Submicron narrow particle size distribution type tungsten powder and tungsten carbide powder and preparation method thereof

A narrow particle size distribution, tungsten carbide powder technology, applied in the direction of tungsten/molybdenum carbide, carbide, etc., can solve the practical application of hard alloy preparation, difficult to measure and control and stable safe production, tungsten carbide powder production process Many problems, to achieve the effect of high production efficiency, low carbon residual content and low cost

Active Publication Date: 2014-02-12
GRIMAT ENG INST CO LTD
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Problems solved by technology

Central South University (200410045065.4) centrifugally spray-dried the organic matter solution of ammonium metatungstate to obtain amorphous powder containing tungsten complexes and free organic matter. 3 A uniformly mixed powder with free C atomic level; in vacuum or H 2 / CH 4 After heat preservation at 850~1000°C, ultrafine tungsten carbide powder with an average particle size of 0.2 μm is obtained by reduction carbonization; this method is only used to prepare ultrafine tungsten carbide powder but cannot prepare tungsten powder, and the residual carbon obtained by thermal decomposition of organic matter is used as The carbon source synthesized by tungsten carbide has a rapid thermal decomposition reaction process, and it is difficult to carry out industrial process measurement and control and stable safe production. It deviates from the existing tungsten carbide powder production process and has not been practically applied in the preparation of cemented carbide.

Method used

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  • Submicron narrow particle size distribution type tungsten powder and tungsten carbide powder and preparation method thereof
  • Submicron narrow particle size distribution type tungsten powder and tungsten carbide powder and preparation method thereof
  • Submicron narrow particle size distribution type tungsten powder and tungsten carbide powder and preparation method thereof

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[0037] The technical process of the submicron narrow particle size distribution tungsten powder and tungsten carbide powder preparation method of the present invention is as follows figure 1 As shown, it includes the following steps: 1APT pyrolysis; 2AMT dissolution; 3 filtration; 4 preparation of liquid after ion exchange or liquid before crystallization; Drying; 9 pyrolysis or mild reduction; 10 hydrogen reduction; 11 carbon matching; 12 ball milling;

[0038] The specific steps of the preparation method of submicron narrow particle size distribution tungsten powder and tungsten carbide powder of the present invention include:

[0039] (1) Solution preparation: Use commercially available ammonium paratungstate (APT) as raw material, and conduct static pyrolysis in a muffle furnace or dynamic pyrolysis in a rotary furnace at 270-350°C for 1-3 hours to obtain amorphous ammonium metatungstate (AMT) ) as the main dissociated material, the weight loss rate is controlled at 7~8%;...

Embodiment 1

[0046] Accurately weigh 5,000 grams of ammonium paratungstate (APT-0), and pyrolyze it in a muffle furnace at 310°C for 1.5 hours to obtain 4,625 grams of dissociated material of amorphous ammonium metatungstate (AMT), with a weight loss rate of 7.5%; L of ammonia solution was stirred and dissolved for 2 hours, filtered after standing for 30 minutes, and diluted with deionized water to obtain a specific gravity of 1.20g / cm 3 12.5L of ammonium tungstate solution; at the same time, 625ml of ammonium polyacrylate aqueous solution and 62.5ml of acetone with a concentration of 10% by weight were added, and stirred for 10min to mix evenly; the GZ-5 high-speed centrifugal spray drying equipment with titanium lining on the inner wall of the tower was used for the above dispersion The treated ammonium tungstate solution is subjected to rapid crystallization and drying, the inlet air temperature is 350°C, the outlet air temperature is 150°C, the feed rate is 2.5L / h, and the rotational sp...

Embodiment 2

[0048] Perform secondary ion exchange and wet removal of molybdenum on the ion-exchanged liquid on the APT production line, and concentrate until the specific gravity of the solution is 1.40g / cm 3 ;According to the ratio of 10% and 10‰ of the volume of ammonium tungstate solution, respectively add polyethylene glycol aqueous solution and n-butanol with a concentration of 10% by weight, and stir for 30 minutes to mix evenly; adopt the GZ-50 type whose inner wall is lined with polytetrafluoroethylene The high-speed centrifugal spray drying equipment performs rapid crystallization and drying on the ammonium tungstate solution after the above-mentioned dispersion treatment. The inlet air temperature is 300°C, the outlet air temperature is 100°C, the feed rate is 20L / h, and the rotational speed of the centrifugal disc is 15,000 rpm. ~50μm, hollow thin-walled spherical ammonium tungstate crystals with a wall thickness of 2.0~5.0μm, the particle morphology is as follows Figure 3-a S...

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Abstract

The invention relates to submicron narrow particle size distribution type tungsten powder and tungsten carbide powder and a preparation method thereof, and belongs to the field of metallurgic powder preparation of refractory metal powder. The submicron narrow particle size distribution type tungsten powder and tungsten carbide powder are characterized in that the average particle size is 0.1 to 1.0 micron, and the maximum particle size is not greater than twice of the average particle size. The preparation method comprises the following steps: taking an ammonium tungstate solution as a raw material and a high molecular surfactant as a dispersing agent; reinforcing the dispersion effect through alcohol or ketone; quickly crystallizing and drying by spray drying to obtain fine particle hollow thin-walled spherical ammonium tungstate crystals; and performing pyrolysis, hydrogen gas reduction and carbonizing; and then generating submicron narrow particle size distribution type tungsten powder and tungsten carbide powder in situ. According to the preparation method, the submicron narrow particle size distribution type tungsten powder and tungsten carbide powder can be prepared in situ; and the technology is reformed and upgraded on the basis of the existing production condition of the enterprise, so that the scale production is easily realized, the production efficiency is high, and the effect is great.

Description

technical field [0001] The invention relates to submicron narrow particle size distribution tungsten powder and tungsten carbide powder and a preparation method thereof, belonging to the field of refractory metal powder metallurgy powder making. technical background [0002] Cemented carbide is the "teeth of industry". Fine-grained, sub-micron, ultra-fine or nano-crystalline WC-Co cemented carbide (the average grain size of the WC hard phase in the alloy is 0.8~1.3μm, 0.5~0.8μm, 0.2~0.5μm, less than 0.2μm) It has excellent properties such as high strength, high hardness, high wear resistance, high reliability, and long service life. It is widely used in the manufacture of wear-resistant parts, metal cutting tools and molds, etc., and meets the development requirements of modern industry and special difficult-to-machine materials. In the past 20 years, it has been a hot spot in the research, development, production and application of cemented carbide at home and abroad. How...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B31/34B22F1/00B22F9/22C01B32/949
Inventor 周增林林晨光惠志林李艳曹瑞军
Owner GRIMAT ENG INST CO LTD
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