Laser cladding of copper with molybdenum for wear resistance enhancement in electrical contacts

• Published in: Applied surface science 2007-05, Vol.253 (14), p.6236-6241
• Main Authors: Ng, K.W., Man, H.C., Cheng, F.T., Yue, T.M.
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Contact resistance, contact potential; Cross-disciplinary physics: materials science; rheology; Cu electrical contact; Electrical contact resistance; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport in interface structures; Exact sciences and technology; Friction, lubrication, and wear; Laser cladding; Materials science; Molybdenum; Physics; Treatment of materials and its effects on microstructure and properties; Wear
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2007.01.086

Laser cladding of Mo on Cu has been attempted with the aim of enhancing the wear resistance and hence increasing the service life of electrical contacts made of Cu. In order to overcome the difficulties arising from the large difference in thermal properties and the low mutual solubility between Cu and Mo, Ni was introduced as an intermediate layer between Mo and Cu. The Ni and Mo layers were laser clad one after the other to form a sandwich layer of Mo/Ni/Cu. Excellent bonding between the clad layer and the Cu substrate was ensured by strong metallurgical bonding. The hardness of the surface of the clad layer is seven times higher than that of the Cu substrate. Pin-on-disc wear tests consistently showed that the abrasive wear resistance of the clad layer was also improved by a factor of seven as compared with untreated Cu substrate. The specific electrical contact resistance of the clad surface was about 5.6 × 10 −7 Ω cm 2.