The goal of this research is to prepare a series of alloys having sharp, reproducible magnetic transitions for calibrating temperature in thermogravimetry from the magnetic transition temperature of pure cobalt (1121°C) to below room temperature. Alloys in the Ni-Co and Ni-Cu systems were prepared by the thermal decomposition of coprecipitated oxalates in argon. The alloys were subsequently annealed under 5% hydrogen. Magnetic transition temperatures were measured using simultaneous thermomagnetometry/differential thermal analysis. Transition temperatures were corrected using well known meltingpoint standards. Magnetic transition temperatures along with precision are reported as a function of composition.