OK, can anyone confirm this theory:Au over Cu means the Cu can diffuse into the AuAu-Cu alloy is very brittleTherefore I am seeing a very brittle FPC...?If this is the case, would a Ni barrier layer solve the problem?I am sure someone out there can answer this one and has been there, done that, got the T Shirt...(Mr Engelmaier usually has good answers to these types of questions...)NeilI've sent photos to Steve (I've been away from the Technet for a few years so forgot some of the rules).  I've just been told that there is possibly no Nickel on the part, only Au over Cu.Neil>----Original Message----> From: [log in to unmask]> Date: May 1, 2008 4:19:13 PM> To: [log in to unmask]> Subj: Re: [TN] Brittle FPC Tracks>>Hi Neil Your photo won't get passed through you need to send it to Steve Gregory who will post it for the forum. There is not much you can do at this point. I believe It is likely that the nickel it standard thickness which is too much for what you are trying to do I suspect.  I worked with Beta Phase 20 years back and we found that low stress nickel should be limited to about 50 micro inches (1.25 microns) Enough to serve as a barrier but thin enough to mitigate the cracking problem. You might get some other comments from the forum Best wishes in your effortsJoe  In a message dated 5/1/2008 8:08:42 A.M. Pacific Daylight Time, [log in to unmask] writes:    Flexible Printed Circuit used to connect to an LCD    >    >Photo attached.    >    >> ----Original Message----    >> From: [log in to unmask]    >> Date: May 1, 2008 1:45:13 PM    >> To: [log in to unmask]    >> Subj: RE: [TN] Brittle FPC Tracks    >>    >> What do you mean by FPC? Can you email me a picture of the components so    >> I can get a better understanding of what you are dealing with?    >>    >> -----Original Message-----    >> From: TechNet [mailto:[log in to unmask]] On Behalf Of [log in to unmask]    >> Sent: Thursday, May 01, 2008 3:15 AM    >> To: [log in to unmask]    >> Subject: [TN] Brittle FPC Tracks    >>    >> I have an FPC which plugs into a surface mount connector.  A very small    >> bend on the terminal end - i.e. > NiAu and has a stiffener on the back) results in the tracks cracking.     >I    >> have other FPCs on the same part which I can bend through 180 degrees    >> with no sign of cracking...    >> My questions are:    >> 1. Does anyone have any similar experiences and if so what could be the    >> causes?    >> 2. Is there any way of making the Cu Ni Au more ductile so it doesn't    >> crack (on parts already manufactured) Many thanks, Neil

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