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A method for preparing large-size molybdenum slabs

A large-size, slab technology, applied in the field of preparing large-size molybdenum slabs, can solve problems such as uneven shrinkage and non-uniform grain growth, and achieve the goal of reducing holes, reducing grain growth, and reducing sintering deformation Effect

Active Publication Date: 2021-10-08
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 large-size molybdenum slabs, which solves two problems of large-size sintered molybdenum plates: one is that uneven holes in the molybdenum plate green body cause uneven shrinkage during sintering; the other is sintering Non-uniform growth of grains during the process

Method used

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  • A method for preparing large-size molybdenum slabs

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Experimental program
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Effect test

Embodiment 1

[0023] The raw molybdenum powder with particle size distribution (d10=1.2 μm, d50=5.7 μm, d90=17.8 μm) was treated by air-jet milling twice by using a jet-jet milling device. In the first jet mill, the pressure of the grinding chamber is set to 0.55MPa, and the frequency of the sorting wheel is set to 30Hz to realize the dispersion and crushing of the powder. In the second jet mill, the pressure of the grinding chamber is set to 0.40MPa, and the frequency of the sorting wheel is 60Hz, which makes the powder surface more smooth and further improves the fluidity of the powder. Nitrogen is used as the grinding medium in both jet mills, so that the oxygen content in the grinding chamber is less than or equal to 0.05%. Finally, the air-milled fine particle size molybdenum powder is obtained, and the particle size distribution is (d10=2.1 μm, d50=3.4 μm, d90=4.3 μm). The fine-grained molybdenum powder treated by the jet mill and the paraffin binder are mixed in a double planetary m...

Embodiment 2

[0025]Using a jet-jet mill device, the raw molybdenum powder with a particle size distribution of (d10=2.8μm, d50=6.3μm, d90=20.6μm) was subjected to two air-jet milling treatments. In the first jet mill, the pressure of the grinding chamber is set to 0.50MPa, and the frequency of the sorting wheel is set to 30Hz to realize the dispersion and crushing of the powder. In the second jet mill, the pressure of the grinding chamber is set to 0.35MPa, and the frequency of the sorting wheel is set to 60Hz, which makes the powder surface smoother and further improves the fluidity of the powder. Nitrogen is used as the grinding medium in both jet mills, so that the oxygen content in the grinding chamber is less than or equal to 0.05%. Finally, the air-milled fine particle size molybdenum powder is obtained, and the particle size distribution is (d10=3.3 μm, d50=4.0 μm, d90=4.9 μm). The fine-grained molybdenum powder treated by the jet mill and the paraffin binder are mixed in a double ...

Embodiment 3

[0027] Using a jet-jet mill device, the raw molybdenum powder with particle size distribution (d10=5.5μm, d50=8.3μm, d90=24.6μm) was subjected to two air-jet milling treatments. In the first jet mill, the pressure of the grinding chamber is set to 0.45MPa, and the frequency of the sorting wheel is set to 20Hz to realize the dispersion and crushing of the powder. In the second jet mill, the pressure of the grinding chamber is set to 0.30MPa, and the frequency of the sorting wheel is set to 50Hz, which makes the powder surface smoother and further improves the fluidity of the powder. Nitrogen is used as the grinding medium in both jet mills, so that the oxygen content in the grinding chamber is less than or equal to 0.05%. Finally, the air-milled fine particle size molybdenum powder is obtained, and the particle size distribution is (d10=6.8 μm, d50=7.3 μm, d90=8.7 μm). The fine-grained molybdenum powder treated by the jet mill and the paraffin binder are mixed in a double plan...

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Abstract

The invention discloses a method for preparing large-size molybdenum slabs, belonging to the technical field of powder metallurgy. First, the reduced molybdenum powder is used as the raw material, and the fine-grained molybdenum powder with uniform dispersion, narrow particle size distribution and nearly spherical shape is obtained by jet milling. Then, the fine particle molybdenum powder and the paraffin wax binder are evenly mixed to obtain a compound. Then, the forming process of secondary cold isostatic pressing is adopted, and the degreased green body is isostatically pressed into a secondary green body under high pressure. Adopt the sintering method of slow temperature rise at low temperature and rapid temperature rise at high temperature. Specifically, the temperature is slowly raised in the low temperature sintering stage to fully reduce the green body to reduce the oxygen content in the green body to maintain its sintering activity. Rapid temperature rise in the high temperature sintering stage can reduce grain growth. After sintering, a thick molybdenum slab with high density and high structural uniformity can be obtained. The preparation method solves the problem that the large-size thick molybdenum slab is prone to local looseness and cracks in the past, and the density of the prepared molybdenum slab reaches more than 99%, 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 large-sized molybdenum slabs. Background technique [0002] Molybdenum is an important refractory metal material with high melting point, low saturated vapor pressure, low coefficient of linear expansion, high high temperature strength, low specific resistance and film stress, good acid and alkali resistance and good environmental performance. Etc. Molybdenum products are widely used in thermal field, heat shield, vacuum coating and other fields. As the main material of the heat shield, the wide and large-sized molybdenum plate can reduce the riveting and welding points, improve the productivity and material utilization rate, and reduce the cost and energy. As an important basic material for vacuum sputtering coating, molybdenum plate has high requirements on the purity, grain size, grain size distribution and texture of molybdenum targ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22F9/04B22F1/00B22F3/04B22F3/10B22F5/00
CPCB22F3/04B22F3/1007B22F3/1021B22F5/006B22F9/04B22F2999/00B22F2998/10B22F2009/041B22F2009/044B22F1/10B22F2201/20B22F2201/013
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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