On Dry Wear of Metallic Materials in Different Configurations of Sliding Electrical Contacts Against a Quenched AISI 1045 Steel

Dry sliding behavior of an AISI 1020 steel and sintered powder composites (pins) at sliding velocities of 5 and 15 m/s has been investigated applying general pin-on-disk and pin-on-ring wear loading configurations. Three main output parameters of the current-collecting tribosystem, namely, the electrical conductivity of the contact, the current density in the contact, and the wear intensity corresponding to the onset of catastrophic wear were chosen to compare the tribotechnical behavior of the materials. It was found that pin-on-ring sliding caused the electrical conductivity of the contact σA(j) = (200–300) S/cm2, whereas pin-on-disk sliding caused σA(j) < 200 S/cm2 in the presence of FeO (wuestite) on the pin sliding surface, but pin-on-ring sliding caused the ultimate current density jc < 300 A/cm2 comparing with jc = (500–600) A/cm2 in pin-on-disk sliding. The absence of FeO on the sliding surface caused unsatisfactory contact characteristics. An increase in the sliding speed has led to a decrease in the electrical conductivity of the contact, but significant changes in the maximum contact current density and wear intensity were not observed. It is shown that two morphologically different images of specimen sliding surface are formed. This was observed for most specimens and was presented as a plastic deformation pattern of specimen sliding surface under electric current of high density.