The materials properties and contact reliability of palladium-cobalt

Palladium and its alloys have become the standard precious metal finishes for high reliability connector. While pure palladium is preferred for high temperature automotive applications, palladium-nickel has become the preferred finish for ambient temperature, high insertion applications such as edge card connectors. However, palladium-nickel, when plated over nickel, iis not without its problems. Quality control issues related to the measurement of composition and thickness by simple, non-destructive XRF analysis remain a significant concern. Palladium-cobalt does not suffer from this shortcoming, and furthermore has been found to outperform palladium-nickel for high durability applications. In this study, the metallurgical structure of palladium-nickel and palladium-cobalt electrodeposits is characterized by X-ray diffraction and electron microscopy. In addition, the hardness, porosity, wear performance and thermal stability, among other properties, are discussed.