Ultra-fine boron carbide polycrystalline powder prepared through organic boron-containing precursor self-propagating method

A precursor, self-propagating technology, applied in the field of boron carbide material preparation, can solve the problems of high cost, low purity of boron carbide ultrafine powder, and difficulty of ultrafine boron carbide, and achieves low preparation cost and simple preparation process. Effect

Inactive Publication Date: 2010-07-28
WUHAN INSTITUTE OF TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although some success and progress have been made in the preparation of boron carbide powder in recent years, the purity of the boron carbide ultrafine powder usually obtained is not high, and it is difficult and costly to manufacture ultrafine boron carbide

Method used

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  • Ultra-fine boron carbide polycrystalline powder prepared through organic boron-containing precursor self-propagating method
  • Ultra-fine boron carbide polycrystalline powder prepared through organic boron-containing precursor self-propagating method
  • Ultra-fine boron carbide polycrystalline powder prepared through organic boron-containing precursor self-propagating method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] Take 10.03 grams of PVA (the degree of polymerization is 1800-2000, and the degree of alcoholysis is not less than 98%), 6.98 grams of boric acid, and 40.07 grams of ethanol (99.5%) are put into a glass bottle, stirred at 50°C for 5 hours, and then heated at 250- Spray drying at 300° C. to obtain 12.93 g of PVA-boric acid precursor powder.

[0040] Mix PVA-boric acid precursor powder, 45.26 grams of boric anhydride, and 49.13 grams of magnesium powder (mass ratio: 1:3.5:3.8, particle size 100-300 mesh powder), then briquetting, and then energize in argon at normal temperature and pressure The hot tungsten wire was ignited and self-propagating combustion occurred, and the furnace was cooled to room temperature to obtain 58.29 grams of combustion reaction products. figure 1 It is a photo of the combustion product obtained by self-propagating reaction after the PVA-boric acid precursor is mixed with boric anhydride and magnesium powder.

[0041] Put the combustion reactio...

Embodiment 2

[0047] Take 10.09 grams of PVA (the degree of polymerization is 1800-2000, the degree of alcoholysis is not less than 98%), 7.06 grams of boric acid, 50.07 grams of ethanol (99.5%) are put into a glass reactor, stirred at 50°C for 5 hours, and then heated at 250 Spray drying at ~300°C to obtain 13.04 g of PVA-boric acid precursor powder.

[0048] PVA-boric acid precursor powder, 46.94 grams of boric anhydride, 54.77 grams of magnesium powder (mass ratio 1:3.6:4.2, particle size 100-300 mesh powder) were mixed and placed in a stainless steel reactor, and ignited at 800 ° C. Propagate the reaction and cool to room temperature with the furnace to obtain 58.79 g of combustion reaction products.

[0049] Take the combustion product and put it into excess 35-38wt.% concentrated hydrochloric acid, stir and soak at 50-70°C for 12 hours, then suction filter, wash the filter cake with distilled water until neutral, and dry the washed filter cake at 80°C for 24 hours. Hour, obtain 12.65...

Embodiment 3

[0052] Take 10.01 grams of PVA (the degree of polymerization is 1800-2000, and the degree of alcoholysis is not less than 98%), 7.11 grams of boric acid, and 39.9 grams of ethanol (99.5%) are put into a glass reactor, stirred at 80°C for 5 hours, and then heated at 250 Spray drying at ~300°C to obtain 12.94 g of PVA-boric acid precursor powder.

[0053] Mix PVA-boric acid precursor powder, 45.94 grams of boric anhydride, and 51.76 grams of magnesium powder (mass ratio: 1:3.55:4.0, powder with a particle size of 100 to 300 meshes) and briquette them, then electrify them in argon gas at normal temperature and pressure The self-propagating reaction was ignited by the tungsten wire, cooled to room temperature with the furnace, and 59.34 grams of combustion reaction products were obtained.

[0054] Put the self-propagating reaction product into excess 35-38% concentrated hydrochloric acid, stir and soak at 50-70°C for 12 hours, then filter with suction, wash the filter cake with di...

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Abstract

The invention relates to ultra-fine boron carbide polycrystalline powder prepared through an organic boron-containing precursor self-propagating method. In the method, the raw materials, namely, PVA- boric acid precursor, boron anhydrous and metal magnesium powder are mixed according to following mass ratio: PVA-boric acid precursor: B2O3: Mg = 100: (350 - 360): (380 - 420); through the self-propagating reaction, the obtained product is stirred and soaked in concentrated hydrochloric acid, and is leached, a filter cake is washed to neutrality with distilled water, and the washed filter cake is dried, the ultra-fine boron carbide polycrystalline powder is obtained. The invention has the advantages that firstly, the problem of small yield, low yield, and low purity of the ultra-fine boron carbide powder is solved , and the preparation process is simple; secondly, the prepared boron carbide is boron-rich type boron carbide B13C2, and has important application value; thirdly, the yield rate of the boron carbide is more than or equal to 95 percent, the free boron content is lower than or equal to 0.65 percent, and the free C content is lower than or equal to 2.65 percent.

Description

technical field [0001] The invention relates to the field of boron carbide material preparation, in particular to an organic boron-containing precursor self-propagating method for preparing ultrafine boron carbide polycrystalline powder. Background technique [0002] Boron carbide was first discovered in 1858. It has a rhombohedral structure. Its structure can be described as a cubic primitive cell lattice extending in the direction of the diagonal in space, forming a fairly regular icosahedron at each corner. It has many excellent properties, such as low density, high melting point, good high temperature strength, superhardness, and its hardness is second only to diamond and the hardest material of cubic boron nitride. [0003] At present, the methods for preparing boron carbide at home and abroad mainly include carbon tube furnace or electric arc furnace carbothermal reduction method, high temperature self-propagating synthesis method (SHS), sol-gel carbon thermal reductio...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B31/36
Inventor 谷云乐王为民赵国伟姜妮龚雪张来平李静
Owner WUHAN INSTITUTE OF TECHNOLOGY
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