Molybdenum powder for ceramic metallization and preparation method thereof

A technology for ceramic metallization and molybdenum powder, which is applied in the field of molybdenum powder for ceramic metallization and its preparation, can solve the problems of high oxygen content in powder, difficult to achieve, impurity pollution, etc., and achieve extremely low residual carbon content and high dispersion efficiency. , the effect of granularity

Active Publication Date: 2016-05-18
GRIMAT ENG INST CO LTD
View PDF11 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Central South University (ZL200710035815.3, 200810030407.3, 200810030666.6) mainly adopts sol-spray drying-two-step or three-step reduction method to prepare ultrafine or nano molybdenum copper, tungsten molybdenum copper and rare earth doped ultrafine molybdenum powder, among which CN200810030666.6 implements Example 1 prepared ultra-fine molybdenum powder with a particle size of less than 0.5 μm, but its raw materials were limited to soluble molybdenum salts—ammonium dimolybdate and ammonium paramolybdate. Good narrow particle size distribution molybdenum powder
The medium-coarse molybdenum powder with a particle size greater than 4.0 μm can partially improve particle agglomeration through fluidized bed airflow crushing (ZL200910023113.2), while the micron and submicron molybdenum powders with a particle size of 0.5-2.0 μm inherit the morphology of the molybdenum oxide precursor. It exists in the form of aggregates of tens of microns and the agglomeration is relatively serious. Even with pre-dispersion treatment, it is easy to re-agglomerate due to its large surface activity. It is very difficult or even difficult to classify by the above physical means. Molybdenum powder has a certain hardness. During the grading process, the powder rubs against the grading wheel and the inner wall of the equipment at high speed, so it is very easy to introduce impurities such as iron, nickel, and chromium. The oxygen content of the processed powder is high, and it is prone to spontaneous combustion and even dust. explode
Beijing University of Science and Technology (ZL200810223084.X) used the uniform precipitation method to prepare ultrafine molybdenum powder, adding glass powder required for ceramic metallization and mixing it in the solution to obtain evenly mixed molybdenum powder particle size nanoscale Ceramic metallized powder, and then sintered to obtain a molybdenum skeleton with a network structure, a well-filled glass phase, and a dense metallized layer microstructure, but there is no evaluation of the sealing strength and airtightness, and no practical application

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Molybdenum powder for ceramic metallization and preparation method thereof
  • Molybdenum powder for ceramic metallization and preparation method thereof
  • Molybdenum powder for ceramic metallization and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0046] The preparation process of molybdenum powder for ceramic metallization of the present invention is as follows figure 1 As shown, it includes the following steps: 1. Dissolving ammonium molybdate; 2. Filtrating; 3. Preparation of liquid after ion exchange or liquid before crystallization; 4. Wet impurity removal; 5. Adding dispersant and strengthening agent; ; 8 pyrolysis; 9 hydrogen reduction; 10 chemical decomposition; 11 filtration and washing; 12 efficient dispersion;

[0047] Firstly, after dissolving ammonium molybdate 1, filter 2 to obtain ammonium molybdate solution, or use ammonium molybdate production line ion-exchanged solution or liquid before crystallization to prepare 3 as raw material, and then remove impurities by wet method 4; Dispersant and strengthening agent 5, uniform mixing 6, spray drying 7, pyrolysis 8, hydrogen reduction 9, chemical decomposition 10, filtration and washing 11, high-efficiency dispersion 12 and dry screening 13, etc., to generate ...

Embodiment 1

[0050] Accurately weigh 5000 grams of ammonium molybdate (MSA-0), stir and dissolve with 7mol / L ammonia solution for 2 hours, and obtain a specific gravity of 1.18g / cm 3 15.0L of ammonium molybdate solution; at the same time, add 750ml of 7% by weight ammonium polyacrylate aqueous solution and 75.0ml of acetone, stir and disperse for 10 minutes to mix evenly, and the stirring speed is 6 revolutions / second; the GZ-5 high-speed Centrifugal spray drying equipment performs rapid crystallization and drying on the ammonium molybdate solution after the above-mentioned dispersion treatment. The inlet air temperature is 330°C, the outlet air temperature is 130°C, the feed rate is 2.8L / h, and the rotational speed of the centrifugal disc is 25,000 rpm. ~25μm, hollow thin-walled spherical ammonium molybdate crystals with a wall thickness of 1.5~3.5μm, the morphology of the ammonium molybdate crystals and traditional ammonium molybdate crystal particles is shown in Figure 2(a) and (b); unde...

Embodiment 2

[0053] Perform secondary ion exchange and wet removal of potassium and tungsten on the ion-exchanged liquid on the ammonium molybdate production line, and the specific gravity of the solution is 1.10g / cm 3 ; According to the ratio of 1% and 1‰ of the ammonium molybdate solution volume, add the polyethylene glycol aqueous solution and n-butanol with a concentration of 5% by weight respectively, stir and disperse for 30min to mix evenly, and the stirring speed is 4 revolutions / second; adopt the inner wall lining of the tower The GZ-50 high-speed centrifugal spray drying equipment of polytetrafluoroethylene performs rapid crystallization and drying on the ammonium molybdate solution after the above dispersion treatment. Rotate at 15,000 rpm to obtain hollow thin-walled spherical ammonium molybdate crystals with a diameter of 2-20 μm and a wall thickness of 0.5-2.5 μm; pyrolyze at 500°C for 3 hours in a nitrogen atmosphere to obtain a precursor of molybdenum oxide; after 300-350-60...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

PropertyMeasurementUnit
diameteraaaaaaaaaa
thicknessaaaaaaaaaa
particle sizeaaaaaaaaaa
Login to view more

Abstract

The invention relates to molybdenum powder for ceramic metallizing and a preparing method of the molybdenum powder and belongs to the field of powder preparing of powder metallurgy of refractory metals. The molybdenum powder is approximately spherical and has the average particle size of 0.5-2.0 microns and the maximum particle size not larger than two times of the average particle size; or the molybdenum powder is flaky and has the average thickness of 0.3-1.5 microns and the specific area of 0.5-4.0m<2> / g. The preparing method uses an ammonium molybdate solution as a raw material, uses a polymeric surfactant as a disperser and uses commonly seen alcanol or ketones for enhancing the dispersing effect, and comprises the steps of adopting spraying drying to perform fast crystallizing and drying so as to obtain fine particle hollow thin-wall spherical ammonium molybdate crystals, and in-situ generating well-dispersed, micron and submicron, approximately spherical or flaky narrow particle-size distributed molybdenum powder by pyrolysis, hydrogen reduction, chemical decomposition, filtering, washing, secondary dispersion, drying and screening. The preparing method is subjected to technology improving and extension based on the existing production conditions of an enterprise, scale production can be easily realized, the production efficiency is high and the effects are good.

Description

technical field [0001] The invention relates to molybdenum powder for ceramic metallization and a preparation method thereof, belonging to the field of refractory metal powder metallurgy powder making. technical background [0002] With the development of vacuum electronic devices in the direction of ultra-high frequency, high power and long life, glass and metal sealing can no longer meet the requirements of tube making, and the development of ceramic-metal sealing technology is gradually put on the agenda. The process has been tested in China since 1958, and it was industrialized in 1975, and it has matured day by day. Common methods of ceramic-metal sealing are sintered metal powder method and active metal method, and others include oxide solder method, vapor deposition process, solid phase process, pressure sealing, electron beam welding, etc. Ceramic parts are mostly used as insulating materials in electric vacuum devices, and their properties are quite different from ...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
Patent Type & Authority Patents(China)
IPC IPC(8): B22F9/22
Inventor 周增林惠志林李艳林晨光
Owner GRIMAT ENG INST CO LTD
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap