High performance piezoelectric composite fabricated at ultra low temperature

• Published in: Composites. Part B, Engineering Engineering, 2022-01, Vol.229, p.109486, Article 109486
• Main Authors: Siponkoski, Tuomo, Nelo, Mikko, Ilonen, Niklas, Juuti, Jari, Jantunen, Heli
• Format: Article
• Language: English
• Subjects: Ceramic-matrix composites (CMCs); Electrical properties; Isostatic processing; Piezoelectric properties; Ultra low temperature fabrication
• ISSN: 1359-8368; 1879-1069
• DOI: 10.1016/j.compositesb.2021.109486

This work presents the next leap in piezoelectric all-ceramic composites fabricated at ultra low temperatures. The “Upside-down” composite method is further developed and instead of the water-soluble lithium molybdate used in our earlier study, an organotitanate based precursor gel is used as a binder. Utilizing heat and pressure the precursor transforms into titanium oxide which, together with lead zirconate titanate particles, forms a high-performance piezoelectric composite. The two-step fabrication method is based only on mixing and uniaxial hot-pressing sequences. The all-ceramic samples are fabricated at ultra low temperatures 275–350 °C with exceptionally high fractions of filler (filler to matrix 84:16 vol ratio) resulting in low porosity and showing excellent dielectric and piezoelectric properties. The charge coefficient d33 ∼150 pC N−1 and the voltage coefficient, g33 ∼52 mVm N−1 obtained with the developed composite outperforms many other known composites (80% and 70% higher than achieved with lithium molybdate bound upside-down composite, respectively) and are comparable even to some bulk piezoceramics and low permittivity polymer-ceramic piezocomposites. The sensor properties of the developed composite and the feasibility of the material from the application point of view are successfully demonstrated by utilizing sample elements in a charge mode acceleration sensor and sensitivities comparable to commercial devices are achieved. [Display omitted] •New fabrication method for piezoelectric all-ceramic composites in ultra low temperatures.•Highest ever piezoelectric response for ultra low temperature fabricated composites.•Utilization of sol-gel precursor and high filler loading with isostatic press.