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Preparation method of high-performance sodium niobate dielectric ceramic powder

A technology of dielectric ceramics and sodium niobate, which is applied in the field of inorganic non-metallic functional materials, can solve the problem of inability to obtain high-quality sodium niobate-based functional ceramic powders, poor size and composition uniformity of sodium niobate nanopowders, and inability to It satisfies the problems of ceramic densification and achieves the effects of large-scale production, room temperature dielectric constant enhancement, good stability and repeatability

Inactive Publication Date: 2016-03-16
NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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Problems solved by technology

Therefore, the existing synthesis technology cannot obtain high-quality sodium niobate-based functional ceramic powder
In 2010, the patent "Preparation method of high-purity sodium niobate nanopowder (CN101774642A)" disclosed that sodium ethoxide and niobium ethoxide were used as raw materials, and sodium niobate nanoparticles with a grain size of about 21nm were synthesized by microemulsion method. Powder, but it involves expensive niobium ethoxide and toxic lauryl polyoxyethylene ether, as well as high temperature heat treatment
Recent studies have also shown that even if high-quality nano-scale ceramic powders are obtained, it is still a great challenge to prepare high-density functional ceramics, mainly because the alkali metal oxides of sodium niobate-based ceramics are easily sintered. Absorbs moisture and reacts with carbon dioxide to produce heterogeneous phases (A.B.Haugenetal.J.Eur.Ceram.Soc.,2015,35,1449–1457)
In 2012, LiPeng et al. synthesized cubic phase sodium niobate powder by polymerization oxidation method derived from sugar alcohol [P.Li,etal.J.Phys.Chem.C2012,115(14) ,7621~7628], but this method has a long reaction time (>120h) and high cost, which is not conducive to large-scale production
2 "A preparation method of high-purity cubic sodium niobate nanopowder (CN104085922A)" discloses a low-temperature in-situ solid-phase synthesis method based on the reaction principle of niobium oxalate or niobium ammonium oxalate and sodium chloride to prepare niobium Sodium niobate nanopowder, but the size and composition uniformity of sodium niobate nanopowder obtained by this method is poor, and it cannot meet the densification of ceramics well.

Method used

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  • Preparation method of high-performance sodium niobate dielectric ceramic powder
  • Preparation method of high-performance sodium niobate dielectric ceramic powder
  • Preparation method of high-performance sodium niobate dielectric ceramic powder

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Experimental program
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Embodiment 1

[0029] Step 1: Add solid sodium hydroxide into 40ml of ethylene glycol according to the concentration ratio of 1.0mol / L, heat and stir, and obtain a reaction solution after it is uniformly mixed with an organic solvent;

[0030] Step 2: Add 0.5 g of niobium pentoxide to the reaction solution obtained in step 1, heat and stir for 30 minutes to form a milky white mixed solution;

[0031] Step 3: Transfer the mixed solution obtained in step 2 to a polytetrafluoroethylene liner with a volume of 60ml, then place the liner in a stainless steel hydrothermal reaction kettle and seal it, and carry out a 6h heat preservation reaction at 180°C. After the reaction is completed, Cool naturally to room temperature to obtain white precipitate;

[0032] Step 4: Using deionized water and absolute ethanol to wash and centrifuge the white precipitated product multiple times respectively, the rotation speed is 3000rpm, and the time is 30min, and all residual ions and organic solvents are washed a...

Embodiment 2

[0037]Step 1: Add solid sodium hydroxide into 40ml of ethylene glycol according to the concentration ratio of 1.0mol / L, heat and stir, and obtain a reaction solution after it is uniformly mixed with an organic solvent;

[0038] Step 2: Add 0.5 g of niobium pentoxide to the reaction solution obtained in step 1, heat and stir for 30 minutes to form a milky white mixed solution;

[0039] Step 3: Transfer the obtained mixed solution to a polytetrafluoroethylene liner with a volume of 60ml, then place the liner in a stainless steel hydrothermal reaction kettle and seal it, carry out a 4h heat preservation reaction at 220°C, and cool it down naturally after the reaction is completed to room temperature to obtain a white precipitate;

[0040] Step 4: Using deionized water and absolute ethanol to wash and centrifuge the white precipitated product multiple times respectively, the rotation speed is 3000rpm, and the time is 30min, and all residual ions and organic solvents are washed awa...

Embodiment 3

[0045] Step 1: Add solid sodium hydroxide into 40ml of ethylene glycol according to the concentration ratio of 1.0mol / L, heat and stir, and obtain a reaction solution after it is uniformly mixed with an organic solvent;

[0046] Step 2: Add 0.5 g of niobium pentoxide to the mixed solution obtained in Step 1, heat and stir for 30 minutes to form a milky white mixed solution;

[0047] Step 3: Transfer the obtained mixed solution to a polytetrafluoroethylene liner with a volume of 60ml, then place the liner in a stainless steel hydrothermal reaction kettle and seal it, carry out a 6h heat preservation reaction at 220°C, and cool naturally after the reaction is completed to room temperature to obtain a white precipitate;

[0048] Step 4: Using deionized water and absolute ethanol to wash and centrifuge the white precipitated product multiple times respectively, the rotation speed is 3000rpm, and the time is 30min, and all residual ions and organic solvents are washed away;

[004...

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Abstract

The invention discloses a method for synthesizing cubic phase sodium niobate dielectric ceramic powder under the low-temperature solvothermal condition. The method comprises the steps of weighing organic solvent to prepare a reaction solution, adding niobium pentaoxide, conducting a hydrothermal reaction and washing and drying. The sodium niobate powder prepared through the method has the advantages that a cubic phase structure and the nanoscale size are achieved, and the sintering activity is high; meanwhile, lattice expansion is produced along with the phase change in the sintering process, low-temperature sintering can be achieved, the densification degree is high, and the room-temperature dielectric constant is significantly enhanced. A low-temperature rapid synthetic method of cubic phase sodium niobate nano powder is provided, and meanwhile a new idea is provided for solving the problem of sodium niobate base function ceramic sintering densification.

Description

technical field [0001] The invention relates to a preparation method of sodium niobate dielectric ceramics, in particular to a method for low-temperature solvothermal synthesis of cubic phase high-performance sodium niobate nanopowder, which belongs to the field of inorganic non-metallic functional materials. Background technique [0002] Sodium niobate has a typical perovskite structure and is an important functional material with important applications in the fields of electronics, optics and photocatalysis. In particular, sodium niobate-based functional ceramics are considered as one of the most promising environmentally friendly functional materials due to their high Curie temperature and good electrical properties. However, in the process of preparing sodium niobate-based functional materials, the sintering temperature range is high and narrow, which causes the volatilization of alkali metal ions to intensify, resulting in a non-dense microstructure and poor uniformity ...

Claims

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Application Information

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IPC IPC(8): C04B35/495
Inventor 朱孔军古其林孙巧梅王婧刘劲松裘进浩
Owner NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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