The paper was written many years ago and I am still looking for it so it too can be made available. With more than 75 publications over 40 years some do get away form you but I will continue to search but the cause was discontinuous exposed metal in the metal/glass frit that was plated with nickel for a Ni barrier on the terminations that trapped the plating solution. This was discovered while evaluating competitors parts while working in a former life. The video was the third or fourth take as the engineer that worked for me and I were laughing so hard that it was distracting to viewers so we had to reshoot the video with fresh parts several times.

John
Sent from my iPad

On Feb 13, 2013, at 3:34 AM, Victor Hernandez <[log in to unmask]> wrote:

> Steve,
> 
>   This is a great video of ceramic resistor tomb stoning on hot plate.   A picture of the suggested cross section interface showing the suspected anomaly.   A picture is worth one thousand words.
> 
> Victor,
> 
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
> Sent: Tuesday, February 12, 2013 9:07 PM
> To: [log in to unmask]
> Subject: Re: [TN] Requesting TechNet Assistance
> 
> Hi John!
> 
> Got your clip and have it posted. Folks can view it here:
> 
> http://stevezeva.homestead.com/1206_BME_Splatter.wmv
> 
> Steve
> 
> -----Original Message-----
> From: John Maxwell
> Sent: Saturday, February 09, 2013 6:16 PM
> To: [log in to unmask]
> Subject: Re: [TN] Requesting TechNet Assistance
> 
> Inge,
> Some time ago I wrote a paper about trapped plating salts, typically nickel sulfamate solution that is trapped as the nickel barrier is plated. This happens when the termination metal glass frit has gaps between metal particles and the nickel bridges gaps trapping the plating solution that boils nicely during reflow. I still have a fun video showing parts hopping about on a hot plate. If Steve's web page is still available we could put it up for everyone's enjoyment.
> 
> John Maxwell
> Sent from my iPad
> 
> On Feb 9, 2013, at 4:06 AM, Inge Hernefjord <[log in to unmask]> wrote:
> 
>> Bill,
>> me again, while looking for references, it struck me that your 
>> resistor end terminations can be thickfilm made and not plated as I 
>> suggested.
>> Thickfilm, whatever type Ag, AuAg, AuPd etc is sometimes porous as a 
>> sponge. Some are designed for attaching by adhesives and are less good 
>> for soldering, because the porosity sucks wet chemistry when you flux, 
>> and in the solder reflow all those volatiles want to come out, 
>> sometimes resulting in real outbursts. So, the quest ion is what 
>> terminations you got:  Au, Au/Ag, Ag, tinned, electroplated, 
>> electroless plated?
>> 
>> Inge
>> 
>> On 8 February 2013 17:55, Inge Hernefjord <[log in to unmask]> wrote:
>> 
>>> Bill, old & well documented. We may seemingly have to do with 
>>> 'farting chps' .Many  finish processes (in fact ALL) leave built-in gas e.g.
>>> hydrogen. Normally the main part of voids in solder joints are from 
>>> the chemistry of the solder paste, and the addition of voids from 
>>> termination gas is negligable, but the opposite can happen if the 
>>> component maker doesn't have good control on the plating process, in 
>>> fact, the outgassing can be so violent that the slder looks like 
>>> whipped cream, which is also what we call it. A blowhole, even large 
>>> ones, do not affect the solder joint strength, but depending on what 
>>> customer you have, it can be seen as bad workmanship. What to do 
>>> then? we simply performed single point soldering of the bad joints 
>>> or, if the bad guys were many, fluxed the board and let it go through 
>>> the soldering once more. You know, the gas generation from the 
>>> terminations can't fart a second time.
>>> 
>>> Inge
>>> 
>>> 
>>> On 8 February 2013 03:56, <[log in to unmask]> wrote:
>>> 
>>>> Fellow TechNetters:  Recently having a problem with solder fillets 
>>>> on various SMT assemblies, we are observing an outgassing in the 
>>>> concave portion of the solder fillet of various resistor package 
>>>> sizes.  Specifically, 0603, 0805, and 2010 packages.  The outgassing 
>>>> is either a slight, hollow bump or a "blowhole" and always in the 
>>>> center of the fillet.  If we observe the condition, we switch the 
>>>> reel, and the problem generally goes away.
>>>> 
>>>> It is only happening with resistors, not any other SMT package.  The 
>>>> observations have now occurred in two separate facilities, with the 
>>>> reels of resistors having date codes from 2009 thru 2011.  We have 
>>>> not changed solder paste, using a no-clean paste from a major 
>>>> manufacturer.
>>>> 
>>>> Is anybody having issues with SMT resistors?  Can anyone shed any 
>>>> light on this absolutely random issue?
>>>> 
>>>> Your thoughts and comments are greatly appreciated.
>>>> 
>>>> THANK YOU,
>>>> Bill
>>>> 
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