scholarly journals Effect of Processing Conditions on the Flash Onset Temperature in Hydroxyapatite

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5229
Author(s):  
Changhun Hwang ◽  
Jondo Yun
Keyword(s):  
Grain Size ◽  
Electric Field ◽  
Color Change ◽  
Onset Temperature ◽  
Processing Conditions ◽  
Conduction Path ◽  
Flash Sintering ◽  
Vacuum Atmosphere ◽  
Lower Temperature ◽  
Short Time

When heat and electric field are applied to the sample, sintering takes place within a short time of a few seconds by the flash phenomenon that occurs. In what condition flash does occur is a main issue for the flash sintering technique. In this study, the effect of processing conditions such as sintering atmosphere, sample size, density and grain size on the flash onset of hydroxyapatite was investigated. In a vacuum atmosphere, a flash occurred at a lower temperature by 50–100 °C than in air. The smaller the thickness of the sample, the higher the flash onset temperature due to the larger specific surface area. Flash was also observed in samples which were presintered, having a density of 86–100% and a grain size of 0.2–0.9 μm. When the density and grain size of the sample were higher and larger, the flash onset temperature was higher. It was because the diffusion and conduction path through the grain boundary and the inner surface of the pores with high defect concentration are blocked with an increase of density or grain size. When an electric field was applied during flash sintering, a color change of the sample was observed and the reason was discussed.

scholarly journals Effects of Flash Sintering Parameters on Performance of Ceramic Insulator

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1157
Author(s):  
Yong Liu ◽  
Xingwang Huang
Keyword(s):  
Grain Size ◽  
Electric Field ◽  
Field Intensity ◽  
Current Density ◽  
Electric Field Intensity ◽  
Unit Cell ◽  
Uniform Structure ◽  
Ceramic Insulator ◽  
Flash Sintering ◽  
Ceramic Insulators

Ceramic outdoor insulators play an important role in electrical insulation and mechanical support because of good chemical and thermal stability, which have been widely used in power systems. However, the brittleness and surface discharge of ceramic material greatly limit the application of ceramic insulators. From the perspective of sintering technology, flash sintering technology is used to improve the performance of ceramic insulators. In this paper, the simulation model of producing the ceramic insulator by the flash sintering technology was set up. Material Studio was used to study the influence of electric field intensity and temperature on the alumina unit cell. COMSOL was used to study the influence of electric field intensity and current density on sintering speed, density and grain size. Obtained results showed that under high temperature and high voltage, the volume of the unit cell becomes smaller and the atoms are arranged more closely. The increase of current density can result in higher ceramic density and larger grain size. With the electric field intensity increasing, incubation time shows a decreasing tendency and energy consumption is reduced. Ceramic insulators with a higher uniform structure and a smaller grain size can show better dielectric performance and higher flashover voltage.

scholarly journals Grain Boundary Resistivity of Yttria-Stabilized Zirconia at 1400°C

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
J. Wang ◽  
A. Du ◽  
Di Yang ◽  
R. Raj ◽  
H. Conrad
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Electric Field ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Brick Layer Model ◽  
Dc Electric Field ◽  
Lower Temperature ◽  
Boundary Width ◽  
Grain Boundary Resistivity

The grain size dependence of the bulk resistivity of 3 mol% yttria-stabilized zirconia at 1400°C was determined from the effect of a dc electric field Ea=18.1 V/cm on grain growth and the corresponding electric current during isothermal annealing tests. Employing the brick layer model, the present annealing test results were in accordance with extrapolations of the values obtained at lower temperature employing impedance spectroscopy and 4-point-probe dc. The combined values give that the magnitude of the grain boundary resistivity ρb=133 ohm-cm. The electric field across the grain boundary width was 28–43 times the applied field for the grain size and current ranges in the present annealing test.

Kinetic analysis of the degradation and its color change of cyanidin-3-glucoside exposed to pulsed electric field

2006 ◽  
Vol 224 (5) ◽  
pp. 597-603 ◽  
Author(s):  
Yan Zhang ◽  
Xiaojun Liao ◽  
Yuanying Ni ◽  
Jihong Wu ◽  
Xiaosong Hu ◽  
...  
Keyword(s):  
Electric Field ◽  
Kinetic Analysis ◽  
Color Change ◽  
Pulsed Electric Field

Electric Field Distribution Analysis of ±1000kV DC Wall Bushing during Polarity Reversal

2012 ◽  
Vol 229-231 ◽  
pp. 807-810
Author(s):  
Li Zhang ◽  
Qing Min Li ◽  
Li Na Zhang ◽  
Yu Di Cong
Keyword(s):  
Electric Field ◽  
Field Distribution ◽  
Potential Distribution ◽  
Electric Field Distribution ◽  
Polarity Reversal ◽  
Distribution Analysis ◽  
The Finite Element Method ◽  
Insulation System ◽  
The Moment ◽  
Short Time

±1000kV DC wall bushing under planning is a complex insulation system which bears the effects imposed by different working conditions. The electric field distribution is concentrated at the bushing outlet terminal, which might result in breakdown discharge especially when short-time abrupt conditions such as polarity reversal occur. In this paper, the finite element method is utilized to analyze electric field distribution and potential distribution of wall bushing during polarity reversal. Electric field distribution and potential distribution at the moment of polarity reversal are obtained, which provides value reference for the study of polarity reversal process.

Electric field-assisted flash sintering of CaCu3Ti4O12: Microstructure characteristics and dielectric properties

2016 ◽  
Vol 682 ◽  
pp. 753-758 ◽  
Author(s):  
Lílian Menezes Jesus ◽  
Ronaldo Santos Silva ◽  
Rishi Raj ◽  
Jean-Claude M’Peko
Keyword(s):  
Dielectric Properties ◽  
Electric Field ◽  
Microstructure Characteristics ◽  
Flash Sintering

Ferroelectric domain-wall logic units

2021 ◽  
Author(s):  
Jing Wang ◽  
Jing Ma ◽  
Houbing Huang ◽  
Ji Ma ◽  
Hasnain Jafri ◽  
...  
Keyword(s):  
Domain Wall ◽  
Electric Field ◽  
Domain Walls ◽  
Logic Gates ◽  
Piezoresponse Force Microscopy ◽  
Ferroelectric Domain ◽  
Conduction Path ◽  
Conductive Atomic Force Microscopy ◽  
Flexible Control ◽  
Force Microscopy

Abstract The electronic conductivities of ferroelectric domain walls have been extensively explored over the past decade for potential nanoelectronic applications. However, the realization of logic devices based on ferroelectric domain walls requires reliable and flexible control of the domain-wall configuration and conduction path. Here, we demonstrate electric-field-controlled stable and repeatable on-and-off switching of conductive domain walls within topologically confined vertex domains naturally formed in self-assembled ferroelectric nano-islands. Using a combination of piezoresponse force microscopy, conductive atomic force microscopy, and phase-field simulations, we show that on-off switching is accomplished through reversible transformations between charged and neutral domain walls via electric-field-controlled domain-wall reconfiguration. By analogy to logic processing, we propose programmable logic gates (such as NOT, OR, AND and their derivatives) and logic circuits (such as fan-out) based on reconfigurable conductive domain walls. Our work provides a potentially viable platform for programmable all-electric logic based on a ferroelectric domain-wall network with low energy consumption.

Austenite in Steel

2015 ◽  
pp. 133-162
Keyword(s):  
Grain Size ◽  
Grain Growth ◽  
Hot Deformation ◽  
Parent Phase ◽  
Austenite Formation ◽  
Processing Conditions ◽  
Austenitic Grain Size

Austenite is the key to the versatility of steel and the controllable nature of its properties. It is the parent phase of pearlite, martensite, bainite, and ferrite. This chapter discusses the importance of austenite, beginning with the influence of austenitic grain size and how to accurately measure it. It then describes the principles of austenite formation and grain growth and examines several time-temperature-austenitizing diagrams representing various alloying and processing conditions. The chapter concludes with a discussion on hot deformation and subsequent recrystallization.

Sign in / Sign up

Export Citation Format

Share Document