[en] Crystallization of strontium fresnoite Sr2TiSi2O8 piezoelectric crystals in Sr-Ti-Si-K-Al-O
parent glasses is investigated with the aim of showing the influence of composition and crystallization
conditions on the microstructure and piezoelectric properties of the resulting glass-ceramic. All the
investigated conditions lead to a surface crystallization mechanism that induces a preferential
orientation of crystal growth in the glasses. Near the surface, all the glass-ceramics obtained exhibit
(002) planes preferentially oriented parallel to their faces. Deeper in the specimens, this preferential
orientation is either kept or tilted to (201) after a depth of about 300 µm. The measurement of
the charge coefficient d33 of the glass-ceramic highlights that surface crystallization induces mirror
symmetry in the polarization. It reaches 11 to 12 pC/N and is not significantly influenced by the
preferential orientation (002) or (201). High temperature XRD shows the stability of the fresnoite
phase in the glass-ceramics up to 1000 °C. Mechanical characterization of the glass-ceramics by
impulse excitation technique (IET) highlights that the softening of the residual glass leads to a
progressive decrease of Young's modulus in the temperature range 600-800 °C. Damping associated
to the viscoplastic transition become severe only over 800 °C.
Author, co-author :
Renoirt, Marie-Sophie ; Université de Mons > Faculté Polytechnique > Science des Matériaux
