Electrical Contact Resistance of Coated Spherical Contacts

The electrical contact resistance of two spherical contacts with coating is studied by using analytical method and finite-element method simulation software. The effects of contact radius, coating thickness, and the ratio of substrate to coating in electrical resistivity are evaluated over a large range of aspect ratios. The total electrical contact resistance could comprise three components of resistance, that is, the spreading resistance, the transition resistance, and the bulk resistance. Subsequently, the correlations of normalized spreading resistance, total contact resistance, and normalized contact radius are calculated and compared with the classical Holm theory.