Thank you very much Anil.
You confirm my suspicion and give me confidence to recommend to my customer to dig deeper (as the others have suggested, on and off-line).
I will also recommend MIL-DTL-45204 type qualification and periodic conformance.
Chris
-----Original Message-----
From: Anil kher [mailto:[log in to unmask]]
Sent: Saturday, July 23, 2011 5:26 AM
To: Chris Mahanna; [log in to unmask]
Subject: RE: hard gold verification
To test hard gold on plating of 1 to 4 micron is not easy. Procedure is - a supplier with very reliable process control and proper documentation of bath maintenance.
Then every 6 months you get a 40 micron gold plated sample and do a test on micro hardness. Then if the bath is maintained at same levels you get reliability. The tracking of Co content is ok to maintain control. Nickel in plating is poor bath working - may be new supplier - whose nickel plating bath is getting dragged into the gold.
Yr customer shd be worried abt wear resistance than pure hardness. If its serious business get in touch offline Anil Kher
Managing Director
Micro Interconnexion Pvt. Ltd.
D3-12A Corlim Ind. Estate, Corlim, ILHAS Goa, India, 403110
+91-832-2284209/ 337
alt email : [log in to unmask]
LEADERS IN GOLD PLATED PCBs
-----Original Message-----
From: Chris Mahanna [mailto:[log in to unmask]]
Sent: Thursday, July 21, 2011 9:51 PM
Subject: hard gold verification
Hello netters
We are an independent test facility. Occasionally we are asked to verify hard gold as part of bare board qualifications.
Our customers in these cases are usually the OEM supply chain QA. The buyer controls the source and Quality's only prayer is to run some first articles through a 3rd party.
Our customer's chance of determining the hard gold formula used on his boards is slim to none. If it weren't for UL, they probably wouldn't even know who supposedly built them.
Some time ago, we tried Nano-indentation and there is a related TechNet thread. It didn't work for us.
I assumed wear studies might be cost prohibitive, so we went to looking for 0.2% cobalt by SEM-EDS. This has worked nicely, until today.
Today we have 0.09% Co and 0.07% Ni. From what I read, 0.1 Co is easily explained by too rapid deposition, and hardness suffers greatly. The question is whether the Ni is supposed to be there as a hardener or not? If yes, then 0.16% total is probably in the ballpark. But what are the chances it just got dragged there? Does it matter?
Thanks in advance
Chris
Chris Mahanna
Robisan Laboratory Inc.
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