Department of Materials Science and Engineering, İzmir Institute of Technology, 35430, İzmir, Türkiye; Department of Industrial Engineering, University of Trento, Via Sommarive 9, 38123, Trento, Italy; Corresponding author Department of Materials Science and Engineering, Izmir Institute of Technology, 35430, Izmir, Turkiye.
Merve Karakaya
Department of Materials Science and Engineering, İzmir Institute of Technology, 35430, İzmir, Türkiye
Umut Adem
Department of Materials Science and Engineering, İzmir Institute of Technology, 35430, İzmir, Türkiye
Vincenzo M. Sglavo
Department of Industrial Engineering, University of Trento, Via Sommarive 9, 38123, Trento, Italy
Mattia Biesuz
Department of Industrial Engineering, University of Trento, Via Sommarive 9, 38123, Trento, Italy
Cekdar Vakifahmetoglu
Department of Materials Science and Engineering, İzmir Institute of Technology, 35430, İzmir, Türkiye
Potassium sodium niobate (KNN) is one of the most promising Pb-free piezo-ceramics. In the present work, KNN was produced by fast-firing with different cooling strategies, i.e., fast and slow cooling. Dielectric, ferroelectric, and piezoelectric properties of fast-fired pellets were determined and compared with those of conventional-sintered products. Although the samples produced by fast-firing had higher density than those obtained by conventional sintering, fast-cooled samples following fast firing show relatively low electrical properties. When fast-firing was combined with slow cooling, the electrical properties, especially piezoelectric d33 values, were improved. The material subjected to fast-firing at 1120 °C using slow cooling gave the highest relative density (about 95 %) with fine grains microstructure and a d33 of 112 pC/N whereas that produced by conventional sintering resulted in d33 of 80 pC/N with a relative density of 88 % for the same dwell time (30 min).
