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  • 1.  Stress corrosion of Cu in NH4- environment

    Posted 09-27-2022 11:49 PM

    Hello all

    There are some reports about stress corrosion cracking of copper(alloyed with zinc) in the NH4- environment , is there any specific case study material?

    Now I have a chiller with pure copper tube (99.9%Cu), does this have risk of stress corrosion cracking in the NH4- or nitrates environment?  Any threshold concentration limit for pure copper NH4- stress corrosion cracking?

     

    Thanks

    BR

     

    Feng Min 
    Fixed Equipment Engineer
    Site Maintenance Department

    Nouryon(诺力昂)



  • 2.  RE: Stress corrosion of Cu in NH4- environment

    Posted 09-28-2022 09:37 AM

    Feng,

    There are several good references on copper alloy SCC in ammonia containing environments, I wrote Chapter 14 of the book;  Stress Corrosion Cracking – Theory & Practice, 2011, Ed. Raja/Shoji, entitled "SCC in Boiler and Cooling Water Systems, where I list several references related to brass (Cu-Zn) SCC.  In this chapter, there is a chart that ranks SCC risk of various classes of copper alloys (from MTI Publication No.15), and I also list a table from AWWA Research Foundation that lists the ppm of ammonia threshold for SCC in Admiralty Brass as less than 0.2 ppm ammonia.

     

    In regards to pure copper (99.9%), I do believe the literature has case histories about SCC failures of high purity copper in ammonia, etc., but typically the ammonia level would be greater to cause SCC in a high purity copper alloy, as compared to Cu-Zn alloys.

     

    • Mel Esmacher

     

    Sent from Mail for Windows

     






  • 3.  RE: Stress corrosion of Cu in NH4- environment

    Posted 10-26-2022 01:24 PM
    Mel, In the table you mentioned from AWWA research foundation, does it include the ppm of ammonia threshold for SCC in 90-10 Cu-Ni?

    In addition, does anyone have data on the cracking initiation time of 90-10 Cu-Ni? There are some data on other copper alloys, but I couldn't find any for Cu-Ni.

    Thanks,
    Yingying

    ------------------------------
    Yingying Wei
    Air Products and Chemicals, Inc.
    Allentown PA
    (610) 481-2245
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  • 4.  RE: Stress corrosion of Cu in NH4- environment

    Posted 10-27-2022 10:53 AM

    If you haven't already looked, I'd recommend reviewing the technical literature at the Copper Development Association.  And, they may also have a spot where you can submit a question & a technical expert will direct you to the right info.

     

    Official Site of Copper Development Association, Inc. (USA)

     

    You may also want to look at this article, but its behind a paywall.

     

    Stress corrosion cracking of pure copper in dilute ammoniacal solutions - ScienceDirect

     

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    Krista L. Heidersbach
    Sr. Engineer, Corrosion, Asset Integrity

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  • 5.  RE: Stress corrosion of Cu in NH4- environment

    Posted 10-27-2022 01:58 PM
    Thank you, Krista.

    ------------------------------
    Yingying Wei
    Air Products and Chemicals, Inc.
    Allentown PA
    (610) 481-2245
    ------------------------------



  • 6.  RE: Stress corrosion of Cu in NH4- environment

    Posted 09-29-2022 12:28 AM
    Edited by Ajit Mishra 09-29-2022 12:28 AM
    Hello Min,
    Is this (NH4-) ammonium hydroxide? MTI MS-6 Ammonia and Caustic Soda is a good reference . As per the handbook, "All copper-based alloys are attacked by ammonium hydroxide unless air is rigorously excluded" "..it is general industry practice to avoid all use of copper-based alloys in ammonia and related services". I'm not sure if you'll definitely notice  SCC but there is a strong possibility of formation of copper-ammonium complexes.

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    Ajit Mishra
    Corteva
    Midland MI
    (765) 416-2879
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