THERMOCHEMICAL CALCULATIONS AND EXPERIMENTAL INVESTIGATIONS ON Mo-Ni-B ALLOY SYSTEM PRODUCED BY COMBUSTION SYNTHESIS
In this study, Mo-Ni-B alloy system which can be a new hard alloy alternative to tungsten base cemented carbides, was investigated by means of thermochemical calculations and experimental trials. Thermochemical calculations were carried out to estimate the adiabatic temperatures and possible product compositions in the alloys by using FactSage 7.0 thermochemical software. The combustion synthesis process was performed under normal gravity and air in Cu copper crucibles by using metal oxides (MoO3 and NiO), boron oxide (B2O3) as a boron source and aluminum (Al) as a metallic reductant. Alumina, (Al2O3) as a functional additive (diluent), were also added in order to reduce the adiabatic temperature of the reaction. Since the attained reaction temperatures for this system during the exothermic SHS process is so high (above 2000 °C), the reaction is self-sustaining and the melt consists of insoluble mixture of metallic compound and oxide phase which can be segregated under normal gravity force.