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-----QQ-N-290 Ductile Nickel Equals What New SAE AMS Standard?
May 12, 2009
We have an specification developed internally for plated contacts fabricated at outside vendors. It calls out a "ductile nickel underplate per QQ-N-290A [link is to free spec at Defense Logistics Agency, dla.mil], 0.0001 inch over copper strike".
I have been told that the QQ-N-290 spec has been superseded by a family of various SAE specifications for nickel plating such as
AMS2403, AMS2423, and AMS2424. I want to update our spec to reflect the proper SAE AMS spec. Can anyone point me in the right direction? Thanks in advance for the insights and assistance.
Quality Inspector - Houston, Texas
Paragraph 1.2 of AMS2403 says
"This process has been used typically to provide moderate corrosion and oxidation resistance to metal parts but without control of other characteristics, and for the buildup of surfaces, but usage is not limited to such applications. If a hard plate is required, AMS2423 should be used; if a low-stressed plate is required, AMS2424 should be used."
So for just the ductile nickel that I'd expect QQ-N-290 to have provided, I'd likely call out AMS2403. Of course, I'd also likely call up my plating supplier and ask for their recommendation, after explaining my application.
Lee Gearhart
metallurgist - E. Aurora, New York
June 2, 2009
Oops! Looks like I spoke too soon in my previous answer!
I found this, from a recent ballot in Committee B:
"AMSQQN290 A was cancelled and superseded to AMS2403 and AMS2423 by AMS Committee B. This ballot proposes reinstatement as AMSQQN290 B. Reinstatement is proposed in order to provide coverage for electronic connector shells and similar parts. Those parts, procured to MIL-DTL-38999, require special qualification which may be jeopardized if all parties do not agree upon the technical equivalence of any superseding specification. This action to reinstate as AMSQQN290 B was authorized by AMS Committee B at the October 2008 (Colorado Springs) meeting as a stop-gap measure to allow additional efforts to resolve any issues concerning technical equivalence and to ensure that the ultimate supersedure of AMSQQN290 includes correlations that are understood by these stakeholders."
So we've done that- we're re-instating AMSQQN290, pretty much as it was, but still suggesting that for new designs people consider using AMS2403 and AMS2423. The re-instatement is being balloted to Aerospace Council, and the balloting closes June 30, 2009. If passed, it will be published soon after that.
Lee Gearhart
metallurgist - E. Aurora, New York
June 3, 2009
So is it fair to say the QQ-N-290B is now in effect?
Teresa Kleemeyer- Cincinnati, Ohio
July 23, 2009
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