Description:
<jats:title>Abstract</jats:title><jats:p>Lead‐free piezoelectric ceramics (K<jats:sub>0.94−<jats:italic>x</jats:italic></jats:sub>Na<jats:sub><jats:italic>x</jats:italic></jats:sub>Li<jats:sub>0.06</jats:sub>)(Nb<jats:sub>0.94</jats:sub>Sb<jats:sub>0.06</jats:sub>)O<jats:sub>3</jats:sub> have been fabricated by a conventional ceramic technique and the effects of K<jats:sup>+</jats:sup>/Na<jats:sup>+</jats:sup> ratio on the structure and piezoelectric properties of the ceramics have been studied. All the ceramics possess a pure perovskite structure. The coexistence of tetragonal and orthorhombic phases is formed at room temperature in the ceramics with 0.45 ≤ <jats:italic>x</jats:italic> ≤ 0.55. The tetragonal–orthorhombic phase‐transition temperature <jats:italic>T</jats:italic><jats:sub>O–T</jats:sub> decreases from 110 to 54 °C with <jats:italic>x</jats:italic> increasing from 0.35 to 0.55 and then increases from 84 to 144 °C with <jats:italic>x</jats:italic> further increasing from 0.6 to 0.7, while the Curie temperature <jats:italic>T</jats:italic><jats:sub>C</jats:sub> deceases from 388 to 348 °C with <jats:italic>x</jats:italic> increasing from 0.35 to 0.70. Because of the coexistence of the two phases near room temperature, the ceramics with <jats:italic>x</jats:italic> = 0.50 exhibit the optimum piezoelectric properties: <jats:italic>d</jats:italic><jats:sub>33</jats:sub> = 230 pC/N and <jats:italic>k</jats:italic><jats:sub>p</jats:sub> = 49%. The ceramics possess good time stability of piezoelectric properties.</jats:p>