Physical vapor deposition of nanocrystalline composites of AG-NI for electrical contacts in automotive industries

Abstract EN

Using vapor deposition as a tool, novel coating structures have been developed for low friction coefficient, fretting wear resistant and high temperature stable electrical contacts.

Thin films of Ag-Ni Nano crystalline composites between 100 and 500-nm thick were deposited by electron beam evaporation onto sputter-cleaned 301 stainless steel substrates.

The structure and composition of the films were studied in detail using x-ray diffraction (XRD), scanning electron microscopy (SEM), electron probe microanalysis (EPMA), and Auger depth profiling.

The contact properties, such as contact resistance, friction coefficient, fretting wear resistance, and thermal stability of these coatings have been measured.

Both the Ag and Ag81Ni19 composite coatings about 500-nm thick passed the 1,000,000 cycle fretting wear test.

These coatings also showed good high temperature stability during heat-aging at 150 ºC in air, especially the Ag81Ni19 composite coating.

This study shows that vapor deposition is a powerful technique which can be used to discover new coating compositions and structures for electrical contact applications.