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)!

09351 Environmentally Induced Failure of a Nickel Based Valve Plating and Modeling the Corrosion Effects on Pure Nickel of H2S, Chlorides, pH and Pressure

Picture for 09351 Environmentally Induced Failure of a Nickel Based Valve Plating and Modeling the Corrosion Eff
Available for download
Product Number: 51300-09351-SG
ISBN: 09351 2009 CP
Author: Hans Hoffmeister
Publication Date: 2009
$0.00
$20.00
$20.00
A failure of a nickel alloy plating of a sour gas ball valve revealed sulfide-and chloride induced local pitting corrosion. With the background of the prevailing field operating conditions, modeling of local corrosion was carried out for pure nickel by coupling of phase precipitation and polarization behavior. The effects of bulk composition on ion migration to the diffusion layer, its sulfide and chloride precipitations affecting anodic polarization are integrated in a time stepwise procedure. As a main parameter the reduction in bulk pH accelerates local corrosion as well as local acidification in pits. The effects of bulk chloride and hydrogen sulfide contents on corrosion rates varies with the respective ranges of those constituents similar to the behavior of pure iron in earlier work. Depending on the hydrogen sulfide to chloride bulk ratio the local environment may either acidify to low pH levels induced by protecting sulfide precipitations leading to reduced corrosion rates or stay at higher pH with precipitation of non protecting chlorides involving higher corrosion rates. Reduced total pressures within the relevant ranges increase the corrosion rates due to acceleration of the cathodic reaction. Closer understanding is provided of the corrosion mechanism based on thermodynamic heterogeneous equilibrium considerations applied to the small reaction volume of the thin diffusion layer.

Keywords: Ball valve failure, H2S-chloride corrosion modeling, nickel sulfide and nickel chloride layers, polarization coupling principle, anodic acidification
A failure of a nickel alloy plating of a sour gas ball valve revealed sulfide-and chloride induced local pitting corrosion. With the background of the prevailing field operating conditions, modeling of local corrosion was carried out for pure nickel by coupling of phase precipitation and polarization behavior. The effects of bulk composition on ion migration to the diffusion layer, its sulfide and chloride precipitations affecting anodic polarization are integrated in a time stepwise procedure. As a main parameter the reduction in bulk pH accelerates local corrosion as well as local acidification in pits. The effects of bulk chloride and hydrogen sulfide contents on corrosion rates varies with the respective ranges of those constituents similar to the behavior of pure iron in earlier work. Depending on the hydrogen sulfide to chloride bulk ratio the local environment may either acidify to low pH levels induced by protecting sulfide precipitations leading to reduced corrosion rates or stay at higher pH with precipitation of non protecting chlorides involving higher corrosion rates. Reduced total pressures within the relevant ranges increase the corrosion rates due to acceleration of the cathodic reaction. Closer understanding is provided of the corrosion mechanism based on thermodynamic heterogeneous equilibrium considerations applied to the small reaction volume of the thin diffusion layer.

Keywords: Ball valve failure, H2S-chloride corrosion modeling, nickel sulfide and nickel chloride layers, polarization coupling principle, anodic acidification
Product tags
Also Purchased
Picture for 05207 Study on Corrosion Resistance of Electroless
Available for download

05207 Study on Corrosion Resistance of Electroless Plating Ni-P Complex Coating

Product Number: 51300-05207-SG
ISBN: 05207 2005 CP
Author: Huang Yan-bin, Wu Chun-sheng, Liu De-gang, Liang Zhi-jie, Shi Xiao-jun, Zhang Qi-Yong, and Lu Ya-hui
$20.00
Picture for 04289 Modeling of Crevice Corrosion of Pure
Available for download

04289 Modeling of Crevice Corrosion of Pure Nickel by Coupling of Phase and Polarization Behavior at Various pH, Chloride, and Oxygen Levels

Product Number: 51300-04289-SG
ISBN: 04289 2004 CP
Author: Hans Hoffmeister, Institute for Failure Analysis
$20.00
Picture for 05232 Corrosion Resistance of UNS NO4400 vs.
Available for download

05232 Corrosion Resistance of UNS NO4400 vs. Electroless Nickel in Simulated Marine Service

Product Number: 51300-05232-SG
ISBN: 05232 2005 CP
Author: Robert D. Klassen and Pierre R. Roberge, Royal Military College; Yueping Wang, DRDC Atlantic
Publication Date: 2005
$20.00

UNS N04400 cladding on steel valves can corrode during marine service.  The uniform corrosion rate of an EN coating in artificial seawater was measured by electrochemical impedance spectroscopy and was found to be less than that for N04400. The main conclusion is that an EN coating could be a viable solution to repair N04400-clad valves in-situ.

 
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