Effect of CuO Doping on (Bi,Na)_0.83Ba_0.17TiO₃ Piezoelectric Ceramics

Abstract

(Bi0.5Na0.5)0.83Ba0.17TiO3–x wt % CuO ceramics were prepared by a conventional ceramics fabrication method. The effects of CuO doping on densification, microstructure, and electrical properties are presented. The 0.2 wt % CuO-doped sample sintered at 1060 °C for 2 h exhibits good properties: a shrinkage rate of 16.5%, a relative density of 97%, a relative dielectric constant ε 33 T /ε 0 of 555 and a dielectric loss of 2.10% at 1 kHz, an electromechanical coupling factor k p of 18.0%, a piezoelectric charge coefficient d 33 of 148 pC/N, a frequency constant N p of 3096 Hz·m, a mechanical quality factor Q m of 52, a depolarization temperature T d of 218 °C, and a temperature corresponding to the maximum dielectric constant T m of 249 °C.

High piezoelectricity in low-temperature sintering potassium–sodium niobate-based lead-free ceramics

“…The improvement of Q m values should be due to the "hard" effect induced by the addition of Cu 2+ . [38][39][40][41][45][46][47][48][49][50][51] The increased Q m was accompanied by the decline of dielectric loss, as shown in Fig. 9 system by restricting the domain wall motions induced by Cu 2+ .…”

“…39,40 On the other hand, the CuO was also applied in other piezoelectrics for improving their electrical properties. 41,42 For example, adding 0.2 wt% CuO can decrease the sintering temperatures form 1180 C to 1060 C and concurrently maintain a high d 33 ($148 pC N À1 ) of (Bi 0.5 Na 0.5 ) 0.83 Ba 0.17 TiO 3 samples. 41 The sintering temperatures of 0.65Pb(Zr 0.42 Ti 0.58 )O 3 -0.35Pb(Ni 1/3 Nb 2/3 )O 3 ceramics could be dropped down to 900 C by doping 1.0 mol% CuO owing to the liquid phases from the reaction of CuO and Pb.…”

“…41,42 For example, adding 0.2 wt% CuO can decrease the sintering temperatures form 1180 C to 1060 C and concurrently maintain a high d 33 ($148 pC N À1 ) of (Bi 0.5 Na 0.5 ) 0.83 Ba 0.17 TiO 3 samples. 41 The sintering temperatures of 0.65Pb(Zr 0.42 Ti 0.58 )O 3 -0.35Pb(Ni 1/3 Nb 2/3 )O 3 ceramics could be dropped down to 900 C by doping 1.0 mol% CuO owing to the liquid phases from the reaction of CuO and Pb. 42 Although both the sinterability and electrical properties (d 33 and Q m ) of KNN ceramics could be promoted by doping CuO or Cu 2+ as a sintering aid, its d 33 (<250 pC N À1 ) is usually low.…”

Low-Temperature Sintering of (Bi,Na)0.83Ba0.17TiO3–0.2 wt % CuO Piezoelectric Ceramics from Nanopowders

“…5(b)]. 15) This phenomenon could be explained that the surface energy between main crystal faces with small Miller indexes and liquid CuO is lower than that with large Miller indexes. The origin of these microstructures is the formation of a liquid transient phase that promotes grain growth by a dissolution-reprecipitation mechanism.…”

“…In the BNT-BT17-x wt % CuO (x ¼ 0{3:0) ceramics, only CuO and the perovskite phases were detected by XRD analysis, and no other phase appeared. Furthermore, their T d and T c were approximately identical at about 215 and 240 C. 15) However, in the Ba(Ti 1Àx Cu 2x )O 3 ceramics, as x increased from 0 to 0.1, T c decreased from 120 to 75 C. 24) We also investigated (Bi,Na …”