All, made a mistake 19-microinches, NOT microns! Steve -----Original Message----- From: Vladimir Igoshev [mailto:[log in to unmask]] Sent: Friday, June 29, 2012 2:41 PM To: TechNet E-Mail Forum; Steve Gregory Subject: Re: [TN] Gold Embrittlement Calculator For that THICK layer of Au it does. Honestly, I don't remember seeing any component with that thick Au plating. One should also keep in mind that bulk percentage of Au in a solder joint may be "deceptive". All it takes is to have enough Au in a narrow band to form Au-Sn intermetallics and cause Au embrittlement. Regards, 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: Steve Gregory <[log in to unmask]> Sender: TechNet <[log in to unmask]> Date: Fri, 29 Jun 2012 14:05:33 To: <[log in to unmask]> Reply-To: TechNet E-Mail Forum <[log in to unmask]>, Steve Gregory <[log in to unmask]> Subject: [TN] Gold Embrittlement Calculator Hi All, Gonna' be another hot weekend here in the Northeast! Mid 90's all weekend long with heat index up around 100. Anyways, I found this excel spreadsheet calculating percentage of gold in a solder joint that was created by Melissa Lau of Lockheed Martin. The link to it is here: http://circuitsassembly.com/cms/magazine/95/3630_ I'm just wondering if I'm using it right. For instance I'm trying to determine what the gold percent is for an 0402 resistor pad on a board that has 19 microns of gold on it and using a 4-mil thick stencil. I looked at a Vishay data sheet and I get a lead termination of roughly 10-mils long X 20-mils wide X 14-mils high. The next input is for lead plating, there's already a .5-mil input there so I'm just going to leave it at that. I can't find what the lead plating thickness should be in the datasheet. The opening in the stencil is 23-mils X 25-mils and it's a 4-mil thick stencil, so I have to change the formula in the cell under the column "Solder Paste Wt" since it's based on a 6-mil thick deposit. The gold is 19-microns thick, so that converts over to .748-mils. What I wind-up with is a solder joint with 36.5% wt in gold! Does that sound right? Steve ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________