Author:

Keywords:

Metal matrix composites, Powder metallurgy, Phase diagrams, Scanning electron microscopy, Science & Technology, Physical Sciences, Technology, Chemistry, Physical, Materials Science, Multidisciplinary, Metallurgy & Metallurgical Engineering, Chemistry, Materials Science, NICKEL, SILVER, MICROSTRUCTURE, TUNGSTEN, BEHAVIOR, 0204 Condensed Matter Physics, 0912 Materials Engineering, 0914 Resources Engineering and Extractive Metallurgy, Materials, 4016 Materials engineering, 5104 Condensed matter physics

Abstract:

In this work, Ni was used as an additive in Ag-WC (60-40 wt.%) metal matrix composites employed as electrical contacts. Increasing the Ni content from 1 to 3 wt.% resulted in an increase in the mean electrical contact resistance (Rc) from ~2 to ~3 mΩ. However, further addition of Ni up to 10 wt.% resulted in the formation of a silver layer on the contact surface after switching, which strongly reduced the Rc from ~3 to ~1.5 mΩ. The influence of Ni addition on the microstructural changes in the contact material was investigated and the mechanism for the transfer of silver from the bulk composite material to the surface as a consequence of thermal cycling during switching was elucidated.