Power Compensated Differential Scanning Calorimeter for Studying of Solidification of Metals and Polymers on Millisecond Time Scale

摘要

Fast scanning calorimetry becomes more and more important because an increasing number of materials are created or used far from thermodynamic equilibrium. Fast scanning, especially on cooling, allows for the in-situ investigation of structure formation, which is of particular interest in a wide range of materials like polymers, metals, Pharmaceuticals to name a few. Freestanding silicon nitride membranes are commonly used as low addenda heat capacity fast scanning calorimetric sensors. A differential setup based on commercially available sensors is described. To enhance performance of the device a new power compensation scheme was developed. The fast analog amplifiers allow calorimetric measurements up to 100,000 Ks~(-1) . The lower limit is defined by the sensitivity of the device and is 1Ks~(-1) for sharp melting or crystallization events in metals and ca. 100 K s~(-1) for broad transitions in polymers. A few examples to demonstrate the performance of the device are given.