Superfine powder preparing method

A technology of ultrafine powder and filaments, applied in the field of ultrafine powder preparation, can solve the problems of large average particle size of nanoparticles, wide range of particle size distribution, low yield of nanoparticles, etc.

Inactive Publication Date: 2004-05-05
HUAZHONG UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The yield of the prepared nanoparticles by this method is not high, and the average particle diamete

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] Example 1: Prepare nano-aluminum powder by ablation of Al filament target with laser beam

[0015] The YAG laser is selected, the pulse laser energy used is 15J / pulse, the average output power is 300W, the pulse repetition frequency is 20Hz, the pulse width is 1.3ms, and the spot diameter is 0.5mm. At this time, the corresponding laser energy density is 7.6×10 3 J / cm 2 , with a power density of 5.9×10 6 W / cm 2. Argon gas was introduced into the reaction chamber, and the vacuum degree was maintained at 500Pa. The diameter of the aluminum wire used is 0.5mm, and the experiment shows that the yield of nano-aluminum powder under this condition (average power 300W) is about 25 grams / hour. If the other parameters are kept constant and the average laser power is increased to 1 kW, the production rate of powder can reach 83 g / h. figure 2 Shown is the particle size distribution histogram of the ultrafine powder, in which the x-axis represents the diameter of the ultrafine...

Embodiment 2

[0016] Embodiment 2: Preparation of nano silver powder by laser ablation silver wire

[0017] The YAG laser is selected, the pulse laser energy used is 30J / pulse, the average output power is 300W, the pulse repetition frequency is 10Hz, the pulse width is 0.5ms, and the spot diameter is 0.5mm. At this time, the corresponding laser energy density is 1.5×10 4 J / cm 2 , with a power density of 3.0×10 7 W / cm 2 . In the experiment, argon gas was introduced into the reaction chamber, and the vacuum degree was maintained at 1000 Pa, and the diameter of the silver wire used was 0.5 mm. Experiments show that the production rate of the nano-silver powder under this condition (average power 300W) is 94.5 grams / hour. If other parameters are kept constant and the average laser power is increased to 1 kW, the production rate of powder can reach 315 g / h. image 3 A histogram of the particle size distribution of the silver superfine powder is shown, in which the x-axis represents the dia...

Embodiment 3

[0018] Embodiment 3: Preparation of nanopowder by laser ablation of graphite

[0019] The YAG laser is selected, the pulse laser energy used is 30J / pulse, the average output power is 300W, the pulse repetition frequency is 10Hz, the pulse width is 0.3ms, and the spot diameter is 0.5mm. At this time, the corresponding laser energy density is 3.8×10 3 J / cm 2 , with a power density of 1.27×10 7 W / cm 2 . The reaction chamber was vented with argon, and the vacuum degree was maintained at 1000Pa. The diameter of the carbon filament used in the experiment is 0.5mm. Experiments show that the production rate of the nano-graphite powder under this condition (average power 300W) is 24.7 grams / hour. If the other parameters remain unchanged and the average laser power is increased to 1 kW, the production rate of ultrafine powder can reach 82.3 g / h. Moreover, the average particle diameter of the ultrafine powder is lower than 6nm, and the particle size distribution range is 1-15nm. ...

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Abstract

In the present invention the fine wire in basically even thickness is fed to a vacuum reaction chamber continuously, and its end is ablated by focused laser beam or electron beam to produce integral explosive evaporation. While laser beam or electron beam acts, inert gas or reactive gas in proper flow rate is led into the reaction chamber to maintain reaction chamber pressure in 10 Pa to 10 Kpa, and the produced superfine powder is collected by using a powder collector. The target material may be preheated. Using the present invention can prepare high-purity superfine powder with small average size and narrow size distribution in high yield.

Description

technical field [0001] The invention belongs to the preparation technology of superfine powder, in particular, it relates to a method for preparing superfine powder. Background technique [0002] Due to its unique volume effect, surface effect, quantum size effect and macroscopic quantum tunneling effect, ultrafine powder (particle size <100nm) shows special optical, electrical, magnetic, thermal and chemical properties, and has been used in information storage, It is widely used in the fields of optical communication, sensor, metallurgy, aviation, chemical industry and medical treatment. Therefore, the governments of various countries have invested a lot of funds and scientific and technological strength to carry out extensive research on this. [0003] At present, the key problem to be solved in the preparation of nanometer ultrafine powder is: how to improve the ultrafine powder as much as possible while obtaining ultrafine powder with high purity, small average parti...

Claims

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Application Information

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IPC IPC(8): B22F9/00B22F9/02B22F9/04B22F9/14
Inventor 曾晓雁王泽敏
Owner HUAZHONG UNIV OF SCI & TECH
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