The development chain in coating materials for electrical contacts

Jian Song, Ostwestfalen-Lippe University of Applied Sciences, Lemgo, Germany
Haomiao Yuan, Ostwestfalen-Lippe University of Applied Sciences, Lemgo, Germany

Noble metals (e.g. gold and silver) are used as protective coatings against corrosion, wear and fretting corrosion in high performance electrical contacts in order to prolong their lifetime. An ideal coating material should possess a combination of different properties such as high corrosion and wear resistance, high electrical conductivity and low costs. As this cannot be realized by a single material only, it is desireable to discover a new structure which guarantees good protection. To achieve this goal, two things are crucial:
• the hard ceramic nanoparticles doped gold layer
• modification of nanoparticle structures, coating structures, proportion of alloy elements

The samples are galvanically plated in the lab. The topographic image of the samples is analyzed using a scanning electron microscope (SEM) and a atomic force microscope (AFM). The wear and fretting corrosion behaviour are characterized by an apparatus developed in the lab. From the experimental investigation, models can be developed to describe the fretting behaviour of coatings. Finally, a semi-empirical simulation model can be established in order to forecast the wear and fretting corrosion process of the coating material and provide a design recommendation.

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