Effect of current on the tribological behavior of Cu-Fe-P immiscible alloy produced by laser powder bed fusion

Cu-based immiscible alloys have significant potential application value in the field of electrical contacts. This study investigated the tribological behavior of Cu-Fe-P immiscible alloys produced via laser powder bed fusion (LPBF) under current-carrying conditions. The alloys consist of softer ε-Cu phase and harder Fe-rich phases. The Fe-rich phase acts as a protective reinforcement during current-carrying friction and wear tests, improving the wear resistance of the alloy. With the increasing current, the coefficient of friction initially rose and then decreased, whereas the wear rate showed a gradual increase. At low currents (0, 2, 3 and 5 A), mechanical wear predominantly governs the wear mechanism. As the current increases, the mechanical wear gradually transitions from adhesive wear to abrasive wear, accompanied by weak oxidative wear. At higher currents (7 A and 10 A), the wear mechanism is dominated by arc erosion wear and oxidative wear. Notably, when the current exceeded 2 A, an oxide film consisting of CuO, Fe₂O₃, and Fe₃O₄ formed, enhancing the frictional properties of the alloy. Once the current surpassed 5 A, the arc discharge occurred at high currents, forming molten phases and arc erosion pits on the worn surface of the Cu-Fe-P immiscible alloy.