1.5 micron gold will have solderability problem anyhow... No exposed
copper (or no exposed base metal) should be part of purchesing
requirement... If nothing being specified...you asking for trouble. (if
it is mil-part, you are OK to return to the vendor... It is in the
Mil-std-xxx reference to another Mil-std-yyy and reference to .... Goes
on and on and on... Even it is not spelled out in the requirement, you
somewhat covered on the issue... Unless someone specifically made
"exception" ;-).
jk
>-----Original Message-----
>From: TechNet [mailto:[log in to unmask]] On Behalf Of
>Barmuta, Mike
>Sent: Thursday, July 24, 2003 6:35 PM
>To: [log in to unmask]
>Subject: Re: [TN] Gold plating shelf life and discoloration resolution
>
>
>Hi Joe: First a couple of questions to help answer your
>question: 1. Has the gold thickness been verified to be > 1.5
>microns on the actual parts? 2. What type of gold plating is
>it? 3. What is the type and thickness of the Ni plating? 4.
>What is the problem the discoloration is causing, is it
>solderability or is it a perception that they will be a problem?
>
>As for comments in general:
>1. If they were "properly" plated with electroplated 3-5
>microns of Ni followed by 1.5 microns of electroplated hard
>gold, the one year shelf life should not be a problem. Thinner
>or different types of plating could be problematic. With a
>proper Ni undercoat as specified I don't think the porosity
>should be an issue. I also don't understand the vendors
>comments on baking, doesn't make sense. If it's a
>solderability problem baking could make them worse and sure
>won't help the discoloration.
>
>2. As for the vendor, I feel they should have been willing to
>have some of the parts returned for analysis to determine if
>the were defective or not and if they met the drawing/spec.
>However you don't say whether it is a real problem or
>perceived, just that the parts are discolored. I think the
>vendor needs to know exactly what the issue is that he's being
>put on the spot for.
>
>
>
>Regards
>
>Mike Barmuta
>
>Fluke Corp.
>
>Everett WA
>
>425-446-6076
>
>
>
>-----Original Message-----
>From: Joe Fjelstad [mailto:[log in to unmask]]
>Sent: Thursday, July 24, 2003 2:56 PM
>To: [log in to unmask]
>Subject: [TN] Gold plating shelf life and discoloration resolution
>
>
>Hello friends from around the globe,
>
>Component time limits seem to be a sore spot these days. This
>brings to mind a related topic.
>
>You see, I have a friend with a problem...
>
>(I know what you might be thinking but the answer is: No, it
>really is not
>me ;-)
>
>At any rate, he received a quantity of ceramic chip carrier
>package shells with gold plated leads over a year ago and upon
>removing them from storage found many of them to be discolored
>near the copper/gold brazed welds (apparently due to moisture
>from micro pores in the welds) The welds with the micro pores
>were over plated with nickel and gold, with the final gold
>plated to an average of greater than 1.5µm (60 millionths of an inch).
>
>The vendor told him to bake them but it is hard to see how
>this will remove and discoloration. They are also refusing to
>replace or repair the parts nor will they say if the packages
>will be reliable in the field or take any responsibility for them.
>
>I realize that times are hard but the response seemed rather
>uncaring and not very service oriented.
>
>So the questions are:
>
>1) What is the consensus expectation for storage life of gold
>plated parts on a shelf in a benign environment with the
>plating series above?
>
>2) What is the concessus on how folks here feel that the
>vendor should respond?
>
>A) Replace the parts? B) Repair them? or C) Tell the customer
>to eat them?
>
>There are no right or wrong answers here. I am just looking
>for the valued opinions of the many here who spend every day
>in the trenches on this
>particular matter.
>
>Thanks in advance to all who respond.
>
>Kindest regards to all,
>Joe ---------------------------------------------------
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