Reference Materials for the Phase Transition Temperatures (Curie Temperature) Based on Alumel, Nickel and Iron Silicide

Abstract

The requirements for thermal analysis instruments are increasing in terms of their metrological support with the development of scientific and technological progress in the field of metrological supervision and electronics industry. The study of determining the phase transition temperature, namely the Curie temperature, is of particular relevance for the metrological support of the applied thermal analysis instruments and traceability to the basic physical units.The purpose of the research was to test the possibility of using materials based on alumel, nickel and iron silicide (trafoperm) as phase transition temperature standards for candidate reference materials of phase transition temperatures (RMs) traceable to the SI unit of the «temperature» value.The procedure for measuring the phase transition temperatures (Curie temperature – TC) was carried out by the thermomagnetometric method using an STA 449 F5 JUPITER thermal analyzer from the State Primary Standard GET 173-2017. The determination of the RM certified value was carried out in accordance with GOST ISO Guide 35–2015, the contributions to the uncertainty from the heterogeneity of the initial materials were evaluated, and the short-term and long-term stability of the materials were studied.A comparison of the certified values of the developed RMs with the reference values of the Curie temperature showed that they are consistent.The theoretical significance of the results obtained is proof of the possibility of using the thermomagnetometric method for the development of certified reference materials of phase transition temperatures GSO 12005–2022/GSO 12007–2022. The possibility of applying the method of differential scanning calorimetry in determining the Curie temperature was also confirmed.The practical significance of the results obtained allows expanding the possibilities for constructing the calibration dependence of measuring instruments for thermogravimetric analysis and monitoring its stability, as well as increasing the measurement precision of the Curie temperature of various substances and materials.