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Method of manufacturing ultrafine molybdenum powder or ultrafine tungsten powder surface clad metal copper

A technology of ultra-fine tungsten powder and ultra-fine molybdenum powder, which can be used in coating and other directions, can solve the problems of negative impact of electric vacuum performance, difficult to achieve, non-magnetic and other problems, and achieve the effect of uniform organization, simple preparation process and dense structure.

Active Publication Date: 2009-05-13
GRIMAT ENG INST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0009] 4. Non-magnetic
[0019] The method of inorganic powder surface metallization announced in CN1401819 patent literature, the electroless plating method that Huang Jianzhong etc. propose produces high activity, high uniformity Cu, Ni clad tungsten composite powder (mining and metallurgy engineering, the 16th volume the 3rd in September, 1996 Issue), and Qin Guangrong et al. (Compilation of papers on new hydrogen storage materials and their application seminars, "863" hydrogen storage materials special group, December 1990, research on the performance of hydrogen storage alloy particle electroless copper plating process P193) proposed surface Copper plating technology uses stannous chloride for sensitization in the surface coating process, but in molybdenum copper and tungsten copper alloys used in electric vacuum materials, tin, aluminum and other low melting point metals should not be introduced, otherwise it will affect the Vacuum performance has a negative impact; the formaldehyde-free chemical copper plating method and the solution used in the method disclosed by CN1502720 patent documents also need catalytic components such as palladium and tin; the microporous copper film disclosed by CN1204291 patent documents and used The electroless copper plating solution for preparing the copper film is not suitable for superfine molybdenum powder and ultrafine tungsten powder surface coating; the chemical copper plating solution formula of rare earth nickel-based hydrogen storage alloy powder disclosed in CN1060697 patent literature and its copper plating Method, Cu 2+ Replacement and reduction can occur on the surface of hydrogen storage alloy powder. On the surface of tungsten powder and molybdenum powder, this reaction is difficult to carry out; on the surface of ultrafine molybdenum powder and tungsten powder with a particle size of submicron and nanometer, the metal copper is uniformly coated , and do not introduce impurities, the thickness of the coating should be in the nanometer range, which is difficult to achieve by conventional electroless plating methods

Method used

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  • Method of manufacturing ultrafine molybdenum powder or ultrafine tungsten powder surface clad metal copper
  • Method of manufacturing ultrafine molybdenum powder or ultrafine tungsten powder surface clad metal copper
  • Method of manufacturing ultrafine molybdenum powder or ultrafine tungsten powder surface clad metal copper

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0062] 1. Preparation of copper-coated ultrafine molybdenum powder by reduction of hydrazine hydrate (D 50 = 500 nm)

[0063] See figure 1 , The average particle size of ultrafine molybdenum powder D 50 = 500 nanometers, the morphology is irregular granular, the molybdenum powder is approximated as a spherical calculation, and the surface of the molybdenum powder is uniformly coated with 20nm thickness of metallic copper. 1kg of ultrafine molybdenum powder requires 230g of metallic copper; because the specific surface area of ​​the actual particles is much larger For the approximate spherical shape, according to this ratio, the thickness of the metal copper that is actually evenly coated is much lower than 20 nm.

[0064] Refer to Figure 8 The process flow, add 80.0ml 0.50M copper sulfate, add 1.00ml concentration of 5% PVP (polyvinylpyrrolidone) with an average molecular weight of 45000-55000 and 1.00ml concentration of 5% polyvinyl alcohol with an average molecular weight of 5...

Embodiment 2

[0069] 2. Preparation of copper-coated ultrafine tungsten powder by reduction of sodium hypophosphite (D 50 = 300 nm)

[0070] See figure 2 , Ultrafine tungsten powder (D 50 =300nm), the morphology is an irregular granular shape close to a square. The W powder is approximated as a spherical shape. The surface is evenly coated with 20nm thick metallic copper. 1kg of ultrafine W powder requires 212.9g of metallic copper; The specific surface area of ​​the particles is much larger than the approximate spherical shape. According to this ratio, the thickness of the metal copper that is actually uniformly coated is much less than 20 nm.

[0071] Take 80.0ml 0.20M copper sulfate, add 1.00ml 5% PEG with an average molecular weight of 12000, 1.00ml 5% vinylpyrrolidone (VP) and acrylic acid (AA) 1:1 copolymer with an average molecular weight of 35000, stir well, add 4.0g nano tungsten powder, stir and mix evenly; adjust the pH to between 4 and 5 with 2.0M and 0.1M NaOH, add 0.5M hexamethyl...

Embodiment 3

[0076] 3. The reduction of sodium dithionite to prepare copper-coated ultrafine tungsten powder (D 50 = 300 nm)

[0077] The same ultrafine tungsten powder in Example 2 was used to prepare the copper-coated ultrafine tungsten powder with a mass ratio of Cu:W of 7:3.

[0078] Take 110.0ml of 1.00M copper nitrate, add 1.00ml of PVA with a concentration of 0.5% and an average molecular weight of 18000, and 0.50ml of a copolymer of α-vinylpyrrolidone and styrene with a concentration of 10.0% and an average molecular weight of 40,000-45000. Stir well and add 3.0g nano tungsten powder, stir and mix evenly; add 20.0ml 0.5M hexamethylenetetramine solution, adjust the pH with dilute NaOH and HCl to make the pH of the system between 6.5 and 7.5, slowly add 250.0ml under stirring. .5M sodium dithionite alkaline solution (pH=11.0~11.5, prepared with NaOH and sodium dithionite to ensure the stability of the sodium dithionite solution and maintain the pH value of the reaction system), react at ...

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Abstract

The invention relates to a preparation method for a metal copper covered on the surface of ultrafine molybdenum powder or ultrafine tungsten powder, which belongs to the field of new materials. The preparation method is characterized in that the method mainly adopts the ultrafine molybdenum powder or the ultrafine tungsten powder with the average particle diameter D50 not more than 1.3 Mum, which is mixed with Cu<2+> soluble salt solution under the continual stirring, polymeric surfactant of coordination group with N atom and O atom is added, one of hydrazine hydrate, sodium hydrosulfite or sodium hypophosphite is added as reducing agent, and an appropriate amount of alkali is dropwise added to adjust pH value in the period so that pH value of the reaction system is from 5.5 to 12.0; in addition, in the range of 20 to 95 DEG C, the reaction continues for 0.5 to 3 hours; the ultrafine molybdenum powder or the ultrafine tungsten powder is filtered through flushing by diluted NH4Cl or NH4NO3 solution, the powder is pulped by alcoholic solution with 0.2-3.0 percent of fatty acid, and the ultrafine molybdenum powder or the ultrafine tungsten powder is filtered again, the powder is heated and dried by H2, to prepare the ultrafine molybdenum powder or the ultrafine tungsten powder of the metal copper covered with the even surface. Through adjusting the proportion of soluble salt of the ultrafine molybdenum powder or the ultrafine tungsten powder and the copper, the ultrafine molybdenum powder or the ultrafine tungsten powder covered by metal copper with different composition proportions can be prepared to meet different demands.

Description

Technical field [0001] The invention relates to a preparation method for coating metal copper on the surface of ultrafine molybdenum powder or ultrafine tungsten powder, in particular to a preparation method for coating metal copper with nanometer thickness on the surface of ultrafine molybdenum powder or ultrafine tungsten powder, and belongs to a novel Material technology field. Background technique [0002] Molybdenum copper material, like tungsten copper material, is a pseudoalloy composed of two immiscible metal phases in structure. Therefore, this material has the characteristics of both constituent metals and has good overall performance. [0003] 1. High electrical and thermal conductivity [0004] Molybdenum and tungsten are elements with good electrical and thermal conductivity in addition to high-conductivity metals such as gold, silver and copper. Therefore, tungsten-copper and molybdenum-copper materials that are further added with highly conductive and thermally con...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F1/02
Inventor 王家君崔舜林晨光宋月清韩胜利朱清玮
Owner GRIMAT ENG INST CO LTD
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