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Preparation method of nano tungsten powder

A nano-tungsten powder, a certain amount of technology, applied in the field of cemented carbide materials and preparation, can solve the problems of not getting nano-tungsten powder, accelerating the volatilization of tungsten oxide, etc.

Active Publication Date: 2013-09-18
NANCHANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the process of preparing tungsten powder by carbon reduction of tungsten oxide, although the influence of water vapor can be eliminated, the high temperature required for carbon reduction will also accelerate the volatilization of tungsten oxide, so nano-tungsten powder cannot be obtained

Method used

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  • Preparation method of nano tungsten powder
  • Preparation method of nano tungsten powder

Examples

Experimental program
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Effect test

Embodiment 1

[0014] Weigh 180g of ammonium metatungstate, 20g of anhydrous glucose, and 1.5g of chromium nitrate, and dissolve them in deionized water at 80°C. After the raw materials are fully mixed, the precursors required for reduction are prepared by spray drying. Put the precursor powder into a tubular atmosphere furnace, pass through hydrogen for reduction, the reduction temperature is 780 °C, and the heating rate is 10 o C / min, the time is 2h. After the reduction, the argon gas was changed to passivation treatment for 30 minutes before the powder came out of the furnace. The obtained powder is nanoscale tungsten powder, and its X-ray diffraction patterns and transmission electron microscope photos are shown in the attached figure 1 and 2 , The particle size of nano tungsten powder is 44nm.

Embodiment 2

[0016] Weigh 180g of ammonium metatungstate, 20g of anhydrous glucose, and 1.5g of chromium nitrate, and dissolve them in deionized water at 80°C. After the raw materials are fully mixed, the precursors required for reduction are prepared by spray drying. Put the precursor powder into a tubular atmosphere furnace, pass through hydrogen for reduction, the reduction temperature is 800 °C, and the heating rate is 15 o C / min, the time is 3h. After the reduction, the argon gas was changed to passivation treatment for 30 minutes before the powder came out of the furnace. The particle diameter of the obtained nano-tungsten powder is 57nm.

Embodiment 3

[0018] Weigh 170g of ammonium metatungstate, 30g of anhydrous glucose, and 2.5g of chromium nitrate, and dissolve them in deionized water at 80°C. After the raw materials are fully mixed, the precursors required for reduction are prepared by spray drying. Put the precursor powder into a tubular atmosphere furnace, pass through hydrogen for reduction, the reduction temperature is 780 °C, and the heating rate is 10 o C / min, the time is 2h. After the reduction, the argon gas was changed to passivation treatment for 30 minutes before the powder came out of the furnace. The particle size of the obtained nano-tungsten powder is 50nm.

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Abstract

A preparation method of nano tungsten powder comprises the following steps: (1) dissolving ammonium metatungstate, chromium nitrate and a water-soluble carbon source substance into in heated deionized water, electrically stirring to sufficiently mix raw materials, and after uniformly mixing the raw materials, performing spray drying to obtain precursor powder, wherein the weight percentage of the water-soluble carbon source substance is 10-30%, the weight percentage of the chromium nitrate is 0.5-2% and the temperature of the deionized water is 70 DEG C; and (2) putting the precursor powder obtained in the step (1) into a tubular atmosphere furnace, performing auxiliary hydrogen reduction, and before discharging the powder out of a furnace, passivating the powder with an inert gas, wherein the temperature is 710-850 DEG C, the heating rate is 10-15 DEG C / min and the reaction time is 2-5h. The particle size of the prepared tungsten carbide is 40-70nm; after the prepared tungsten carbide is crushed, agglomeration-free nano tungsten powder can be obtained; the environment is polluted; and the development of a nanocrystalline WC-Co hard alloy can be effectively promoted.

Description

technical field [0001] The invention belongs to the field of cemented carbide material and its preparation. Background technique [0002] Nanocrystalline WC-Co (tungsten carbide-cobalt) cemented carbide has become the development direction of cemented carbide due to its expected characteristics of high hardness and high strength (that is, both high wear resistance and high toughness). One of the problems restricting the development of nanocrystalline WC-Co (tungsten carbide-cobalt) cemented carbide is the difficulty in the preparation of nano-tungsten powder. [0003] The difficulty in the preparation of nano-tungsten powder is actually the difficulty in controlling the "volatility-deposition" of tungsten oxide. At present, the preparation methods of tungsten powder mainly include hydrogen reduction of tungsten oxide and carbon reduction of tungsten oxide. During the reduction process, tungsten powder will grow through the volatilization-deposition mechanism of tungsten oxi...

Claims

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Application Information

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IPC IPC(8): B22F9/26
Inventor 唐建成叶楠卓海鸥
Owner NANCHANG UNIV
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