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2019-06-19 - Colloque/Présentation - communication orale - Anglais - page(s)

Dupla Florian , Renoirt Marie-Sophie , Gonon Maurice , Smagin Nikolay, Duquennoy Marc, Martic Grégory, RGuiti Mohamed, "Development of high temperature surface acoustic wave sensors based on a piezoelectric glass-ceramic" in XVI ECerS Conference, Torino, Italie, 2019

  • Codes CREF : Sciences de l'ingénieur (DI2000)
  • Unités de recherche UMONS : Science des Matériaux (F502)
  • Instituts UMONS : Institut de Recherche en Science et Ingénierie des Matériaux (Matériaux)
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Abstract(s) :

(Anglais) OBJECTIVE: This work is part of a project aiming at developing high temperature pressure sensors using surface acoustic waves (SAW). To this end, a non-ferroelectric piezoelectric glass-ceramic containing fresnoite crystals is evaluated to be used as substrate for the interdigitated electrodes (IDT). The ability of this glass-ceramic to work up to 800°C is evaluated. MATERIALS & METHODS: A parent glass plate is obtained by mixing reagent-grade SrCO3, TiO2, SiO2, K2CO3 and Al2O3, melting the mixture at 1500°C, and then casting the molten glass. This glass is crystallized at 900°C in a powder bed to induce surface crystallization, leading to a piezoelectric glass-ceramic. Glass transition temperature Tg is estimated by thermal expansion technique. The crystal structure is characterized in temperature by HT-XRD. Young’s modulus and damping are measured by high temperature IET. A testing device composed of two platinum IDT (emitter and receiver), deposited on a glass-ceramic substrate is realized to evaluate the ability of the material to generate and propagate SAW in temperature. RESULTS: A fresnoite glass-ceramic was successfully synthesized through isothermal heat treatment of a glass. To obtained material is composed of 70 vol% Sr2TiSi2O8 crystals and 30 vol% residual glass. The crystals are preferentially oriented over a depth sufficient to generate and propagate SAW. It is proven by HT-XRD that the crystal structure is stable up to 1000°C. Dilatometry measurements show that the glass transition temperature of the residual glass is around 650°C. Above this specific temperature, the IET measurements show a decreasing elastic modulus and an increasing damping. These phenomena become more drastic above 800°C. The evolution of relative amplitude of the SAW collected on the receiving IDT over temperature can be divided in 3 parts. First, there is a slow decrease from RT to Tg, probably due to the thermal expansion mismatch between the crystal and the glassy phase leading to stress and microcracks. Then, the amplitude strongly increases from Tg to 800°C, as the piezoelectric crystals are less constrained by the residual glass which is becoming viscoplastic. Finally, the amplitude drastically falls above 800°C because of a high damping due to the residual glass low viscosity. CONCLUSIONS: A SAW device based on a piezoelectric non-ferroelectric glass-ceramic was developed, and its ability to generate and propagate SAW up to 800°C was shown. The realization of high temperature pressure sensors based on this material is under development.