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Method for preparing high-density tungsten sintered product

A sintered product and densification technology, applied in the field of powder metallurgy, can solve problems such as hindering the uniform densification of tungsten slabs, and achieve the effect of reducing the phenomenon of loose pores, high organizational uniformity, and realizing regular accumulation.

Active Publication Date: 2018-12-21
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] The purpose of the present invention is to provide a method for preparing high-density tungsten sintered products, which solves two problems that hinder the uniform densification of tungsten slabs: one is the size of holes in the green tungsten plate; the other is the size of the holes in the sintering process. gas

Method used

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  • Method for preparing high-density tungsten sintered product

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Experimental program
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Effect test

Embodiment 1

[0026] Using a counter-jet jet milling device, the raw material tungsten powder with particle size distribution (d10=1.1 μm, d50=4.8 μm, d90=15.3 μm) was subjected to two jet milling treatments. For the first jet mill, the pressure of the grinding chamber is set to 0.80MPa, and the frequency of the sorting wheel is 30Hz to realize the dispersion and crushing of powder. In the second jet mill, the pressure of the grinding chamber is set to 0.70MPa, and the frequency of the sorting wheel is 60Hz to make the powder surface smoother and further improve the fluidity of the powder. Both jet mills use nitrogen as the grinding medium, so that the oxygen content in the grinding chamber is ≤0.05%. Finally, jet-milled fine-grained tungsten powder is obtained, and the particle size distribution is (d10=1.3 μm, d50=1.9 μm, d90=2.8 μm). The fine-grained tungsten powder processed by the jet mill and the paraffin wax binder were mixed in a double planetary mixer at 110 ° C and a speed of 40 ...

Embodiment 2

[0028]Using a counter-jet jet milling device, the raw material tungsten powder with particle size distribution (d10=1.5 μm, d50=5.2 μm, d90=16.8 μm) was subjected to two jet milling treatments. For the first jet mill, the pressure of the grinding chamber is set to 0.78MPa, and the frequency of the sorting wheel is 25Hz to realize the dispersion and crushing of powder. The second jet mill sets the pressure of the grinding chamber to 0.68MPa, and the frequency of the sorting wheel to 55Hz to make the powder surface smoother and further improve the fluidity of the powder. Both jet mills use nitrogen as the grinding medium, so that the oxygen content in the grinding chamber is ≤0.05%. Finally, jet-milled fine-grained tungsten powder is obtained, and the particle size distribution is (d10=1.8 μm, d50=2.5 ​​μm, d90=3.9 μm). The fine-grained tungsten powder processed by the jet mill and the paraffin wax binder were mixed in a double planetary mixer at 110 ° C and a speed of 40 rpm f...

Embodiment 3

[0030] Using a counter-jet jet milling device, the raw material tungsten powder with a particle size distribution of (d10=2.9 μm, d50=7.1 μm, d90=20.3 μm) was subjected to two jet milling treatments. For the first jet mill, the pressure of the grinding chamber is set to 0.75MPa, and the frequency of the sorting wheel is 20Hz to realize the dispersion and crushing of powder. The second jet mill sets the pressure of the grinding chamber to 0.70MPa and the frequency of the sorting wheel to 50Hz to make the powder surface smoother and further improve the fluidity of the powder. Both jet mills use nitrogen as the grinding medium, so that the oxygen content in the grinding chamber is ≤0.05%. Finally, jet-milled fine-grained tungsten powder is obtained, and the particle size distribution is (d10=3.4 μm, d50=4.4 μm, d90=5.9 μm). The fine-grained tungsten powder processed by the jet mill and the paraffin wax binder were mixed in a double planetary mixer at 130°C and a speed of 50 rpm ...

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Abstract

The invention discloses a method for preparing a high-density tungsten sintered product, and belongs to the technical field of powder metallurgy. Tungsten powder is subjected to airflow grinding treatment to obtain fine-grain-size tungsten powder, and the near-spherical fine-particle tungsten powder is uniformly mixed with a paraffin binding agent to obtain a mixture. A secondary cold isostatic pressing process is adopted, the mixed materials are pressed into a secondary blank at a low pressure in a static pressure mode, thermal degreasing is carried out in a hydrogen atmosphere so as to completely remove a binder, isostatic pressing is carried out on the degreased green body at high pressure to form a secondary green body, and a high-density and high-texture-uniformity thick tungsten slabis obtained by adopting a method of slowly heating at low temperature and rapidly heating at a high temperature. Through low-temperature sintering and slow heating, the green body can be sufficientlyrestored to reduce the oxygen content in the green body, the sintering activity of the green body is kept, high-temperature sintering and rapid heating can be achieved, grain growth can be reduced, the problem that a large-size thick tungsten plate is prone to local looseness and cracks is solved, the density of the obtained tungsten plate blank reaches 98% or more, and the uniform consistency ofthe surface of the slab and the central position structure can be ensured.

Description

technical field [0001] The invention belongs to the technical field of powder metallurgy, and particularly provides a method for preparing high-density tungsten sintered products. Background technique [0002] Due to its high melting point, good thermal conductivity, low thermal expansion and excellent radiation resistance, tungsten exhibits good thermophysical and mechanical properties at high temperatures, and is an irreplaceable key material in the fields of national defense, nuclear engineering or aerospace. Among them, tungsten products are widely used in important parts of ultra-high temperature furnaces and sputtering targets for physical vapor deposition. The development of high-end equipment such as large-scale crystal growth and coating has put forward higher and higher requirements for large-scale tungsten crucibles, thermal field components and high-purity targets. For example, the tungsten crucible is a key component for containing the melt in the sapphire crys...

Claims

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Application Information

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IPC IPC(8): B22F9/04B22F3/04B22F3/10
CPCB22F3/04B22F3/1007B22F9/04B22F2009/044B22F2998/10B22F1/10B22F3/1021
Inventor 曲选辉李星宇章林秦明礼陈刚王光华龙莹
Owner UNIV OF SCI & TECH BEIJING
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