Influence of magnetic field on surface modification and the friction behavior of sliding couple aluminium/XC 48 steel

We have studied the surface modification and tribological behavior of the paramagnetic aluminum alloy/ferromagnetic steel XC 48 sliding couple in the presence and absence of a d.c. magnetic field. Experiments were conducted on pin/disc tribometer in ambient atmosphere under an applied normal load P = 3.4 N and a sliding speed nu = 0.67 m s(-1). The magnetic field was applied to the aluminum pin and remained constant during the test. Our experimental results show that the presence of a magnetic field around the tribocontact modifies the mechanical properties of the contact surfaces and their friction behavior. The modifications induced in contact surfaces and subsurfaces of aluminum and steel by a magnetic field of H = 4500 A m(-1) after sliding for 1 h are analyzed by Vickers microhardness, scanning electron microscopy and energy dispersive spectroscopy (EDS) analysis. The microhardness gradient in the pin is about 12 H-v mu m(-1) in a thin layer of 30 mu m of material, and the mirohardness gradient in the disc is about 9.5 H-v mu m(-1) in 20 mu m of the material depth. The oxygen consumed by the magnetized sliding surfaces increases by a factor of 4. The friction coefficient becomes more stable and decreases from mu = 0.55 to 0.45. The wear rates of both the pin and the disc are increased. (C) 1999 Elsevier Science S.A. All rights reserved.