Spark plasma effect on microstructure and mechanical properties of alumina-nickel-cobalt composite

Abstract

Spark plasma sintering (SPS) is an advanced process of sintering materials at low temperatures and short time by creating spark plasma at very high temperatures in the small points and short times, by which materials with high sintering temperature can sinter at lower temperatures. In this study, alumina-nickel-cobalt composites were sintered by SPS and RHP (rapid hot press) methods to investigate the effects of electric pulse on their microstructure and mechanical properties. To this end, sample powders containing alumina, nickel-cobalt aluminate spinel, and aluminum were sintered at 1380 °C under 30 MPa pressure for 10 min by SPS and RHP and then investigated. The densities of both samples were about 98% of theoretical density. Also, hardness and fracture toughness of both samples were about 11 GPa and 14 MPa.m0.5, respectively. The bending strengths of the SPS and RHP samples were 380 and 336 MPa, respectively.