Prepn and application of Li and Ti doped nickel oxide-base ceramic

A nickel oxide-based, co-doped technology, applied in ceramics, inorganic insulators, etc., can solve the problems of unstable dielectric constant of ferroelectric materials, poor material uniformity, unfavorable environmental protection requirements, etc., and achieve good temperature stability and short time. , the effect of saving energy

Inactive Publication Date: 2002-12-11
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

All of the above materials have obvious disadvantages: (1) the dielectric constants of the first two types of materials are small, both less than 1000; (2) the dielectric constants of ferroelectric materials are unstable and change significantly with temperature; Ferroelectric materials with large electrical constants are generally Pb-containing materials (PZN, PFW, PFN, PNN, etc.), which are very polluting during preparation and use, which is not conducive to environmental protection requirements
Currently doping nickel oxide is generally prepared by solid phase method (Woosuck Shin, et al.Materials Letters.2000, 45, 302-306; Jpn.J.Appl.Phys.2000, 39(3), 145), which This traditional method takes a long time to sinter, consumes a lot of energy, and the uniformity of the obtained material is poor, resulting in a decline in performance

Method used

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  • Prepn and application of Li and Ti doped nickel oxide-base ceramic
  • Prepn and application of Li and Ti doped nickel oxide-base ceramic
  • Prepn and application of Li and Ti doped nickel oxide-base ceramic

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] Ni(NO 3 ) 2 (0.093mol) and LiNO 3 (0.005mol) was dissolved in 250ml deionized water, stirred to obtain a transparent solution, 0.121mol citric acid was dissolved in the above solution, and stirred at 70°C for about 3 hours to obtain a viscous sol, which was put into an oven and dried at 110°C for about 12 Hours, a dry gel was obtained, ground, and pre-calcined at 400°C for 2 hours to obtain a black Li-Ni-O precursor powder. The powder and TiO 2 (0.002mol) powder mixing, ball milling, drying, dry pressing at 4Mpa, sintering at 1300°C for 4 hours to obtain bulk Li 0.05 Ti 0.02 Ni0.93 oCeramic materials. At room temperature, the relative permittivity ε = 12190 (10000Hz). For material characterization and properties see figure 1 , image 3 , Figure 10 and Figure 11 ; The precursor is a spherical particle with a size of about 30 nm (see figure 2 ).

Embodiment 2

[0039] Ni(NO 3 ) 2 (0.088mol) and LiNO 3 (0.01mol) was dissolved in 250ml deionized water, stirred to obtain a transparent solution, 0.176mol citric acid was dissolved in the above solution, stirred at 80°C for about 3 hours to obtain a viscous sol, put the sol in an oven, and dry at 130°C for about 12 Hours, to obtain a dry gel, ground, 600 ° C pre-calcination for 1 hour, to obtain black Li-Ni-O precursor powder. The powder and TiO 2 (0.002mol) powder mixing, ball milling, drying, dry pressing at 5 MPa, and sintering at about 1100 °C for 8 hours to obtain bulk Li 0.1 Ti 0.02 Ni 0.88 oCeramic materials. At room temperature, the relative permittivity ε = 52280 (10000Hz). For material characterization and properties see figure 1 , Figure 4 and Figure 12 .

Embodiment 3

[0041] Ni(NO 3 ) 2 (0.076mol) and LiNO 3 (0.02mol) was dissolved in 250ml deionized water, stirred to obtain a transparent solution, 0.128mol citric acid was dissolved in the above solution, and stirred at 70°C for about 3 hours to obtain a viscous sol, which was put into an oven and dried at 120°C for about 12 hours, a dry gel was obtained, ground, and pre-calcined at 450° C. for 1 hour to obtain a black precursor powder. The powder and TiO 2 (0.004mol) powder mixing, ball milling, drying, dry pressing at 5 MPa, and sintering at about 1280 °C for 6 hours to obtain bulk Li 0.2 Ti 0.04 Ni 0.76 oCeramic materials. At room temperature, relative permittivity ε = 200850 (10000Hz). For material characterization and properties see figure 1 , Figure 5 and Figure 13 .

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Abstract

The Li and Ti doped NiO-base ceramic is prepared through a sol-gel process of preparing Li doped NiO precursor powder and subsequent mixing with TiO2 and sintering. The precursor powder prepared through sol-gel process has msll grain size and homogeneous chemical performance, and is easy to sintered and favorable to raising material performance. Regulating the doped Li and Ti amount can alter thedielectric performance of the ceramic material for different requirement. The ceramic has very high dielectric constant, greater than 10 to the power 4 at 1-10 MHz, and high temperature stability andmay be used in thermoelectric electricity generation, thermoelectric refrigeration, producing high-density capacitor and other fields.

Description

technical field [0001] The invention relates to an oxide ceramic material, in particular to a preparation method and application of a lithium-titanium co-doped nickel oxide-based ceramic material, belonging to the technical field of thermoelectric and dielectric materials. Background technique [0002] Palchik et al pointed out in their article (Nanostructured Materials.1999, 11(3), 415-420) that NiO is a very widely used material and can be used in the field of catalysis, fuel cell electrodes and gas sensors. Woosuck Shin et al pointed out in their article (Materials Letters.2000, 45, 302-306; Jpn.J.Appl.Phys.2000, 39(3), 145) that lithium-doped NiO or lithium-sodium co-doped Miscellaneous NiO ceramics can also be used as thermoelectric conversion materials. [0003] The commonly used dielectric materials with high permittivity can be roughly divided into the following categories. One type is the high dielectric oxide or perovskite structure composite oxide represented by...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/28C04B35/624H01B3/12
Inventor 南策文邬俊波南军邓元
Owner TSINGHUA UNIV
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