Piezoelectric glass‐ceramics: Crystal chemistry, orientation mechanisms, and emerging applications

Abstract

Piezoelectric materials have coupled mechanical and electrical energies and have long been used in devices for actuators, sensors, energy harvesters, frequency filters, and various additional applications. Piezoelectricity requires a non‐centrosymmetric crystal structure and is therefore confined to materials that possess a periodic crystalline structure. Due to the non‐crystalline nature of glass, piezoelectricity is fundamentally forbidden. However, one way to exploit piezoelectric properties in a glassy matrix is by developing glass‐ceramics that possess controlled growth of a crystalline phase. Growth and orientation of piezoelectric crystals in a glassy matrix is a non‐trivial process that has long been explored to combine the formability of glass with the thermal and mechanical resilience of glass‐ceramics. While extensive work has been done in the field of functional glass‐ceramics, the results are presented in isolated articles and a comprehensive review pertaining to symmetry breaking methods to exploit anisotropic properties in glass‐ceramics has been absent from the literature. Here, we present a global review of the fundamental symmetry requirements for piezoelectricity, the development of polar, piezoelectric glass‐ceramic compositions (specifically those with LiNbO3 and fresnoite‐based crystal phases), and various crystal growth and orientation mechanisms, including relevant kinetic and thermodynamic driving forces. Lastly, we discuss the challenges associated with implementing gradients to drive oriented crystal growth to develop non‐centrosymmetry, and the need for future modeling work to produce adequate time‐temperature‐transformation (TTT) diagrams that take into account kinetic and thermodynamic driving forces for oriented crystal growth. Going beyond technical challenges, we conclude with an examination of current and potential applications for piezoelectric glass‐ceramics that combine the formability of glass with the symmetry‐dependent properties of ceramics.

Piezoelectricity in Nominally Centrosymmetric Phases

“…[59], where introduction of heterogeneous chemical reduction leads to d 33 = 321 pm/V in Na 0.5 Bi 0.5 TiO 3 -BaTiO 3 , which exceeds the piezoelectric coefficients of most ferroelectrics and is comparable to that of lead zirconium titanate (PZT) [85]. Moreover, because the influence of polar nanostructures on the forbidden piezoelectric effect can be seen over hundreds of degrees above ferroelectric Curie temperatures and freezing temperatures associated with relaxors, high temperature piezoelectric applications, including energy harvesting, can be envisioned via the guided-growth/synthesis of materials via chemical, stress, thermal, and electrical gradients [34,59,86].…”

Glass-ceramics, 70 Years Since the Discovery

“…Međutim još je nekoliko područja u kojima se uskoro može očekivati značajan napredak, poput staklokeramike za primjenu u dijagnostici i terapiji raka, 48 vodljive staklokeramike za čvrste elektrolite u baterijama, 49 supstrate za fotonaponske ćelije 50 itd. Zanimljiva su i istraživanja u području samoiscjeljujućih materijala, 51 piezoelektrične staklokeramike, 52 mehanoluminiscencijske staklokeramike, 53 porozne staklokeramike za filtre, hidroponiju, apsorbense, mikrospremnike, zvučnu izolaciju 54 itd.…”

Effect of Partial Ba Substitutions on the Crystallization of Sr2TiSi2O8 (STS) Glass–Ceramics and on the Generation of a SAW Signal at High Temperatures

“…The crystallization treatment is the most important step of the synthesis of a fresnoite glass–ceramic because it determines the final piezoelectric properties. As explained by Gerace et al [ 32 ], oriented crystal growth can be achieved by using kinetic and thermodynamic controls. The kinetic control is the result of the anisotropic growth rate of the crystal.…”