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.

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 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.

Study on the Influence of High Temperature Homogenizing and Solution on the Microstructure and Property of 4Cr5MoSiV1 Steel

2012 ◽  
Vol 549 ◽  
pp. 567-571
Author(s):  
Luo Yi
Keyword(s):  
High Temperature ◽  
Chemical Composition ◽  
Impact Toughness ◽  
Thermal Fatigue ◽  
Fatigue Behavior ◽  
Fatigue Property ◽  
Eutectic Carbides ◽  
The Core ◽  
Thermal Fatigue Behavior ◽  
The Impact

4Cr5MoSiV1 steel, a widely used for hot work mould, contains Cr, Mo, V alloying elements that easily form carbides. The Micro-area chemical composition, microstructure, impact toughness and thermal fatigue behavior of 4Cr5MoSiV1 and 4Cr5MoSiV1H steels were investigated, the latter was carried on high temperature homogenizing and solution based on the former. The results showed that bulk eutectic carbides and elements segregation contained in the 4Cr5MoSiV1 steel reduced the impact toughness. But the impact toughness of the core of the mould steel block and thermal fatigue property of 4Cr5MoSiV1H steel were improved because the elements segregation and eutectic carbides was eliminated through the high temperature homogenizing and solution.

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 The Effect of Ultrasonic Cleaning on the Secondary Electron Yield, Surface Topography, and Surface Chemistry of Laser Treated Aluminum Alloy

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 296
Author(s):  
Jie Wang ◽  
Yong Gao ◽  
Zhiming You ◽  
Jiakun Fan ◽  
Jing Zhang ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Surface Chemistry ◽  
Secondary Electron ◽  
High Energy ◽  
Surface Cleaning ◽  
Secondary Electron Yield ◽  
Ultrasonic Cleaning ◽  
Electron Yield ◽  
Vacuum Systems ◽  
The Impact

Laser ablation technique is a novel method for obtaining a surface with a low secondary electron yield (SEY) that can mitigate electron cloud in high-energy accelerators. Before the installation of laser processed aluminum alloy, surface cleaning is of the essence to reduce the contaminations of ultra-high vacuum systems for providing appropriate pressure for beam operation consequently. Laser processed aluminum alloy is one of the crucial candidates for the vacuum system construction of future accelerators. Moreover, ultrasonic cleaning is an essential procedure for most materials applied in vacuum systems. Therefore, in order to verify the stability of the laser created structures by ultrasonic cleaning and evaluate the impact of the cleaning on the SEYs, the surface topographies, and the surface chemistries of laser treated aluminum alloy, SEY measurements and related tests were performed. After ultrasonic cleaning, the SEYs of laser treated aluminum alloy increased from 0.99, 1.05, and 1.16 to 1.43, 1.74, and 1.38, respectively. Compared to the surface roughness of uncleaned laser treated aluminum samples, the cleaned laser treated ones decreased from 10.7, 7.5, and 14.5 to 9.4, 6.9, and 12.9, respectively. The results indicate that ultrasonic cleaning can induce the SEY increase of laser processed aluminum alloy. The correlative mechanism between the surface morphology, the surface chemistry, and SEY increase were analyzed for the first time.

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.

scholarly journals Effect of Ternary Basicity of Iron Ore-Fluxed Pellets on Melting and Softening Properties in a Blast Furnace

2020 ◽  
Author(s):  
Fábio R. Silva ◽  
Leandro R. Lemos ◽  
Paulo de Freitas Nogueira ◽  
Marcelo Bressan
Keyword(s):  
Blast Furnace ◽  
High Temperature ◽  
Chemical Composition ◽  
Cohesive Zone ◽  
Iron Ore ◽  
Elevated Temperatures ◽  
Softening Temperature ◽  
Reduction Degree ◽  
High Temperature Properties ◽  
The Impact

Abstract The cohesive zone is a region of low permeability in a blast furnace. This study shows the impact of the chemical composition of pellets on the metallurgical processes occurring in this region during the iron ore reduction process. Sixteen pellets containing varying contents of MgO, CaO, and SiO2 were investigated. The results indicate that increasing the MgO content of pellets improves their high-temperature properties; e.g., reduction degree and softening temperature. Modern equipment was used to replicate the phenomena that occur in the cohesive zone to measure the softening temperature, pressure drop, and the reduction degree of pellets at elevated temperatures and different pellet basicities. These experimental results were used to develop mathematical correlations between parameters related to high-temperature properties and the ternary basicity of the pellets ((CaO + MgO)/SiO2). Defining such relationships will facilitate evaluating the effects of pellet chemical composition on blast furnace processes.

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