Hi Victor, 
The great and all-knowing Wikipedia says hard gold often contains a small amount of cobalt or nickel.  
I am also not an expert, but I believe hard gold is an electrolytic process.  Although the electrolytic process can be stopped any time, typically target thicknesses are considerably thicker (30 micro-inches or more).  If you are looking at 5 micro-inches, I'd guess it is immersion gold.  The best action is to ask the supplier.  If that's not an option, try EDS looking for cobalt.  That's no guarantee, but positive results for cobalt would be informative.  5 micro-inches would be too thin to look for nickel.  Good luck.

Did I pass the test?


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of [log in to unmask]
Sent: Tuesday, November 01, 2016 7:19 AM
To: [log in to unmask]
Subject: Re: [TN] Test

Fellow TechNetters:

   I did not receive a response the FIRST time .   therefore I pose the inquiry once again.

“Is there a test or method to determine if gold plating is hard gold or ENIG?     XRF will determine thickness of gold but will not verify plating process.   I am working with a measurement of 5 micro inches of gold.”

Victor,

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of David Hillman
Sent: Tuesday, November 01, 2016 7:14 AM
To: [log in to unmask]
Subject: Re: [TN] Test

I don't know about the rest of the folks but I received an A+ and its rumored  you received a C-

Dave

On Tue, Nov 1, 2016 at 7:09 AM, Douglas Pauls < [log in to unmask]> wrote:

> And what percentage of our grade is this test?
>
>
> Doug Pauls
> Principal Materials and Process Engineer Rockwell Collins
>
> On Mon, Oct 31, 2016 at 9:17 AM, Vadim Matveyev 
> <[log in to unmask]>
> wrote:
>
> > Test
> >
>