Orientation Control of (Sr,Ca)₂NaNb₅O₁₅Ceramics by Spin-Forming-Extended Method

Orientation factor and piezoelectric property in textured (K,Na)NbO3system ceramics with minimal templates

“…A rolling-extended orientation technique, which we developed, was employed for preparing oriented green sheets. [27][28][29][36][37][38][39] The rolling-extended orientation technique is a TGG method for the easy fabrication of highly textured ceramics having a large thickness, which would be difficult to prepare by a conventional tape casting method. [27][28][29][36][37][38][39] The NN templates were mixed with the KNN calcined powder (matrix), an organic binder, and an organic solvent, and the mixture was damp-dried and kneaded until it reached claylike softness.…”

“…The details of this orientation technique were described in previous papers. [27][28][29][36][37][38][39] The extended green sheets were cut into rectangular bars with standard sizes of 35 × 6 × 2 mm 3 , shaped and dewaxed at 450 °C for 4 h, and then fired using a dual-step sintering process, 29) in which the firing conditions of the first and second steps were 1000 °C for 1 h and 1150-1180 °C for 8 h, respectively.…”

“…[18][19][20][21][22][23][24][25][26][27][28][29][30] On the other hand, even when the templates with smaller sizes are employed, their grain sizes are usually one or two orders of magnitude larger than those of calcined powder. 1,[7][8][9][10][11][12][13][14][15][16][17][18][19][20][27][28][29][30][31][32][33][34][35][36][37][38][39] To reduce the sintering temperature, it is more reasonable to reduce the mixing ratio of the templates to the calcined powder. In addition, even in the single-step molten salt synthesis, many 2SN 23,24,26,35) and relatively costly fabrication processes are needed to produce a large amount of NN templates.…”

Reduction effects of orientation control on nonlinear piezoelectricity in (K, Na)NbO₃ system ceramics

“…27),28),32)34) The rolling-extended orientation technique is a reactive template grain growth method, which can easily fabricate highly textured ceramics with a large rectangular shape that would be difficult to prepare by conventional grain orientation techniques. 32),38), 39) In this study, by comparing the nonlinear piezoelectricity of conventional randomly oriented samples with that of textured samples with various orientation factors, the effects of grain orientation on the nonlinear piezoelectricity were studied for KNN ceramics. In order to quantitatively estimate the non-linear piezoelectricity, a nonlinear coefficient for the thirdorder term of the electric field ² D31 was used.…”

Preparation of cubic Na0.5Sr0.25NbO3 particles by molten salt synthesis

“…Na 0.5 Sr 0.25 NbO 3 lead-free ceramics had no received considerable attention, which were only detected as second phase [18,19]. This may be because Na 0.5 Sr 0.25 NbO 3 ceramics had a poor densification process owing to the volatilization of alkali metal ion, occurrence of abnormal grain growth, formation of macroscopic cracking and so on.…”