opps, Many thanks for Wayne to point out.  I did calculation mistake. 
0.038 micron is 1.5 micro-inches.  still thin.  my apology... getting
really old.
          jk
>
 Concur, IMHO,  below 2uin, and depending on it's porosity,  Au is unlikely
> to protect the Ni from passivating.  A traditional spec would be on the
> order of 6 +/- 4uin with suppliers typically shipping at between 2 and
> 3uin..
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Joyce Koo
> Sent: Friday, October 09, 2015 5:53 AM
> To: [log in to unmask]
> Subject: Re: [TN] Solder joint peel off from ENIG board
>
> does not like to have that much gold... 0.038 micron is less than 1
> micro-inch of gold.  you might have Ni oxide on surface to prevent good
> joint... you might also have some Cu oxide on the surface, if your Ni
> plating is crappy and porosity is high... can't see picture... did you buy
> cheap?  (based on the amount of gold you are having).
>> EDS doesn't normally show the correct P content you begin with.Â
>>
>> I can not see any images.
>>
>> ‎Regards,
>>
>> Vladimir
>> SENTEC
>>
>> Sent from my BlackBerry 10 smartphone.
>>   Original Message Â
>> From: Deng RongJun
>> Sent: Friday, October 9, 2015 10:13
>> To: [log in to unmask]
>> Reply To: TechNet E-Mail Forum
>> Subject: [TN] Solder joint peel off from ENIG board
>>
>> Hi all:
>>
>>
>> I have got a solder joint strength issue on ENIG board, the cables
>> soldered on board can be easily detach from pads by a small external
>> force(1kg), the cable mounting process is hand soldering. Failure rate
>> is about 20%.
>>
>>
>>
>> We have made SEM and EDS test for solder joint and peel off surface, P
>> Wt% is high than normal. And we have also made SEM test for 10pcs bare
>> board, the Au thickness is 0.038-0.05um, Ni thickness is 2.8-4.0um.
>>
>>
>>
>> As I know high P Wt% will affect solder joint strength, what issue is
>> happened during PCB fabrication process? Anybody know anything about
>> this?
>>
>> Here comes pictures:
>> http://pan.baidu.com/s/1sjl7Ynb
>>
>> Best regards
>> Deng
>>
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