Preparation method for synthesizing lanthanum hafnate powder by using sol-gel process

A technology of sol-gel method and lanthanum hafnate, applied in the field of preparation of sol-gel method to synthesize lanthanum hafnate powder, can solve the problems of easy mixing of impurities, high energy consumption, grain growth and the like, and achieve the synthesis of powder Controllable chemical composition, low calcination temperature and good uniformity

Inactive Publication Date: 2020-11-17
NORTHWESTERN POLYTECHNICAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] Literature 2 "Popov, V.V., et al., La 2 f 2 o 7 crystal and local structure changes on the fluorite -pyrochlore phase transition[J].Journal of Physics:ConferenceSeries,2016.747."Using co-precipitation method to prepare La 2 f 2 o 7 Powder, this method is easy to mix impurities during the preparation process, resulting in abnormal grain growth and agglomeration
[0005] Patent No. CN201010611587.1 and Patent No. CN201910929796.1 respectively disclose the preparation of lanthanum yttrium hafnate and europium hafnate ceramic powders by solid-phase method. This process has the disadvantages of high energy consumption, low efficiency, powder is not fine enough, and easy to mix into Impurities and other issues

Method used

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  • Preparation method for synthesizing lanthanum hafnate powder by using sol-gel process
  • Preparation method for synthesizing lanthanum hafnate powder by using sol-gel process
  • Preparation method for synthesizing lanthanum hafnate powder by using sol-gel process

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Experimental program
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Effect test

Embodiment 1

[0026] A kind of molten salt method of the present embodiment synthesizes La 2 f 2 o 7 Powder preparation method.

[0027] Step 1: Weigh a certain amount of hafnium tetrachloride (HfCl 4 ) and hydrated lanthanum nitrate (La(NO 3 ) 3 ·xH 2 O), ensure that the molar ratio of hafnium-lanthanum element is 1:1, be dissolved in deionized water with a mass ratio of hafnium-lanthanum compound and deionized water of 1:5-15, fully stir for 1-2h, The molar ratio is 1:1-2, and the citric acid powder is weighed and dissolved in the mixed solution, and the mixed solution is placed in a constant temperature water bath at a temperature of 50-80°C and stirred for 1-3 hours to form a sol.

[0028] Step 2: According to the 1:1 molar ratio of ethylene glycol and citric acid, weigh a certain amount of ethylene glycol solution and pour it into the solution obtained in step 1, and place it in a constant temperature water bath at 70-90°C for evaporation and stirring 2 to 4 hours to form a gel....

Embodiment 2

[0031] A kind of molten salt method of the present embodiment synthesizes La 2 f 2 o 7 Powder preparation method.

[0032] Step 1: Weigh a certain amount of hafnium tetrachloride (HfCl 4 ) and hydrated lanthanum nitrate (La(NO 3 ) 3 ·xH2 O), ensure that the molar ratio of hafnium-lanthanum element is 1:1, be dissolved in deionized water with a mass ratio of hafnium-lanthanum compound and deionized water of 1:5-15, fully stir for 1-2h, The molar ratio is 1:1-2, and the citric acid powder is weighed and dissolved in the mixed solution, and the mixed solution is placed in a constant temperature water bath at a temperature of 50-80°C and stirred for 1-3 hours to form a sol.

[0033] Step 2: According to the molar ratio of ethylene glycol and citric acid as 1:2, weigh a certain amount of ethylene glycol solution and pour it into the solution obtained in step 1, and place it in a constant temperature water bath at 70-90°C for evaporation and stirring 2 to 4 hours to form a gel...

Embodiment 3

[0036] A kind of molten salt method of the present embodiment synthesizes La 2 f 2 o 7 Powder preparation method.

[0037] Step 1: Weigh a certain amount of hafnium tetrachloride (HfCl 4 ) and hydrated lanthanum nitrate (La(NO 3 ) 3 ·xH 2 O), ensure that the molar ratio of hafnium-lanthanum element is 1:1, be dissolved in deionized water with a mass ratio of hafnium-lanthanum compound and deionized water of 1:5-15, fully stir for 1-2h, The molar ratio is 1:1-2, and the citric acid powder is weighed and dissolved in the mixed solution, and the mixed solution is placed in a constant temperature water bath at a temperature of 50-80°C and stirred for 1-3 hours to form a sol.

[0038] Step 2: According to the 1:3 molar ratio of ethylene glycol and citric acid, weigh a certain amount of ethylene glycol solution and pour it into the solution obtained in step 1, and place it in a constant temperature water bath at 70-90°C for evaporation and stirring 2 to 4 hours to form a gel....

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Abstract

The invention relates to a preparation method for synthesizing lanthanum hafnate powder by using a sol-gel process. The method comprises the following steps: dissolving hafnium tetrachloride (HfCl4) and lanthanum nitrate hydrate (La(NO3)3.xH2O) in deionized water, conducting sufficient stirring, adding a certain amount of citric acid powder, and performing stirring at 50-80 DEG C for 1-3 hours toform sol; weighing a certain amount of ethylene glycol, dissolving the ethylene glycol in the solution obtained in the step 1, and carrying out stirring for 2-4 hours at a temperature of 70-90 DEG C to form gel; and fully drying the gel obtained in the step 2, and calcining the gel at a temperature of 800-100 DEG C for 8-10 hours to obtain the lanthanum hafnate (La2Hf2O7) powder. The preparation method disclosed by the invention has the advantages of controllable chemical components of the synthetic powder, low calcining temperature, good uniformity, high purity and the like.

Description

technical field [0001] The invention belongs to the field of powder synthesis and relates to a preparation method for synthesizing lanthanum hafnate powder by a sol-gel method. Background technique [0002] A with pyrochlore structure 2 B 2 o 7 Ternary rare earth oxides exhibit high structural flexibility (change in structural composition through doping and process control), high cation conductivity, thermal resistance, thermochemical stability, and can remain intact after long-term radiation With a series of excellent chemical and physical properties such as crystal structure, it is widely used as electrochemical devices, thermal insulation coatings, solid electrolytes in high-temperature solid oxide fuel cells, neutron absorption and nuclear waste storage materials. However, lanthanide rare earth hafnates in A 2 B 2 o 7 Among the oxides of the lanthanum hafnite group (La 2 f 2 o 7 ) is the most thermodynamically stable substance among the rare earth hafnate oxides...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/48C04B35/486C04B35/50C04B35/624C04B35/626
CPCC04B35/48C04B35/486C04B35/50C04B35/624C04B35/62605C04B2235/3227C04B2235/3248C04B2235/5445C04B2235/5454
Inventor 张守阳丛龙康顾生越李伟李贺军
Owner NORTHWESTERN POLYTECHNICAL UNIV
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