Electrochemical deposition of iridium and iridium-nickel-alloys

To develop durable and reliable electronic contacts, precious metals are still very important for finish plating of contact surfaces. The lesser-known iridium might be an interesting alternative to substitute gold alloys, platinum or rhodium for applications with highest demands to wear and corrosio...

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Bibliographic Details
Published in:IOP conference series. Materials Science and Engineering 2017-03, Vol.181 (1), p.12041
Main Authors: Näther, J, Köster, F, Freudenberger, R, Schöberl, C, Lampke, T
Format: Article
Language:English
Subjects:
Bromine compounds
Corrosion resistance
Corrosive wear
Deposits
Electrolytes
Gold base alloys
Iridium compounds
Materials substitution
Microhardness
Nickel
Organic compounds
Oxidation
Plating
Rhodium
Substrates
Valence
Wear resistance
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Summary:To develop durable and reliable electronic contacts, precious metals are still very important for finish plating of contact surfaces. The lesser-known iridium might be an interesting alternative to substitute gold alloys, platinum or rhodium for applications with highest demands to wear and corrosion resistance such as sliding and plug contacts. As matters stand there is no commercial electrolyte for iridium plating. Initial investigation screened the parameter range for different iridium compounds when an iridium layer occurred on the substrates. This approach showed that the oxidation state of iridium is crucial to reach contenting deposits. Best results came from Ir(IV) electrolyte with high bromine concentration coming from the starting compound, while electrolytes made from Ir(III) compounds gave very poor deposits. In subsequent experiments different organic compounds were added to the electrolytes to improve plating efficiency and stability of the solutions. So found electrolytes gave crack-free deposits up to two microns with a micro-hardness of 600 HV. To reduce the iridium content in the layer, iridium-nickel-alloys were investigated, finding that a nickel-content of 10 wt% raised the layer hardness to more than 900 HV.
ISSN:1757-8981
1757-899X
DOI:10.1088/1757-899X/181/1/012041