Good advice, TIM.
I'll have an eye on the pin plating. As AMP says in the article, corrosion will not start if there is proper barrier and a dense gold. These connectors are circular bayonet, ordinary MIL type, and use to be very tough, but the inside was not meant to be exposed to corrosive liquid.
The AMP paper was a good lesson, I have saved it and distributed copies to companeros here.
Once again, many thanks!
Ingemar
-----Original Message-----
From: Tim Reeves [mailto:[log in to unmask]]
Sent: den 11 juni 2003 19:20
To: Ingemar Hernefjord (EMW); [log in to unmask]
Subject: RE: Technical question, Vigon cleaning
Porosity of gold plating may be an issue. There are tests for gold porosity and Tyco/AMP has done work on this. I dealt with it in a case of a connector circuit board for a cable used for surgical equipment where the unit, cable and all, had to be sterilized in a dilute aqueous solution of peracetic acid, which is corrosive. The edge connectors, gold with Ni underplate over copper, corroded after several cycles (I don't know how many) of sterilization.
There are IPC test methods for testing gold porosity as well. IPC-TM-650 2.3.24 et al.
I know they at one time had a paper on their website dealing with gold porosity but I can't find it now. Here's a link to a more general paper, perhaps you could contact one of the authors of some of the other papers. It looks like Glenn Staudt would be quite knowledgeable in this area, based on the papers authored or co-authored by him. I don't know Mr. Staudt, so if you contact him, let him know the basis for my referral. (It's a guess)
http://www.amp.com/PRODUCTS/TECHNOLOGY/aurulrep.pdf
Tim Reeves
-----Original Message-----
From: Ingemar Hernefjord (EMW)
[mailto:[log in to unmask]]
Sent: Tuesday, June 10, 2003 3:54 AM
Subject: Technical question, Vigon cleaning
Hi,
thought I might interrupt all social q with a tech one?
Had a chat with Brian long ago about the highly alcalic A200. Today, actual story: We have made a mistake, machine washed circular receptacles after we had mounted flexes on the backside (of the receptacles). This cleaning agent penetrated to the inside of con body, because it's not potted. Now, that volume consists of numerous gold plated pins, with or without filter caps. Obviously, the A200 caused serious damage to the inside, because we got corrosion, leakage current, and finally ignitions. Connector body is P nickel plated aluminium, and even the body's inside was attacked by some type of corrosion. The corrosion products are blue-green (between pins) or colourless (body inside). EDAX gives high Cl+Cu for the blue-green stuff and high Cl+Ni for the body ditto. The 'dielectric' material, which separates the pins and also tries to make connector tight, is a fluorized silicon + unknown assistive polymer.
Question is how the corrosion can start so early in the product's life and also how it can go so far, remembering that the pins are goldplated, and that the aluminium body has a very thick and dense nickel plate.
We have changed to Isopropanol, and have no such problems any more, but we were really scared by the Vigon disaster. Anyone with similar experience?
Ingemar Hernefjord
Ericsson Microwave Systems
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