======== Original Message ======== Sender: [log in to unmask] Received: from simon.ipc.org (IPC.ORG [168.113.24.64]) by dub-img-5.compuserve.com (8.6.10/5.950515) id LAA10184; Sun, 3 Mar 1996 11:57:29 -0500 Received: from ipc.org by simon.ipc.org via SMTP (940816.SGI.8.6.9/940406.SGI) id KAA05062; Sun, 3 Mar 1996 10:59:17 -0800 Resent-Date: Sun, 3 Mar 1996 10:59:17 -0800 Received: by ipc.org (Smail3.1.28.1 #2) id m0ttGwF-00006jC; Sun, 3 Mar 96 10:47 CST Old-Return-Path: <[log in to unmask]> From: [log in to unmask] Date: Sun, 3 Mar 1996 17:52:40 +0100 Message-Id: <[log in to unmask]> X-Sender: [log in to unmask] (Unverified) X-Mailer: Windows Eudora Light Version 1.5.2 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: [log in to unmask] Subject: FAB:Questions about pink-ring Resent-Message-ID: <"f5uEq1.0.oj4.HqSEn"@ipc> Resent-From: [log in to unmask] X-Mailing-List: <[log in to unmask]> archive/latest/2972 X-Loop: [log in to unmask] Precedence: list Resent-Sender: [log in to unmask] There are some things that I can't understand about the black oxide, pink ring and the use of DMAB Pink ring is the result of the attack of BO by acids in the electroless copper line. DMAB prevents this attack. The black oxide treated with DMAB can resist a lot of time in a 10% HCl solution but only a mom in a sulphuric/hidrogen peroxide solution. Then, why we don't have pink-ring using DMAB? The peel-off for the black oxide treated is lower than the non treated. During the drilling , I think it would be easier to delaminate. Again ,why we don't have pink-ring using DMAB? I would like to understand how DMAB works, because sometimes it doesn't do. Is there another systems to protect de black oxide? I would like also to find some papers, articles, etc. about this process. Thanks and excuse my bad english. Toni. ======== Fwd by: Tony King / N ======== I can state that DMAB does reduce the defect known as pink ring, I have used it for about 3 years with almost complete elimination of the defect. Control must be placed at the oxide process to insure adequate reduction, the reduced surface should withstand 5 minutes in a 5% sulfuric acid solution. This can easily be tested in production by placing a copper clad strip of material on each rack with the product, and then dip the test strip in a sulfuric solution afterwards for 5 minutes, a coating should still exist. The reduced oxide does reduce the adhesion, testing on light black oxide that yielded 7-8 lbs/in before reduction yielded 4.5-5.5 lbs/in after reduction. The real key to the process is the oxide coating itself, the thickness and color. Oxide is a combination of CuI and CuII, the percentage of each in the coating defines the color of the oxide and the chemical characteristics. I have seen that light black oxide (25-30 mg/sqcm) has the best performance with the DMAB reduction process. If oxide thickness exceeds 40-50 mg/sqcm the DMAB is not able to reduce the entire thickness of oxide and pink ring results. Some oxide solutions are more self-limiting in thickness than others, there can also be a problem with the self limited oxide coating, because even though thickness does not increase, the percentage of CuI/CuII does change. Extended dwells in a self limiting oxide bath also result in pink ring. The best way to control the quality of the oxide deposit is by monitoring the time required to initiate the DMAB reaction. The oxide coated product should initiate (begin to violently outgas) in the DMAB within 15-30 seconds after contact, if initiation is delayed beyond a minute the oxide should be reviewed (most people would expect the DMAB concentration to be bad however this is usually not the case). Standard oxide dwell time should be 3-5 min. at 160-170 F. If initiation is delayed on the 5 minute oxide coating, try reducing the time in oxide (within your operating window) to 4 min. Tony King Elexsys International Inc. Nashua, N.H. 603-886-0066