Fabrication of crystal-oriented barium-bismuth titanate ceramics in high magnetic field and subsequent reaction sintering

Abstract

High magnetic field was applied to fabricate novel lead-free piezoelectric ceramics with a textured structure. A compact of crystallographically oriented grains was prepared by dry forming in a high magnetic field from a mixed slurry of bismuth titanate and barium titanate powders. Bismuth titanate particles with a size of about 1 µm were used as the host material. In the forming process, the slurry was poured into a mold and set in a magnetic field of 10 T until completely dried. Bismuth titanate particles were highly oriented in the slurry under the magnetic field. The dried powder compact consisted of highly oriented bismuth titanate particles and randomly oriented barium titanate particles. Barium bismuth titanate ceramics with a-and b-axis orientations were successfully produced from the dried compact by sintering at temperatures above 1100• C.

In Situ Observations of Templated Grain Growth in (Na0.5K0.5)0.98Li0.02NbO3 Piezoceramics: Texture Development and Template–Matrix Interactions

“…1,2 Textured ceramics can be produced by a variety of techniques in which ceramic powders are aligned during green forming. [3][4][5][6][7][8] Templated grain growth (TGG) and reactive templated grain growth (RTGG) methods were developed in the 1990s to amplify texture produced in the green state by taking advantage of preferred growth of larger particles oriented in a dense, fine-grained matrix. 1 In these methods, large anisometric template particles are sparsely dispersed in a fine matrix powder and preferentially oriented during green forming.…”

Hybrid processing and anisotropic sintering shrinkage in textured ZnO ceramics

“…By combining magnetic field method with TGG, one can hope to achieve good alignment of grains, as templates are big particles which can be aligned at much lower magnetic field strengths [17]. In some recent studies anisometric, large inclusions were utilized in order to take advantage of their different properties [31,32] from those of the matrix. In conventional TGG process, matrix particles around templates are usually randomly oriented whereas the matrix particles would be oriented in the same manner as the templates when using a hybrid process.…”

Crystal-oriented (Bi_0.5, Na_0.5)_0.85–Ba_0.15TiO₃ ceramics prepared by colloidal processing in rotating high magnetic field

“…The specimens in silicone oil at 100°C were poled for 10 min parallel to the oriented direction under an electric field of 6.0 kV/mm. The piezoelectric constant d 33 was measured with d 33 meter (ZJ-6B, Institute of Acoustics, Chinese Academy of Sciences). .…”