High-temperature chip calorimeter with atmosphere control

A nanocalorimeter operating in various gas atmospheres and under controllable pressure at temperatures at least up to 1093 K is presented. It was developed to investigate nano-sized samples like nanoparticles and thin films under variable conditions. A special chip with two facing measurement cells for differential measurements was designed. Each cell consists of a thin, free-standing beam of silicon nitride instead of a continuous membrane. Joule heaters and temperature sensors are located at the tip of the SiN cantilevers. The calorimeter chip is mounted in a mobile measurement chamber that allows for preparation of surface-sensitive materials in a glove box. Subsequently the chamber is transferred to the measurement device. The chips are operated as AC calorimeter for sensitive detection of phase transitions. The functionality was demonstrated by calibration with different reference substances. Frequency scans with varying temperatures and gas atmospheres were performed to test the frequency dependency of the chip.

► A new differential chip calorimeter device for high temperatures in various atmospheres and pressures is presented.
► The calorimeter chip itself consists of free-standing silicon-nitride membrane beams with the heated sample area at their tip.
► The operability of the device was proven up to 1093 K.
► The device is operated as differential AC-calorimeter to maximize sensitivity. Alternatively, the calorimeter could also operate as a DSC.
► The heat-transfer-model of A. Minakov for addenda calibration and heat capacity calculation can be applied within the known limits.