A nano-indenter with a Berkovich tip is suited for this application, a
round tip is a close second.

Reference:
Gane, N., and J. M. Cox. "The micro-hardness of metals at very low
loads." *Philosophical
Magazine* 22.179 (1970): 0881-0891.


On Wed, Nov 2, 2016 at 1:07 PM, George Wenger <[log in to unmask]>
wrote:

> Richard,
>
> I'm confused with your post. Your statement about Vickers hardness test
> can tell the difference in hardness between 5 uinches of "hard" gold from
> ENIG, which is immersion plated and the approximately 40 uinches of soft
> gold used for wirebonding is just not correct. First the 5 uinches of
> immersion gold plating on ENIG is "soft" gold not "hard" gold. Secondly,
> you really can't use Vickers to measure the hardness of 5 uinches of
> immersion gold on ENIG. Five uinches of immersion gold is too and the
> Vickers hardness measurement will really give you an indication of the
> hardness of the underlying electroless nickel. I know there are people in
> the industry who are trying to use nano-hardness measurements to measure
> the hardness of thin platings but I haven't seen any encouraging results
> that it is accurate.
>
> George
>
> ----- Original Message -----
>
> From: "Richard D. Stadem" <[log in to unmask]>
> To: [log in to unmask]
> Sent: Wednesday, November 2, 2016 9:15:17 AM
> Subject: Re: [TN] Test
>
> I agree. The Vickers hardness test I posted at the beginning of this
> thread is the best method. It can tell the difference in hardness between 5
> uinches of "hard" gold from ENIG, which is immersion plated and the
> approximately 40 uinches of soft gold used for wirebonding applications.
> Remember the original question was if there is a test to determine if the
> finish is hard or soft gold, not the thickness.
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Gerry Gagnon
> Sent: Wednesday, November 02, 2016 7:59 AM
> To: [log in to unmask]
> Subject: Re: [TN] Test
>
> Andy I'll give you a pass! More detail for history buffs.
>
>
> If we are talking about a true hard gold for hi-rel connector/contact/PWB
> Tab applications, we are talking about a cobalt modified gold electroplated
> from an acid gold cyanide solution electro-plated over a low stress nickel.
> Solution looks like grape Kool Aid.
>
>
> The test for determining the hardness of the gold is to use a Vickers
> diamond indenter. Be aware that to do the test, you must electroplate a
> thick deposit of gold from the production plating bath over the nickel. I
> remember using 200 micro-inches minimum gold thickness for the test. The
> reason for the heavy thickness is to be sure there is plenty of bulk gold
> below the indenter, otherwise you are testing the hardness of the nickel
> under-plate, copper, and laminate.
>
>
> Hard gold plated to 100 micro-inches over 300 micro-inches will pass the
> "old" nitric acid porosity and easily pass the more modern variants using a
> few "wiping type" connector insertions before the nitric acid porosity test
> (which is worst case (compared to a LIF or ZIF.
>
>
> Due to gold cost, the thickness went down to 70 micro-inches, then 50,
> then 30, then 15, to the point of who cares. None of this stuff will pass
> the original nitric acid test.
>
>
>
>
> ________________________________
>
> From: TechNet <[log in to unmask]> on behalf of Giamis, Andy <
> [log in to unmask]>
> Sent: Tuesday, November 1, 2016 10:45 AM
> To: [log in to unmask]
> Subject: Re: [TN] Test
>
> 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
> > >
> >
>



-- 
Bhanu Sood
Tel: (202) 468-8449