Use of Solid Insertion Probe Mass Spectrometry and Constant Rate Thermal Analysis in the Study of Materials: Determination of Apparent Activation Energies and Mechanisms of Solid-State Decomposition Reactions

Thermally induced reactions are of great importance in the manufacture and characterization of a very wide range of increasingly complex materials covering areas as diverse as ceramics and heterogeneous catalysts. Subsequently, there is a need for improved thermoanalytical methods that can provide enhanced resolution and a greater understanding of the energetics and mechanisms involved. This paper describes a new solid insertion probe mass spectrometer (SIP-MS) system that is designed to meet these needs by operating high vacuum with small sample masses. The SIP-MS system supports both conventional linear heating and a range of sample-controlled thermal analysis (SCTA) techniques including constant rate thermal analysis (CRTA). Its ability, in conjunction with the latter technique, to obtain reliable apparent activation energy measurements throughout a process under near-ideal experimental conditions is demonstrated. In addition, the system can discriminate between different reaction mechanisms and provide information on the often complex solid-state reactions found in calcination processes.