Method for preparing nanometer tungsten combined powder by collosoling, spraying and desiccating and hot reducing

A composite powder and drying technology, applied in the "ultra-uniform, ultra-fine" nano-scale tungsten-based composite powder, ultra-pure field, can solve the problems of complex process, agglomeration, powder inclusion, etc., to achieve high purity, improve The effect of strength and fine grain structure

Inactive Publication Date: 2005-01-19
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Its process is too complex and not suitable for mass production of powder
[0005] In recent years, composite powders such as nanocrystalline W-Ni-Fe hav

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Take the preparation of 90W-7Ni-3Fe nano-phase tungsten-based composite powder as an example.

[0023] ① Prepare salt mixed salt solution, weigh 122.1g of ammonium metatungstate (3(NH 4 ) 2 O12WO 3 ·3H 2 O), 34.5g nickel nitrate crystals (Ni(NO 3 ) 2 6H 2 O) and 21.6g ferric nitrate crystals (Fe(NO 3 ) 3 9H 2 O);

[0024] ② Add 397.8ml, 50.5ml, and 34.3ml of distilled water to prepare saline solutions with a mass percentage of 30%;

[0025] ③Quickly mix and stir the solution, add a small amount of HNO 3 Stir and mix with 2g polyethylene glycol (PEG), control the pH value to 3, and obtain a transparent near-sol;

[0026] ④ It is required that the powder has good dispersibility to prevent precipitation in the solution;

[0027] ⑤The sol is spray-dried, the spray-drying speed is 30,000 rpm, and the spray-drying temperature is 350°C to obtain the precursor of compound salt powder (or compound oxide powder) of tungsten, nickel and iron; at this time, the aggregat...

Embodiment 2

[0038] Take the preparation of 95W-3.5Ni-1.5Fe nano-phase composite powder as an example.

[0039] ①Weigh metal, ammonium paratungstate (APT, 5(NH 4 ) 2 o 12 WO 3 ·5H 2 O) nickel chloride crystals (NiCl 2 ·H 2 O) ferrous chloride crystal (FeCl 2 4H 2 O) 134.8g, 7.7g, 4.1g;

[0040] ② Add 650.6ml, 17.5ml, and 11.5ml of distilled water to prepare solutions with a mass percentage concentration of 20% respectively;

[0041] ③Quickly mix and stir the solution, add a small amount of ammonia water to control the pH value to 10, and obtain a translucent sol;

[0042] ④ Add 0.9g polyethylene glycol (PEG) and stir to mix evenly to prevent precipitation and disperse the powder evenly;

[0043] ⑤ Spray-dry the colloid, the spray-drying speed is 25,000 rpm, and the spray-drying temperature is 200°C to obtain the compound salt powder precursor of tungsten, nickel, and iron. At this time, the powder is an aggregate; it is in the shape of a hollow sphere, and the particle size is le...

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Abstract

The invention relates to a powder preparation process, especially for preparing a nano composite powder, which belongs to the field of powder metallurgical technique. The preparation process is characterized by: weighing the different metal salts in proportion for preparing a salt solution and a mixed salt solution; adding a few acid or alkali for controlling the pH value in a range of less than 4 or more than 10, adding 0.1% to 5% of surfactant, spray drying at the temperature of between 300 C. and 350 C. for preparing the nano oxide composite powder or composite salt powder precursor; obtaining the nano tungsten base composite powder by first reduction at 400 C. to 600 C. and second reduction at 650 C. to 1000 C. . The nano tungsten base composite powder prepared by the process has superfine granularity, uniform distribution, high purity, and good sintering activity.

Description

technical field [0001] The present invention relates to a method for preparing powder metallurgy materials, especially a method for preparing nanoscale tungsten-based composite powders with high performance, such as W-Ni-Fe, W-Cu, W- Ni-Cu etc. Background technique [0002] Tungsten-based alloy has high density and excellent mechanical properties, electrical properties and thermal properties, and has no pollution to the environment. It is used to prepare armor-piercing bullets, armor-piercing drug-type cover materials, electrical contact materials, electrode materials, and heat sinks for microelectronic packaging. Tungsten-based alloys prepared by traditional micron-sized W, Ni, Fe and other element powders have coarse tungsten grain structure, low density, and low mechanical properties, which cannot meet the performance requirements of new materials. While grain refinement can improve alloy properties, it can also improve adiabatic shear resistance. For example, through a...

Claims

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Application Information

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IPC IPC(8): B22F9/20
Inventor 范景莲马运柱黄伯云汪登龙陈仲伯吴恩熙
Owner CENT SOUTH UNIV
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