TY - JOUR
T1 - Corrosion resistance of copper-coated contacts
AU - Reid, M.
AU - Punch, J.
AU - Grace, G.
AU - Garfias, L. F.
AU - Belochapkine, S.
PY - 2006
Y1 - 2006
N2 - Corrosion of electronic components can produce a wide range of failure signatures, from intermittent electrical faults to complete functional breakdown. This paper presents an investigation on the exposure of a simple connector-coating system. The system consists of a copper contact coated with a nickel layer underneath a gold finish layer. The system was characterized using the following techniques: optical microscopy, atomic force microscopy (AFM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDAX), secondary ion mass spectroscopy (SIMS) and focused ion beam (FIB). After initial characterization, the connector was exposed to 2, 4, 7, 15, and 30 days in an aggressive environment consisting of 90% relative humidity, 40°C, and 4 ppm H2 S. Digital images of the corrosion products that developed on the contacts after exposure clearly demonstrated localized corrosion by-products present on the connector surface. SEM, EDAX, and SIMS analysis of the corrosion sites demonstrated the presence of copper sulfide and nickel sulfur corrosion product, which suggest a two-step mechanism: first, the Ni layer is attacked by the aggressive environment at the sites where the gold layer is not available, followed by the diffusion of copper through the nickel layer. FIB cross-sectional analysis revealed that surface defects in the gold layer resulted in sites for corrosion initiation and subsequent development of a thick copper sulfide layer of approximately 5 μm. It is concluded that this copper connector coating system does not prevent the formation of insulating corrosion products on the surface of the connector in a very aggressive environment.The Electrochemical Society
AB - Corrosion of electronic components can produce a wide range of failure signatures, from intermittent electrical faults to complete functional breakdown. This paper presents an investigation on the exposure of a simple connector-coating system. The system consists of a copper contact coated with a nickel layer underneath a gold finish layer. The system was characterized using the following techniques: optical microscopy, atomic force microscopy (AFM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDAX), secondary ion mass spectroscopy (SIMS) and focused ion beam (FIB). After initial characterization, the connector was exposed to 2, 4, 7, 15, and 30 days in an aggressive environment consisting of 90% relative humidity, 40°C, and 4 ppm H2 S. Digital images of the corrosion products that developed on the contacts after exposure clearly demonstrated localized corrosion by-products present on the connector surface. SEM, EDAX, and SIMS analysis of the corrosion sites demonstrated the presence of copper sulfide and nickel sulfur corrosion product, which suggest a two-step mechanism: first, the Ni layer is attacked by the aggressive environment at the sites where the gold layer is not available, followed by the diffusion of copper through the nickel layer. FIB cross-sectional analysis revealed that surface defects in the gold layer resulted in sites for corrosion initiation and subsequent development of a thick copper sulfide layer of approximately 5 μm. It is concluded that this copper connector coating system does not prevent the formation of insulating corrosion products on the surface of the connector in a very aggressive environment.The Electrochemical Society
UR - http://www.scopus.com/inward/record.url?scp=33750812428&partnerID=8YFLogxK
U2 - 10.1149/1.2352042
DO - 10.1149/1.2352042
M3 - Article
AN - SCOPUS:33750812428
SN - 0013-4651
VL - 153
SP - B513-B517
JO - Journal of the Electrochemical Society
JF - Journal of the Electrochemical Society
IS - 12
M1 - 003612JES
ER -