High Temperature Corrosion of Spray-Atomized FeAl (40at.%) Based Alloys:Immersed in a Molten Salt Mixture of V2O5-Na2SO4

1998 ◽  
Vol 552 ◽  
Author(s):  
M. Amaya ◽  
E. J. Lavernia ◽  
L. Martinez
Keyword(s):  
Weight Loss ◽  
High Temperature ◽  
Molten Salt ◽  
Passive Layer ◽  
High Temperature Corrosion ◽  
Electrochemical Technique ◽  
Salt Mixture ◽  
Protective Oxide ◽  
Metal Base ◽  
Temperature Range

ABSTRACTWe studied the high temperature corrosion of spray atomized and deposited FeAl40at% based intermetallic alloys immersed in a molten salt mixture of 80%V2O 5+20%Na2SO4 (wt%) over the temperature range of 600–900°C. Experiments were realized by the weight loss method and the potentiodynamic polarization electrochemical technique in three different samples: FeA140at%, FeA140+0.lat%B and FeA140+0.lat%B+10at%A12O3. Measurements of weight loss and corrosion current density as a function of the molten salts temperature were obtained and discussed in terms of the passive layer morphology and corrosion products formed during the tests. It was found that the iron aluminide doped with boron and reinforced with alumina particulate was more corrosion resistant in the test temperature range. The weight loss experiments revealed that at 700°C all alloys developed maximum corrosion rate. This behavior was related with the dissolution of protective oxide layer on metal base due the formation of vanadate phases which are highly corrosive at this temperature.

scholarly journals Exploring the Effect of Silicon on the High Temperature Corrosion of Lean FeCrAl Alloys in Humid Air

2021 ◽  
Author(s):  
T. Sand ◽  
A. Edgren ◽  
C. Geers ◽  
V. Asokan ◽  
J. Eklund ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Oxidation Behavior ◽  
High Temperature Corrosion ◽  
The Other ◽  
Oxide Scales ◽  
Protective Oxide ◽  
New Approach ◽  
Fecral Alloys ◽  
Cr Evaporation

AbstractA new approach to reduce the chromium and aluminium concentrations in FeCrAl alloys without significantly impairing corrosion resistance is to alloy with 1–2 wt.% silicon. This paper investigates the “silicon effect” on oxidation by comparing the oxidation behavior and scale microstructure of two FeCrAl alloys, one alloyed with silicon and the other not, in dry and wet air at 600 °C and 800 °C. Both alloys formed thin protective oxide scales and the Cr-evaporation rates were small. In wet air at 800 °C the Si-alloyed FeCrAl formed an oxide scale containing mullite and tridymite together with α- and γ-alumina. It is suggested that the reported improvement of the corrosion resistance of Al- and Cr-lean FeCrAl’s by silicon alloying is caused by the appearance of Si-rich phases in the scale.

Electrochemical Studies on High-Temperature Corrosion of Silicon-Iron Coatings and Iron Aluminide Intermetallic Alloys by Molten Salts

CORROSION ◽  
2001 ◽  
Vol 57 (6) ◽  
pp. 489-496 ◽  
Author(s):  
M. Amaya ◽  
J. Porcayo-Calderon ◽  
L. Martinez
Keyword(s):  
High Temperature ◽  
Molten Salt ◽  
Electric Power ◽  
Molten Salts ◽  
Corrosion Current ◽  
High Temperature Corrosion ◽  
Iron Aluminide ◽  
Fuel Oil ◽  
Silicon Iron ◽  
Salt Corrosion

Abstract The performance of Fe-Si coatings and an iron aluminide (FeAl) intermetallic alloy (FeAl40at%+0.1at%B+10vol%Al2O3) in molten salts containing vanadium pentoxide (V2O5) and sodium sulfate (Na2SO4) is reported. Corrosion and fouling by ash deposits containing V2O5 and Na2SO4 are typical corrosion problems in fuel oil-fired electric power units. High-temperature corrosion tests were performed using both electrochemical polarization and immersion techniques. The temperature interval of this study was 600°C to 900°C, and the molten salts were 80wt%V2O5-20wt%Na2SO4. Curves of corrosion current density vs temperature obtained by the potentiodynamic studies are reported, as well as the weight loss vs temperature curves from molten salt immersion tests. Both Fe-Si coatings and FeAl40at%+0.1at%B+10vol%Al2O3 showed good behavior against molten salt corrosion. The final results show the potential of these coatings and alloys to solve the high-temperature corrosion in fuel oil-fired electric power units.

HIGH TEMPERATURE CORROSION OF THIN SHEET STEEL 08KP IN AIR

2021 ◽  
Vol 11 (2) ◽  
pp. 48-55
Author(s):  
Nikolay M. BOCHAROV
Keyword(s):  
Thermal Analysis ◽  
High Temperature ◽  
Elevated Temperatures ◽  
Sheet Steel ◽  
Thin Sheet ◽  
High Temperature Corrosion ◽  
Metal Base ◽  
Processing Modes ◽  
Temperature Time ◽  
Thin Sheet Steel

The study of the nature of high-temperature corrosion of metals is one of the tasks in substantiating the relevance of the use of corrosion-resistant, heat-resistant coatings and barrier layers obtained on the basis of the natural oxidation process. The article presents the gradation of oxidation of surfaces of 08kp thin-sheet steel at diff erent temperature-time parameters of one cycle “heating-cooling”. To regulate the processing modes and register thermal eff ects, a diff erential thermal analysis device was used. It is shown that the eff ect of elevated temperatures on steel in air at atmospheric pressure triggers an intensive growth of scale, which peels off from the metal base and breaks down. After descaling on the steel surface, in addition to blue tarnishing, in some cases, fi lms of a red tint were found. Based on the data of diff erential thermal analysis, an att empt was made to separate and interpret transformations related directly to steel and to reactions in scale associated with iron oxides.

High Temperature Corrosion Studies in Molten Salt Using Salt Purification and Alloy Coating

2016 ◽  
Vol 59 (3) ◽  
pp. 242-257 ◽  
Author(s):  
S.S. Sawant ◽  
B.D. Gajbhiye ◽  
S. Tyagi ◽  
C.S. Sona ◽  
R. Divya ◽  
...  
Keyword(s):  
High Temperature ◽  
Molten Salt ◽  
Alloy Coating ◽  
High Temperature Corrosion ◽  
Corrosion Studies

High Temperature Corrosion of Microturbine Combustor Material

2007 ◽  
Author(s):  
Hiroshi Yakuwa ◽  
Tadashi Kataoka
Keyword(s):  
High Temperature ◽  
Oxide Film ◽  
High Temperature Corrosion ◽  
Protective Oxide ◽  
Lean Burn ◽  
Protective Oxide Film ◽  
Unburned Hydrocarbons ◽  
The Rich ◽  
Good Heat Resistance ◽  
Good Heat

Two particular types of high temperature corrosion in a microturbine Rich-burn, Quick-mix, Lean-burn (RQL) combustor are discussed and reported in this paper. One type occurred in mixing tubes, part of fuel supply into the combustor. Dense concentrations of carbon monoxide and unburned hydrocarbons in a high temperature environment carburized the mixing tube, leaving it vulnerable to corrosion. The Co-based alloy was selected for the advantage of good heat resistance was exchanged for a Ni-Cr based alloy of good carburization resistance and the life of combustor successfully extended. The second type is a pitting corrosion on the inner wall of liner in the rich-burn zone. It is inferred that the corrosion was metal dusting caused from defects of the oxide film on the inner wall surface. As a countermeasure, a preoxidation step was applied to the combustor to maintain a protective oxide film for a longer period of time. This paper discusses the mechanisms and the countermeasures for these types of corrosion, which relate to carbon from the fuel origin activated in the fuel-rich environment in the combustor.

High temperature corrosion studies in molten salt-FLiNaK

2013 ◽  
Vol 49 (4) ◽  
pp. 287-295 ◽  
Author(s):  
C. S. Sona ◽  
B. D. Gajbhiye ◽  
P. V. Hule ◽  
A. W. Patwardhan ◽  
C. S. Mathpati ◽  
...  
Keyword(s):  
High Temperature ◽  
Molten Salt ◽  
High Temperature Corrosion ◽  
Corrosion Studies
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