The feasibility of the use of potassium nitrate and potassium perchlorate as temperature standards in Differential scanning calorimetry has been studied. The solid-state phase transition temperatures of KNO3 and KClO4 were determined by means of DSC. The metrological properties of these salts as calibration materials were examined. The reliability of KNO3 and KClO4 calibrations was investigated by twofold determination of the bismuth melting temperature after the apparatus had been calibrated with indium and lead, and with KNO3 and KClO4. Conclusions were drawn concerning the suitability of these salts for use as DSC temperature calibrants.
Eight inorganic substances recommended by ICTA as temperature standard reference materials for DTA and DSC were studied: KNO3, KClO4, Ag2SO4, K2CrO4, quartz, K2SO4, BaCO3 and SrCO3. The content of pure component in each of these substances was determined by classical chemical analysis. The temperatures and the heats of polymorphic transformations of these substances were measured with a Perkin-Elmer DSC-2 differential scanning calorimeter, and DTA studies were performed on a MOM 1500 D Q-derivatograph. The plot heat of transformation by DSCvs. DTA peak area is advanced as a calibration line for the approximate estimation of quantitative DTA effects. The substances studied will be certified as temperature standard reference materials for use in DTA and DSC.