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A-site ion vacancy induced sodium bismuth titanate-based self-retractable refrigeration perovskite ceramic material and preparation method thereof

A technology of sodium bismuth titanate and ceramic materials, which is applied in the direction of refrigerators, refrigeration and liquefaction, and the operation mode of machines, etc., can solve problems such as endangering human health and environmental safety, and achieve high electric card effect, good stability, and preparation low cost effect

Active Publication Date: 2021-11-26
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

On the one hand, most of the materials with high electric card effect contain toxic lead elements, which endanger human health and environmental safety. European countries have successively issued relevant laws and regulations to restrict the use of lead-containing materials, and the world has also begun to pay attention to the development of environmentally friendly materials. Therefore, It is very important to study lead-free electric card materials

Method used

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  • A-site ion vacancy induced sodium bismuth titanate-based self-retractable refrigeration perovskite ceramic material and preparation method thereof
  • A-site ion vacancy induced sodium bismuth titanate-based self-retractable refrigeration perovskite ceramic material and preparation method thereof
  • A-site ion vacancy induced sodium bismuth titanate-based self-retractable refrigeration perovskite ceramic material and preparation method thereof

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preparation example Construction

[0040] The above-mentioned preparation method of bismuth sodium titanate-based self-shrinking refrigeration perovskite ceramic material induced by A-site ion vacancies includes the following steps:

[0041] S1: Select Bi with a purity greater than 99% 2 o 3 、Na 2 CO 3 , SrCO 3 、BaCO 3 and TiO 2 As a raw material for bismuth sodium titanate-based self-shrinking refrigeration perovskite ceramic materials;

[0042] S2: according to (Bi 0.5+x / 3 Na 0.5-x ) 0.915 Sr 0.025 Ba 0.06 TiO 3 The stoichiometric ratio weighs raw materials (to ensure the absence of Na ions, and the overall chemical formula charge is conserved), and then dried after ball milling;

[0043] S3: pre-burning the dried powder obtained in step S2, and keeping it warm;

[0044] S4: Secondary ball milling the powder obtained in step S3, granulating and pressing to obtain a ceramic green body, and debinding to obtain a ceramic green body;

[0045] S5: sintering the ceramic green body obtained in step S4,...

Embodiment 1

[0057] (1) Select Bi with a purity greater than 99% 2 o 3 、Na 2 CO 3 , SrCO 3 、BaCO 3 and TiO 2 As the raw material of bismuth sodium titanate-based perovskite ceramic material, according to (Bi 0.5067 Na 0.4800 ) 0.915 Sr 0.025 Ba 0.06 TiO 3 Chemical formula, adding absolute ethanol to a nylon tank for ball milling, the ball milling time is 12h. Discharging and drying at a temperature of 90°C. The dried powder was put into an alumina crucible and pre-fired in a muffle furnace at 3°C ​​min -1 The heating rate was raised to 850°C, and the temperature was kept for 4 hours.

[0058] (2) Secondary ball milling of the synthesized powder obtained in step (1). The ball milling time is 12 hours, and then the material is discharged and dried at a temperature of 90°C. Add 0.2-0.3mL of 8wt% PVA binder per gram of powder to the dried powder for granulation, and press molding under a pressure of 6MPa to obtain a ceramic green body with a diameter of 10mm and a thickness of 1m...

Embodiment 2

[0063] (1) Select Bi with a purity greater than 99% 2 o 3 、Na 2 CO 3 , SrCO 3 、BaCO 3 and TiO 2 As the raw material of bismuth sodium titanate-based perovskite ceramic material, according to (Bi 0.5100 Na 0.4700 ) 0.915 Sr 0.025 Ba 0.06 TiO 3 Chemical formula, adding absolute ethanol to a nylon tank for ball milling, the ball milling time is 12h. Discharging and drying at a temperature of 90°C. The dried powder was put into an alumina crucible and pre-fired in a muffle furnace at 3°C ​​min -1 The heating rate was raised to 850°C, and the temperature was kept for 4 hours.

[0064] (2) Secondary ball milling of the synthesized powder obtained in step (1). The ball milling time is 12 hours, and then the material is discharged and dried at a temperature of 90°C. Add 0.2-0.3mL of 8wt% PVA binder per gram of powder to the dried powder for granulation, and press molding under a pressure of 6MPa to obtain a ceramic green body with a diameter of 10mm and a thickness of 1m...

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Abstract

The invention belongs to the technical field of electronic functional materials and devices, and particularly relates to an A-site ion vacancy induced sodium bismuth titanate-based self-retractable refrigeration perovskite ceramic material and a preparation method thereof, the chemical general formula of the A-site ion vacancy induced sodium bismuth titanate-based self-retractable refrigeration perovskite ceramic material is (Bi0.5+x / 3Na0.5-x) 0.915Sr0.025Ba0.06TiO3, and x is more than or equal to 0.02 and less than or equal to 0.03. Compared with the prior art, the A-site ion vacancy induced sodium bismuth titanate-based self-retractable refrigeration perovskite ceramic material disclosed by the invention has a relatively high synergistic response of an electrocaloric effect and an electrostrictive strain effect under an electric field of 6kV mm<-1>, and the electrostrictive strain effect can transfer heat in an electrocaloric cycle process to another position by changing the strain of the material, and the material has a great application prospect in the aspect of application of a self-retractable refrigeration device.

Description

technical field [0001] The invention belongs to the technical field of electronic functional materials and devices, and in particular relates to a bismuth sodium titanate-based self-shrinking refrigeration perovskite ceramic material induced by A-site ion vacancies and a preparation method thereof. Background technique [0002] The traditional fluoride gas refrigeration technology often causes environmental pollution problems, and the research on related traditional refrigeration technology has reached the bottleneck. The volatilized gas of the refrigerant enters the atmosphere, causing environmental problems such as the greenhouse effect, and at the same time destroying the earth's ozone layer, causing a large amount of ultraviolet rays to enter the ground, threatening human health. The electric card refrigeration technology is expected to replace the traditional and backward refrigeration methods. The electric card refrigeration device made of electric card material has hi...

Claims

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Application Information

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IPC IPC(8): C04B35/475C04B35/622F25B21/00
CPCC04B35/475C04B35/622F25B21/00C04B2235/3201C04B2235/3213C04B2235/3215C04B2235/6562C04B2235/6567C04B2235/768C04B2235/96Y02B30/00
Inventor 沈波李国辉翟继卫
Owner TONGJI UNIV