Sintering Temperature Effect on Phase Formation, Microstructure and Electrical Properties of Modified KNLNTS Solid Solution Prepared via the Solid-State Combustion Technique

Abstract

In this study, the effect of sintering temperature (1000–1100 °C for 2 h) on phase formation, phase transition, microstructure and electrical properties of lead-free piezoelectric (K_0.44Na_0.52Li_0.04)(Nb_0.84Ta_0.10Sb_0.06)O₃ (KNLNTS) solid solution with 0.3 wt%Bi₂O₃ + 0.4 wt%Fe₂O₃ + 0.2 wt%CuO additive (abbreviate as modified KNLNTS) was investigated. Modified KNLNTS ceramics were synthesized by the solid-state combustion technique using glycine as fuel. The modified KNLNTS powders were prepared using the calcination condition of 650 °C for 2 h. The XRD pattern of all sintered ceramics exhibited a pure perovskite phase. Using Rietveld refinement to analyze the phase formation showed that the modified KNLNTS ceramics had co-existing phases of orthorhombic and tetragonal in all sintered ceramics and the orthorhombic phase increased when the sintering temperature increased. The average grain size, T_O-T, T_c, P_r and Ec increased with increasing sintering temperature. At the sintering temperature of 1025 °C, the modified KNLNTS ceramic showed the best electrical properties (C_ε ≈ 6745, S_max ≈0.274% and d*₃₃ ≈ 548 pm/V). The good electrical properties of the modified KNLNTS ceramics makes them good candidates for lead-free applications to replace Pb-based ceramics.

Keywords:

• Modified KNLNTS
• combustion technique
• Rietveld refinement
• microstructure
• dielectric properties

Acknowledgments

The authors wish to thank the Department of Physics, Faculty of Science, Naresuan University. Thanks, are also given to Asst. Prof. Dr. Kyle V. Lopin for his help in editing the manuscript.

Disclosure Statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work supported by The National Science, Research and Innovation Fund (NSRF) through Naresuan University [R2565B059].