Method for preparing large-size molybdenum plate blank

A large-size, slab technology, which is applied in the field of preparing large-size molybdenum slabs, can solve problems such as uneven shrinkage and non-uniform grain growth, so as to reduce holes, reduce grain growth, and suppress abnormal grain growth. big effect

Active Publication Date: 2018-11-30
UNIV OF SCI & TECH BEIJING
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  • 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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  • Method for preparing large-size molybdenum plate blank

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Experimental program
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Effect test

Embodiment 1

[0023] The raw material molybdenum powder with a particle size distribution of (d10=1.2 μm, d50=5.7 μm, d90=17.8 μm) was subjected to jet milling treatment twice by using a counter-jet jet milling device. For the first jet mill, the pressure of the grinding chamber is set to 0.55MPa, and the frequency of the sorting wheel is 30Hz to realize the dispersion and crushing of powder. The second jet mill sets the pressure of the grinding chamber to 0.40MPa and the frequency of the sorting wheel to 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%. Molybdenum powder with jet milling treatment and fine particle size was finally obtained, and the particle size distribution was (d10=2.1 μm, d50=3.4 μm, d90=4.3 μm). The fine-grained molybdenum powder and the paraffin wax binder processed by the jet mill were mixed for 60 minutes at 90 ° ...

Embodiment 2

[0025]Using a counter-jet jet milling device, the raw material molybdenum powder with particle size distribution (d10=2.8 μm, d50=6.3 μm, d90=20.6 μm) was subjected to two jet milling treatments. For the first jet mill, the pressure of the grinding chamber is set to 0.50 MPa, and the frequency of the sorting wheel is 30 Hz to realize the dispersion and crushing of 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 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%. Molybdenum powder with jet milling treatment and fine particle size was finally obtained, and the particle size distribution was (d10=3.3 μm, d50=4.0 μm, d90=4.9 μm). The fine-grained molybdenum powder and the paraffin wax binder processed by the jet mill were mixed for 60 minutes at 90 ° ...

Embodiment 3

[0027] The molybdenum powder with particle size distribution (d10=5.5 μm, d50=8.3 μm, d90=24.6 μm) was subjected to jet milling treatment twice by adopting a counter-jet jet milling device. For the first jet mill, the pressure of the grinding chamber is set to 0.45MPa, and the frequency of the sorting wheel is 20Hz to realize the dispersion and crushing of powder. In the second jet mill, the pressure of the grinding chamber is set to 0.30 MPa, and the frequency of the sorting wheel is 50 Hz 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%. Molybdenum powder with jet milling treatment and fine particle size was finally obtained, and the particle size distribution was (d10=6.8 μm, d50=7.3 μm, d90=8.7 μm). The fine-grained molybdenum powder and the paraffin wax binder processed by the jet mill were mixed for 90 minutes at 100 ° C and...

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Abstract

The invention provides a method for preparing a large-size molybdenum plate blank, and belongs to the technical field of powder metallurgy. The method includes the steps that reducing molybdenum powder serves as a raw material, and small-granularity molybdenum powder which is evenly dispersed, has narrow granularity distribution and is nearly spherical is obtained through airflow milling treatment; then the small-granularity molybdenum powder and a paraffin binder are evenly mixed, and a mixture is obtained; and then by the adoption of a secondary isostatic cool pressing forming process, a degreased blank is isostatically pressed into a secondary blank under high pressure intensity. A sintering method of low-temperature slow heating and high-temperature rapid heating is adopted, specifically, slow heating is carried out at a low-temperature sintering stage, the blank is fully reduced in order to reduce the oxygen content in a blank body, and therefore the sintering activity of the blank is kept; and rapid heating is carried out at a high-temperature sintering stage, grain growth can be reduced, and after sintering is completed, the thick molybdenum plate blank with high density andhigh tissue uniformity can be obtained. By means of the preparation method, the problems that local looseness and cracks are easily generated in former large-size thick molybdenum plates are solved,the density of the prepared molybdenum plate blank reaches 99% or above, and the uniformity and the consistency of tissue of the surface and the center position of the plate blank can be guaranteed.

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, small linear expansion coefficient, high high temperature strength, small specific resistance and film stress, good acid and alkali resistance and good environmental protection performance Etc. Molybdenum products are widely used in thermal field, heat shield, vacuum coating and other fields. Wide and large-sized molybdenum plates are used as the main material of the heat shield, which can reduce riveting and welding points, improve productivity and material utilization, and reduce cost and energy. Molybdenum plate is an important basic material for vacuum sputtering coating. In order to ensure the uniformity of sputtering film, there are high requirements on the purity, ...

Claims

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Application Information

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Patent Type & Authority Applications(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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