superionic conductor, NASICON ceramic (Na1+xZr2SixP3-xO12, x=2), was hot-press sintered under different temperatures and the electrical properties of the obtained different samples were investigated. Results show that the relative density of the ceramics can be improved by hot-press process efficiently and the crystal size of the samples are closely related to sintering temperature. With the increase of sintering temperature, both the density and the crystal size of samples increase obviously, resulting in the increase of ionic conductivity of samples as the sintering temperature. When the sintering temperature reaches 1150oC, the ionic conductivity of sample is as high is 3.6×10-3S/cm, which is obviously higher than that of sample sintered at 1000oC (2.13×10-3S/cm). As the frequency increase, the real parts and the imaginary parts of complex dielectric constants for all the samples decrease in 8.2 GHz~12.4GHz frequency band. The ceramics obtained at the higher temperature possess the higher dielectric constant.

Sign in / Sign up

Export Citation Format

Share Document