Effect of temperature on the crevice corrosion resistance of Ni-Cr-Mo alloys as engineered barriers in nuclear waste repositories

2012 ◽  
Vol 1475 ◽  
Author(s):  
Edgar C. Hornus ◽  
C. Mabel Giordano ◽  
Martín A. Rodríguez ◽  
Ricardo M. Carranza
Keyword(s):  
Corrosion Resistance ◽  
Crevice Corrosion ◽  
Chloride Concentration ◽  
Localized Corrosion ◽  
Effect Of Temperature ◽  
Corrosion Susceptibility ◽  
Engineered Barriers ◽  
Corrosive Environments ◽  
Waste Repositories

ABSTRACTNi-Cr-Mo alloys offer an outstanding corrosion resistance in a wide variety of highly corrosive environments. Alloys 625, C-22, C-22HS and HYBRID-BC1 are considered among candidates as engineered barriers of nuclear repositories. The objective of the present work was to assess the effect of temperature on the crevice corrosion resistance of these alloys. The crevice corrosion repassivation potential (ER,CREV) of the tested alloys was determined by the Potentiodynamic-Galvanostatic-Potentiodynamic (PD-GS-PD) method. Alloy HYBRID-BC1 was the most resistant to chloride-induced crevice corrosion, followed by alloys C-22HS, C-22 and 625. ER,CREV showed a linear decrease with temperature. There is a temperature above which ER,CREV does not decrease anymore, reaching a minimum value. This ER,CREV value is a strong parameter for assessing the localized corrosion susceptibility of a material in a long term timescale, since it is independent of temperature, chloride concentration and geometrical variables such as crevicing mechanism, crevice gap and type of crevice former.

Effect of Alloy Composition on the Localized Corrosion Resistance of Nickel Alloys

2012 ◽  
Vol 1475 ◽  
Author(s):  
Santiago Sosa Haudet ◽  
Martín A. Rodríguez ◽  
Ricardo M. Carranza
Keyword(s):  
Corrosion Resistance ◽  
Crevice Corrosion ◽  
Chloride Concentration ◽  
Testing Temperature ◽  
Localized Corrosion ◽  
Chloride Solutions ◽  
Equivalent Number ◽  
Engineered Barriers ◽  
Nickel Base ◽  
30 G 35

ABSTRACTNickel base alloys are considered among candidate materials for engineered barriers of nuclear repositories. The localized corrosion resistance is a determining factor in the materials selection for this application. This work compares the crevice corrosion resistance of selected nickel base alloys, namely 625, G-30, G-35, C-22, C-22HS and HYBRID-BC1. The crevice corrosion repassivation potential (ER,CREV) of the tested alloys was determined by the Potentiodynamic-Galvanostatic-Potentiodynamic (PD-GS-PD) method. The testing temperature was 60ºC and the chloride concentrations used were 0.1 M, 1 M and 10 M.A linear relationship between ER,CREV and the logarithm of chloride concentration was found. ER,CREV increased linearly with PREN (Pitting Resistance Equivalent Number) in concentrated chloride solutions. ER,CREV is the sum of three contributions: ECORR*, η and ΔΦ. ECORR* and η increased linearly with PREN, while ΔΦ increased linearly with PREN for concentrated chloride solutions, not showing a definite trend with PREN for the less concentrated solutions.

scholarly journals Thickness and corrosion resistance optimization of Micro-ARC oxidation coating on Mg-Al-Li-Zn alloy using Taguchi approach

2020 ◽  
pp. 62-66
Author(s):  
Do Le Hung Toan, Shuo-Jen Lee Do
Keyword(s):  
Corrosion Resistance ◽  
Processing Time ◽  
Electrical Potential ◽  
Surface Protection ◽  
Alkaline Electrolytes ◽  
Micro Arc Oxidation ◽  
Corrosive Environments ◽  
Zn Alloy ◽  
Main Factor

Micro arc oxidation method has been developed in the field of surface protection of magnesium alloys and considered as a simple, highly effective, commercial and environmentally friendly method in industry. MAO coatings are fabricated on novel Mg-Al-Li-Zn alloy to improve the anti-corrosion performance of surface by using friendly alkaline electrolytes under a high electrical potential. The Taguchi method and optimal analysis are used to identify the effects of the three factors including current density, processing time and electrical frequency on coating’s characteristics. The results have shown that the main factor that affects coating thickness and corrosion resistance of coating is the processing time. The results obtained by optimal conditions are consistent with prediction values of Taguchi analysis. The thickness of the coating can help to improve the long-term corrosion protection of a MAO coating in corrosive environments.

Effect of Long-Term Service Exposure on the Localized Corrosion and Stress Corrosion Cracking Susceptibility of Type 347 Stainless Steel

CORROSION ◽  
10.5006/2612 ◽  
2017 ◽  
Vol 74 (3) ◽  
pp. 350-361 ◽  
Author(s):  
K. Ravindranath ◽  
N. Tanoli ◽  
B. Al-Wakaa
Keyword(s):  
Stainless Steel ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Localized Corrosion ◽  
X Ray Diffraction ◽  
Degree Of Sensitization ◽  
Corrosion Susceptibility ◽  
Service Exposure

The paper presents the results of a study conducted on the effects of long-term service exposure of Type 347 stainless steel (SS) on the microstructure and corrosion susceptibility. The material subjected to the study was in service in a petroleum refinery as heater tube at 620°C for 31 years. The microscopic and x-ray diffraction studies of the service-exposed specimen revealed the precipitation of chromium-rich carbides along the grain boundaries. The microstructural changes that occurred as a result of service exposure affected the ductility and toughness of the alloy. The sensitization of the alloy was assessed by scanning electron microscopy and double loop electrochemical potentiodynamic reactivation. The studies have indicated some degree of sensitization in the alloy. The service exposure resulted in a marginal increase in the susceptibility of Type 347 SS to pitting in environments containing NaCl and NaCl + H2S. Environments such as H2SO4 and K2S4O6 at the tested concentrations did not differentiate between service-exposed and solution annealed specimens for their corrosion susceptibility. Slow strain rate testing of Type 347 SS in both the service-exposed and solution annealed conditions showed susceptibility to stress corrosion cracking in environment containing NaCl + H2S, while the alloy did not show susceptibility to SCC in H2SO4 and K2S4O6. The long-term service exposure did not noticeably influence the SCC susceptibility of Type 347 SS under the tested conditions.

Localized Corrosion of Nuclear Grade Alloy 800 Under Steam Generator Layup, Startup and Operating Conditions

2012 ◽  
Vol 1 (1) ◽  
pp. 13-20 ◽  
Author(s):  
Y. Lu
Keyword(s):  
Corrosion Resistance ◽  
Steam Generator ◽  
Elevated Temperatures ◽  
Chloride Concentration ◽  
Operating Conditions ◽  
Nuclear Grade ◽  
Localized Corrosion ◽  
Pitting Potential ◽  
Alloy 800 ◽  
Secondary Side

The localized corrosion resistance of nuclear-grade Alloy 800, which is one of the preferred steam generator (SG) heat exchange tube materials of CANDU and PWR reactors, was studied under simulated SG secondary side crevice chemistry conditions at ambient temperature as well as at elevated temperatures. Series of cyclic potentiodynamic polarization tests were performed to study the localized corrosion resistance of Alloy 800 as a function of chloride ion concentration in the SG crevice solution at 40°C, 150°C and 300°C. Based on the experimental results, empirical equations were provided for calculating the pitting potential of nuclear grade Alloy 800 in the SG secondary side crevice chemistries with different levels of chloride concentration at SG layup, startup and operating temperatures.

Evaluation of The Long-Term Stability of Passive Corrosion On The Drip Shield and Waste Package Under Yucca Mountain Conditions

2002 ◽  
Vol 713 ◽  
Author(s):  
D.W. Shoesmith
Keyword(s):  
Environmental Conditions ◽  
Yucca Mountain ◽  
Localized Corrosion ◽  
Waste Package ◽  
Long Term Stability ◽  
Alloy 22 ◽  
Aqueous Environments ◽  
Engineered Barriers ◽  
Titanium Grade

ABSTRACTPossible long term corrosion scenarios for the engineered barriers proposed for the Yucca Mountain (Nevada, USA) repository are reviewed.Introduction:The materials proposed for the engineered barriers in the Yucca Mountain repository (Nevada, USA), Alloy-22 for the waste packages (WP) and titanium Grade-7 (Ti-7) for the drip shield (DS), appear unlikely to suffer localized corrosion (LC) and have very low passive corrosion (PC) rates (1–3). Since environmental conditions will become more benign as temperatures decline and aqueous environments become more dilute (4), this leads to the prediction of exceedingly long waste package lifetimes. In this review, possible corrosion scenarios are discussed in the context of the anticipated evolution in the repository environment.

scholarly journals Localized Corrosion Resistance on Additively Manufactured Ti Alloys by Means of Electrochemical Critical Localized Corrosion Potential in Biomedical Solution Environments

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7481
Author(s):  
Dong-Il Seo ◽  
Jae-Bong Lee
Keyword(s):  
Corrosion Resistance ◽  
Additive Manufacturing ◽  
Passive Film ◽  
Human Body ◽  
Corrosion Potential ◽  
New Method ◽  
Localized Corrosion ◽  
Ti Alloys ◽  
Corrosive Environments ◽  
Repassivation Kinetics

This study proposes a new method, electrochemical critical localized corrosion potential (E-CLCP), in order to evaluate localized corrosion resistance of biomedical additive manufacturing (AM) titanium (Ti) alloys. The procedures for determining E-CLCP are completely different from that of the electrochemical critically localized corrosion temperature (E-CLCT) method (ISO 22910:2020). However, its application should be limited to pH and temperature of the human body because of the temperature scan. E-CLCP displays the localized corrosion resistance of AM Ti alloys based on the human body’s repassivation kinetics, whereas E-CLCT displays the localized corrosion resistance of the alloys based on passive film breakdown in much harsher corrosive environments.

scholarly journals The Proposed Yucca Mountain Repository from a Corrosion Perspective

2006 ◽  
Vol 932 ◽  
Author(s):  
Joe H. Payer
Keyword(s):  
Corrosion Resistance ◽  
Nuclear Waste ◽  
Yucca Mountain ◽  
Department Of Energy ◽  
Process Models ◽  
Localized Corrosion ◽  
Waste Package ◽  
Advanced Technologies ◽  
The U.S

ABSTRACTIn this paper, the proposed Yucca Mountain Repository is viewed from a corrosion perspective. A major component of the long-term strategy for safe disposal of nuclear waste at the Yucca Mountain Repository is first to completely isolate the radionuclides in the waste packages for long times and to greatly retard the egress and transport of radionuclides from penetrated packages. Therefore, long-lived waste packages are important. The corrosion resistance of the waste package outer canister is reviewed, and a framework for the analysis of localized corrosion processes is presented. An overview is presented of the Materials Performance targeted thrust of the U.S. Department of Energy/Office of Civilian Radioactive Waste Management's Office of Science and Technology and International. The thrust program strives for increased scientific understanding, enhanced process models and advanced technologies for corrosion control.

Effect of [HCO3-+CO32−[ on Corrosion Crevice Repassivation Potential of Carbon Steel in Simulated Bentonite Environment

1995 ◽  
Vol 412 ◽  
Author(s):  
Takanori Fukuda ◽  
Masatsune Akashi
Keyword(s):  
Carbon Steel ◽  
Crevice Corrosion ◽  
Localized Corrosion ◽  
Potential Range ◽  
Free Corrosion Potential ◽  
Critical Potential ◽  
Corrosion Susceptibility ◽  
The Relationship ◽  
Critical Ph ◽  
Critical Initiation

AbstractIn order to evaluate the localized corrosion susceptibility of carbon steel in water containing bentonite, the critical pH for depassivation, pHd, the critical potential for crevice corrosion, ERCREV, and the free corrosion potential, Esp, were determined in simulated aqueous solutions of 1 to 100 mmol/L [HCO3- - CO32−], 1 to 1000 mmo!/L [NaCI], and pH of 7 to 12. The Following results were obtained; 1)ER, CREV. increases with increasing [HCO3− CO32−] concentration. The relationship can be described as a function of the ratio of [CI-I HCO3−- CO32−], 2)The Esp increases with increasing pH in the passive region, and 3)ThepHd shows [HCO3− - CO32−] concentration dependency. This paper also discusses the relationship between critical initiation potential for crevice corrosion of carbon steel, [CI-], and [HCO3− CO32−] anion. The crevice corrosion that occurs on passivated metals and alloys is characterized by determinable critical initiation potential that can be induced in a potential range nobler than its critical potential.

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