Study of the synthetic process of CaBi2Ta2O9 powder by the molten‐salt method

Abstract

The molten-salt method was used to synthesize CaBi 2 Ta 2 O 9 (CBTa) powder, and the influence of temperature on the structure and micromorphology of products was investigated using X-ray diffraction and the scanning and transmission electron microscope. The results showed that highly crystalline CBTa nanoplates exhibit single orthorhombic symmetry and could be obtained in the temperature range of 850-900°C. Among which, the nanoplates prepared at 900°C have optimal properties (average grain size of 1.7 μm and uniform size distribution). Above 900°C, various CaO-Ta 2 O 5 binary compounds, Bi 2 O 3, and BiTaO 4 formed due to the decomposition of CBTa and subsequent reactions of decomposition products, transforming plate-like grains to cuboid nano-particles with a small amount of prismatic grains. Possible reaction mechanisms at different synthesizing temperature were proposed. This work provides a method for the preparation of template grains to synthesize textured CaBi 2 Ta 2 O 9 high-temperature piezoelectric ceramics by the template grain growth method.

Membraneless, self-powered immunosensing of a cardiac biomarker by exploiting a PEC platform based on CaBi2Ta2O9 combined with bismuth oxyiodides

“…CaBi 2 Ta 2 O 9 (CBTO) was obtained using the molten-salt method by adapting some previous works. 1,23,24 Briefly, 0.1 g CaCO 3 , 0.465 g Bi 2 O 3 , 0.442 g Ta 2 O 5 , 0.9 g NaCl, and 1.1 g de KCl were mixed and ground for 40 min using a mortar and pestle. The powder was calcined in a muffle furnace at 750 °C for 2 h. The obtained powder was washed to remove the residual KCl/NaCl with deionized water and centrifuged at 2500 rpm for 10 min.…”

“…Nowadays, bismuth-layered oxides, such as ABi 2 Ta 2 O 9 (where A = Sr, Ba, Ca and B = Ta 5+ , Nb 5+ , Ti 4+ ), based on Aurivillius-type compounds have received significant attention because of their high Curie temperature and thermal stability 1 and exquisite photocatalytic 2 and ferroelectric properties. 3 These Aurivillius phases present a general formula based on (A n −1 B n O 3 n +1 ) 2− units sandwiched between (Bi 2 O 2 ) 2+ layers, where n is the number of octahedral layers in the perovskite slab, A is a chemical element or combination of elements of dodecahedral coordination, and B is a transition element suitable for octahedral coordination.…”