Ed, Text book "Microelectronics Packaging Handbook" by R. Tummala et.al p.742 stated that: The ductility of the this (60/40 solder)solder with about 8% to 10% dissolved gold is practically zero. Although pure gold coatings provide an excellent surface for soldering, the coating thickness has to be kept to a minimum and under close control. The book also has list of references regarding the same issue...Good luck. jk At 03:28 PM 4/5/99 -0600, you wrote: >Please don't blast me on bringing this subject up again. I have searched >the TechNet archives and found lots of good information, and also noted that >it is a somewhat sensitive subject, having been around for 30+ years. We >have a condition that I believe is clearly unreliable based on what I have >read. The condition is: > >- 4 lead LCCC's (leadless with castellations) >- Approximately 50 microinches of glod plating on untinned castellations. >- Untinned parts mass reflow soldered onto PWB's (parts were supplied on >tape and reel, so subcontractors did not see that they were untinned). >- Microsectioning shows a 50 to 100 microinch layer of Au/Sn intermetallic >after soldering, on top of copper/nickel surface. Au concentration averages >about 25% in this intermetallic region. >- These assemblies will be subjected to high vibration and long term (years) >thermal cycling in actual use. > >Replacement of these parts would be expensive since they are on many boards >installed in closed and tested boxes. For this reason, mangement is hoping >that testing will qualify this condition. I hate to see the affected >program waste time and money, and am afraid they might even get a warm fuzzy >and fly these parts. > >Can any of the numerous industry experts in this group give me something >concrete to present to the program such as actual experiences or obtainable >reports? Is the above condition a no-brainer or is it not as bad as it >looks to me? I tried getting copies of the 2 reports listed in the >J-STD-001 Handbook, but struck out. > >Thank you for your time. > >Ed Knowles >Lockheed Martin >[log in to unmask] > >################################################################ >TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c >################################################################ >To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: >To subscribe: SUBSCRIBE TechNet <your full name> >To unsubscribe: SIGNOFF TechNet >################################################################ >Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. >For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 >################################################################ > ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################