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Preparation method of submicron nearly spherical tungsten powder

A near-spherical, sub-micron technology, applied in the field of powder metallurgy powder making, can solve the problems of high cost and coarse tungsten powder particles, and achieve the effects of low cost, elimination of agglomeration and simple process

Active Publication Date: 2012-06-06
中国有研科技集团有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the above five methods to prepare spherical tungsten powder all need to use conventional hydrogen reduction tungsten powder or even tungsten wire of a certain specification as raw materials, the cost is high, and after high temperature treatment, the tungsten powder particles become obviously thicker

Method used

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  • Preparation method of submicron nearly spherical tungsten powder
  • Preparation method of submicron nearly spherical tungsten powder
  • Preparation method of submicron nearly spherical tungsten powder

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] Accurately weigh 1000g of ammonium paratungstate (APT), place it in a porcelain boat, and pyrolyze it in a muffle furnace at 310°C for 1.5h to obtain 925g of amorphous ammonium metatungstate (AMT) with a weight loss rate of 7.5%; The obtained AMT was dissolved in an aqueous ammonia solution, the dosages of deionized water and ammonia water were 925ml and 1220ml respectively, stirred for 4h, and allowed to stand for 30min; the supernatant and the undissolved material were subjected to vacuum filtration to obtain 2100ml of ammonium tungstate solution with a density of 1.255 g / cm 3 , wherein the effective W content is 525g; based on the effective W content of 5% by weight, add 23ml of low molecular weight polyacrylate (PAANH) of an aqueous system to the ammonium tungstate solution 4 , diluted 10 times) as a dispersant, stir for 10 minutes and mix well; add 1100ml of concentrated nitric acid as a precipitant under strong mechanical stirring, first generate scheelonic acid, ...

Embodiment 2

[0042] Add 10 weight ‰ of methoxy polyethylene glycol (MPEG) and polyvinyl alcohol (PVA) as dispersant, add 1100ml concentrated hydrochloric acid as precipitant; in addition, vacuum filtration to obtain tungstic acid gel and place it in a quartz boat , dried at -60°C for 20h in a vacuum freeze dryer; the same as in Example 1, except that the type and amount of dispersant, the type of precipitant, and the drying method of tungstic acid gel are different from those in Example 1.

[0043] Observed by field emission scanning electron microscope (FESEM), the particle morphology of the prepared tungsten powder is nearly spherical, and the diameter of most particles is between 0.5 and 0.9 μm, such as figure 2 (b).

Embodiment 3

[0045] Add 15% by weight of polyvinylpyrrolidone (PVP) as a dispersing agent, and add 1100 ml of concentrated hydrochloric acid as a precipitating agent.

[0046] Observed by field emission scanning electron microscope (FESEM), the particle morphology of the prepared tungsten powder is nearly spherical, and the diameter of most particles is between 0.3 and 0.7 μm, such as figure 2 (c).

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Abstract

The invention belongs to the powder preparation field adopting powder metallurgy, and relates to a preparation method of submicron nearly spherical tungsten powder. The method comprises the following steps of: (1) pyrolyzing commercial ammonium paratungstate to obtain ammonium metatungsten; (2) dissolving the ammonium metatungsten in ammonia water; (3) filtering to obtain an ammonium tungstate solution; (4) adding a dispersant in the ammonium tungstate solution to mix evenly; (5) adding a precipitator while stirring to obtain tungstic acid sol; (6) performing vacuum filtration to obtain tungstic acid gel; (7) performing common drying or freeze drying; (8) crushing; (9) pyrolyzing to obtain tungsten trioxide; (10) performing ball milling; and (11) performing hydrogen reduction to obtain the submicron nearly spherical tungsten powder. By adopting the preparation method, the submicron nearly spherical tungsten powder can be prepared stably; and the technology is simple, the cost is lower, and mass production can be realized.

Description

technical field [0001] The invention relates to a preparation method of submicron nearly spherical tungsten powder, and belongs to the field of powder metallurgy. technical background [0002] The tungsten powder commonly used in the industry is mainly obtained by reducing tungsten oxide with hydrogen. The particle shape of such tungsten powder is irregular, the fluidity is poor, and the bulk density is low, and it is difficult to obtain a tungsten body with connected micropores by sintering. In recent years, the demand for nearly spherical or spherical tungsten powder is increasing day by day, and it is widely used in powder metallurgy processes such as porous material preparation, thermal spraying and injection molding. The tungsten body prepared with nearly spherical or spherical tungsten powder has uniformly distributed and interconnected pores, so it is gradually replacing conventional tungsten powder in the production of porous tungsten parts, such as high-power microw...

Claims

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Application Information

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IPC IPC(8): B22F9/26
Inventor 周增林崔舜林晨光惠志林
Owner 中国有研科技集团有限公司
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