High temperature potential/pH diagrams for the chlorine–water system

1985 ◽  
Vol 63 (4) ◽  
pp. 935-939 ◽  
Author(s):  
Barbara Kolodziej ◽  
Fathi Habashi
Keyword(s):  
High Temperature ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Water System ◽  
Temperature Potential ◽  
Lower Temperature ◽  
Hcl Concentration ◽  
Chlorine Water

Thermodynamic evidence supports the view that the reaction [Formula: see text] takes place above 127 °C at pH = 0. An increase in HCl concentration and/or oxygen partial pressure allow the reaction to proceed at lower temperature.

Characterization of YBa2Cu4O8 high temperature electrical properties and thermodynamic stability

1991 ◽  
Vol 6 (10) ◽  
pp. 2054-2058 ◽  
Author(s):  
B-S. Hong ◽  
T.O. Mason
Keyword(s):  
High Temperature ◽  
Electrical Property ◽  
Electrical Properties ◽  
Seebeck Coefficient ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Pressure Range ◽  
Stability Range

Via in situ electrical property measurements (conductivity, Seebeck coefficient) over the temperature range 500–800 °C and oxygen partial pressure range 10−4-1 atm, the equilibrium transport properties and stability range of YBa2Cu4O8 were determined. YBa2Cu4O8 behaves like the intrinsically mixed-valent compound, magnetite (Fe3O4), with small variations in electrical properties with changes in oxygen partial pressure. The decomposition boundary to YBa2Cu3O6+y (or YBa2Cu3.5O7.5±z) and CuO occurs at log(po2, atm) = −1.24 × 104/T(K) + 11.01(773 ⋚ T(K) ⋚ 1073).

High temperature X-ray diffraction studies of the decomposition mechanism of YBa2Cu3O7−δ at an oxygen partial pressure less than 10 Pa

1995 ◽  
Vol 10 (3) ◽  
pp. 165-169 ◽  
Author(s):  
W. Pitschke ◽  
W. Bieger ◽  
G. Krabbes ◽  
U. Wiesner
Keyword(s):  
High Temperature ◽  
Solid State ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Solid State Reaction ◽  
Peritectic Reaction ◽  
Decomposition Reaction ◽  
Primary Decomposition ◽  
X Ray Diffraction ◽  
X Ray

The crystallographic data of YBa2Cu3O7−δ, Y2BaCuO5, BaCu2O2, and YBa4Cu3O9 at high temperatures and p(O2)<10 Pa have been derived on the basis of HT-XRD measurements. Whereas Y2BaCuO5 expands nearly isotropically, YBa2Cu3O7−δ and BaCu2O2 show anisotropic expansions. Furthermore, the first decomposition step of the considered compounds at p(O2)<10 Pa was observed. BaCu2O2 melts congruently at T ≍ 1273 K and Y2BaCuO5 decomposes via a peritectic reaction into Y2O3, Y2BaO4 and melts at T ≍ 1323 K. A solid-state reaction into Y2BaCuO5 and BaCu2O2 was indicated for YBa2Cu3O7−δ at T ≍ 1123 K. Because YBa4Cu3O9 becomes unstable at T ≍ 1123 K, this compound cannot be formed by the primary decomposition reaction of YBa2Cu3O7−δ

“Migration of Sintered Nanosilver Die-attach Material on Alumina Substrate at High Temperatures”

2010 ◽  
Vol 2010 (HITEC) ◽  
pp. 000026-000031 ◽  
Author(s):  
Yunhui Mei ◽  
Dimeji Ibitayo ◽  
Xu Chen ◽  
Susan Luo ◽  
Guo-Quan Lu
Keyword(s):  
High Temperature ◽  
Electric Field ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
External Pressure ◽  
Alumina Substrate ◽  
Electrode Pair ◽  
Electrode Gap ◽  
Die Attach ◽  
Silver Dendrites

A nanoscale silver paste that can be sintered at temperatures below 300°C without external pressure is emerging as a promising die-attach material for implementing the low-temperature joining technology in high-temperature packaging. In this paper, we report our findings on silver migration in sintered nanosilver electrode-pair patterns on alumina substrate. The electrode pairs were biased at electric field ranging from 10 to 100 V/mm and at temperature between 250 °C and 400°C in dry air. Leakage currents across the electrodes were measured as the silver patterns were tested in an oven. Silver dendrites formed across the electrode gap were observed under an optical microscope and analyzed using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Silver migration was found in samples tested at 400°C, 350°C, and 300°C, and 250°C. The measurements on leakage current vs. time were characterized by an initial incubation period, called “lifetime”, followed by a sharp rise as silver dendrites were shorting the electrodes. A rapid rise in the “lifetime” with decreasing oxygen partial pressure was also found. A simple phenomenological model was derived to account for the observed dependence of “lifetime” on electric field, temperature, and oxygen partial pressure. The reliability of sintered nanosilver die-attachment over silver migration in high temperature applications can be significantly improved through packaging or encapsulation to reduce oxygen exposure.

COMPARISON OF MAGNETIC PROPERTY OF Cu-, Al-, AND Li-DOPED ZnO DILUTE MAGNETIC SEMICONDUCTOR THIN FILMS

2008 ◽  
Vol 15 (01n02) ◽  
pp. 81-85 ◽  
Author(s):  
L. H. VAN ◽  
J. DING ◽  
M. H. HONG ◽  
Z. C. FAN ◽  
L. WANG
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Magnetic Property ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Dilute Magnetic Semiconductor ◽  
Magnetic Semiconductor ◽  
Semiconductor Thin Films ◽  
Doped Zno ◽  
Lower Temperature

The properties of Cu -, Al -, and Li -doped ZnO dilute magnetic semiconductor (DMS) have been analyzed and compared. Zincite with wurtzite structures have been synthesized successfully on SiO 2 (101) and SiO 2 (110) substrates in both the Cu – ZnO and Li – ZnO DMS. The highly textured ZnO (002) peaks were able to form in the Cu – ZnO system at 400°C. However, it formed at even much lower temperature in the Li – ZnO system, that is only 25°C. ZnO (002) peaks in both systems were formed without any impurity phases. However, no crystalline structure is synthesized in the Al – ZnO system. The thin films formed are amorphous. The structural and related magnetic properties of the films were analyzed by XRD, AFM, and VSM. The films were found to be at their highest magnetism at the value of 3.1 emu/cm3 for Co – ZnO and 2.5 emu/cm3 for Li – ZnO , synthesized at 400°C, and under 1 × 10-4 Torr oxygen partial pressure.

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