Solderability Characteristics of Palladium , Palladium Nickel , Hard and Soft
Palladium and palladium alloys are the only serious ahematives to gold as an "electronic finish". In the past, the major impetus for such a substitution has been economic; however, today palladium's technological advantages are generally recognized. This is especially true in the connector markets where the material properties (e.g. hardness, ductility, thermal stability, etc.) of palladium are in many instances superior to hard gold. Recent advances in plating technologies coupled with a m r e thorough understanding of the materials properties have expanded the use of electroplated palladium and palladium alloys in the PCB, semiconductor and optoelectronic packaging markets. To assess the suitability for such applications, the wire bondability and solderability of these finishes need to be investigated.
WEAR RELIABILITY OF GOLD-FLASHED PALLADIUM VS. HARD GOLD ON A HIGH-SPEED DIGITAL CONNECTOR SYSTEM
Analyse par microscopie optique, microscopie electronique a balayage et fluorescence RX de la resistance a l'usure des depots electrolytiques de palladium destines a la fabrication de contacts electriques.
Degradation Mechanisms in Tin- and Gold-Plated Connector Contacts
Degradation mechanisms in tin-plated contacts (Sn contacts) and gold-plated contacts (Au contacts) are clarified. Contact resistance and corrosion characteristics for both types of contacts are investigated and compared. Contact resistance is more stable for Sn contacts than for Au contacts in a SO 2 + NO 2 + C1 2 atmosphere. This is because relatively few corrosion products are formed on Sn contacts. Also, the surface films formed on Sn contacts shatters more easily upon plastic deformation. Corrosion experiments in atmospheres containing different combinations of SO 2 , NO 2 , and Cl 2 demonstrate that two types of corrosion processes take place in plated contacts. One is surface corrosion which occurs when the surface finish is severely attacked by a corrosive atmosphere. The other is pore corrosion which occurs when the underplating materials are attacked to a greater extent than surface corrosion. Both processes occur in Sn contacts and the former is dominant in atmospheres containing Ci 2 . On the other hand, only pore corrosion occurs in Au contacts. Furthermore, galvanic corrosion either enhances or inhibits the formation of outcroppings in the pore corrosion process, depending on the electrode potential of the surface finish and underplating materials.