scholarly journals Manipulating the grain boundary properties of BaCeO3-based ceramic materials through sintering additives introduction

2019 ◽  
Vol 6 (2) ◽  
pp. 38-45 ◽  
Author(s):  
G. K. Vdovin ◽  
◽  
A. O. Rudenko ◽  
B. D. Antonov ◽  
V. B. Malkov ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Ceramic Materials ◽  
Sintering Additives ◽  
Boundary Properties

Oxide Nonlinear Conductors: A Review

1990 ◽  
Vol 195 ◽  
Author(s):  
Lionel M. Levinson ◽  
Herbert R. Philipp
Keyword(s):  
Grain Boundary ◽  
Ceramic Materials ◽  
Electrical Behavior ◽  
Widespread Application ◽  
Variable Resistor ◽  
Current Voltage ◽  
Boundary Properties ◽  
Order Of Magnitude ◽  
Zno Varistors ◽  
Current Voltage Relationship

ABSTRACTOxide nonlinear conductors are granular electronic ceramic materials whose electrical behavior is dominated by grain boundary interfaces states. The material is typically comprised of relatively conducting oxide grains with electrical barriers at the grain boundaries induced by segregated impurity ions. Oxide nonlinear conductors can exhibit a highlynonlinear current-voltage relationship with a 5% change in voltage serving to increase the current flow an order of magnitude or more.This review outlines our understanding of the microstructure, grain boundary properties and electrical behavior of these variable resistor or “varistor” granular materials. ZnO varistors currently have widespread application in protecting power and signal level electrical circuits against dangerous voltage surges and a brief overview will be given of the applications of this material.

Examination of Fracture Interfaces in Silicon Nitride

1975 ◽  
Vol 33 ◽  
pp. 60-61
Author(s):  
Nancy J. Tighe
Keyword(s):  
Silicon Nitride ◽  
Grain Boundary ◽  
Crack Growth ◽  
Subcritical Crack Growth ◽  
Slow Crack Growth ◽  
Ceramic Materials ◽  
Grain Boundary Sliding ◽  
Boundary Phase ◽  
Turbine Engines ◽  
Boundary Sliding

Silicon nitride is one of the ceramic materials being considered for the components in gas turbine engines which will be exposed to temperatures of 1000 to 1400°C. Test specimens from hot-pressed billets exhibit flexural strengths of approximately 50 MN/m2 at 1000°C. However, the strength degrades rapidly to less than 20 MN/m2 at 1400°C. The strength degradition is attributed to subcritical crack growth phenomena evidenced by a stress rate dependence of the flexural strength and the stress intensity factor. This phenomena is termed slow crack growth and is associated with the onset of plastic deformation at the crack tip. Lange attributed the subcritical crack growth tb a glassy silicate grain boundary phase which decreased in viscosity with increased temperature and permitted a form of grain boundary sliding to occur.

Sintering and Grain Boundary Properties of ZnO-Bi2O3-Sb2O3-Mn3O4-NiO Varistors

2013 ◽  
Vol 51 (5) ◽  
pp. 363-369
Author(s):  
Youn-Woo Hong ◽  
Young-Jin Lee ◽  
Sei-Ki Kim ◽  
Jin-Ho Kim
Keyword(s):  
Grain Boundary ◽  
Boundary Properties

Light Effects on Grain Boundary Properties in Silicon

1981 ◽  
Vol 5 ◽  
Author(s):  
L. J. Cheng ◽  
C. M. Shyu
Keyword(s):  
Experimental Data ◽  
Grain Boundary ◽  
Minority Carrier ◽  
State Density ◽  
Boundary State ◽  
Carrier Recombination ◽  
Boundary Properties ◽  
Light Effects ◽  
Recombination Velocity ◽  
P Type

ABSTRACTWe have studied the photoconductivity of grain boundaries in p–type silicon. The result demonstrates the applicability of the technique for the measurement of minority carrier recombination velocity at the grain boundary. The experimental data are consistent with the thought that the recombination velocity increases with the boundary state density and light intensity.

scholarly journals Micromagnetic simulation of the orientation dependence of grain boundary properties on the coercivity of Nd-Fe-B sintered magnets

AIP Advances ◽  
2016 ◽  
Vol 6 (5) ◽  
pp. 056028 ◽  
Author(s):  
Jun Fujisaki ◽  
Atsushi Furuya ◽  
Yuji Uehara ◽  
Koichi Shimizu ◽  
Tadashi Ataka ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Orientation Dependence ◽  
Micromagnetic Simulation ◽  
Sintered Magnets ◽  
Boundary Properties

Effect of rare-earth species on the wear properties of α sialon and β silicon nitride ceramics under tribochemical type conditions

2004 ◽  
Vol 19 (9) ◽  
pp. 2750-2758 ◽  
Author(s):  
Mark I. Jones ◽  
Kiyoshi Hirao ◽  
Hideki Hyuga ◽  
Yukihiko Yamauchi
Keyword(s):  
Rare Earth ◽  
Grain Boundary ◽  
Wear Behavior ◽  
Rare Earth Oxide ◽  
Lower Amount ◽  
Boundary Phase ◽  
Wear Properties ◽  
Sintering Additives ◽  
Nitride Ceramics ◽  
Worn Surfaces

The wear properties under low loads of β Si3N4 and α sialon materials sintered with different rare-earth oxide sintering additives have been studied under dry sliding conditions using block-on-ring wear tests. All the worn surfaces showed an absence of fracture and smooth surfaces with the presence of an oxygen-rich filmlike debris indicating tribochemically induced oxidation of the surfaces. Extensive grain boundary removal was observed on the worn surfaces thought to be due to adhesion between this silicate phase and the tribochemically oxidized surfaces. The resistance to such oxidation and the properties of the residual grain boundary phase are thought to be important parameters affecting the wear behavior under the present testing conditions. For both the β Si3N4 and α sialon materials, there was an increase in wear resistance with decreasing cationic radius of the rare earth, thought to be due to improved oxidation resistance, and this was more remarkable in the case of the sialon materials where the incorporation of the sintering additives into the Si3N4 structure results in a lower amount of residual boundary phase.

Reversed anisotropy of grain boundary properties and its effect on grain boundary engineering

2010 ◽  
Vol 58 (6) ◽  
pp. 1930-1937 ◽  
Author(s):  
Pavel Lejček ◽  
Aleš Jäger ◽  
Viera Gärtnerová
Keyword(s):  
Grain Boundary ◽  
Grain Boundary Engineering ◽  
Boundary Properties
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