FURTHER-STUDIES ON THE USE OF SIMULTANEOUS TM/DTA TO ESTABLISH MAGNETIC TRANSITION-TEMPERATURES

Earlier work reported on the use of simultaneous thermomagnetometry/differential thermal analysis (TM/DTA) to obtain the Curie temperature (T-c) of nickel. The precision of the measurement was substantially improved through the simultaneous use of appropriate DTA standards involving the melting of pure metals which define the International Temperature Scale. That work was confirmed using two additional operators. It also was extended to include other alloys and metals, some of which are also in the ICTAC/NIST series of standards. It is suggested that an appropriate set of standards would involve homogeneous alloys in the nickel-cobalt system that could cover the wide range of temperature from approximately 358 to 1130 degrees C. The feasibility of preparing such alloys through the controlled decomposition of solid solutions in the (nickel-cobalt) oxalate system is also described.