Effect of sintering parameters on densification, corrosion and wear behaviour of Ni-50Fe alloy prepared by spark plasma sintering

Spark plasma sintering (SPS) technique was used to fabricate Ni50Fe alloys. Powders were sintered at various temperatures, pressure and holding times ranging between 900 and 1100 degrees C, 40-50 MPa and 5 -10 min respectively. Microstructural characterisation was carried out using scanning electron microscopy (SEM). Archimedes' method for density measurements, vickers microhardness, and tribometer were used to study the effect of various sintering parameters on the densification, electrochemical properties in 1 M H2SO4 solution, coefficient of friction (CoF) and dry sliding wear resistance. An increase in sintering temperature was found to enhance densification and the highest density was reported at 1100 degrees C sintered for 10 min with 50 MPa, with a slight decrease in microhardness. Increasing temperature was also found to be reducing corrosion resistance but improving alloy wear resistance against the tungsten carbide counter body. The effect of sintering time and pressure was found to be of minor effect on both corrosion and wear resistance. Fractography studies indicated the dominant fracture micro mechanism as ductile fracture of sintering necks. The main wear mechanism of Ni-50Fe alloy was attributed to the simultaneous actions of ductile and brittle friction mechanism with the existence of abrasion and delamination of worn surfaces. (C) 2016 Elsevier B.V. All rights reserved.