Morphology and electrical contact properties of electrical connection materials in corrosive atmosphere

Abstract

The impact mechanism of environmental factors, such as corrosive atmosphere, on connector materials was investigated, and the porosity of gold plating was tested. Series of inspections and analytical research methods were introduced in this article. The surface morphology of specimens after corrosion was observed by stereoscopic microscope and scanning electron microscope. Chemical constitution was examined by X-ray energy spectrum. The contact resistances were measured by four-point method. The experiment results show that after exposure to certain environment, the corrosion products, such as Cu2O, Cu(NO3)2·3H2O, and NiO, are observed on the surface of the specimens without gold coatings, whereas the corrosion products appear to have circle-shaped spots on gold-plating surface after corrosion test, which indicate that the gold plating has good corrosion protection. The porosity is increased with the increase of corrosion time for every kind of specimens gold plated, and the corrosion degree of gold-plating specimens is decreased with the increase of the thickness of gold coatings. The static contact resistances of circle-shaped spots appear higher contact resistance than normal value, which can reach to 2,000 mΩ nearly. It is found that the high and unstable contact resistance of the pore and products is more likely to cause contact failure.