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Thesis defence

Last 31st of March, 2021, our colleague Dr. Innocent Nomel, has successfully presented his research work entitled: “Development of a new process for thick film deposition of lead-free piezoelectric materials by aerosol deposition for the manufacture of energy recovery micro-devices”

This thesis focused on new process development by aerosol deposition coating, so-called ADM (Aerosol Deposition Method), allowing thick layers realisation from lead-free piezoelectric materials for the manufacturing of energy harvesting micro-devices. Two synthesis ways were studied, and the optimisation of deposition parameters allowed obtaining the desired thick layers on metallic substrate. Despite high electrical losses, the films obtained exhibit a good dielectric behaviour with a relative permittivity estimated at 100. The high resistivity values (1010 Ω.m) and the breakdown voltage deficiency under a high electric field (E> 10 kV/mm) reflect good densities and microstructures of films obtained without annealing. Despite the absence of real ferroelectric cycles, studies suggest piezoelectric properties at a local scale (nanometric) rather than at a macroscopic scale. The objectives were achieved through, on one hand, the control and the reproducibility to obtain thick layers up to 100 µm and, on the other hand, the development of a simple energy harvesting device with electromechanical conversion.

5×40 mm2 samples obtained: a) before et b) after upper metallisation – ©CTTC

This research work was realised at the Institute for Research on Ceramics (IRCER Lab, CNRS #7315), under the responsibility of Dr. Pascal Marchet, Associate Professor, and in collaboration with GREMAN Lab at the University of Tours.

CTTC thanks Region Nouvelle-Aquitaine for the financial support all along the research work.