Nucleation kinetics analyses of deeply undercooled metallic liquids by fast scanning calorimetry

Abstract

Fast chip calorimetry (FSC) offers fascinating new opportunities for calorimetric analyses that are based on the unprecedentedly wide range of heating and cooling rates that are accessible for controlled experiments. Coupled with the high rates that are applicable, FSC offers also ideal conditions for nucleation kinetics analyses that are based on a statistical approach, since such analyses require data sets with a sufficiently high statistical significance. Thus, applying high rates and thus performing many measurements per given time allows achieving high accuracy for the determined nucleation kinetics parameters. Yet while the calibration procedure for conventional differential scanning calorimeters (DSC) is well known, new procedures need to be established for fast chip calorimetry, because the calibration behavior depends on the position of the sample on the measurement area. In addition to a detailed discussion of the calibration of FSC, the nucleation rates of the solidification transformation as obtained from FSC measurements are discussed for two case examples that display the opportunities offered and the issues encountered in FSC-based nucleation kinetics analyses.