De-zincification is a problem only if subjected to a corrosive environment or submerged in an electrolyte with other metals. I doubt ImAg would be sufficient to slow this process down. I might want electroplated nickel or tin for that. I've seen other posts on TechNet which panic over exposed brass, so I did some long term tests with relatively high current densities and Pb based solder--absolutely no issues. And the dissolution rate of brass into molten solder appears to be at least as low as copper. If it's an outdoor location subjected to salt spray, I'd certainly want it coated, but I see no reason why it should be looked at as more susceptible to failure than standard leaded components (which will always be conformal coated for harsh environments). Wayne -----Original Message----- From: Rex Waygood [mailto:[log in to unmask]] Sent: Tuesday, September 21, 2010 11:30 AM To: TechNet E-Mail Forum; Thayer, Wayne - IIW Subject: RE: [TN] Solderability of nickel plating Does the ImAg stop de-zincification? Rex -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Thayer, Wayne - IIW Sent: 21 September 2010 16:22 To: [log in to unmask] Subject: Re: [TN] Solderability of nickel plating Why nickel? I use ImAg over brass for lots of stuff around here. Works great, but will tarnish over time. Wayne -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Glidden, Kevin Sent: Tuesday, September 21, 2010 9:38 AM To: [log in to unmask] Subject: Re: [TN] Solderability of nickel plating OK, pardon the lack of knowledge, but why is that? I also see reference to nickel-boron platings, which supposedly improve both conductivity and solderability for electronics applications. Is it recommended then that I need to apply gold over the EN on this electrical tab? A portion of it is soldered (internally) and a portion of it remains exposed for connection (think 120V plug tabs). The base material is brass. Kevin Glidden Manufacturing Engineer Astronics Luminescent Systems Inc. -----Original Message----- From: vladimir Igoshev [mailto:[log in to unmask]] Sent: Tuesday, September 21, 2010 9:24 AM To: TechNet E-Mail Forum; Glidden, Kevin Subject: Re: [TN] Solderability of nickel plating Kevin, You wouldn't want to solder directly to unprotected E-Ni. Vladimir SENTEC Testing Laboratory Inc. 11 Canadian Road, Unit 7. Scarborough, ON M1R 5G1 Tel: (416) 899-1882 Fax: (905) 882-8812 www.sentec.ca -----Original Message----- From: "Glidden, Kevin" <[log in to unmask]> Sender: TechNet <[log in to unmask]> Date: Tue, 21 Sep 2010 08:52:39 To: <[log in to unmask]> Reply-To: TechNet E-Mail Forum <[log in to unmask]>, "Glidden, Kevin" <[log in to unmask]> Subject: [TN] Solderability of nickel plating All, Can anyone comment on the solderability of the nickel plate, particularly with regard to type of plating: high phosphor / low phosphor, and also storage conditions: I've been gathering info, and seen conflicting information. From one article: http://corrosion-doctors.org/MetalCoatings/Electroless.htm A paper submitted at the Electroless Nickel conference of 1989 held in Cincinnati Ohio, Titled "Solderability Parameters of Elecroless Nickel Bearing Electronic Finishes" By Louis Kosarek of STB Systems, Inc. report that "An electroless nickel deposit which contains a concentration of phosphorus ranging from 0.1% to 3.0% is readily solderable on an "As-plated Basis" per Mil-Std 883c method 2003. The frequency of solderability tests which fail per Mil-Std 883c will increase as the phosphorus content of electroless nickel alloy increases from 3.0 to 7.0% phosphorus. A solderability test conducted per Mil-Std 883c method 2003 incorporating an as-plated surface finish containing phosphorus in excess of 7%, the components will consistently fail. The mode of failure is non-wetting of the surface." This indicates low phosphorous plating is best for solderability. Many other papers seem to agree with this. ------------------------------------------------------------------------ --------------------------------------------- From another article: http://www.pfonline.com/articles/pfd0024.html Solderability/Weldability. An important aspect of electroless nickel to the electronics industry is its solderability. All electroless nickel deposits are solderable provided the soldering conditions are matched to the condition of the particular electroless nickel deposit. Lower-phosphorus electroless nickel is more easily solderable immediately after plating than higher-phosphorus electroless nickel. However, this advantage disappears after 12 - 24 hrs. At this point, the ease of solderability depends upon the characteristics of the passive layer that forms on the surface of the electroless nickel deposit. Those deposits plated from baths containing heavy metal and sulfur-bearing brighteners and stabilizers, such as most commercial low- and mid-phosphorus electroless nickel systems, form a thicker tenacious passive layer than those that do not, such as most high-phosphorus electroless nickel systems. High-phosphorus electroless nickel systems tend to be more solderable in aged deposits. Other important factors influencing the solderability of electroless nickel deposits include residual contamination left on the surface after plating and storage conditions after drying. Surface contamination and exposure to environments containing sulfur dioxide, chlorine, high humidity and high ambient temperatures will detrimentally affect solderability. Therefore, it is imperative that parts be thoroughly rinsed in clean DI water, dried and stored in a cool, dry atmosphere, preferably nitrogen. This article indicates high phosphorous plating is best for long term solderability, and also that parts must be stored carefully (cool, dry, sealed, nitrogen). Other articles seem to state this is a highly stable finish and is even used as a corrosion inhibitor. Thanks, Kevin Glidden Manufacturing Engineer Astronics Luminescent Systems Inc.<http://www.astronics.com> 4 Lucent Drive Lebanon, NH 03766 (603) 643-7766 x3152 Please note, LSI operates on a 9/80 work schedule, and is closed on alternating Fridays. Please click the link provided to view the days LSI will be closed. http://www.astronics.com/LSI/documents/2010calendar-NH.pdf NOTICE: This communication is intended specifically for the recipient(s) named above and may include proprietary, confidential or privileged information. If you are not a named recipient, you should immediately delete or destroy all electronic and physical copies of this communication. 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