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 cov ering areas as diverse as ceramics and heterogeneous catalysts. Subsequentl y, there is a need for improved thermoanalytical methods that can provide e nhanced resolution and a greater understanding of the energetics and mechan isms involved. This paper describes a new solid insertion probe mass spectr ometer (SIP-MS) system that is designed to meet these needs by operating hi gh vacuum with small sample masses. The SIP-MS system supports both convent ional linear heating and a range of sample-controlled thermal analysis (SCT A) techniques including constant rate thermal analysis (CRTA). Its ability, in conjunction with the latter technique, to obtain reliable apparent acti vation energy measurements throughout a process under near-ideal experiment al conditions is demonstrated. In addition, the system can discriminate bet ween different reaction mechanisms and provide information on the often com plex sold-state reactions found in calcination processes.