Performance evaluation of lead-free potassium sodium niobate-based piezoceramics for ultrasonic motor design

The transition to lead-free piezoelectric materials is imperative to meet RoHS (Restriction of Hazardous Substances) regulations, which limit the use of lead in electronic components. Despite the necessity, lead-free alternatives often exhibit lower efficiency compared to traditional lead zirconate titanate (PZT) variants utilized in piezoelectric motors. This study addresses this challenge by employing a numerical simulation framework based on the Finite Element Method (FEM) to assess the feasibility of potassium sodium niobate (KNN)-based piezoceramics. The inherent complexity in experimentally determining material constants complicates their precise characterization. The synthesis of (KNN)-based piezoceramics was conducted via the solid-state reaction method and characterized through a comprehensive set of techniques, including density measurements, X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), ferroelectric hysteresis analysis, and impedance spectroscopy. These methodologies provided a comprehensive analysis of the material's structural, dielectric, piezoelectric, and ferroelectric properties. Finally, a detailed impedance spectrum-based FEM analysis enabled the extraction of critical piezoelectric parameters and the performance evaluation of KNN-based piezoceramics for their application in piezoelectric motors. By comparing the dynamic behavior of KNN-based piezoceramics with that of two commercial PZT ceramics (one hard and one soft), this research aims to foster the development of efficient lead-free piezoceramic materials, potentially revolutionizing piezoelectric applications while meeting stringent environmental standards. © 2025