50067

Evaluation of Plating Depth  

September 23, 2008

Hi I am a recent graduate who is spending a few months in the plating dept of an aerospace company. I need to evaluate the plating depth of an internal bore that has been lead then iridium plated. I need to do this without destroying the thin plate surfaces (please note base material is 30% lead bronze). I'd be grateful if anyone could help me with this!

Jennifer Douglas
Plating shop Chemist - Birmingham, West Mids UK

Assuming the hole is a reasonable diameter, you could poke a boroscope into it; this is a fibre-optic lens, with a ring light attached to it, that can be attached to a suitable (usually video) camera; then you can see where the plating stops.

Trevor Crichton R&D practical scientist - UK

First we need to clarify the question.Are you looking for:-
a/ How far down the hole the plating has gone - a question of throwing power of the solution often complicated by air etc trapped in small (particularly blind) holes
or
b/ The thickness of plating in the hole. This very much depends on the size of the hole.

Assuming the worst case of a small blind hole with a large aspect ratio, I suggest that you include some test pieces with similar holes in with the plating batch and then overplate and microsection them.

Remember that soft plating layers smear during microsection so this is not accurate for plating less than c. 1 micron

Or - mill the hole in half and use XRF

Or - drill out the hole, dissolve the turnings and analyse for lead and indium (gives average plating not a spot thickness)

What accuracy are you looking for?

Geoff Smith Hampshire, England