Method for preparing WC-Co (tungsten carbide-cobalt) nano-powder

A technology of cobalt nano and tungsten carbide, applied in the direction of nanotechnology, can solve the problems of expensive fluidized bed equipment, high production cost, long reaction time, etc., achieve good sintering activity, reduce raw material cost and energy consumption, and low degree of agglomeration Effect

Inactive Publication Date: 2011-06-01
SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage of this method is that the fluidized bed equipment used is expensive and the process is difficult to control; high-purity gas is used and the reaction time is long, and the production cost is high

Method used

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  • Method for preparing WC-Co (tungsten carbide-cobalt) nano-powder
  • Method for preparing WC-Co (tungsten carbide-cobalt) nano-powder

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Weigh 0.1mol ammonium metatungstate, 20mmol cobalt nitrate and 0.1mol citric acid, dissolve in 100ml deionized water to prepare a clear mixed solution; carry out complexation reaction in a water bath at 70°C for 5 hours; Dry for 12 hours to obtain a tungsten oxide-cobalt oxide precursor; calcinate the tungsten oxide-cobalt oxide precursor in an air atmosphere at 700°C for 1 hour to obtain a tungsten oxide-cobalt oxide powder.

[0029] Put the obtained tungsten oxide-cobalt oxide powder in a tube furnace, pass ammonia gas for nitriding, the flow rate of ammonia gas is controlled at 3L / min, the temperature is 750°C, the heating rate is 2°C / min, and the temperature is kept for 3 hours to obtain Tungsten nitride-cobalt nitride powder.

[0030] Mix 12 grams of tungsten nitride-cobalt nitride powder with 0.62 g of carbon black, use ethanol as a solvent and tungsten carbide-cobalt balls as a grinding medium, mix on a roller mill for 24 hours, and dry by rotary evaporation to o...

Embodiment 2

[0033] The difference between this example and Example 1 is that the obtained tungsten nitride-cobalt nitride powder is directly placed in a tube furnace, and a mixed gas of methane and hydrogen is passed through for carbonization. The volume ratio of methane to hydrogen is The ratio is 1:8, the flow rate of the mixed gas is 200ml / min, the carbonization temperature is 750°C, and the carbonization time is 2 hours to obtain WC-Co nanopowder with an average particle size of 45nm.

[0034] The rest of the content is exactly the same as described in Example 1.

[0035] figure 1 It is the TEM photo of the WC-Co nanopowder made by figure 1 It can be seen that the powder particles are fine and the average particle size is 45nm.

[0036] The WC-Co nano-powder prepared in this example was sintered by hot pressing at 1200-1400°C / 1h and 25 MPa, and the relative density was higher than 97%, indicating that the prepared WC-Co nano-powder had good sintering activity.

Embodiment 3

[0038] The only difference between this example and Example 1 is that the obtained 12g tungsten nitride-cobalt nitride powder is mixed with 0.62g carbon black, put in a mixing tank, use ethanol as solvent, tungsten carbide ball As a grinding medium, it was mixed on a roller ball mill for 24 hours, and then dried by rotary evaporation to obtain W 2 N / CoN / C mixed dry powder, W 2 N / CoN / C mixed dry powder is placed in a graphite crucible, and argon gas is introduced into the sintering furnace, and the reactant is heated to 900°C and kept for 2 hours to obtain WC-Co nanopowder with an average particle size of 120nm.

[0039] The rest of the content is exactly the same as described in Example 1.

[0040] The WC-Co nano-powder prepared in this example was sintered by hot pressing at 1200-1400°C / 1h and 25 MPa, and the relative density was higher than 97%, indicating that the prepared WC-Co nano-powder had good sintering activity.

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Abstract

The invention discloses a method for preparing WC-Co (tungsten carbide-cobalt) nano-powder, which comprises the following steps of: firstly, preparing tungsten oxide-cobalt oxide powder by adopting a citrate or package method; secondly, introducing ammonia gas into the obtained tungsten oxide-cobalt oxide powder for nitridation to obtain tungsten nitride-cobalt nitride powder; and thirdly, mixing the obtained tungsten nitride-cobalt nitride powder with carbon black, performing ball milling, and performing heat treatment under a vacuum or inert atmosphere with the air pressure of less than 200Pa to obtain the WC-Co nano-powder; or directly charging the obtained tungsten nitride-cobalt nitride powder into a tube furnace, and introducing mixed gas of methane and hydrogen gas into the tube furnace for carbonization to obtain the WC-Co nano-powder. The preparation process disclosed by the invention has the advantages of simplicity and practicality, strong maneuverability, and easiness of large-scale production. Moreover, the prepared powder has the advantages of small particle diameter, uniform particle size distribution and good sintering activity.

Description

technical field [0001] The invention relates to a preparation method of tungsten carbide-cobalt nano powder, in particular to a method for preparing tungsten carbide-cobalt nano powder based on a nitride conversion method, belonging to the technical field of nano powder preparation. Background technique [0002] Since the advent of cemented carbide in the 1930s, it has always occupied an important position in industrial production because of its high hardness and high strength. It is known as the "teeth of industry". Various fields of modern technology have a wide range of uses in metal cutting, oil drilling, rock drilling tools, abrasive materials, etc. [0003] WC-Co cemented carbide is a brittle material, and its hardness and strength are a pair of contradictions. Increasing the hardness of the alloy will lead to a decrease in strength, and conversely increasing the strength of the alloy will result in a decrease in hardness. Studies in recent years have shown that for W...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F9/20B82Y40/00
Inventor 阚艳梅孙世宽张国军
Owner SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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