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Process for preparing nano WC-Co cemented carbide

A cemented carbide and nanotechnology, which is applied in the field of preparing nano-WC-Co cemented carbide, can solve the problems of increasing brittleness and porosity, and achieve the effects of improving surface activity, easy operation, and fine grains

Inactive Publication Date: 2004-11-10
EAST CHINA NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, too much grain growth inhibitor will cause a large amount of carbides to precipitate at the WC / Co grain boundary, which increases brittleness and porosity, so the application of grain growth inhibitors has certain limitations.

Method used

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  • Process for preparing nano WC-Co cemented carbide
  • Process for preparing nano WC-Co cemented carbide
  • Process for preparing nano WC-Co cemented carbide

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Get average particle size and be 200 mesh WC, Co powder, press WC: Co=94wt%: 6wt% proportioning, prepare WC-Co mixed powder, use WC cemented carbide ball in ball mill tank with rotating speed 200rpm and ball-powder ratio 15 : 1, ball milled for 55 hours, and the nano WC-Co mixed powder was taken out from the ball mill jar. Then prepare a polyvinyl acid solution with a concentration of 1.5%, and immerse the nanometer WC-Co mixed powder in it for 55 minutes. Dry at 60°C for 7 hours. Put the powder prepared in the above steps into a carbon casting mold, conduct plasma activation sintering, maintain a constant uniaxial pressure of 25 MPa during the sintering process, sintering temperature 1250 ° C, sintering time 2 minutes, and obtain nano-WC-Co cemented carbide with a dense structure . The alloy has the following technical indicators:

[0021] Density 14.7g / cm 3 , hardness (HV 30 ) 1890, fracture toughness (Kic) 17.8MPam.

Embodiment 2

[0023] Get average particle size and be 200 mesh WC, Co powder, press WC: Co=94wt%: 6wt% proportioning, prepare WC-Co mixed powder, use WC cemented carbide ball in ball mill pot with rotating speed 200rpm and ball-powder ratio 30 : 1, ball milled for 40 hours, and the nano WC-Co mixed powder was taken out from the ball mill jar. Then prepare a polyvinyl acid solution with a concentration of 2.5%, and immerse the nanometer WC-Co mixed powder in it for 35 minutes. Dry at 90°C for 4 hours. Put the powder prepared in the above steps into a carbon casting mold, conduct plasma activation sintering, maintain a constant uniaxial pressure of 25 MPa during the sintering process, sintering temperature 1000 ° C, sintering time 3 minutes, and obtain nano-WC-Co cemented carbide with a dense structure .

Embodiment 3

[0025] Get average grain size and be 200 mesh WC, Co powder, press WC: Co=94wt%: 6wt% proportioning, prepare WC-Co mixed powder, use WC cemented carbide ball in ball mill tank with rotating speed 200rpm and ball-powder ratio 45 : 1, ball milled for 25 hours, and the nanometer WC-Co mixed powder was taken out from the ball mill jar. Then prepare a polyvinyl acid solution with a concentration of 3.5%, and immerse the nanometer WC-Co powder in it for 15 minutes. Dry at 120° C. for 1 hour. Put the powder prepared in the above steps into a carbon casting mold, conduct plasma activation sintering, maintain a constant uniaxial pressure of 25 MPa during the sintering process, sintering temperature 800 ° C, sintering time 4 minutes, and obtain nano-WC-Co cemented carbide with a dense structure .

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Abstract

The invention is a method of preparing nano WC-Co hard alloy, preparing WC-Co mixed powder, making ball milling, finishing powder surface and making plasma activation and sintering to obtain nano WC-Co hard alloy. Its advantages: after finishing, the surface of Co powder is coated with a carbon film, improving surface structure, enhancing surface activity, beneficial to sintering powder, able to obviously shortening sintering time, and effectively controlling crystal particle growth, and the sintered product has fine crystal particles, high hardness and good flexibility. It is specially applied to preparation of nano WC-Co hard alloy.

Description

technical field [0001] The invention relates to a method for preparing nanometer WC-Co hard alloy, which belongs to the technical field of hard alloy preparation. Background technique [0002] Nano WC-Co cemented carbide is widely used in various fields of modern technology because of its special wear resistance, high hardness, excellent fracture toughness and compressive strength, and has been made into micro drills for processing integrated circuit boards, Dot matrix printer printing needles, overall hole processing tools, woodworking tools, precision molds, dental drills, tools for difficult-to-machine materials, etc. The performance improvement of nano-WC-Co cemented carbide comes from the reduction of grain size. The finer the grains, the fewer defects, and the higher values ​​of flexural strength and hardness can be maintained. Sintering is a process that has a decisive influence on the structure and properties of cemented carbide. The following...

Claims

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Application Information

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IPC IPC(8): C22C1/04C22C29/08
Inventor 马学鸣
Owner EAST CHINA NORMAL UNIVERSITY
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