Corrosion Behaviour of Truw Base and Reference Glasses

1983 ◽  
Vol 26 ◽  
Author(s):  
P. Van Iseghem ◽  
W. Timmermans ◽  
R. De Batist
Keyword(s):  
Valence State ◽  
Chemical Resistance ◽  
Diffusion Processes ◽  
Corrosion Behaviour ◽  
Partial Replacement ◽  
Distilled Water ◽  
Corrosion Rates ◽  
Weight Losses ◽  
Diffusion Controlled ◽  
Iron Valence

ABSTRACTThe corrosion behaviour of five TRUW base and reference glasses in distilled water has been investigated for times up to 8 months. The glasses were chosen to evaluate some of the main features of the basaltic slag as produced by the prototype FLK incinerator, i.e. the iron valence state and the relative influence of Al2O3 vs FeOx. Diffusion processes control the corrosion for times below 80 d at 90°C at the SA.V-1 value currently considered (1 cm-1), resulting in the formation of complex films enriched in Al, Fe and Mg over 200 nm thick. The partial replacement of 10 mole 7 Fe2Ox by Al2O3 improves the chemical resistance and strongly accelerates saturation of the leachate for Si, and apparently also for Na and K. The iron valencestate in the glass does not seem to influence the corrosion behaviour. When leaching at temperature up to 200°C, the surfaces of all glasses crystallize, while the corrosion rates do not decrease with time. At SA.V−1 ≠ 0.1 cm−1 , 90°C, the weight losses increase by a factor up to 10 relative to SA.V−1 ≠ 1 cm−1 , 90°C, and the initial diffusion controlled stage might be followed by matrix dissolution reactions.

Parametric Study of the Corrosion Behaviour in Static Distilled Water of Simulated European Reference High Level Waste Glasses

1984 ◽  
Vol 44 ◽  
Author(s):  
Pierre Ph. Van Iseghem ◽  
W. Timmermans ◽  
R. De Batist
Keyword(s):  
Diffusion Processes ◽  
Glass Composition ◽  
Corrosion Behaviour ◽  
Research Programme ◽  
Community Research ◽  
High Level Waste ◽  
Distilled Water ◽  
Controlling Mechanism ◽  
Saturation Effects ◽  
High Level

AbstractThe corrosion behaviour in distilled water of five simulated European reference high level waste glasses has been investigated for times up to 8 months. The glasses were chosen in accordance with the Joint European Community research programme on HLW form characterization: two French glasses (SON58, SON64), one British glass (UK209) and two glasses designed to incorporate HLW stored at the Eurochemic plant in Belgium (SM58 and SAN60). In the reference condition (90°C, SA.V−1 = 1 cm−1) the leaching was characterized mainly by diffusion processes and by the onset of saturation in the leachate (these saturation effects were found to depend on glass composition). In more dilute conditions (SA.V−1 = 0.1 cm−1), matrix dissolution was the rate controlling mechanism. Increasing the leachant temperature to 150°C and higher lead to pronounced surface crystallization and, at least for one glass (SAN60), to an increased corrosion.

MICROSTRUCTURE AND TEMPERATURE STABILITY OF SINTERED Nd-Dy-Fe-Co-Mo-Al-B MAGNETS

1993 ◽  
Vol 07 (01n03) ◽  
pp. 721-724
Author(s):  
W. RODEWALD ◽  
P. SCHREY ◽  
B. WALL
Keyword(s):  
Solid Solution ◽  
Surface Treatment ◽  
Corrosion Behaviour ◽  
Temperature Stability ◽  
Partial Replacement ◽  
Compound A ◽  
Corrosion Tests ◽  
Sintered Magnets ◽  
Load Line ◽  
Intrinsic Coercivity

Simultaneous additions of Co and Mo or V, respectively, to Nd-Dy-Fe-Al-B alloys improve the temperature stability of sintered magnets. The intrinsic coercivity at 150 ºC amounts to 9 kA/cm for magnets with a Dy-content of 3 at.%. Hence magnets with a load line, B/μoH=−2, may be operated at temperatures up to 200 ºC. The additions of Mo or of V result in the precipitation of a tetragonal Mo2FeB2 compound, a=0.58 nm, c=0.32 nm, or of a tetragonal V3–xFexB2 compound, x=0.2...1.2, within the (Nd, Dy)2(Fe, Co, A1)14B grains. The dimensions of the precipitates range from 10 to 600 nm. Besides Mo2FeB2- or V3–xFex+B2-grains, respectively, with dimensions up to 10 μm were observed within the Nd-rich constituents. The intrinsic coercivity, however, is determined by nucleation of reversed domains. The addition of Co results in a partial replacement of the Nd-Fe solid solution by the Nd3Co compound. Corrosion tests revealed, that the corrosion behaviour is not improved significantly and depends much more on the surface treatment.

Anticorrosive Property of Potassium Dichromate Film on Galvanized Coating in Distilled Water

2015 ◽  
Vol 227 ◽  
pp. 135-138
Author(s):  
Olayide Rasaq Adetunji ◽  
Peter Olaitan Aiyedun ◽  
Oladimeji Suleiman Bello
Keyword(s):  
Potassium Dichromate ◽  
Optical Microscope ◽  
Distilled Water ◽  
White Rust ◽  
Steel Sheets ◽  
Weight Losses ◽  
Water Ph ◽  
Analysis Of Results ◽  
Galvanized Coating ◽  
Microsoft Office

Hot Dip Galvanized (HDG) coating protects steel from corrosion by providing a thick, tough metallic zinc envelope, which completely covers the steel surface and seals it from the corrosive action of its environment. The anti-corrosion ability of this sacrificial anode cathodic protection can be improved upon through the protective nature of passivation films on zinc like potassium dichromate.This study investigated the anti-corrosion effect of potassium dichromate (K2Cr2O7) film on freshly galvanized coating in distilled water (pH=7.92). The K2Cr2O7film passivity on the hot-dip zinc coated steel sheets (taken as treated in the context of this study) was used in direct comparison with their untreated counterparts. The test was run for 30 days at 120 hours interval during which the corresponding weight losses, corrosion rates, inhibitor efficiencies, and pH of the final solutions were obtained of the coupons. Analysis of results was made using Microsoft office applications. The surface morphology of the samples was obtained using Optical microscope. The results obtained revealed the greater influence of the action of the K2Cr2O7film on selected and examined HDG steel sheets corrosion performance. Weight losses increased with increase in immersion time. Inhibitor efficiency of 4.1% was achieved. The photomicrographs confirmed the occurrence of corrosion on untreated coating more than the treated ones. Conclusively, potassium dichromate was effective in passivating galvanized coating from white rust.

The corrosion behaviour of copper in neutral tap water. Part II: Determination of corrosion rates

1996 ◽  
Vol 38 (3) ◽  
pp. 387-395 ◽  
Author(s):  
Y. Feng ◽  
W.-K. Teo ◽  
K.-S. Siow ◽  
A.-K. Hsieh
Keyword(s):  
Corrosion Behaviour ◽  
Tap Water ◽  
Corrosion Rates

Study of the Effect of Diatomite as a Partial Replacement of Cement in Cement Pastes

2016 ◽  
Vol 865 ◽  
pp. 22-26
Author(s):  
Jana Zahalkova ◽  
Pavla Rovnanikova
Keyword(s):  
Bending Strength ◽  
Chemical Resistance ◽  
Reference Sample ◽  
Partial Replacement ◽  
High Porosity ◽  
Cement Pastes ◽  
Pozzolanic Material ◽  
Thermal Insulating ◽  
Insulating Properties ◽  
Scanning Electron

The article is focused on study of the effect of filtering diatomite as a partial replacement of cement in an amount of 5-30%. Diatomite is used in civil engineering especially for its high content of an amorphous SiO2, chemical resistance, high porosity, and good thermal insulating properties. Diatomite can be used as a pozzolanic material due to the high content of amorphous SiO2.Cement was replaced by filtering diatomite in amount of 5, 10, 15, 20, 25 and 30% by weight. Diatomite was characterized by chemical composition, granulometry and pozzolanic activity.The specimens were tested in bulk density, bending strength and compressive strength, hydration process was investigated using thermal analysis, and microstructure was observed by scanning electron microscopy. All results were compared to reference sample.

The importance of the iron valence state in NiCoFe nanosheet array catalysts for the oxygen evolution reaction

2021 ◽  
Author(s):  
Hua-Shuai Hu ◽  
Yang Li ◽  
Gao Deng ◽  
Ya-Ru Shao ◽  
Ke-Xin Li ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Valence State ◽  
Nanosheet Array ◽  
Iron Valence ◽  
Catalytic Performances

The catalytic performances of NiCoFe nanosheet array catalysts for the OER are strongly dependent on the valence state of iron cations in the precursors.

A COMPARATIVE STUDY TO EVALUATE THE CORROSION PERFORMANCE OF FRICTION STIR WELDED AZ31B MAGNESIUM ALLOY UNDER IMMERSION, SALT FOG, PITTING AND GALVANIC CORROSION TESTS UNDER NACL ENVIRONMENT

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Ashok Kumar M ◽  
Thirumalaikumarasamy D ◽  
Paventhan R ◽  
Thirumal P
Keyword(s):  
Magnesium Alloy ◽  
Corrosion Behaviour ◽  
Galvanic Corrosion ◽  
Salt Spray ◽  
Welding Process ◽  
Ion Concentration ◽  
Az31b Magnesium Alloy ◽  
Corrosion Tests ◽  
Friction Stir ◽  
Corrosion Rates

An investigation was carried out to quantify and characterize the corrosion behaviour of AZ31B magnesium alloy joints. Extruded Mg alloy plates of 6 mm thick of AZ31B grade were butt welded using a solid state, environmentally cleaner welding process, friction stir welding process. The weld specimens were underwent immersion, salt spray, pitting and galvanic corrosion tests in order to quantify and characterize the corrosion rates of the welds with the influence of different pH values, chloride ion concentration and the corrosion time. The corrosion rates, microstructure, scanning electron microscopy and X-ray diffraction analysis concludes the optimum parameter for the usage of the magnesium alloy welds for the best service applications. Keywords: Keywords: EDM, Alumina and Genetic Algorithm

The relaxation dynamics, iron valence state, and Mössbauer effect in PFN ceramics

2011 ◽  
Vol 75 (5) ◽  
pp. 731-733 ◽  
Author(s):  
A. V. Pavlenko ◽  
A. T. Kozakov ◽  
S. P. Kubrin ◽  
A. A. Pavelko ◽  
K. A. Guglev ◽  
...  
Keyword(s):  
Valence State ◽  
Mössbauer Effect ◽  
Relaxation Dynamics ◽  
Mossbauer Effect ◽  
Iron Valence

Long Term Corrosion Behaviour of Carbon Steel During Anaerobic to Aerobic Cycling Under Near-Neutral pH Saline Conditions

2010 ◽  
Author(s):  
Brent W. A. Sherar ◽  
Peter G. Keech ◽  
Zack Qin ◽  
Fraser King ◽  
David W. Shoesmith ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Focused Ion Beam ◽  
Corrosion Behaviour ◽  
Ion Beam ◽  
Cycle Number ◽  
Corrosion Rates ◽  
Anaerobic Corrosion ◽  
Film Porosity ◽  
Electrochemical Microscopy

This paper investigates the long term corrosion behaviour of pretreated carbon steel under alternating anaerobic to aerobic cycles over 238 days. Changes in steel behaviour were observed electrochemically by monitoring the corrosion potential, and calculating changes to corrosion rate from linear polarization resistance. With increasing cycle number the corrosion process becomes localized at a small number of locations, consistent with the formation of tubercles. Periods of aerobic corrosion were associated with more positive potentials (between −500 mV to −350 mV) and high corrosion rates (70 to 120 μm yr−1); whereas anaerobic corrosion yielded more negative potentials (< −650 mV) and lower corrosion rates (40 to 50 μm yr−1). Upon termination of the experiment, corrosion product deposits were characterized by several techniques: scanning electrochemical microscopy to detect morphology; focused ion beam and cross sectioning to judge film thickness and film porosity; and Raman Spectroscopy to identify iron phases.

Use of multivariate analysis for synchrotron micro-XANES analysis of iron valence state in amphiboles

2016 ◽  
Vol 101 (5) ◽  
pp. 1171-1189 ◽  
Author(s):  
M. Darby Dyar ◽  
Elly A. Breves ◽  
Mickey E. Gunter ◽  
Antonio Lanzirotti ◽  
Jonathan M. Tucker ◽  
...  
Keyword(s):  
Multivariate Analysis ◽  
Valence State ◽  
Iron Valence ◽  
Xanes Analysis
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