Crystal structure and orthorhombic–tetragonal phase transition of nanoscale (Li0.06Na0.47K0.47)NbO3

Intergranular Stress Induced Phase Transition in CaZrO3 Modified KNN‐Based Lead‐Free Piezoelectrics

“…This is further certified by the Raman results. It is reported that the wave number of ν 1 mode will decrease with the size of the crystalline at RT, whereas in our results the ν 1 mode of the bulk and powder specimens locates nearly the same position at RT. Hence, the grain size effect on phase transitions in this study should be excluded.…”

Dielectric, ferroelectric and piezoelectric proprieties of GdCoO3 doped (K0.5Na0.5)NbO3

“…In order to further improve the piezoelectric properties of KNN, a series of methods have been proposed: compositional substitution -(K, Na)(Nb, Ta)O 3 [6] or [K,(Na, Li)]NbO 3 [7], use of sintering additive -CuO for [K, (Na, Li)](Ta, Sb, Nb)O 3 [8], alternative synthesis methods -hydrothermal [9] or hot pressing [10], and simple doping-CeO 2 doped KNN [11] or other perovskite structure doping: KNN + BaTiO 3 [12], KNN + BiFeO 3 [13] or KNN + BiScO 3 [14]. Recent finds in lead free piezoelectric materials, show that perovskite structure doping can be an effecting way of improving the electrical properties of potassium-sodium niobate, with a reported value of the piezoelectric constant close to that of commercial PZT: d 33 = 425 pCN À1 for [(K, Na), Li](Nb, Sb)O 3 -BaZrO 3 [15], d 33 = 366 pCN À1 for (K, Na)NbO 3 -0.005BiScO 3 -Bi(Na, K, Li)ZrO 3 [16], d 33 = 460 pCN À1 for (K, Na)(Nb, Ta, Sb)O 3 -(Bi, Na, K)ZrO 3 [17], d 33 = 388-465 pCN À1 for (K, Na)(Nb, Sb)O 3 -(Bi, Na, K)ZrO 3 [18] and a maximum ever recorded for KNN -based lead free piezoceramics reported by Wang et al [19] of d 33 = 490 pCN À1 .…”

Influence of ball milling on sintering behavior and electrical properties of (Li,Na,K)NbO3 lead-free piezoceramics

“…To solve this problem, pressurized sintering process such as spark plasma sintering is effective, which has been proved by the high density and fine grains [19,20,23]. However, there is less investigation concerning influence of particle size of calcined powder on sintering processes as well as phase transformations [24,25]. According to the theory of solidstate reaction, particle size together with the homogeneity of mixing plays an important role in affecting grain growth and resultant grain size.…”