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Surface modifications of a non-ferromagnetic copper/ferromagnetic steel XC48 couple in magnetized sliding contact

1996; Elsevier BV; Volume: 86-87; Linguagem: Inglês

10.1016/s0257-8972(96)03078-2

1879-3347

Mohamed El Mansori, H. Zaïdi, E.K. Kadiri, D. Paulmier,

Electromagnetic Launch and Propulsion Technology

The effect of a magnetic field on the wear of steel/copper rubbing systems has been investigated in air. The applied magnetic field is normal to the sliding contact surface. Experiments have shown that the wear rates of pin and disc and microhardness of the sliding surfaces of both ferromagnetic and non-ferromagnetic materials increase with application of a magnetic field. The applied magnetic field signficantly influences the mechanical properties of the metals and modifies the surface hardness of materials by magnetoplastic effect. The surface of the materials becomes harder under the simultaneous effects of the normal load and the sliding speed in the presence of the magnetic field. A model of dislocation flow enhanced by the presence of a magnetic field explains the increase of dislocation density in sliding surfaces and particularly in the junctions of asperities submitted to high stresses; the microhardness subsequently increases. Brittleness of harder asperities induces the sliding wear behavior of magnetized materials. The applied magnetic field also enhances and activates the surface oxidation. The size of the oxide wear particles is thinned in sliding contact. Experimental results from the sliding surface modifications, with and without magnetic field (wear rate, microhardness), are presented. A simple model to explain the observed phenomenon is proposed.