Hi Jon - the IPC JSTD 006 document is a baseline material specification with specific solder alloy composition requirements and does not contain solder application requirements (that is the responsibility of the user to determine if a particular solder alloy is applicable for their product). Antimony does inhibit tin pest but so does other solder alloy constituent elements (Pb, Bi,) so the historical misrepresentation has been that antimony is the element responsible for tin pest elimination which is not correct. Don't think of it as our parents lying, our mentors just had a skewed perception! : - ) Dave "Roberts, Jon (SA-1)" <[log in to unmask]> Sent by: TechNet <[log in to unmask]> 01/21/2010 10:35 AM Please respond to TechNet E-Mail Forum <[log in to unmask]>; Please respond to "Roberts, Jon (SA-1)" <[log in to unmask]> To [log in to unmask] cc Subject Re: [TN] Antimony in solder Where antimony is reference in IPC and I have one question related to the ongoing testing. Antimony is reference in: IPC-J-Std-001D in Par 3.2 uses the letter A and B after the three for solder alloys. The letter ties back to IPC-J-Std-006 Par 3.3.1 through 3.3.3 for maximum amount of antimony. Question: Does the testing included temperature changes with extreme cold condition? Just curious. Technet discussions are extremely valuable to myself. Finding out the purpose of antimony to help prevent tin pest is not real is like finding out your parents lied to you all those years. I thank all of you for your expertise, Jon -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Graham Collins Sent: Thursday, January 21, 2010 5:23 AM To: [log in to unmask] Subject: Re: [TN] Antimony in solder Technet is a great resource, thanks Dave, Mike, and everyone else who has chimed in here. If I'm understanding what has been said here, I am concluding about Sn63Pb37Sb.4A the following: 1) based on the responses it does not sound like a popular alloy choice (nobody here has said "I use it because...") 2) Adding antimony improves wetting 3) tribal knowledge suggests other benefits, such as avoidance of Tin Pest, not substantiated by data. Am I missing or misunderstanding anything? regards, - Graham -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of David D. Hillman Sent: Wednesday, January 20, 2010 7:45 PM To: [log in to unmask] Subject: Re: [TN] Antimony in solder Hi folks! Just a couple of comments to add to the discussion. Antimony gives solder a number of beneficial characteristics including wetting and tin pest resistance as has been mentioned in our TechNet discussion. Bev Christian and I published a paper at the 2006 SMTAI Conference on tin pest which did indeed show that the potential of tin pest in a solder joint is not very probable. In fact , I am still monitoring those test assemblies and after 4.5 years, we still have no tin pest phenomena occurring (I gave an update of the investigation at the 2008 SMTAI Conference). As part of the 2006 paper/ investigation, I pulled a bunch of literature references which turned into a very fascinating tour of the industry solder specification evolution. Antimony was part of several industry research projects by Becker and Borneman in the late 1950's. Their data (including the role of antimony) was part of the basis for the ASTM and QQ-S-571 specification requirements. When the QQ-S-571 specification was replaced by the IPC-JSTD-006 specification, there was a huge debate on the necessity of antimony and unfortunately most of discussions were based on tribal knowledge instead of looking at the original investigation data/results. Some very good summary papers were published by the International Tin Research Institute (Thwaites, McKay, etc) which allowed the industry committees to work out a compromise of "violent agreement". The literature search was a great demonstration of how industry investigation results evolve over time and sometimes get positively/negatively mutated in ways the never imagined. Dr. Chris Hunt and Dr. William Plumbridge have published some very good papers in the last couple of years expanding our knowledge of the tin pest phenomenon. Dave Hillman Rockwell Collins [log in to unmask] Mike Fenner <[log in to unmask]> Sent by: TechNet <[log in to unmask]> 01/20/2010 11:19 AM Please respond to [log in to unmask] To [log in to unmask] cc Subject Re: [TN] Antimony in solder There are many myths about tin pest, some of them you really want to be true like: the reason Napoleon lost against the Russians was that the French Uniform buttons were made of tin, they succumbed to tin pest and their trousers all fell down...... Our European office gets about 3 tin pest questions a year, but it never is. The failures are due to more boring things like poor wetting, inappropriate joint design and so on. Or sometimes people report tin pest when they mean tin whiskers. NPL here did look into this quite thoroughly. You can get their report on line, a very nice piece of science. More dramatically satisfying you can see video from their research showing tin pest eating a lump of tin. They concluded tin pest was not a worry and so far as I know there has NEVER been a proven case of tin pest in electronics. Presence or absence of 0.X%Sb in tin is not significant compared to ~40% Pb. Possibly the Sb made the solder harder/stronger, but more likely other changes were made as indicated above. Regards Mike Mike Fenner, Technical Manager Indium Corporation Europe Mob: + 44 7810 526 317 Skype: mike.fenner Tel: + 44 1908 580 400 Fax: + 44 1908 580 411 www.indium.com --------------------- Indium Corporation Incorporated in New York, USA Registered office: (Not for correspondence) 77-97 Harpur Street, Bedford , UK Registered number: fc16473 * Please think before you print -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Roberts, Jon (SA-1) Sent: Wednesday, January 20, 2010 4:35 PM To: [log in to unmask] Subject: Re: [TN] Antimony in solder I was always trained during my early years working with the Cat A under the WS6536, DoD Std 2000, etc days that Bev stated to reduce tin pest. I was informed that during the cold war in the 70's that line of radars were installed in the northern part of Canada to detect incoming missiles attacks. The extreme cold temperature caused solder failures related to tin pest or was attributed to tin pest. I believe my Cat A without question. Anyone else remember being told that? I am one of the older ones here. Jon -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Bev Christian Sent: Wednesday, January 20, 2010 9:56 AM To: [log in to unmask] Subject: Re: [TN] Antimony in solder Graham, I think it was historically added because of a fear of tin pest. Which is weird since lead is an excellent deterrent to tin pest. Bev -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Nigel Burtt Sent: Wednesday, January 20, 2010 10:51 AM To: [log in to unmask] Subject: Re: [TN] Antimony in solder Antimony affects wetting speed Useful reference here: http://www.kester.com/en-us/documentation/EffectsofMetallicImpurities.pd f Nigel --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- This communication is intended only for use by the addressee(s) named herein and may contain business confidential and/or legally privileged information. 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