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Black electrically conductive finish over temperature

I am looking for a black electrically conductive finish for aluminium with good corrosion and abrasion resistance. The coating will also have to maintain these properties up to about 90 °C for extended periods. Black electrolytic nickel is mentioned on your site, however, I have heard elsewhere that it can develop a powdery finish above about 60 C. Can anyone confirm this or offer any much needed advice on alternatives?

Many thanks in advance,

John Ord
- Suffolk, UK

Black electrolytic nickel layers are normally about 2 µm thick. The corrosion resistance is poor, it is necessary to plate with an undercoat of nickel or zinc. With some oil or grease it is possible to improve the corrosion resistance.(if this is allowed) The abrasion resistance is also not very good. Above ~180 °C the deposit will decompose under development of sulfur gasses (H2S,SO2 and so on) and ammonia. I think black chromium can be an alternative.

Kind regards,

Sjamp van Esch
- Eindhoven, The Netherlands

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