Processing optimization and toxicological evaluation of “lead-free” piezoceramics: A knn-based case study


Iacomini A., Tamayo-Ramos J. A. , Rumbo C., Urgen I., Mureddu M., Mulas G., ...More

Materials, vol.14, no.15, 2021 (Journal Indexed in SCI) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 14 Issue: 15
  • Publication Date: 2021
  • Doi Number: 10.3390/ma14154337
  • Title of Journal : Materials
  • Keywords: lead-free piezoceramics, sodium potassium niobate, processing, toxicity assays, X-ray diffraction, mechanochemistry, SODIUM-POTASSIUM NIOBATE, CERAMICS, BEHAVIOR, POWDERS

Abstract

© 2021 by the authors. Licensee MDPI, Basel, Switzerland.Due to the ever-increasing limitations of the use of lead-based materials, the manufacturing of lead-free piezoceramics with competitive piezoelectric properties and established nontoxicity is considered a priority for the scientific and industrial community. In this work, a lead-free system based on sodium potassium niobate (KNN), opportunely modified with MgNb2O6 (MN), was prepared through a combination of a mechanochemical activation method and air sintering, and its toxicity was evaluated. The effect of the mechanical processing on the microstructure refinement of the processed powders was established by X-ray diffraction and the average crystallite size content of the Nb2O5 species was evaluated. The experimental evidence was rationalized using a phenomenological model which permitted us to obtain the amount of powder processed at each collision and to optimize the activation step of the pre-calcined reagents. This influenced the final density and piezoresponse of the as-sintered pellets, which showed optimal properties compared with other KNN systems. Their toxicological potential was evaluated through exposure experiments to the pulverized KNN-based pellets, employing two widely used human and environmental cellular models. The in vitro assays proved, under the selected conditions, the absence of cytotoxicity of KNN-bases systems here studied.