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Environment-friendly nano tungsten carbide powder preparation method

A technology of tungsten carbide powder and nano-tungsten powder, which is applied in the field of powder metallurgy, can solve the problems of unstable powder particle size and difficult to achieve, and achieve the effects of uniform particle size, slowing down particle growth and similar production methods.

Active Publication Date: 2018-08-21
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At the same time, the current industrial production of nano-WC powder preparation methods, such as spraying method, coating method, the particle size of the final powder is unstable, and it is difficult to reach below 100nm

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] (1) Put the ammonium paratungstate (APT) powder in a vacuum intermediate frequency induction heating furnace, first evacuate to below 133Pa, then rapidly raise the temperature to 500°C within 3 minutes, keep it warm for 40 minutes, and then quickly cool it with liquid nitrogen, so that the temperature is raised in a cycle Cool three times to obtain tungsten trioxide powder with a particle size of 19 nm;

[0021] (2) Add 0.5wt.% grain growth inhibitor chromium nitrate and ammonium metavanadate to the nano-tungsten trioxide powder of step (1), add alcohol and press the ball-to-material ratio of 6:1 for high-energy ball milling for 20 hours, and ball milling The final material is dried in a Z-shaped mixing dryer;

[0022] (3) Put the powder of step (2) in a tube furnace for hydrogen reduction, the material layer thickness is 5mm, and the hydrogen flow rate is 35ml / (min cm 2 ), kept at 650°C for 45 minutes, and packed into a container under a protective atmosphere to obtai...

Embodiment 2

[0026](1) Put the ammonium paratungstate (APT) powder in a vacuum intermediate frequency induction heating furnace, first evacuate to below 133Pa, then rapidly raise the temperature to 700°C within 5 minutes, keep it warm for 60 minutes, and then quickly cool it with liquid nitrogen, so that the temperature is raised in a cycle Cool three times to obtain tungsten trioxide powder with a particle size of 15 nm;

[0027] (2) Add 2wt.% grain growth inhibitor to the nano-tungsten trioxide powder in step (1), add alcohol and press the ball-to-material ratio of 10:1 for high-energy ball milling for 24 hours, and the material after ball milling is placed in a Z-shaped mixing and drying drying in the container;

[0028] (3) Put the powder of step (2) in a tube furnace for hydrogen reduction, the thickness of the material layer is 3mm, and the flow rate of hydrogen is 25ml / (min·cm 2 ), kept at 600°C for 30 minutes, and packed into a container under a protective atmosphere to obtain nan...

Embodiment 3

[0032] (1) Put the ammonium paratungstate (APT) powder in a vacuum intermediate frequency induction heating furnace, first evacuate to below 133Pa, then rapidly raise the temperature to 600°C within 4 minutes, keep it for 50 minutes, and then quickly cool it with liquid nitrogen. Cool three times to obtain tungsten trioxide powder with a particle size of 17 nm;

[0033] (2) Add 1wt.% grain growth inhibitor to the nano-tungsten trioxide powder in step (1), add alcohol and press the ball-to-material ratio of 8:1 for high-energy ball milling for 22 hours, and the material after ball milling is placed in Z-shaped mixing and drying drying in the container;

[0034] (3) Put the powder of step (2) in a tube furnace for hydrogen reduction, the thickness of the material layer is 4mm, and the flow rate of hydrogen is 30ml / (min·cm 2 ), kept at 620°C for 40 minutes, and packed into a container under a protective atmosphere to obtain nano-tungsten powder with a particle size of 46nm;

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Abstract

The invention provides an environment-friendly nano tungsten carbide powder preparation method and belongs to the field of powder metallurgy. The method includes: performing quick heating and rapid cooling on APT to obtain nano tungsten trioxide, adding a crystal grain growth inhibitor through wet milling, and reducing to obtain nano tungsten powder; combining with carbon black and an isolating agent, and carbonizing to obtain nano tungsten carbide powder. The nano tungsten carbide powder is finally obtained by refining tungsten trioxide through quick heating and cooling and high-energy ball milling, inhibiting reduction and carbonized particle growth through the crystal grain growth inhibitor and controlling reducing temperature and carbonizing temperature on a low level. The method is easy in obtaining nanoscale WC powder, and individual thick and big particles are avoided, so that granularity is uniform. Nanoscale tungsten trioxide is obtained not by adopting a water solution method, and the preparation method is free of wastewater generation and environment pollution and convenient to operate. The method is stable and reliable in process, close to conventional methods in production mode and easy in industrial upgrading.

Description

technical field [0001] The invention relates to a preparation method of nanometer tungsten carbide powder, which belongs to the field of powder metallurgy. Background technique [0002] Cemented carbide has unique properties that enable it to be widely used in metal and non-metal cutting, transportation, construction and other fields. In the early research on cemented carbide, high hardness was achieved by reducing the cobalt content, but when the cobalt content was reduced below 6%, the fracture toughness of the material would be significantly reduced. In the application of the mechanical industry, when the cobalt content is much greater than 6% %, excessive wear will reduce the service life of the material, so the cobalt content in the alloy must be moderate. In the case of a certain cobalt content, the way to improve the strength and toughness and increase the wear resistance is to reduce the grain size of WC, and this must be achieved by reducing the particle size of th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B32/949B82Y40/00
CPCB82Y40/00C01B32/949C01P2004/64
Inventor 林涛赵学斌邵慧萍田一彤何新波
Owner UNIV OF SCI & TECH BEIJING
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