Sintering kinects of (K-0.48 Na-0.52)NbO3 lead-free piezoelectric ceramics densified by spark plasma sintering: Construction of master sintering curve

摘要

In this work, (K0.48Na0.52)NbO3 (KNN) ceramics were prepared by using Spark Plasma Sintering (SPS) method applying different heating rates. The microstructural evolution of the ceramics was analyzed and the results were correlated with possible sintering mechanisms. The analysis revealed homogeneous microstructures with nanometric grains. It was noticed that with increasing the heating rate the grain size decreases and the bimodal grain growth is suppressed. The Master Sintering Curve was constructed and an apparent activation energy of 660 kJ/mol was determined. From this result, it was possible to predict the possible densification mechanisms present in the KNN by SPS route.