Formation of Protective Cr2O3 Scale at High Temperature and the Effect of Mass Transport in the Presence of Water Vapor

2011 ◽  
Vol 402 ◽  
pp. 412-420 ◽  
Author(s):  
Hanafi Ani Mohd ◽  
Raihan Othman
Keyword(s):  
Water Vapor ◽  
High Temperature ◽  
Mass Transport ◽  
Oxidation Rate ◽  
Oxygen Permeability ◽  
Critical Concentration ◽  
Alloy Oxidation ◽  
Permeability Increase ◽  
Cr Concentration ◽  
Wagner’S Theory

The formation of protective Cr2O3scale at high temperature was evaluated using Wagner’s theory of binary alloy oxidation. The results show that at 1073 K, around 9.8 wt% of Cr is required to form external Cr2O3scale, and 3.5wt% of Cr is needed to maintain the scale. Introduction of water vapor has shifted the critical Cr concentration to higher value. The effects of water vapor in increasing Cr critical concentration to form external Cr2O3scale was disscussed from view of oxygen permeablility and Cr diffusivity in the alloy. It is concluded that Cr diffusivity has negligible effect, while oxygen permeability increase with the presence of water vapor, thus increase the oxidation rate.

scholarly journals Corrosion of indium doped E-AlMgSi aluminum conductor alloy (Aldrey)

2021 ◽  
Vol 7 (1) ◽  
pp. 21-30
Author(s):  
Izatullo N. Ganiev ◽  
Firdavs A. Aliev ◽  
Haydar O. Odinazoda ◽  
Ahror M. Safarov ◽  
Rakhmazhon Usmonov
Keyword(s):  
Electrical Conductivity ◽  
High Temperature ◽  
Oxidation Rate ◽  
Copper Wire ◽  
Electrochemical Corrosion ◽  
Aluminum Wire ◽  
Temperature Oxidation ◽  
Alloy Oxidation ◽  
Temperature Exposure ◽  
Almgsi Alloy

The effect of impurities on the electrical conductivity of aluminum has been studied in detail. The electrical conductivity of aluminum is 65.45% of that of copper. The tensile strength of aluminum wire is 150–170 MPa which, at equal conductivity, is about 65% of the strength of copper wire. This strength of aluminum wire is sufficient for bearing the wire’s own weight but may be too low in case of snow, ice or wind overloads. One way to improve the strength of aluminum wire is to use aluminum alloys having higher strength combined with sufficiently high electrical conductivity, e.g. the E-AlMgSi alloy (Aldrey). The key strengthening agent of the E-AlMgSi alloy (Aldrey) is the Mg2Si phase which imparts high mechanical strength to aluminum. In this work we present experimental data on the kinetics of high-temperature oxidation and electrochemical corrosion of indium doped E-AlMgSi aluminum conductor alloy (Aldrey). Thermal gravimetric study has shown that indium doping and high temperature exposure increase the oxidation rate of E-AlMgSi alloy (Aldrey), with the apparent alloy oxidation activation energy decreasing from 120.5 to 91.8 kJ/mole. Alloy oxidation rate data determined using a potentiostatic technique in NaCl electrolyte media have shown that the corrosion resistance of the indium doped alloy is 20–30% superior to that of the initial alloy. With an increase in NaCl electrolyte concentration the electrochemical potentials of the alloys decrease whereas the corrosion rate increases regardless of alloy composition.

Effect of Water Vapor on the High-Temperature Oxidation of Pure Ni

2012 ◽  
Vol 78 (1-2) ◽  
pp. 51-61 ◽  
Author(s):  
M. Auchi ◽  
S. Hayashi ◽  
K. Toyota ◽  
S. Ukai
Keyword(s):  
Water Vapor ◽  
High Temperature ◽  
High Temperature Oxidation ◽  
Temperature Oxidation ◽  
Effect Of Water

Effect of Rare Earth on High Temperature Properties of Heat-Resisting Steel

2012 ◽  
Vol 557-559 ◽  
pp. 108-111
Author(s):  
Xiao Liu ◽  
Hu Fei Zhang
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Rare Earth ◽  
High Temperature ◽  
Oxidation Resistance ◽  
Cleavage Fracture ◽  
Oxidation Rate ◽  
High Temperature Mechanical Properties ◽  
Dimple Fracture ◽  
Reduction Of Area

The oxidation resistance and high temperature mechanical properties of FeCrNi heat-resisting steel are analyzed and studied. The results show that the oxidation resistance of the heat-resisting steel is improved remarkably after adding RE. The value of oxidation rate of Sample 1 (without adding RE) is 1.71 times higher than Sample 2, respectively at 1423K. And the value of oxidation rate of Sample 1 is 1.4 times higher than Sample 2, respectively at 1473K. The fracture mode of heat-resisting stainless steel is typical cleavage fracture, but dimple fracture after adding RE into the steel. The high temperature mechanical properties of heat-resisting steel is improved obviously by RE. In comparison with heat-resisting stainless steel without RE, the reduction of area of heat-resisting stainless steel with RE is increased 26.27% at 1123K.

In situ regeneration of commercial NH3-SCR catalysts with high-temperature water vapor

2018 ◽  
Vol 116 ◽  
pp. 57-61 ◽  
Author(s):  
Yao Shi ◽  
Pei Zhang ◽  
Tuotuo Fang ◽  
Erhao Gao ◽  
Fujuan Xi ◽  
...  
Keyword(s):  
Water Vapor ◽  
High Temperature ◽  
Nh3 Scr ◽  
High Temperature Water ◽  
In Situ Regeneration ◽  
Scr Catalysts ◽  
Temperature Water

Water Vapor–Mediated Volatilization of High-Temperature Materials

2013 ◽  
Vol 43 (1) ◽  
pp. 559-588 ◽  
Author(s):  
Peter J. Meschter ◽  
Elizabeth J. Opila ◽  
Nathan S. Jacobson
Keyword(s):  
Water Vapor ◽  
High Temperature ◽  
High Temperature Materials

scholarly journals BEHAVIOR OF CARBON AND URANIUM AT RADIOACTIVE GRAPHITE HEATING IN WATER VAPOR. THERMODYNAMIC MODELING

2018 ◽  
Vol 59 (9) ◽  
pp. 16 ◽  
Author(s):  
Nikolaiy M. Barbin ◽  
Anton M. Kobelev ◽  
Dmiriy I. Terent’ev ◽  
Sergeiy G. Alexeev
Keyword(s):  
Water Vapor ◽  
High Temperature ◽  
Thermodynamic Modeling ◽  
Radioactive Carbon ◽  
Radioactive Graphite

The behavior of radioactive graphite was studied by the method of thermodynamic modeling at high temperature in water vapor. The distribution of radioactive carbon and uranium on phase states is given.

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