Finite element modelling of thermoelastic behavior for high-temperature quartz crystal microbalance

This work focuses on the study of high-temperature microbalances to be used in space, exploring the feasibility of reaching relatively high working temperatures, i.e up to 300°C. The studied microbalance, based on a quartz crystal sensor, is equipped with an integrated heater on the crystal surface that provides localized heating on the sensor, thus achieving the operative temperature more efficiently than by using external heaters. A finite element model of the crystal assembly was developed and tuned by thermal testing in a vacuum chamber aimed to identify equivalent thermal resistance and at the same time, verify the mechanical resistance of the crystal assembly when heated at high temperatures. The tuned model allowed evaluation of the thermo-elastic stress state on the crystal, showing that the achieved operative condition is critical for the quartz crystal mechanical resistance.