Determining Activation Energy Of Ammonium Salts Decomposition Using Mems Thermopile-Based Differential Scanning Calorimetry (Dsc)

Differential Scanning Calorimetry (DSC) has been an effective technique for determining the activation energy of thermal decomposition by fitting the endothermic peak temperatures at corresponding heating rates with Kissinger equation. However, conventional DSC apparatus using a furnace-crucible-thermocouple structure often suffers from significant thermal lag and a limited range of heating rates (1-60°C/min), which can introduce substantial errors in the measurement of activation energy. In this paper, we fabricated MEMS differential thermopiles, integrating a microheater and 54 pairs of single-crystal silicon thermocouples on a SiNx membrane. We then developed a power-compensated DSC based on the fabricated differential thermopiles, which features reduced thermal lag, high heating rates up to 1200 °C /min, and a higher power responsivity (148.7 V/W). Using the MEMS thermopile-based DSC, we measured the thermal decomposition of ammonium carbonate and ammonium carbamate at heating rates from 20 to 1200 °C/min and calculated the activation energies to be 67.59 ± 1.83 kJ/mol and 62.53 ± 1.98 kJ/mol, respectively. Our MEMS DSC holds promise for efficient and accurate characterization of material thermal decomposition in various applications.