Magnetotribology of ferromagnetic/ferromagnetic sliding couple

Applied magnetic field around the rotating sliding ferromagnetic steel/steel modifies the friction and the wear behaviour of the contact. The friction tests where conducted in ambient air or in high vacuum chamber 10−5 Pa. The applied normal loads are 0.1, 18.5 and 37 N. Without magnetic field, the contact is ductile steel against steel in a severe adhesive grooving mode. When a magnetic field is applied, the contact in ambient air progressively became black, covered by a brittle thick black layer of oxides which leads to a low friction and a low wear mode after some hundred cycles. Under the low normal load P = 0.1 N, a positive wear rate for the pin and for the disc was measured for magnetized contact. This mass increase is due to the activation by applied magnetic field of the oxygen chemisorption.