Preparation method of fine globular tungsten powder

Abstract

The invention relates to a powder material preparation method, in particular to a method for preparing fine spherical tungsten powder. Plasma parameters are adjusted by building a stable argon plasma, thereby heating tungsten powder material and acquiring the fine spherical tungsten powder through the separation after cooling and solidification, and the obtained tungsten powder has better fluidity, higher density, purity and particle cleanliness of surface, and lower powder particle porosity compared with the tungsten original powder; and the method has advantages of changing shapes of tungsten powder particles, high sphericity, increasing the apparent density of powder, improving the tungsten powder fluidity and physical characteristics of the tungsten powder, and reducing costs.

Description

technical field [0001] The invention belongs to a method for preparing powder materials, in particular to a method for preparing spherical tungsten powder. Background technique [0002] Using plasma as a heat source has great technical advantages in the spheroidization of micron, submicron and certain nanometer powder materials. The radio frequency plasma torch has a large arc body, stable arc flow, and easy adjustment and control, making it easy to apply to the field of ultrafine powder material processing technology. The porous material prepared with spherical tungsten powder has more uniform pores, and the air permeability of the product can be controlled according to the process in production, so it will replace conventional tungsten powder for the production of porous tungsten parts, such as the cathode of high-power pulsed microwave tubes, Electronic barium tungsten cathode, gas distribution plate at high temperature and gas filter material, etc. In the field of ther...

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Problems solved by technology

[0004] 1. From WF by Vapor Deposition 6 The process of obtaining spherical tungsten powder with large particle size (40-650 μm) in the middle, but this process involves strongly corrosive HF, the working conditions are harsh, and the requirements for environmental protection are very high.

[0005] 2. Pass powders such as Ti, Mo and WC through a vertical carbon tube furnace filled with a protective atmosphere, so that the powder is heated and melted by the carbon tube furnace during the falling process, thereby transforming into a spherical powder, but this method is applied to The spheroidization of tungsten powder has not been successful. The problem is that the powder is easy to stick to the tube wall, and the temperature in the carbon tube furnace cannot reach the melting point of tungsten (about 3400°C) at the current technical level.

[0006] 3. Use inductively coupled plasma torch to spheroidize and air-cool Cr, Ta, Mo, W, MgO and other powders. This method requires a large cooling chamber, which must be filled with high-purity Ar gas, and the cost is very high. High, and the spheroidization rate of the powder after one treatment can only reach 85%. To obtain all spherical powders, it is necessary to carry out multiple sorting and re-spheroidization processes, which greatly increases the cost

[0008] 1. Using the technology of secondary oxidation and reduction of tungsten powder, quasi-spherical tungsten powder can be obtained, and the cost is low, but the spheroidization is not sufficient

[0009] 2. The use of granulation and sintering method to produce spherical powder for thermal spraying can produce spherical tungsten powder with a particle size of 40-750 μm, but the density of the prepared tungsten powder is not high, and the particle diameter is large, and the powder is relatively coarse

[0011] 4. Spherical tungsten powder is prepared by rotating electrode direct current arc plasma method for tungsten rods. This method can only prepare coarse powder (150-1700 μm), but cannot prepare small and fine spherical tungsten powder, and the equipment cost is very expensive.

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