High-Performance 0-3 Type Niobate-Based Lead-Free Piezoelectric Composite Ceramics with ZnO Inclusions

Abstract

Because of their high toxicity, lead-based materials in electronic devices must be replaced by lead-free piezoelectric materials. However, some issues remain that hinder the industrial applications of these alternative ceramics. Here, we report the construction of a 0-3-type ceramic composite (KNNS-BNKZ: xZnO), where the Sb-doped ZnO submicronic particles were randomly distributed throughout the potassium-sodium niobate-based ceramic matrix. In this (K,Na)NbO (KNN)-based ceramic composite, superior temperature stability, excellent piezoelectric properties, and a high Curie temperature were simultaneously achieved. The unipolar strain varied from +20 to -16% when the temperature was increased from 23 to 200 °C in KNNS-BNKZ: xZnO with x = 0.75. By increasing the ZnO content from x = 0 to x = 5.0, the Curie temperature was increased from 227 to 294 °C. More importantly, the piezoelectric coefficient remained high ( d = 480-510 pC/N) for a wide range of compositions, x = 0.25-1.0. Transmission electron microscopy (TEM) experiments showed that the compensatory electric fields generated by the Sb-doped ZnO submicronic particles were responsible for the improved temperature stability. The high piezoelectricity was due to the existence of nanodomains, which were clearly observed in the TEM experiments. The results presented in this work clarify some of the physical mechanisms in this KNN-based ceramic composite, thus advancing the development of lead-free ceramics.

Refreshing doping concept in perovskite piezoceramics: Composite modulation hidden behind lattice substitution

“…Compared with the four existing elements (Zn 2+ , Nb 5+ , Zr 4+ , and Ti 4+ ) in the B-site of the perovskite matrix of PZN-PZT, the doped Cu 1+ ions have an ion radius close to that of the Zn 2+ ions (Table 1); this indicates that there placement of the Zn 2+ ions by the Cu 1+ ions is thermodynamically preferred. On the other hand, Cu 1+ ions and Zn 2+ ions have the exact outer electronic configuration, 3d 10 (Table 1). If the expected substitution the Zn 2+ ions by the Cu 1+ ions occurs, the induced random field effect will be weak, unlike the substitution of the Nb 5+ , Zr 4+ , or Ti 4+ ions by the Cu 1+ ions.…”

“…However, we predict that if suitable doping ions can be selected to accurately substitute the specific matrix ions that can spontaneously crystallize into the secondary phase at the grain boundary, it is possible to achieve dual functions of lattice substitution and composite modulation ( Figure 1B). It is worth noting that in the recent years, some researchers have confirmed the advantages of the heterogeneous interface effects, caused by the composite structure, in boosting the electrical performances (eg piezoelectricity, 10,11,12 and depolarization temperature 13,14,15 ) of piezoceramics. Therefore, we expect that the new doping method with both lattice substitution as well as composite construction will be able to effectively alter the properties of materials, thereby producing high performance piezoelectric composites.…”

Nano-domains in lead-free piezoceramics: a review

“…6,9,12,14,15,41,44 Ferroelectric domains, acting as the extrinsic contribution, are also responsible for the temperature Recently, the PBE proposed by Wu et al was widely reported to simultaneously improve the piezoelectric properties and relieve the temperature dependence. 62,93,157,231,233,235,236,239,266,285,290,296 To understand the enhanced temperature stability, Wu et al compared the temperature stability of ferroelectric domains among KNN-based ceramics with different phase structures. 262 Figure 19(a-c)…”

Stable piezoelectric response of 0-3 type CaBi2Nb2O9:xwt%BiFeO3 composites for high-temperature piezoelectric applications

“…The CBN (smaller particles) grains have created the 3D matrix in which BFO (large particles) grains are embedded and isolated from each other. It shows that 0-3 type connectivity has been established in CBN:40 wt%BFO composite [23][24][25]28].…”