High-speed/high performance differential scanning calorimetry (HPer DSC): Temperature calibration in the heating and cooling mode and minimization of thermal lag

The temperature calibration of high performance DSC in the heating and cooling mode is discussed. Several primary and secondary calibration standards are studied at different sample masses – from 0.4 μg to 10 mg – and various heating and cooling rates – from 1 to 500 °C/min and from 1 to 300 °C/min, respectively. The experimental onset and peak temperatures of Indium with different sample masses are measured at different heating rates and the two related correction factors are presented. The symmetry of the HPer DSC with respect to the cooling and the heating modes is checked and found to be good. The liquid crystals M24, HP-53 and BCH-52, being substances with no or very small supercoolings, are recommended as secondary standards for temperature calibration in both the cooling and heating mode. In order to verify whether the proposed correction factors of Indium can also be used in the cooling mode, the melting behavior of Indium and the phase transition temperatures of the secondary standards obtained in heating are compared, and it turns out that the latter are usable as well. Finally, recommendations for both an extensive temperature calibration and a rather quick calibration procedure of scanning calorimeters in the heating and the cooling mode for various sample masses and various rates are given. The calibration procedure developed for HPer DSC facilitates making the right choices to minimize the thermal lag with respect to the sample mass and scan rates at the start of the measurement, instead of just making corrections afterwards.