High Temperature Sulphidation Behavior of Fe20Cr6Al-Y,Hf Steel

2008 ◽  
Vol 595-598 ◽  
pp. 763-768
Author(s):  
Martah Homa ◽  
Zbigniew Żurek
Keyword(s):  
High Temperature ◽  
Chemical Composition ◽  
Vapor Pressure ◽  
Phase Analysis ◽  
High Temperature Corrosion ◽  
Vapor Pressures ◽  
Scale Layer ◽  
Phase And Chemical Composition ◽  
Xrd Techniques ◽  
Scale Surface

The high temperature corrosion behavior of Fe20Cr6Al-Y,Hf steel was studied in the range of temperature 800-1000oC in H2/H2S atmospheres at pS2=10-2 ,10-3 and 10-4 Pa sulphur vapor pressures. Kinetics depend on the temperature and sulphur vapor pressure. After 24 hours the whole specimen was practically consumed because the samples were 0,06 cm thick. Morphology of the scales have been performed by SEM techniques. Phase and chemical composition have been studied by EDX and XRD techniques. It was found that scale formed on Fe20Cr6Al-Y,Hf alloy was built with porosity sulphides layer. EDX analysis of the scale surface show that the any aluminum, hafnium and yttrium sulfides were found in the formed scale layer, however small amounts of Al2S3 was detected in scale/steel interface. Also internal sulphidation was observed. A phase analysis of the formed scale revealed that it is composed mainly of an FeS, Fe7S8 phases and CrS, Cr5S6. Result were compared with data obtained on the pure Fe and Cr samples.

scholarly journals Microstructure and Chemical Composition of Fe-Cr Alloy Tempered in High Temperature and Atmosphere Containing Ar-SO2

2016 ◽  
Vol 61 (3) ◽  
pp. 1607-1612 ◽  
Author(s):  
A. Radziszewska ◽  
A. Kranzmann ◽  
I. Dörfel ◽  
M. Mosquera Feijoo ◽  
M. Solecka
Keyword(s):  
Stainless Steel ◽  
Phase Composition ◽  
High Temperature ◽  
Chemical Composition ◽  
Steel Surface ◽  
High Temperature Corrosion ◽  
Corrosion Process ◽  
Gas Atmosphere ◽  
Amorphous Zone ◽  
Scale Surface

AbstractThe paper presents the microstructure, chemical and phase composition of thin scale, obtained as a result of high-temperature corrosion of X20Cr13 stainless steel. Samples were exposed to gas atmosphere of the following composition: 0.25 vol.% of SO2and 99.75 vol.% of Ar at 600 °C for 5 h. As a consequence, thin compact scale was formed on steel surface. This scale consisted of three different zones. An amorphous zone was formed close to steel surface. Then, nanocrystalline zone could be observed. Finally, larger grains were formed during the corrosion process. The analysis of the chemical composition revealed higher concentration of chromium near steel surface. In contrast, to chromium, the content of iron, increased near the scale surface. It was found out that the (Cr, Mn, Fe)5O12phase appeared in the thin scale.

NICROFER 5520 Co

Alloy Digest ◽  
1995 ◽  
Vol 44 (3) ◽  
Keyword(s):  
High Temperature ◽  
Chemical Composition ◽  
Physical Properties ◽  
Tensile Properties ◽  
High Temperatures ◽  
Heat Treating ◽  
High Temperature Corrosion ◽  
Creep Properties ◽  
Nickel Chromium ◽  
Temperature Performance

Abstract NICROFER 5520 Co is a nickel-chromium-cobalt-molybdenum alloy with excellent strength and creep properties up to high temperatures. Due to its balanced chemical composition the alloy shows outstanding resistance to high temperature corrosion in the form of oxidation and carburization. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: Ni-480. Producer or source: VDM Technologies Corporation.

High-Temperature Sulfurization of Crofer 22APU in H2/H2S Atmosphere

2010 ◽  
Vol 654-656 ◽  
pp. 566-569 ◽  
Author(s):  
Zbigniew Żurek ◽  
Artur Jaron ◽  
Adam Stawiarski ◽  
Aleksander Gil
Keyword(s):  
High Temperature ◽  
Corrosion Behavior ◽  
High Temperature Corrosion ◽  
Vapor Pressures ◽  
Temperature Range

The authors present studies of behavior of Crofer steel in H2 polluted by H2S. The high temperature corrosion behavior of Crofer 22APU steel pre-oxidized samples and not pre-oxidized ones were studied in the temperature range of 600 – 900°C in H2/H2S atmospheres in sulphur vapor pressures in the range of 10-7-10-1 Pa. Kinetics depend on the temperature and sulphur pressure, however the process of sulfurization for pre-oxidized samples was slower.

Experimental Investigation to the Properties of Eutectic Salts by NaCl-KCl-ZnCl2 for Application as High Temperature Heat Transfer Fluids

2014 ◽  
Author(s):  
Kai Wang ◽  
Edgar Molina ◽  
Ghazal Dehghani ◽  
Ben Xu ◽  
Peiwen Li ◽  
...  
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Melting Point ◽  
Vapor Pressure ◽  
Mole Fraction ◽  
Heat Transfer Fluid ◽  
Test Facility ◽  
Vapor Pressures ◽  
Heat Transfer Fluids ◽  
Temperature Heat

A group of eutectic ternary halide salts were surveyed and studied for the objective of developing a high temperature heat transfer fluid with a freezing point below 250°C and a low vapor pressure, below 1.0 atm, at temperatures up to 800°C. The studied salts include: 1) NaCl-KCl-ZnCl2 with a mole fractions of 18.6%-21.9%-59.5% and a melting point of tm=213°C; 2) NaCl-KCl-ZnCl2 with a mole fraction of 13.4%-33.7%-52.9% and a melting point of tm=204°C; and 3) NaCl-KCl-ZnCl2 with mole fraction of 13.8%-41.9%-44.3% and a melting point of tm=229 °C. Vapor pressures of these salts at different temperatures were experimentally obtained using an in-house developed test facility. The results show that vapor pressures of all the three eutectic molten salts are below 1.0 atm at a temperature of 800 °C. The salt of ZnCl2-KCl-NaCl in mole faction of 44.3%-41.9%-13.8% has lowest vapor pressure which is only about 1.0 atm even at a temperature of 900 °C. Viscosities of these salts were measured in the temperature range from after melting to 850°C. At low temperatures near their melting points of the salts, the viscosities are about 16 × 10−3Pa s, while at high temperatures above 700°C the viscosities are around 4 × 10−3Pa s, which is satisfactorily low to serve as heat transfer fluid for circulation in a CSP system. Both the vapor pressure and the viscosities of the studied three eutectic salts demonstrated satisfaction to serve as high temperature heat transfer fluids. Other thermal and transport properties of these salts are expected to be reported in the future for screening out a satisfactory high temperature heat transfer fluid.

3-Dimensional Microstructure Investigation of High Temperature Corrosion of Boiler Tube Material

2021 ◽  
Vol 889 ◽  
pp. 147-152
Author(s):  
Ariyana Dwiputra Nugraha ◽  
Rasgianti
Keyword(s):  
High Temperature ◽  
Chemical Composition ◽  
Chemical Elements ◽  
Hardness Test ◽  
Local Heat ◽  
Optical Microscope ◽  
Mechanical Tests ◽  
Visual Observation ◽  
High Temperature Corrosion ◽  
3 Dimensional

The material of the tubes has suffered localized overheating and corrosion, probably as a result of local heat flux impingement phenomenon, combined with high temperature corrosion. Boiler tubes that experienced failure indications were tubes material SA 213 T22 with the dominant alloy elements is Cr. Materials with these specifications are which should be resistant to corrosion, so it is necessary to carry out laboratory testing to answer suspected indications of failure. The methodology of analysis and identification carried out is by observing the microstructure in 3 dimensions supported by other mechanical tests, namely visual observation, hardness testing, chemical composition testing using SEM and EDAX and testing the chemical composition of the material using a spectrum analyzer. Observation using an optical microscope shows that the microstructure condition of the tube is ferritic and the results of 3D metallography observations show that the tube has undergone micro crack with a measured depth of 1853,28 μm. After the metallography testing is carried out, the hardness test is carried out with the hardness vickers (HV) unit and the minimum hardness is 149 HV and the maximum hardness is 177 HV. Testing of the chemical composition of the deposit showed that there were chemical elements found in seawater that trigger corrosion such as sodium and chlorine which enter the water vapor system. The results showed that the tube had pitting corrosion, which was indicated by the presence of microcrack at the grain boundaries and an oxide deposit had been formed which would cause an overheating phenomenon and deterioration.

scholarly journals Nanoporous Anodic Aluminum-Iron Oxide with a Tunable Band Gap Formed on the FeAl3 Intermetallic Phase

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3471 ◽  
Author(s):  
Paulina Chilimoniuk ◽  
Robert P. Socha ◽  
Tomasz Czujko
Keyword(s):  
Chemical Composition ◽  
Band Gap ◽  
Intermetallic Phase ◽  
Oxide Coating ◽  
Anodic Oxide ◽  
Intermetallic Alloy ◽  
Protective Atmosphere ◽  
Composition Analysis ◽  
Phase And Chemical Composition ◽  
Xrd Techniques

Nanostructured anodic oxide layers on an FeAl3 intermetallic alloy was prepared by two-step anodization in 20 wt.% H2SO4 at 0 °C. The obtained anodic oxide coating was subjected to phase and chemical composition analysis using XPS and XRD techniques. An analysis of the band gap of individual coatings was also performed. The applied parameters of the anodization process were determined, enabling the formation of a nanostructured coating on the FeAl3 intermetallic alloy. Tests were carried out on samples produced at a voltage between 10 V and 22.5 V in 2.5 V steps. The produced coatings were subjected to an annealing process at 900 °C for 2 h in an argon protective atmosphere. Moreover, the influence of the substrate chemical composition on the chemical and phase composition of the anodic oxide are discussed. Band gaps of 2.37 eV at 22.5 V and 2.64 eV at 10 V were obtained directly after the anodizing process. After applying the heat treatment, band gap values of 2.10 eV at 22.5 Vand 2.48 eV for the coating produced at 10 V were obtained.

Preparation Process of Antioxidation Coating of Prebaked Carbon Anode Steel Claw

2012 ◽  
Vol 164 ◽  
pp. 132-136
Author(s):  
Zhi Xiang Liu ◽  
Zhe Sheng Qiu ◽  
Ji Kang Yan ◽  
Guo You Gan ◽  
Rui Jiao Jia ◽  
...  
Keyword(s):  
High Temperature ◽  
Chemical Composition ◽  
Phase Analysis ◽  
Antioxidant Properties ◽  
Carbon Anode ◽  
Preparation Process ◽  
X Ray Diffraction ◽  
Optimal Thickness ◽  
X Ray ◽  
Aluminium Anode

In this paper, the preparation and antioxidant properties of SnO2coating of steel claw of prebaked carbon used as electrolytic aluminium anode was investigated. A denser SnO2coating on steel claw was prepared by high temperature glaze method . Phase Analysis , microstructure and chemical composition of the steel claw antioxidant coating were by Japan Rigaku D/Max2200 type X-ray diffraction, the Philip XL30 ESEM and EDS. the Oxidation resistance experiments results showed that the better anti-oxidation coating has a optimal thickness size of about 0.4mm.

Corrosion Mechanisms and Alloy Performance in Waste-to-Energy Boiler Combustion Environments

2004 ◽  
Author(s):  
George Y. Lai
Keyword(s):  
High Temperature ◽  
Combustion Products ◽  
High Temperature Corrosion ◽  
Waste To Energy ◽  
Vapor Pressures ◽  
Boiler Tube ◽  
Metal Chlorides ◽  
Protection Method ◽  
High Vapor ◽  
Corrosion Mechanisms

The combustion of municipal solid waste in a boiler for power generation produces a very corrosive environment for the boiler tube materials. The environment contains HCl, SO2, various metal chlorides and sulfates along with typical combustion products. Due to their low melting points and high vapor pressures, metal chlorides are believed to be primarily responsible for the boiler tube corrosion problems encountered in waste-to-energy (WTE) boilers. Without some sort of corrosion protection method, the standard materials of the construction for the boiler, such as carbon and Cr-Mo steels, are subject to severe high temperature corrosion attack. The present paper discusses the possible modes of high temperature corrosion for waterwalls and boiler tubes in the convection section, and the prevailing protection method for these components as well as the performance of various alloys in these hostile combustion environments.

Investigation of Cathodic Cleaning Processes of Aluminum Alloy

2015 ◽  
Vol 220-221 ◽  
pp. 684-692 ◽  
Author(s):  
Raimonda Lukauskaitė ◽  
Algirdas Vaclovas Valiulis ◽  
Olegas Černašėjus
Keyword(s):  
Free Energy ◽  
Aluminum Alloy ◽  
High Temperature ◽  
Chemical Composition ◽  
Electric Discharge ◽  
Surface Cleaning ◽  
High Temperature Corrosion ◽  
Continuous Film ◽  
Pre Treatment ◽  
The Impact

On covering aluminum and its alloys with coatings resistant to high-temperature corrosion and attrition, abundant technological problems arise. The key problem is a removal of the film of aluminum oxide Аl2O3 from the aluminum substrate. This permanent, chemically continuous film of oxide reduces adhesion between the substrate and the coating. For improving cohesion of the coating with the substrate, an appropriate pre-treatment of aluminum is required. In the paper, cleaning of aluminum alloy AW 5754 by electric discharge is investigated. This method is considered one of most environmentally friendly methods of surface cleaning. The impact of the parameters of aluminum alloy cathodic cleaning on the surface cleaning width, its roughness and free energy of the surface were examined. In addition, the topography, microstructure and chemical composition of the surface of cleaned aluminum alloy were estimated.

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