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Lead-free ferroelectric material for ferroelectric refrigerator and preparation method of lead-free ferroelectric material

A ferroelectric material and refrigerator technology, applied in the field of electronic ceramics, to achieve the effect of forced cooling and the effect of promoting sintering

Inactive Publication Date: 2016-02-24
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] Among the ferroelectric materials, lead-based ferroelectric ceramics usually have a high electric card effect, but lead-containing materials will cause serious environmental pollution and human poisoning problems, which are subject to Lead restrictions cannot be used to manufacture ferroelectric refrigeration equipment
Lead-free ferroelectric materials are typically represented by barium titanate-based ferroelectric materials, which have large latent heat of phase change and strong electric card effect, but the temperature change peak area of ​​electric card effect is too narrow and far away from room temperature, which greatly limits its practical application

Method used

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  • Lead-free ferroelectric material for ferroelectric refrigerator and preparation method of lead-free ferroelectric material
  • Lead-free ferroelectric material for ferroelectric refrigerator and preparation method of lead-free ferroelectric material
  • Lead-free ferroelectric material for ferroelectric refrigerator and preparation method of lead-free ferroelectric material

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Embodiment 1

[0026] Table 1:

[0027]

Embodiment 2

[0028] Embodiment 2, adopt BaCO 3 、TiO 2 、Nd 2 o 3 As the initial raw material, according to the chemical formula Ba 1-1.5x Nd x TiO 3(x=0.03~0.06) Weigh and mix the raw materials; use absolute ethanol as the medium, ball mill for 6 hours, dry at 80°C, pass through a 200-mesh sieve, pre-fire at 1000°C, and keep warm for 4 hours to form a single perovskite Mineral phase: The obtained pure single-phase perovskite structure ceramic powder is ball-milled for 24 hours, dried at 80°C, sieved, added 5% polyvinyl alcohol (PVA) as a binder, ground and granulated, and formed. Sintering under oxygen atmosphere at 1400°C for 10 hours to form the final ceramic ferroelectric material sample. The electric card effect adiabatic temperature change ΔT-T curve of the test sample, such as figure 2 shown.

Embodiment 3

[0029] Embodiment 3, adopt BaCO 3 、TiO 2 、Gd 2 o 3 、Sm 2 o 3 As the initial raw material, according to the chemical formula Ba 0.94 SM 0.02 Gd 0.02 TiO 3 Weigh and mix the raw materials; use absolute ethanol as the medium, ball mill for 8 hours, dry at 80°C, pass through a 200-mesh sieve, pre-fire at 1000°C, and keep warm for 4 hours to form a single perovskite phase; the obtained powder Secondary ball milling for 24 hours, drying at 80°C, sieving, adding 5% polyvinyl alcohol (PVA) as a binder, grinding and granulating, molding, and sintering at 1400°C for 10 hours in an air atmosphere to form the final ceramic ferroelectric material sample. The electric card effect adiabatic temperature change ΔT-T curve of the test sample, such as image 3 shown.

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Abstract

The invention provides a lead-free ferroelectric material for a ferroelectric refrigerator and a preparation method of the lead-free ferroelectric material, belonging to the field of electronic ceramics. The material adopts barium titanate ceramic as a basis material, comprises one or more rear earth ion R3<+>substitutes, wherein A site substitution-(Ba1-1.5xRx)TiO3, B site substitution-Ba(RyTi1-0.75y)O3 and A-B-site simultaneous substitution-(Ba1-1.5xRx)(R`yTi1-0.75y)O3 can be performed in a rear earth ion barium titanate lattice, wherein R represents one or a combination of more different rear earth elements of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium and yttrium. According to the material, the sintering density can reach over 98 percent, the electrical resistivity reaches over the order of magnitude of 10<11> omega.cm, the electrocaloric effect is higher than 0.20K.m / MV, an adiabatic temperature change peak of the electrocaloric effect is continuously adjustable in an ultra-wide temperature range of 50 DEG C below zero to 150 DEG C, so that the practical application requirements of the ferroelectric refrigerator can be met.

Description

[0001] Technical field: [0002] The invention belongs to the field of electronic ceramics, in particular to a rare earth element-doped barium titanate ferroelectric ceramic material which can be used as a working medium of a ferroelectric refrigerator. [0003] Background technique: [0004] At present, the refrigerating working substance commonly used in most refrigeration equipment and air conditioners is chlorofluorocarbon, but it will deplete the ozone layer of the atmosphere, enhance the greenhouse effect, and cause great environmental harm. Therefore, people have to gradually stop production, use and eventually abolish it. Freon substances. Therefore, the development of new refrigeration equipment that does not contain CFCs has become an urgent and important issue for scientific researchers. In recent years, researchers have gradually turned their attention to solid-state refrigeration technology that does not contain volatile refrigeration working media. At present...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/468
CPCC04B35/4682C04B2235/3224C04B2235/3227C04B2235/6567C04B2235/6583
Inventor 白洋韩飞谢思乔利杰
Owner UNIV OF SCI & TECH BEIJING