---------- From: Crawford, John A. To: TechNet-request Subject: RE: Ni contamination Date: 6 Sep 95 1:20PM Following from the EMPF in Indianapolis: Jeff Kukelhan, our solderability expert prepared this suggestion. My guess is that the insulative substance is nickel oxide. It is very tenacious, and gives nickel some of its corrosion resistant properties. You might have them try spot plating the area in question with gold or palladium. These are corrosion resistant, relatively soft, and make excellent electrical contacts. If you would like to discuss this you can phone the EMPF HelpLine at 317.226.5616. We can do an analysis for you within our frame of 16 hours free consulting and determine exactly what the contaminant is if you prefer. ---------- From: TechNet-request To: Technet Subject: Ni contamination Date: 6 Sep 95 10:41AM Return-Path: <[log in to unmask]> Resent-Date: Wed, 6 Sep 1995 10:07:48 -0500 Old-Return-Path: <miso!hadco.com!dhoover> Date: Wed, 06 Sep 95 10:41:18 EST From: [log in to unmask] Encoding: 1489 Text Message-Id: <[log in to unmask]> To: [log in to unmask] Subject: Ni contamination Resent-Message-ID: <"pQTOC2.0._PD.sFRJm"@ipc> Resent-From: [log in to unmask] X-Mailing-List: <[log in to unmask]> archive/latest/1031 X-Loop: [log in to unmask] Precedence: list Resent-Sender: [log in to unmask] ---------------------------------------------------------------------------- -- I manage a captive PWB shop that produces 4,000 square feet per week of double sided plated thru hole product from .062 FR-4 copper laminate. Our product is a bit uncommon in that it has about .0004 inch hard nickel plated over the copper traces. Thru testing, we find a VERY thin layer (maybe 150 angstroms) of some contaminate that affects the surface conductivity when it is used as a switch half with a stainless steel snap dome. Using a Scotchbrite pad to burnish the surface provides a solution, but I would like to know the source of the substance and how to prevent it in the original process. Any ideas on the subject? Have it analyized. Try Auget (OJ) testing. You'll probably find that one of your post Ni Plate processes is depositing the film and producing the contaminate. Nickel is also prone to passivation when it's alone and left exposed for some time or exposed to thermal excursions. (eg, high temp bakes) Hadco Printed Circuits Tech Center Two / Watsonville _/_/_/_/_/_/_/ _/_/_/_/ _/_/_/_/_/_/ _/_/_/_/_/_/ _/_/ _/ _/_/ _/_/ _/_/ _/ _/_/ _/_/ _/_/ _/_/_/_/ _/_/_/_/_/_/ _/_/_/_/_/_/ Dave Hoover (408) 728-6677 Senior Process Engineer (408) 728-1728 Fax [log in to unmask]