Iridite NCP (inspection) How do you know it is there? 2

[ingrish]

Our aluminium parts are specified as being coated with Iridite NCP, which is clear (colourless). The older Alochrom 1200 coating was easy to see as it was yellow.

Of course one should use a trusted supplier who does what the drawing says, but is there a way to check it? Our purchasing guy just says "of course they are doing it". I would like to spot check the parts occassionaly.

 

[IRstuff]

Isn't Iridite a coating that's also conducting?

> You ought to be able to measure its thickness with a film thickness analyzer, like an ellipsometer

> There ought to be some resistivity difference between iridite and bare aluminum. I recall having to sand off some Iridited bonding pads because the resistivity came in too high.

TTFN

FAQ731-376

 

[KENAT]

Chem film comes in a couple of different grades. There's a 'thin' one for where electrical conductivity is primary concern & corrosion secondary. Then there's the thick version where corrosion is primary concern. There may be a couple others, I can't recall for sure, I believe some of the grades come from ROHS compliance.

Not sure this really helps the OP directly though, sorry. That said I had similar concerns to the OP when we first started getting ROHS compliant parts in. We even tried sending some back because they weren't 'gold'. Then we did the digging on the ROHS stuff which last I heard you can't get in gold.

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(probably not aimed specifically at you)
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[ingrish]

Thanks guys.

 

[ingrish]

Just for reference in case anyone else has a similar problem:

I contacted the manufacturer of Iridite, MacDermid. They do a kit called ARP 90 which consists of a pair of liquids which when combined give a chemical test of the presence of a protective layer, or not.

You try the test on bare metal and see how long it takes for the liquid to turn brown. Then you try it on the protected surface and it should resist going brown for some time, depending on the coating thickness. They have yet to tell me the cost, but it sounds like just what I need.