Ultrahigh thermal stability and piezoelectricity of lead-free KNN-based texture piezoceramics.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39424820.
- Also identified by DOI 10.1038/s41467-024-53437-5 and PMC identifier 11489714.
- Licence recorded as CC BY-NC-ND.
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Abstract
The contradiction between high piezoelectricity and uniquely poor temperature stability generated by polymorphic phase boundary is a huge obstacle to high-performance (K, Na)NbO<sub>3</sub> -based ceramics entering the application market as Pb-based substitutes. We possess the phase boundary by mimicking Pb(Zr, Ti)O<sub>3</sub>'s morphotropic phase boundary structure via the synergistic optimization of diffusion phase boundary and crystal orientation in 0.94(Na<sub>0.56</sub>K<sub>0.44</sub>)NbO<sub>3</sub>-0.03Bi<sub>0.5</sub>Na<sub>0.5</sub>ZrO<sub>3</sub>-0.03(Bi<sub>0.5</sub>K<sub>0.5</sub>)HfO<sub>3</sub> textured ceramics. As a result, a prominent comprehensive performance is obtained, including giant d<sub>33</sub> of 550 ± 30 pC/N and ultrahigh temperature stability (d<sub>33</sub> change rate less than 1.2% within 25-150 °C), representing a significant breakthrough in lead-free piezoceramics, even surpassing the Pb-based piezoelectric ceramics. Within the same temperature range, the d<sub>33</sub> change rate of the commercial Pb(Zr, Ti)O<sub>3</sub>-5 ceramics is only about 10%, and more importantly, its d<sub>33</sub> (~ 350 pC/N) is much lower than that of the (K, Na)NbO<sub>3</sub>-based ceramics in this work. This study demonstrates a strategy for constructing the phase boundary with MPB feature, settling the problem of temperature instability in (K, Na)NbO<sub>3</sub>-based ceramics.