Sodium bismuth titanate-barium titanate lead-free transparent electro-optic ceramic and preparation method thereof

A technology of sodium bismuth titanate and electro-optical ceramics is applied in the field of sodium bismuth titanate-barium titanate lead-free transparent electro-optical ceramics and its preparation, which can solve the problems of opacity of ceramics, difficult to control volatilization, long sintering time, etc., and achieve inhibition and elimination Air holes, high electro-optic coefficient, the effect of suppressing the generation of impurity

Active Publication Date: 2015-07-01
中国科学院上海硅酸盐研究所苏州研究院
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AI Technical Summary

Problems solved by technology

To prepare NBT-BT optoceramics by hot pressing and sintering, in order to completely eliminate pores, the sintering time of the material is longer, and the corresponding Na 2 O, Bi 2 o 3 It is difficult to control the volatilization of ceramics, and the composition of ceramics is easy to deviate from the design to form impurity phases. If the sintering system control is not ideal during the volatilization process of volatile components, more pores will be formed in the material.
Due to light irradiation on the impurity phase and pores, light absorption, reflection, refraction, scattering, etc. will occur, which will cause the ceramics to be opaque.

Method used

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  • Sodium bismuth titanate-barium titanate lead-free transparent electro-optic ceramic and preparation method thereof
  • Sodium bismuth titanate-barium titanate lead-free transparent electro-optic ceramic and preparation method thereof
  • Sodium bismuth titanate-barium titanate lead-free transparent electro-optic ceramic and preparation method thereof

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preparation example Construction

[0031] The invention provides a preparation method of bismuth sodium titanate-barium titanate lead-free transparent electro-optic ceramics, the chemical composition of the bismuth sodium titanate-barium titanate lead-free transparent electro-optic ceramics is (1-x)(Na 0.5 Bi 0.5 )TiO 3 -xBaTiO 3 , where 0.05≤x≤0.08. The preparation method adopts an oxygen-flowing-hot-pressing sintering process, controls the powder synthesis and sintering technology, suppresses the formation of impurity phases and eliminates pores, and achieves the purpose of improving the optical transmittance and electro-optic effect of the material. Specifically, as an example, the preparation method of the present invention may include the following steps.

[0032] (1) Ingredients: using Na 2 CO 3 、 Bi 2 o 3 、TiO 2 、BaCO 3 As raw materials, each raw material powder is accurately weighed according to the chemical composition of the above sodium bismuth titanate-barium titanate lead-free transparent ...

Embodiment 1

[0051] Press (1-x)(Na 0.5 Bi 0.5 )TiO 3 -xBaTiO 3 , where x=0.06 ingredients, using φ2mm ZrO 2 The mixed ball is used as the ball milling medium for planetary ball milling for 6 hours, and after drying, the raw material obtained is ground into powder, and then passed through a 200-mesh sieve to keep the components uniform. After sieving, the powder is put into an alumina crucible and pre-fired at 850°C for 2 hours to synthesize. After the synthesis, the powder is crushed through a 100-mesh sieve, planetary ball milled for 4 hours, then dried and added with a mass concentration of 6% PVA binder, and formed The pressure is 300MP, the forming mold is a cylinder of φ20×15, and then sintered by oxygen-hot pressing. The parameters of the sintering process are: the temperature rise rate is 200°C / hour from room temperature to 900°C, and the temperature is kept for 1 hour; then 100°C ℃ / hour to heat up, and gradually increase the pressure to 250MPa, then keep the pressure constant, ...

Embodiment 2

[0053] Press (1-x)(Na 0.5 Bi 0.5 )TiO 3 -xBaTiO 3 , where x=0.05, ingredients, using φ2mm ZrO 2 The mixed ball was used as the ball milling medium for ball milling for 5 hours. After drying, the obtained raw material was ground into powder, and then passed through a 200-mesh sieve to keep the components uniform. After sieving, the powder is put into an alumina crucible and pre-fired at 850°C for 3 hours to synthesize. After the synthesis, the powder is crushed through a 100-mesh sieve and ball milled for 4 hours. Add a PVA binder with a mass concentration of 6%. The molding pressure is 350MPa. The molding mold is The φ20×15 cylinder is then sintered by oxygen-hot pressing. The parameters of the sintering process are: the temperature rises from room temperature to 830°C at a rate of 200°C / hour, and the temperature is kept for 1 hour; then the temperature is raised at 100°C / hour, and Gradually increase the pressure to 240MPa, then keep the pressure constant, heat up to 1000°...

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Abstract

The invention relates to a sodium bismuth titanate-barium titanate lead-free transparent electro-optic ceramic and a preparation method thereof; the electro-optic ceramic has the chemical composition of (1-x)(Na0.5Bi0.5)TiO3-xBaTiO3, wherein 0.05<=x<=0.08; the preparation method includes the steps: batching Na2CO3, Bi2O3, TiO2 and BaCO3 as raw materials according to the stoichiometric ratio, carrying out ball milling, and mixing evenly to obtain a powder; carrying out heat preservation on the powder for 2-4 h at the temperature of 850-950 DEG C, and thus obtaining a synthetic material; crushing the synthetic material, sieving, carrying out ball milling, adding a binder, and carrying out press molding to obtain a blank; next, placing the blank in a sintering furnace, heating up from room temperature to 800 DEG C-850 DEG C at the speed of 200 DEG C-250 DEG C/h, and carrying out heat preservation for 0.5-1.5 h; and heating up at the speed of 100 DEG C/h and gradually pressurizing to 200-250 MPa, followed by keeping the pressure unchanged, heating up to 1000 DEG C-1050 DEG C, then carrying out heat preservation for 2 h, then heating up to 1100 DEG C-1200 DEG C at the speed of 50 DEG C/h, carrying out heat and pressure preservation for 8-24 h, then releasing the pressure, cooling to 900 DEG C at the speed of 100 DEG C/h, and cooling to room temperature along with a furnace, wherein oxygen is introduced with the flow quantity of 3-5 L/minute when the heating is started and introduction of oxygen is stopped when the pressure is released.

Description

technical field [0001] The invention belongs to the field of transparent functional ceramic materials, in particular to a bismuth sodium titanate-barium titanate lead-free transparent electro-optic ceramic and a preparation method thereof. Background technique [0002] The development of optical communication is closely related to optical passive devices (optical switches, optical attenuators, optical couplers), and the quality of optical passive devices depends largely on the materials used to prepare optical passive devices. At present, the electro-optic material widely used in optical passive devices at home and abroad is lithium niobate single crystal material. This kind of crystal with perovskite structure has strong primary electro-optic effect, high Curie temperature and high response speed. However, due to the lack of breakthrough in growth technology for a long time, it is still difficult to grow lithium niobate crystals that meet the stoichiometric ratio, making it...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/475C04B35/622
Inventor 程文秀何夕云仇萍荪曾霞夏彬
Owner 中国科学院上海硅酸盐研究所苏州研究院
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