#16- Mass Diffusion in Polycrystalline Metal/Electroplated Gold Planar Couples from Materion Technical Materials
Abstract: The steady increase in automotive under hood temperatures has prompted empirical evaluation of connector contact materials in order to determine suitability for use. In this Materion Technical Materials paper, the diffusion of cobalt, copper and nickel in soft gold electroplate was studied after exposure of planar couples to temperatures in the range of 100°C to 250°C.
Changes in surface electrical properties were monitored by measuring contact resistance as a function of exposure time. Concentration profiles on selected samples were obtained using scanning Auger spectroscopy. The chemical interdiffusion coefficients, D0, were calculated. The diffusion distance, 2(Dt) ½ was correlated to the contact resistance data. It was found that once oxide layers formed on Au-Cu and Au-Co surfaces, the rate of contact resistance change increased. No rate change was observed for Au-Ni surfaces.