Analysis and characterization of corrosion products on gold‐plated contacts for electrical contacts

Methods for measuring the thickness and composition of corrosion products due to pin-holes on gold-plated contacts using an energy dispersive X-ray analyzer are described. The thickness and composition of the corrosion products measured using the methods are also described, and their effects on electrical characteristics of the contacts are discussed. The thickness of the corrosion products is about 1 μm at the center of the pinhole and decreases in the peripheral area. The corrosion products in the peripheral area consist mainly of copper sulfate of lower resistivity and less copper oxide which has higher resistivity. This results in higher contact resistance in the center of the pinhole and lower contact resistance in the peripheral area. However, the contact resistance rarely exceed 60 O even at the center. Electrical and mechanical breakdown phenomena of the corrosion products are also discussed. It is shown that continuous poor contact is rarely caused by corrosion products on gold-plated contacts.