Rod Martens wrote:

>      Here are the ASTM specs for determining porosity:
>
>      Standard Test Method for Porosity in Gold Coatings on Metal
> Substrates
>      by Nitric Acid Vapor, B735-89.
>
>      Standard Test Methods for Porosity in Gold Coatings on Metal
>      Substrates by Paper Electrography, B741-90.
>
>      Standard Test Method for Porosity in Metallic Coatings by Humid
> Sulfur
>      Vapor ("Flowers-of-Sulfur"), B809-90.
>
>      Standard Guide for Selection of Porosity Tests for
> Electrodeposits and
> Related Metallic Coatings, B765-86.
>
> Editorial comments - These are all subjective tests designed to
> "decorate"
> pores in noble platings for determining the degree of porosity.  They
> do
> not have acceleration factors such as x hours in the nitric acid
> environment = x hours in the field.  You have to look to MFG testing
> for
> that. Enjoy!
> Rod Martens
> Hewlett-Packard.
>
> ______________________________ Reply Separator
> _________________________________
> Subject: Re: [TN] Contact resistance
> Author:  Non-HP-ddhillma ([log in to unmask]) at
> HP-ColSprings,mimegw4
> Date:    3/12/98 6:47 AM
>
> Hi Gaby - you could use SERA to determine the extend of the gold
> plating
> porosity but it won't tell you anything direct about contamination.
> Give
> Mike Pavlov or Peter Bratin an email at [log in to unmask] for more help.
> I
> have had some success and some failures using the SERA tester for
> noble
> metal porosity. You could also use the fuming nitric acid test to
> determine
> your level of plating porosity (hey TechNet - anyone know the ASTM
> method
> number for the test?) but the test is somewhat subjective. You might
> also
> conduct a Scanning Electron microscopy analysis to see what the level
> of
> porosity is plus grab some compositional info - you might be able to
> find
> some contamination this way. Good Luck.
>
> Dave Hillman
> Rockwell Collins
> [log in to unmask]
>
> [log in to unmask] on 03/11/98 05:06:37 PM
>
> Please respond to [log in to unmask]; Please respond to
>       [log in to unmask]
>
> To:   [log in to unmask]
> cc:    (bcc: David D Hillman/CedarRapids/Collins/Rockwell)
> Subject:  [TN] Contact resistance
>
> Dear Technetters!
> We experience high contact resistance on keyboards.
> The plating is 0.15u Au on 6u Ni.
> 1.Could I use SERA in order to see if there is a contamination on the
> keypads
> in comparison to the bare boards?
> 2.If YES, HOW?
> 3.How could I compare the porosity of the gold plating of two
> different
> batches ?
> Thank you in advance
> Gaby
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   Thank you very much for your information.
Which test would you recommend for gold coatings of less than 0,2um?
From my experience in the past,the nitric acid test is too severe for
such
thin gold coatings in order to give results for comparison,but maybe
someone
has good news for me,since I have all the materials for it in the lab.
Gaby

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