Improvement of Grain-Boundary Conduction in 15 mol % Calcia-Stabilized Zirconia by Postsintering Heat-Treatment

2003 ◽  
Vol 150 (10) ◽  
pp. J49 ◽  
Author(s):  
Young-Soo Jung ◽  
Jong-Heun Lee ◽  
Je-Hun Lee ◽  
Doh-Yeon Kim
Keyword(s):  
Heat Treatment ◽  
Grain Boundary ◽  
Stabilized Zirconia ◽  
Boundary Conduction

The influence of alumina addition and its distribution upon grain-boundary conduction in 15 mol.% calcia-stabilized zirconia

2001 ◽  
Vol 27 (3) ◽  
pp. 269-276 ◽  
Author(s):  
Jong-Heun Lee ◽  
Toshiyuki Mori ◽  
Ji-Guang Li ◽  
Takayasu Ikegami ◽  
Satoshi Takenouchi
Keyword(s):  
Grain Boundary ◽  
Stabilized Zirconia ◽  
Alumina Addition ◽  
Boundary Conduction

Precursor scavenging of the resistive grain-boundary phase in 8 mol% yttria-stabilized zirconia: Effect of trace concentrations of SiO2

2001 ◽  
Vol 16 (8) ◽  
pp. 2377-2383 ◽  
Author(s):  
Jong-Heun Lee ◽  
Toshiyuki Mori ◽  
Ji-Guang Li ◽  
Takayasu Ikegami ◽  
John Drennan ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Yttria Stabilized Zirconia ◽  
Impurity Level ◽  
Boundary Phase ◽  
Inhomogeneous Distribution ◽  
Stabilized Zirconia ◽  
Boundary Area ◽  
Average Grain Size ◽  
Trace Concentrations ◽  
Boundary Conduction

The influence that trace concentrations of SiO2have on improving grain-boundary conduction via precursor scavenging using additional heat treatment at 1200 °C for 40 h before sintering was investigated. At a SiO2-impurity level (SIL) ≤160 ppm by weight, the grain-boundary resistivity (ρgb) decreased to 20% of its value, while no improvement in grain-boundary conduction was found at a SIL ≥ 310 ppm. The correlation between the resistance per unit grain-boundary area, rgb, and average grain size indicated that the inhomogeneous distribution of the siliceous phase in the sample with a SIL ≥ 310 ppm hampered the scavenging reaction.

Improvement of grain-boundary conduction in gadolinia-doped ceria via post-sintering heat treatment

2006 ◽  
Vol 177 (19-25) ◽  
pp. 2125-2128 ◽  
Author(s):  
D KIM ◽  
P CHO ◽  
J LEE ◽  
D KIM ◽  
S LEE
Keyword(s):  
Heat Treatment ◽  
Grain Boundary ◽  
Doped Ceria ◽  
Boundary Conduction

Strain-induced martensite effects on transgranular carbide precipitation in type 304 stainless steels

1991 ◽  
Vol 49 ◽  
pp. 604-605
Author(s):  
A.H. Advani ◽  
L.E. Murr ◽  
D. Matlock
Keyword(s):  
Heat Treatment ◽  
Grain Boundary ◽  
Stress Corrosion Cracking ◽  
Stainless Steels ◽  
Deformation Twin ◽  
Austenitic Stainless Steels ◽  
Carbide Precipitation ◽  
Strain Induced Martensite ◽  
Type 304

Thermomechanically induced strain is a key variable producing accelerated carbide precipitation, sensitization and stress corrosion cracking in austenitic stainless steels (SS). Recent work has indicated that higher levels of strain (above 20%) also produce transgranular (TG) carbide precipitation and corrosion simultaneous with the grain boundary phenomenon in 316 SS. Transgranular precipitates were noted to form primarily on deformation twin-fault planes and their intersections in 316 SS.Briant has indicated that TG precipitation in 316 SS is significantly different from 304 SS due to the formation of strain-induced martensite on 304 SS, though an understanding of the role of martensite on the process has not been developed. This study is concerned with evaluating the effects of strain and strain-induced martensite on TG carbide precipitation in 304 SS. The study was performed on samples of a 0.051%C-304 SS deformed to 33% followed by heat treatment at 670°C for 1 h.

Effect of thermal annealing on grain boundary chemistry of polycrystalline TiBa2Ca2Cu3Oy films

1994 ◽  
Vol 52 ◽  
pp. 968-969
Author(s):  
Z. L. Wang ◽  
C. L. Briant ◽  
J. DeLuca ◽  
A. Goyal ◽  
D. M. Kroeger ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Weak Link ◽  
Zero Field ◽  
Stabilized Zirconia ◽  
Local Texture ◽  
Transmission Electron ◽  
Axis Alignment ◽  
Boundary Chemistry ◽  
Small Misorientation ◽  
Misorientation Angles

Recent studies have shown that spray-pyrolyzed films of the Tl-1223 compound (TlxBa2Ca2Cu3Oy, with 0.7 < × < 0.95) on polycrystalline yttrium stabilized zirconia substrates can be prepared which have critical current density Jc near 105 A/cm2 at 77 K, in zero field. The films are polycrystalline, have excellent c-axis alignment, and show little evidence of weak-link behavior. Transmission electron microscopy (TEM) studies have shown that most grain boundaries have small misorientation angles. It has been found that the films have a nigh degree of local texture indicative of colonies of similarly oriented grains. It is believed that inter-colony conduction is enhanced by a percolative network of small angle boundaries at colony interfaces. It has also been found that Jc is increased by a factor of 4 - 5 after the films were annealed at 600 °C in oxygen. This study is thus carried out to determine the effect on grain boundary chemistry of the heat treatment.

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