Abstract
Aluminum is widely used in electrical contacts
due to its electrical properties and inexpensiveness when
compared to copper. In this study, we investigate the
influence of operating conditions like contact load (pressure),
sliding speed, current, and surface roughness on the
electrical and tribological behavior of the interface. The
tests are conducted on a linear, pin-on-flat tribo-simulator
specially designed to investigate electrical contacts under
high contact pressures and high current densities. Control
parameters include sliding speed, load, current, and surface
roughness. The response of the interface is evaluated in the
light of coefficient of friction, contact resistance, contact
voltage, mass loss of pins, and interfacial temperature rise.
As compared to sliding speed, load, and roughness, current
is found to have the greatest influence on the various
measured parameters. Under certain test conditions, the
interface operates in a ‘‘voltage saturation’’ regime,
wherein increase in current do not result in any increase in
contact voltage. Within the voltage saturation regime the
coefficient of friction tends to be lower, a result that is
attributed to the higher temperatures associated with the
higher voltage (and resulting material softening). Higher
interfacial temperatures also appear to be responsible for
the higher wear rates observed at higher current levels as
well as lower coefficients of friction for smoother surfaces
in the presence of current.