Method for preparing nearly-spherical tungsten powder

A technology of nearly spherical and tungsten powder, applied in the field of preparation of nearly spherical tungsten powder, can solve the problems of expensive equipment, low production capacity, powder coarsening, etc., achieve good shape distribution uniformity, avoid oxidation loss, and low production cost Effect

Active Publication Date: 2011-03-09
浙江至信新材料股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, the main methods for preparing spherical tungsten powder are: 1. Plasma chemical vapor phase synthesis method (Journal of Refractory Metals & Hard Materials 27 (2009) 149–154), which uses hydrogen thermal plasma to vaporize and decompose tungsten salt Reduction can prepare spherical tungsten powder, but because it is solidified by gaseous state, it is generally nano-scale particles, the equipment is very expensive, complicated, and the production capacity is low; 2. Plasma spheroidization method (Nonferrous Metals, 2008, 60 (1): 41 -42), this method uses the high temperature of the plasma to melt the surface or the whole of the polygonal tungsten powder, forms spherical particles due to surface tension, and solidifies at a very

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] A. Dry the industrial polygonal tungsten powder with an average Fischer particle size of 7.5 μm at 100°C until the moisture content is 0.1%;

[0018] B. Oxidize the dried tungsten powder at 450°C for 120 minutes, and cool to room temperature when the oxidation weight gain is 8g / 100g;

[0019] C. Add the powder treated in step B to OH - In a NaOH solution with a concentration of 3mol / L, the ratio of powder to solution is 1g:5ml, and the reaction temperature is 70°C, then let it stand until the solution is transparent and the color of the precipitate is consistent with the color of the original tungsten powder, then remove the supernatant;

[0020] D. clean the alkali washing powder of C step with deionized water 2 times, the ratio of powder and deionized water is 1g / 25ml, then clean with alcohol, the ratio of powder and alcohol is 1g / 25ml;

[0021] E. Dry the powder cleaned in step D under argon protection at a drying temperature of 50°C until the moisture content drops...

Embodiment 2

[0024] A. Dry the industrial polygonal tungsten powder with a Fibonacci average particle size of 8.5 μm at 100°C until the moisture content is 1%;

[0025] B. Oxidize the dried tungsten powder at 520°C, and cool to room temperature when the oxidation weight gain is 11g / 100g;

[0026] C. Add the powder treated in step B to OH - In the NaOH solution with a concentration of 8mol / L, the ratio of powder to solution is 1g:15ml, and the reaction temperature is 100°C, then let it stand until the solution is transparent and the color of the precipitate is consistent with that of the original tungsten powder, then remove the supernatant;

[0027] D. Clean the alkali-washed powder in step C with deionized water, the ratio of powder to deionized water is 1g / 50ml, and then wash with alcohol 6 times, the ratio of powder to alcohol is 1g / 50ml;

[0028] E. Dry the powder cleaned in step D under the protection of argon at a drying temperature of 100°C until the moisture content drops to 1%. ...

Embodiment 3

[0031] A. Dry the industrial polygonal tungsten powder with a Fibonacci average particle size of 9 μm at 80°C until the moisture content is 0.6%;

[0032] B. Oxidize the dried tungsten powder at 490°C, and cool to room temperature when the oxidation weight gain is 9g / 100g;

[0033] C. Add the powder treated in step B to OH - In the KOH solution with a concentration of 5mol / L, the ratio of powder to solution is 1g:12ml, and the reaction temperature is 85°C, then stand until the solution is transparent and the color of the precipitate is consistent with the color of the original tungsten powder, then remove the supernatant;

[0034] D. Clean the alkali-washed powder in step C with deionized water 5 times, the ratio of powder to deionized water is 1g / 44ml, and then wash with alcohol, the ratio of powder to alcohol is 1g / 50ml;

[0035] E. Dry the powder cleaned in step D under vacuum at a drying temperature of 80°C until the moisture content drops to 0.8%.

[0036] The nearly sp...

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PUM

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Abstract

The invention provides a method for preparing nearly-spherical tungsten powder, which comprises the steps of drying at a temperature of 50 to 100 DEG C, oxidation at a temperature of 450 to 520 DEG C, alkaline washing by alkaline solution of which the OH<-> concentration is 3 to 8mol/L, cleaning, drying, and the like. In the invention, the oxidation treatment is performed on tungsten powder subjected to drying process. Because the area of sharp corners and edges of projecting parts of the tungsten powder is lager than the superficial area of the tungsten powder, the activity thereof is bigger, and the oxidation rate thereof in the process of oxidation is significantly higher than that of the flat surface of the tungsten powder. After removing the sharp corners and edges of projecting parts of the tungsten powder subjected to partial preferential re-oxidation by alkaline solution, nearly-spherical particles with surfaces smoother than that of original tungsten powder particles are formed. The nearly-spherical tungsten powder prepared by using the method of the invention has the advantage of good shape distribution uniformity; and meanwhile, the method of the invention is simple in process, low in production cost, and suitable for industrial production.

Description

technical field [0001] The invention relates to a preparation method of nearly spherical tungsten powder. Background technique [0002] Metal tungsten has a series of excellent properties such as high hardness, high strength, low vapor pressure, good corrosion resistance and high temperature corrosion resistance. The tungsten porous body made of it has particularly excellent dimensional stability and durable life, and has been more and more widely used in electronics, aviation, weapons and other application fields. With the development of the electronics and aviation fields, the requirements for the morphology and structure of tungsten materials are required to be spherical and compact. For example, when preparing high-emissivity tungsten-based cathode materials for electric vacuum devices, Cronin J L pointed out in 1981 that in order to meet the higher requirements for the quality and performance of reserve cathode materials, polygonal tungsten powders that are currently u...

Claims

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Application Information

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IPC IPC(8): B22F1/00
Inventor 李周邱文婷汪明朴
Owner 浙江至信新材料股份有限公司
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