Dry sliding wear and corrosion studies of cobalt based nanocomposites by powder metallurgy process

Abstract

The limitations of achieving good mechanical properties such as high strength, density, better stiffness, toughness, wear resistance and corrosion resistance in conventional materials results in the need for the development of new composite materials forever demanding growing industrial and medical applications. The composite materials have a wide scope because of the ability to tailor the desired properties in order to suit particular applications. The hybrid nanocomposites have also developed into a major research area in materials engineering. In this aspect, the present research deals with the development of MgCo, Co-Gr and Co-25Gr-W nanocomposites through classical powder metallurgy/ Mechanical alloying process and the effect of reinforcement materials such as Gr and W on the base materials was investigated. The various proportions of the developed composites (Mg-5Co, Mg-10Co, Mg-15Co, Mg20Co, Mg-25Co, Co-5Gr, Co-10Gr, Co-15Gr, Co-20Gr, Co-25Gr, Co-25Gr-2W, Co-25Gr-4W, Co-25Gr-6W, Co-25Gr-8W) were mechanically blended using high energy ball mill based on weight percentage. The homogenously blended composites are then shaped into a cylindrical pellet of 10mm diameter by compacting using a hydraulic press at a load of 500 MPa. The compacted green compacts of different composites are then sintered at different temperatures based on the base materials used and optimized after various trails (550oC for Mg-based composites, 900o C for cobalt-based composites). The sintered composite pellets are subjected to various characterizations such as structural, Mechanical, wear and corrosion resistance properties. The surface morphology studies of the different composite materials were carried out using a Scanning Electron Microscope (SEM). The Scanning Electron Microscope-Energy Dispersive Spectrum (SEM-EDS) module was used to study the elemental composition of the composite materials. The Atomic Force Microscope (AFM) was utilized to study the topography of the compositematerials under non-contact mode. The microhardnes