Reply to: RE>goldfinish on PC boards Wolfgang: A general rule to follow is, "If the gold content of the solder joint is less than 2% by volume, the solder joint will have long-term reliability". With gold greater than 2%, the solder joint will become brittle and subject to cracking under thermal and/or mechanical stresses over the life of the product. This is based on an extensive test report published by Hewlett Packard at least 5-7 years ago. I do NOT have the report number. Maybe someone has a more recent report on the subject. Solder paste is ~50% by volume metal (90% by weight). Based on that rule, a board with 30uinch of gold must have at least 0.003" of solder paste to have good, reliable solder joints. Good Luck! Bill Fabry Truevision, inc. [log in to unmask] -------------------------------------- Date: 11/4/96 12:46 PM To: Bill Fabry From: Wolfgang ERAT Would appreciate any source for info on effects on solderjoint reliability when assembling (solderpaste / IR Reflow ) a full gold (approx 30 microinches thick) finished board. What are the effects of the gold alloying with the tinlead in the joint ? / Thank you. *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * *************************************************************************** ------------------ RFC822 Header Follows ------------------ Received: by rainbow.truevision.com with SMTP;4 Nov 1996 12:29:56 U Received: from ipc.org by simon.ipc.org via SMTP (940816.SGI.8.6.9/940406.SGI) id OAA28672; Mon, 4 Nov 1996 14:11:14 -0800 Resent-Date: Mon, 4 Nov 1996 14:11:14 -0800 Received: by ipc.org (Smail3.1.28.1 #2) id m0vKUCr-0000WYC; Mon, 4 Nov 96 12:57 CST Resent-Sender: [log in to unmask] Old-Return-Path: <[log in to unmask]> Message-Id: <[log in to unmask]> X-Mailer: DeskLink [Version B.02 95/10/31] MIME-Version: 1.0 Date: 4 Nov 96 13:11 +0500 Sender: [log in to unmask] (Wolfgang Erat) To: [log in to unmask] Subject: goldfinish on PC boards X-HPDESK-ID: 5627572 0 0 0 "NTMAIL " X-HPDESK-PRIORITY: 3 X-HPDESK-SYSTEM: 525 From: [log in to unmask] (Wolfgang ERAT) X-FROM: "Wolfgang ERAT"@[GBY/QC] X-HPDESK-TO: "A"@[[log in to unmask]] Content-Type: text/plain; Name="/HPOFFICE/NETMAIL/C0947488.txt" Content-Disposition: inline; Filename="/HPOFFICE/NETMAIL/C0947488.txt" X-HPDESK-SUBJECT: Message text Resent-Message-ID: <"aiyHd.0.fB3.snZVo"@ipc> Resent-From: [log in to unmask] X-Mailing-List: <[log in to unmask]> archive/latest/7370 X-Loop: [log in to unmask] Precedence: list Resent-Sender: [log in to unmask] *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * ***************************************************************************