Addition of a Sr, K, Nb (SKN) Combination to PZT(53/47) for High Strain Applications

Abstract

A lead zirconate titanate composition incorporating the dopants Sr, K, and Nb (SKN) in the specific ratio 4:1:3 has been studied.In principle, the SKN should act as a donor dopant but since its addition reduced the grain size from 11.4 lm (for 1% SKN) to 1.5 lm (for 5% SKN), the overall effect was found to be more complicated. It was observed that the addition of SKN reduced the Curie temperature, by 161C/mol (%) and broadened the dielectric peak. X-ray measurements further suggested that the ceramic was a mixture of rhombohedral and tetragonal phases and that the room temperature c/a ratio of the tetragonal phase decreased with SKN addition. The piezoelectric coefficient d 33 , determined from high field unipolar drives, gave an optimum value of 779 pm/V for the 0.02 SKN compositions, which also exhibited a relatively high Curie temperature of 3561C. Competing effects of enhanced domain wall mobility from donor doping and reduced mobility due to smaller grain size may explain the observed compositional variation in the measured material properties. Materials based on this composition are attractive for high performance piezoelectric actuator applications such as fuel injection.

Progress in engineering high strain lead-free piezoelectric ceramics

“…PZT possesses superior dielectric and piezoelectric properties arising from the existence of a morphotropic phase boundary (MPB) between tetragonal and rhombohedral phases at ∼48 mol% PbTiO 3 content [5][6][7]. Piezoelectric coefficients (d 33 ) as high as 779 pC N −1 have been reported for modified PZT [8] with Curie temperatures (T C ) in the range 300-400…”

Base Metal Co-Fired Multilayer Piezoelectrics

“…The generation of oxygen vacancies reached equilibrium with the oxygen in the atmosphere, as shown in Equation (7). As a consequence of the high volatilization, the PZT was often sintered with excess PbO or lead sources (PZ) to compensate for the loss of volatile PbO [23,29,30]. Figure 2 shows the ionic conductivity change over time; the gentle slope in the N 2 zone means that the Pb-losing rate is low.…”

“…There were published works on co-firing a Cu electrode [37] with PZTbased materials. Takayama et al [38] reported the work on fabricating Cu co-fired PZT-SKN (PZTSr(K0.25Nb0.75)O3) [20,21,23] multilayer actuators. An acrylic binder system was used to lower the burnout temperature, instead of the more widely used PVB; however, this acrylic binder was difficult to handle.…”

Comparative investigations on dielectric, piezoelectric properties and humidity resistance of PZT–SKN and PZT–SNN ceramics

“…Some piezoelectric materials are added separately or together to the PZT system to form ternary or quaternary solid solutions, such as PZT-SKN [5], PZT-PMN [6], and PZT-PMN-PZN [7]. The Pb(Zr 0.53 ,Ti 0.47 ) O 3 -Sr(K 0.25 ,Nb 0.75 )O 3 (PZT-SKN) system were first reported by Helke et al [8].…”