Method for preparing bismuth ferrite-barium titanate (BiFeO3-BaTiO3) ceramic through two-step sintering

Abstract

The invention discloses a method for preparing bismuth ferrite-barium titanate (BiFeO3-BaTiO3) ceramic through two-step sintering, and belongs to the technical field of lead-free ceramic preparation. The preparation method comprises the following steps: calculating and weighing according to a chemical formula (1-x) Bi (1 + y) FeO3-xBaTiO3, ball-milling and mixing, drying, sieving, putting into an alumina crucible, and pre-sintering at 780-950 DEG C for 2-12 hours to obtain pre-sintered powder; carrying out secondary ball milling, drying at 70-120 DEG C, sieving dried powder, adding polyvinyl alcohol with the concentration of 2wt% into the sieved dried powder, carrying out grinding granulation, and putting the granulated powder into a mold for compression molding; placing the ceramic green body in a muffle furnace, heating to 300-440 DEG C, discharging glue for 2-4 hours, heating to 950-1060 DEG C, preserving heat for 1-10 minutes, cooling to 900-1060 DEG C, sintering for 4-12 hours, and cooling to room temperature along with the furnace to prepare the required ceramic. According to the two-step sintering method disclosed by the invention, by ingeniously controlling the two-step sintering temperature and the heat preservation time, an impure phase generation temperature interval in the bismuth ferrite-barium titanate ceramic can be avoided; the prepared ceramic is good in crystallinity, uniform in component, small in grain size, compact in structure, low in dielectric loss, high in insulativity, high in remanent polarization intensity and excellent in piezoelectric property and photovoltaic property.

Description

technical field [0001] The invention belongs to the technical field of preparation of lead-free ceramics, in particular to a two-step sintering preparation of bismuth ferrite-barium titanate (BiFeO 3 -BaTiO 3 ) method of ceramics. Background technique [0002] Piezoelectric ceramics can realize mutual conversion between electrical energy and mechanical energy, and are important functional materials for mechatronics, intelligent structural components and other technologies, and have been widely used in various fields of social production and life. The market scale of piezoelectric ceramics is huge. In 2009, the global market scale of piezoelectric drive-related products reached 6.6 billion US dollars, and the annual growth rate is about 13%. Lead zirconate titanate (Pb(Zr,Ti)O 3 , PZT) piezoelectric ceramics occupy a dominant position in the market because of their excellent comprehensive performance, but Pb is a toxic element that will cause great harm to human health and...

AI Technical Summary

Problems solved by technology

At the same time, bismuth oxide (Bi 2 o 3 ) is easy to volatilize at high temperature, making bismuth ferrite-barium titanate (BiFeO 3 -BaTiO 3 ) The composition of lead-free piezoelectric ceramics deviates from the optimal ratio during the sintering process, resulting in a large number of oxygen vacancies, resulting in increased leakage current, it is difficult to achieve sufficient polarization under high electric field and high temperature, and the piezoelectric performance is low

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