Electrochemical deposition of iridium and iridium-nickel-alloys

19th Chemnitz Seminar on Materials Engineering – 19. Werkstofftechnisches Kolloquium

Näther, J.^1 ; Köster, F.^1 ; Freudenberger, R.^2 ; Schöberl, C.^2 ; Lampke, T.^3

HS Mittweida Univ. of Appl. Sci. Fak. Ingenieurwissenschaften Fb. Fertigungs- und Werkstofftechnik, Technikumplatz 17, Mittweida

09648, Germany^1

Forschungsinstitut für Edelmetalle und Metallchemie FEM, Katharinenstraße 17, Schwäbisch Gmünd

73525, Germany^2

Institute of Materials Science and Engineering, Chemnitz University of Technology, Chemnitz

09125, Germany^3

关键词: Contact surface;    Crack free;    Oxidation state;    Parameter range;    Plating efficiency;    Reliable electronics;    Starting compounds;    Wear and corrosion resistance;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/181/1/012041/pdf
DOI  :  10.1088/1757-899X/181/1/012041

来源: IOP

【 摘 要 】

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.