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A method for preparing high-density tungsten sintered products

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 narrow grain size distribution, accelerated densification, and ensure uniformity and consistency

Active Publication Date: 2021-09-21
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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  • A method for preparing high-density tungsten sintered products
  • A method for preparing high-density tungsten sintered products

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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

A method for preparing high-density tungsten sintered products belongs to the technical field of powder metallurgy. First, the tungsten powder is processed by jet mill to obtain fine-grained tungsten powder, and then the nearly spherical fine-grained tungsten powder is uniformly mixed with paraffin wax binder to obtain a compound. Then adopt the secondary cold isostatic pressing process, first press the mixture into a primary green body under low pressure, then perform thermal degreasing in a hydrogen atmosphere to completely remove the binder, and then degrease the green body under high pressure Isostatic pressing is used to form a secondary green body, and sintering is carried out by slow heating at low temperature and rapid heating at high temperature to obtain a thick tungsten slab with high density and high uniformity. Low-temperature sintering slowly raises the temperature, which can fully reduce the green body to reduce the oxygen content in the green body so as to maintain its sintering activity. High-temperature sintering heats up quickly and can reduce grain growth. To solve the problem of cracks, the obtained tungsten slab has a density of more than 98%, and can ensure the uniformity of the surface and center of the slab.

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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Patent Type & Authority Patents(China)
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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