A kind of sintering method of cobalt-free tungsten carbide

A sintering method and cobalt tungsten carbide technology are applied in the sintering of cobalt-free tungsten carbide and tungsten carbide sintering process, which can solve the problems of material densification, sintering performance influence, and high sintering temperature when the sintering temperature is increased, and the sintering temperature can be reduced. , The effect of high density and high hardness

Inactive Publication Date: 2017-06-16
SHANGHAI MARITIME UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The sintering temperature used in the method is too high, and the material is already dense at 1700°C, and it is not meaningful to increase the sintering temperature for the densification of the material; at 1800°C and 1900°C, the grains begin to grow, which has a certain impact on the sintering performance. influences

Method used

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  • A kind of sintering method of cobalt-free tungsten carbide

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] (1) Ingredients: Prepare WC powder with a graphene content of 0.2w%. Put 49.9g of nano-WC powder and 0.1g of graphene into a ball mill, add an appropriate amount of alcohol, set the rotation speed at 400 rad / min, take out the slurry after 48 hours, put it in an oven, bake at 90°C for 24 hours, and pass through a 100-mesh screen.

[0023] (2) Firing: Take an appropriate amount of the above-mentioned dried powder and put it into a graphite mold with an internal diameter of 20mm for compaction, and place it together with the mold between the upper and lower electrodes of the SPS device, and draw a vacuum (to make the vacuum degree reach 6Pa) After power on, heat up and pressurize at a rate of 200°C / min to reach a sintering temperature of 1700°C. The axial pressure is 50MPa and then keep warm for 5 minutes. After power off and cooling, the sample is taken out.

[0024] (3) Cleaning: Grinding and cleaning the products after they are released from the furnace to remove the ca...

Embodiment 2

[0027] (1) Ingredients: Prepare WC powder with a graphene content of 0.4w%. Put 49.8g of nano-WC powder and 0.2g of graphene into a ball mill, add an appropriate amount of alcohol, set the rotation speed at 400 rad / min, take out the slurry after 48 hours, put it in an oven, bake at 90°C for 24 hours, and pass through a 100-mesh screen.

[0028] (2) Firing: Take an appropriate amount of the above-mentioned dried powder and put it into a graphite mold with an internal diameter of 20mm for compaction, and place it together with the mold between the upper and lower electrodes of the SPS device, and draw a vacuum (to make the vacuum degree reach 6Pa) After power on, heat up and pressurize at a rate of 200°C / min to reach the sintering temperature of 1590°C, keep the temperature for 5 minutes after the axial pressure is 50MPa, and take out the sample after power off and cooling.

[0029] (3) Cleaning: Grinding and cleaning the products after they are released from the furnace to remo...

Embodiment 3

[0032] (1) Ingredients: Prepare WC powder with a graphene content of 0.6w%. Put 49.7g of nano-WC powder and 0.3g of graphene into a ball mill, add an appropriate amount of alcohol, set the rotation speed at 400 rad / min, take out the slurry after 48 hours, put it in an oven, bake at 90°C for 24 hours, and pass through a 100-mesh screen.

[0033] (2) Firing: Take an appropriate amount of the above-mentioned dried powder and put it into a graphite mold with an internal diameter of 20mm for compaction, and place it together with the mold between the upper and lower electrodes of the SPS device, and draw a vacuum (to make the vacuum degree reach 6Pa) After power on, heat up and pressurize at a rate of 200°C / min to reach a sintering temperature of 1500°C. The axial pressure is 50MPa and then keep warm for 5 minutes. Take out the sample after power off and cooling.

[0034] (3) Cleaning: Grinding and cleaning the products after they are released from the furnace to remove the carbon ...

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Abstract

The invention discloses a sintering method of cobalt-free tungsten carbide. The sintering method comprises: 1, respectively weighing graphene and nanometer WC powder, uniformly mixing, and drying; and 2, placing the dried graphene and nanometer WC powder mixture into a graphite mold, compacting, sintering at a temperature of 1500-1700 DEG C with a discharge plasma sintering device, carrying out thermal insulation for 5 min, cooling, and taking out the sample. According to the sintering method of the present invention, the high toughness and the high breaking strength of the graphene are utilized to enhance the fracture toughness of the sample; and the graphene is electrically conductive, such that the sintering performance can be changed during the use of the discharge plasma sintering. With the method of the present invention, the sintering temperature is substantially reduced, the sintering time is short, the thermal insulation time is short, and the obtained tungsten carbide has the superfine structure.

Description

technical field [0001] The invention belongs to the field of cemented carbide powder sintering, and relates to a sintering process of tungsten carbide. Specifically, it relates to a sintering method of cobalt-free tungsten carbide. The main raw materials are nano-tungsten carbide (WC) and graphene, and electric discharge is adopted. Plasma sintering (SPS). Background technique [0002] Tungsten carbide (WC) is the most commonly used cemented carbide material. Since the melting point of WC is as high as 2870°C, it is usually sintered in the form of WC-Co, and Co is used as a sintering aid. However, the addition of a binder phase such as Co reduces the hardness, corrosion resistance, and oxidation resistance of the material, and it is easy to cause thermal stress due to the difference in thermal expansion coefficient with WC. [0003] Since the sintering temperature of cemented carbide without a binder phase is very high during the sintering process (often as high as 2000 ° ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/56C04B35/645
CPCC04B35/5626C04B35/645C04B2235/425C04B2235/5454C04B2235/666C04B2235/77C04B2235/785C04B2235/96
Inventor 赵煊束晨阳董丽华尹衍升其他发明人请求不公开姓名
Owner SHANGHAI MARITIME UNIVERSITY
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