Server maintenance is scheduled for Saturday, December 21st between 6am-10am CST.

During that time, parts of our website will be affected until maintenance is completed. Thank you for your patience.

Menu
Search
Filters
Close
Menu

Use GIVING24 at checkout to save 20% on eCourses and books (some exclusions apply)!

00226 DIFFUSION KINETIC ISSUES DURING INTERGRANULAR CORROSION OF Ni-BASE ALLOYS

Picture for 00226 DIFFUSION KINETIC ISSUES DURING
Available for download
Product Number: 51300-00226-SG
ISBN: 00226 2000 CP
Author: E. P. Simonen, L. E. Thomas and S. M. Bruemmer
$0.00
$20.00
$20.00
Exposure of Ni-base alloys to hot water results in corrosion reactions at advancing stress corrosion cracks and intergranular degradation at crack walls. The morphology of the corrosion is characterized by very narrow widths of oxides for long distances along grain boundaries. Of particular interest is that this response of alloys occurs during exposure to non- oxidizing water at 330°C. The mechanisms by which oxidation reactions occur in these tight restricted pathways have critical impact on stress corrosion cracking susceptibility. In the present paper, diffusion kinetic analyses are related to observations of corrosion behavior ahead of crack tips and at grain boundaries intersecting cracks behind crack tips. It is concluded that solid-state diffusion of oxygen within alloy grain boundaries is not significant at the low temperatures of interest by conventional diffusion mechanisms. It is not possible for grain boundary internal oxidation to occur by direct analogy to high temperature matrix internal oxidation. However, solid-state diffusion is predicted to be highly promoted by assumed vacancy injection during corrosion and may contribute to reactions within the grain boundary. Nonequilibrium vacancy injection enhances diffusion of substitutional solute (Ni, Cr, Fe) and promotes ingress of interstitial oxygen by vacancy-oxygen binding interactions. Liquid-state diffusion and gas-state diffusion in the restricted open crack volumes of interest are very rapid and provide adequate kinetics to support observed penetration and cracking rates. Although ionic transport is rapid in aqueous solutions, the expected ionic concentrations are too low to rationalize oxide precipitation from aqueous solution during cooling from the exposure temperature. Finally, gas phase kinetics are shown to be very rapid and capable of supporting observed penetration and crack advance rates. However to maintain rapid transport over significant distances, the interconnected porosity required for transport must not be blocked by any solid path length. Kevwords: Grain boundary diffusion, corrosion, oxidation, Ni-base alloys.
Exposure of Ni-base alloys to hot water results in corrosion reactions at advancing stress corrosion cracks and intergranular degradation at crack walls. The morphology of the corrosion is characterized by very narrow widths of oxides for long distances along grain boundaries. Of particular interest is that this response of alloys occurs during exposure to non- oxidizing water at 330°C. The mechanisms by which oxidation reactions occur in these tight restricted pathways have critical impact on stress corrosion cracking susceptibility. In the present paper, diffusion kinetic analyses are related to observations of corrosion behavior ahead of crack tips and at grain boundaries intersecting cracks behind crack tips. It is concluded that solid-state diffusion of oxygen within alloy grain boundaries is not significant at the low temperatures of interest by conventional diffusion mechanisms. It is not possible for grain boundary internal oxidation to occur by direct analogy to high temperature matrix internal oxidation. However, solid-state diffusion is predicted to be highly promoted by assumed vacancy injection during corrosion and may contribute to reactions within the grain boundary. Nonequilibrium vacancy injection enhances diffusion of substitutional solute (Ni, Cr, Fe) and promotes ingress of interstitial oxygen by vacancy-oxygen binding interactions. Liquid-state diffusion and gas-state diffusion in the restricted open crack volumes of interest are very rapid and provide adequate kinetics to support observed penetration and cracking rates. Although ionic transport is rapid in aqueous solutions, the expected ionic concentrations are too low to rationalize oxide precipitation from aqueous solution during cooling from the exposure temperature. Finally, gas phase kinetics are shown to be very rapid and capable of supporting observed penetration and crack advance rates. However to maintain rapid transport over significant distances, the interconnected porosity required for transport must not be blocked by any solid path length. Kevwords: Grain boundary diffusion, corrosion, oxidation, Ni-base alloys.
PRICE BREAKS - The more you buy, the more you save
Quantity
1+
5+
Price
$20.00
$20.00
Product tags
Also Purchased
Picture for 00221 SCC CRACK GROWTH RATES OF TYPE 304
Available for download

00221 SCC CRACK GROWTH RATES OF TYPE 304 STAINLESS STEEL AT HIGH K REGION IN SIMULATED BWR ENVIRONMENT

Product Number: 51300-00221-SG
ISBN: 00221 2000 CP
Author: M. Itow and M. Kikuchi, S. Suzuki
$20.00
Picture for 00222 STRESS CORROSION CRACK GROWTH IN ALLOY
Available for download

00222 STRESS CORROSION CRACK GROWTH IN ALLOY 600 EXPOSED TO PWR AND BWR ENVIRONMENTS

Product Number: 51300-00222-SG
ISBN: 00222 2000 CP
Author: Markus O. Speidel and Ruth Magdowski
$20.00
Picture for 00214 CORROSION FATIGUE CRACK GROWTH BEHAVIOR
Available for download

00214 CORROSION FATIGUE CRACK GROWTH BEHAVIOR OF DUPLEX STAINLESS STEELS WITH DIFFERENT NITROGEN CONTENTS

Product Number: 51300-00214-SG
ISBN: 00214 2000 CP
Author: Chuan-Ming Tseng, Horng-Yih Lieu, and Wen-Ta Tsai
$20.00
Categories
Industry
Recently viewed
Popular tags
View all

Association for Materials Protection and Performance

© AMPP All Rights Reserved.
Membership Terms of Content Use
Contact Customer Support