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Method for preparing mesoporous hexagonal boron nitride ceramic powder based on urea activation

A hexagonal boron nitride and ceramic powder technology, applied in the field of materials, can solve problems such as ammonia leakage, production equipment, production safety, human safety and environmental protection threats

Active Publication Date: 2021-12-21
SHENYANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] The current activation method for preparing mesoporous hexagonal boron nitride mainly uses potassium hydroxide or potassium carbonate as the activator, boric acid as the boron source, and mesoporous hexagonal boron nitride is synthesized under a flowing ammonia atmosphere; but the problem faced by this method is Flowing ammonia gas is used as the nitrogen source. Ammonia gas is a highly corrosive gas, which is easy to cause ammonia gas leakage and poses a great threat to production equipment, production safety, human safety and environmental protection. Therefore, it has not been promoted and applied so far.

Method used

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  • Method for preparing mesoporous hexagonal boron nitride ceramic powder based on urea activation
  • Method for preparing mesoporous hexagonal boron nitride ceramic powder based on urea activation
  • Method for preparing mesoporous hexagonal boron nitride ceramic powder based on urea activation

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Experimental program
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Effect test

Embodiment 1

[0029] Prepare boron source boric acid, primary nitrogen source urea, network agent acrylamide, N,N-methylenebisacrylamide and ammonium persulfate, activator potassium hydroxide; prepare hard template sucrose at the same time; sucrose accounts for 10% of the total mass of boric acid , potassium hydroxide accounts for 5% of the total mass of boric acid, urea accounts for 5% of the total mass of boric acid, network agent accounts for 5% of the total mass of boric acid, acrylamide, N,N-methylenebisacrylamide and persulfuric acid in the network agent The mass ratio of ammonium is 140:4:25;

[0030] Add potassium hydroxide, boric acid, sucrose and urea in deionized water in sequence, stir until completely dissolved, then add acrylamide and N,N-methylenebisacrylamide in sequence, and then stir in a water bath at 60-70°C until completely Dissolve, finally add ammonium persulfate, continue to stir until the precursor gel is formed; the amount of deionized water is based on the complet...

Embodiment 2

[0035] Method is with embodiment 1, and difference is:

[0036] (1) sucrose accounts for 15% of the total mass of boric acid, potassium hydroxide accounts for 15% of the total mass of boric acid, urea accounts for 15% of the total mass of boric acid, and network agent accounts for 15% of the total mass of boric acid;

[0037] (2) The molar ratio of the secondary nitrogen source to boric acid is 20; wherein the drying temperature is 100°C, and the time is 16 hours; (3) The activation synthesis reaction temperature is 800°C, and the time is 4 hours;

[0038] (4) Carbon removal is carried out at 600°C for 4 hours; the mesoporous pore diameter of the mesoporous hexagonal boron nitride ceramic powder is 3 to 17.2 nanometers, and the specific surface area is 405.6m 2 / g.

Embodiment 3

[0040] Method is with embodiment 1, and difference is:

[0041] (1) sucrose accounts for 20% of the total mass of boric acid, potassium hydroxide accounts for 20% of the total mass of boric acid, urea accounts for 20% of the total mass of boric acid, and network agent accounts for 20% of the total mass of boric acid;

[0042] (2) The molar ratio of the secondary nitrogen source to boric acid is 40; wherein the drying temperature is 150° C., and the drying time is 8 hours;

[0043](3) The activation synthesis reaction temperature is 850°C, and the time is 4 hours;

[0044] (4) Carbon removal is carried out at 630°C for 3 hours; the mesoporous pore diameter of the mesoporous hexagonal boron nitride ceramic powder is 5-19.7 nanometers, and the specific surface area is 385.1m 2 / g.

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Abstract

A method for preparing mesoporous hexagonal boron nitride ceramic powder based on urea activation, the following steps are carried out: (1) preparing boric acid, urea, network agent, activator and sucrose; (2) preparing potassium hydroxide, boric acid, sucrose and Add urea to water and stir to dissolve, add acrylamide and N,N-methylenebisacrylamide, add ammonium persulfate after a water bath at 60-70°C, and stir until a gel is formed; (3) Dry and dehydrate with a secondary nitrogen source Grinding and mixing; (4) Heating the temperature in the heating furnace to 760-900°C under the pressure higher than the atmospheric pressure to carry out the activation synthesis reaction, and then pickling, water washing, alcohol washing and grinding; (5) Decarbonizing at 550-650°C, followed by Furnace cools. In the method of the invention, various gases are generated during the reaction process to increase the porosity while improving the reaction activity, and finally obtain the mesoporous hexagonal boron nitride powder.

Description

technical field [0001] The invention belongs to the field of material technology, in particular to a method for preparing mesoporous hexagonal boron nitride ceramic powder based on urea activation. Background technique [0002] Mesoporous hexagonal boron nitride has the advantages of high specific surface area, high adsorption, the lightest specific gravity among ceramic materials, the largest thermal conductivity and high electrical insulation; compared with activated carbon with high specific surface area, mesoporous hexagonal boron nitride is also It has high high temperature oxidation resistance, high strength, high pulverization resistance, can be recycled, and does not infiltrate all high temperature molten metals. It has high-tech fields such as metallurgy, catalysis, adsorption, water treatment and hydrogen storage materials. Wide application prospects. [0003] At present, the method for activating and preparing mesoporous hexagonal boron nitride mainly uses potass...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/5833C04B35/626
CPCC04B35/583C04B35/626C04B2235/3409C04B2235/48
Inventor 张宁崔世强徐晨辉马洋洋
Owner SHENYANG UNIV