Measurement and control of oxygen partial pressure at elevated temperatures

2013 ◽  
Vol 187 ◽  
pp. 503-508 ◽  
Author(s):  
Michal Schulz ◽  
Holger Fritze ◽  
Christian Stenzel
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Elevated Temperatures ◽  
And Control ◽  
Measurement And Control

Tensile Properties and Creep Behavior of SiC-Based Fibers under Various Oxygen Partial Pressures

2005 ◽  
Vol 475-479 ◽  
pp. 1333-1336 ◽  
Author(s):  
Jan Ji Sha ◽  
J.S. Park ◽  
Tatsuya Hinoki ◽  
Akira Kohyama ◽  
J. Yu
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Tensile Properties ◽  
Creep Behavior ◽  
Elevated Temperatures ◽  
Low Oxygen ◽  
X Ray Diffraction ◽  
Sic Fibers ◽  
Partial Pressures ◽  
Ar Gas

Three kinds of atmospheres (air, highly-pure Ar and ultra highly-pure Ar gas) with different oxygen partial pressures were applied to investigate the tensile properties and creep behavior of SiC fibers such as Hi-NicalonTM and TyrannoTM-SA. These fibers were annealed and crept at elevated temperatures ranging from1273-1773 K in such environments. After annealing at 1773 K, the room temperature tensile strengths of SiC-based fibers decreased with decreasing the oxygen partial pressure and the near stoichiometric fiber TyrannoTM-SA shows excellent strength retention. At temperatures above the 1573 K, the creep resistance of SiC fibers evaluated by bending stress relaxation (BSR) method under high oxygen partial pressure was lower than that of in low oxygen partial pressure. The microstructural features on these fibers were examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD).

Effect of Low Oxygen Partial Pressure on the Chromium Partition in CaO-MgO-SiO2-Cr2O3-Al2O3Synthetic Slag at Elevated Temperatures

2013 ◽  
Vol 84 (7) ◽  
pp. 670-679 ◽  
Author(s):  
Galina Albertsson ◽  
Lidong Teng ◽  
Bo Björkman ◽  
Seshadri Seetharaman ◽  
Fredrik Engström
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Elevated Temperatures ◽  
Low Oxygen

Space Shuttle Orbiter Oxygen Partial Pressure Sensing and Control System Improvements

1992 ◽  
Author(s):  
Robert F. Frampton ◽  
Dennis M. Hoy ◽  
Kevin J. Kelly ◽  
James J. Walleshauser
Keyword(s):  
Control System ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Space Shuttle ◽  
Pressure Sensing ◽  
And Control

Electrical Conductivity Prediction in Langasite for Optimized Microbalance Performance at Elevated Temperatures

2002 ◽  
Vol 756 ◽  
Author(s):  
Huankiat Seh ◽  
Harry Tuller ◽  
Holger Fritze
Keyword(s):  
Electrical Conductivity ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
High Temperatures ◽  
Gas Sensors ◽  
Elevated Temperatures ◽  
Operating Conditions ◽  
Total Conductivity ◽  
Defect Model ◽  
Partial Pressures

ABSTRACTThe performance of the langasite-based crystal microbalance is limited due to reductions in its resistivity at high temperatures and reduced oxygen partial pressures. In this work, we utilize a recently developed defect model to predict the dependence of the ionic and electronic contributions to the total conductivity of langasite on temperature, oxygen partial pressure and acceptor and donor dopants. These results are used to select the type and concentrations of dopants expected to provide extended operating conditions for langasite-based gas sensors and crystal microbalances.

scholarly journals The changes of Ba0.5Sr0.5Co0.8Fe0.2O3-δ perovskite oxide on heating in oxygen and carbon dioxide atmospheres

2014 ◽  
Vol 79 (9) ◽  
pp. 1141-1154 ◽  
Author(s):  
Sasa Zeljkovic ◽  
Toni Ivas ◽  
Sebastien Vaucher ◽  
Dijana Jelic ◽  
Ludwig Gauckler
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Elevated Temperatures ◽  
Oxygen Deficiency ◽  
Perovskite Oxide ◽  
X Ray ◽  
Equilibrium Reaction ◽  
Increasing Temperature

In the first part of this study, the oxygen deficiency, ?, in Ba0.5Sr0.5Co0.8Fe0.2O3 - ? (BSCF) was measured by means of thermogravimetry as a function of oxygen partial pressure, p(O2), in the range of 1.1?10?6 < p(O2)/% < 41.67 at elevated temperatures ranging 873 ? T/K ? 1073. It was shown that ? becomes more pronounced with increasing T and with decreasing p(O2). The isotherms ? vs. p(O2) were determined. The second part of this study relates to the reaction of CO2 with Ba0.5Sr0.5Co0.8Fe0.8O3-? perovskite oxide in the absence and presence of O2 at temperatures ranging from 673 to 973 K also by thermogravimetry. The reactivity of CO2 with BSCF increased with increasing temperature and increasing exposure to CO2. Reaction of CO2 with BSCF was described by a equilibrium reaction isotherms. The results of X-ray diffractometry evidenced that the exposure to CO2 leads to the formation of carbonates.

Cross Effect Between Ion and Electron Flows in Fe3–δO4

2002 ◽  
Vol 17 (5) ◽  
pp. 1213-1219 ◽  
Author(s):  
Jeong-Oh Hong ◽  
Han-Ill Yoo
Keyword(s):  
Electrical Conductivity ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Elevated Temperatures ◽  
Cross Effect ◽  
Fixed Temperature ◽  
Total Electrical Conductivity ◽  
A Value ◽  
Effective Valence ◽  
The Cross

The effective valence,of mobile cations (Fe2+, Fe3+) in semiconducting Fe3O4was determined at elevated temperatures via Tubandt-type electrotransport experiments in association with the literature data on the cation diffusivity and total electrical conductivity. It has been found that the value forvaries systematically from below 2 up to 3 with oxygen partial pressure at a fixed temperature. The effective valence is determined not only by the mobility difference of Fe2+and Fe3+ionsbut also by the cross effect between the cations and electrons upon their transfer. A value ofbetween 2 and 3 may be attributed to the mobility difference between Fe2+and Fe3+ions even in the absence of the cross effect, but the values of< 2 clearly indicate that the cross effect is in play in Fe3O4.

The Kinetics of Electromigration Damage in Copper Films Studied by Isothermal Resistance Change Analysis

1991 ◽  
Vol 225 ◽  
Author(s):  
C. W. Park ◽  
R. W. Vook
Keyword(s):  
Elevated Temperatures ◽  
Cathode Region ◽  
Vlsi Circuits ◽  
Scanning Electron Micrographs ◽  
Change Analysis ◽  
Resistance Change ◽  
Cu Films ◽  
Average Value ◽  
And Control ◽  
Measurement And Control

ABSTRACTElectromigration damage is one of the primary causes of the failure of interconnects in VLSI circuits. In this work, the response of Cu films to electromigration stress has been studied by an isothermal electrical resistance method. Accurate temperature measurement and control of Cu stripes stressed at elevated temperatures and high current densities were accomplished by use of a thin film thermistor. The activation energy and current density exponent were measured for vacuum evaporated Cu films and the values that were obtained are 0.79±0.02eV and 3.6±0.2, respectively. Scanning electron micrographs of stripes that underwent electromigration damage showed many voids in the cathode region, hillocks in the anode region, and both voids and hillocks in the rest of the stripe. The activation energies of two aluminum stripes were also measured by the same method. An average value of 0.54±0.02eV was obtained.

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