Quantitative determination of neodymium iron boron powder’s size distribution

May 9
19:24

2012

David Yvon

David Yvon

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Neodymium iron boron powder materials have very broad application prospects in the high-tech field whose representative is the computer. Meanwhile, with the research, development and application of Nd-Fe-B permanent magnet materials, the production process and performance of this material is also increasingly with high demand. Thus it promotes the Nd-Fe-B permanent magnetic materials, relating technology research and development work.

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High quality NdFeB powder not only requires fine particle size,Quantitative determination of neodymium iron boron powder’s size distribution Articles but also requires extremely narrow particle size distribution. Therefore, in order to optimize the production process of the Nd-Fe-B permanent magnet materials, the final performance of the products, the development of neodymium iron boron powder material particle size, shape and distribution determination is increasingly important. However, due to the Nd-Fe-B powder with high magnetic each other stick together, it is difficult to separate, affecting the measurement accuracy of the results. To this end, the dispersion of the powder material and using an optical microscope to measure the particle size, size and distribution, automatic control statistics and analysis to make timely and accurate evaluation of the quality of the materials and production processes optimize the proposed recommendations. Of great significance to improve the product quality of NdFeB powder and occupation of the international high-end products market as soon as possible.

Analysis of magnetic properties of Nd-Fe-B powders have gathered to the following four aspects: When the powder is exposed to the atmosphere, because of the imbalance of the surface force field is strongly adsorbed water due to water molecules between hydrogen bond association together, powder bonded into college ball, and the powder particles are finer, more adsorption of water and air. Particles caused by Sri Lankan forces due to van molecules between long-range gravitational force, this force is proportional to the particle diameter, and is inversely proportional to the square of the distance between the particles. Nd-Fe-B belongs to the ferromagnetic material, the spontaneous magnetization of ferromagnetic materials, which caused the static magnetic attraction between the particles, and thus the existence of potential energy between the particles with the particle diameter is proportional to the cube of the distance between the particles three times Fang Cheng inversely proportional. The thermal motion prevents the static magnetic attraction. Kinetic energy to prevent static magnetic attraction. Effective gravity when the density differences between the liquid and the particles in a liquid medium, settlement by settlement of force and particle diameter is proportional to the cube.

Neodymium iron boron powder during the manufacturing process inevitable contact with the atmosphere due to the imbalance of the gravitational field of the particle surface, making it very easy adsorption of a thin layer of invisible water and air, which caused the powder to stick into small groups to form hydrophilic hate oily surface, in order to make it change into We hope that the lipophilic surface dehydration anti-rust oil soaked sample, the powder particle surface adsorption of water and air will be able to film replacement out. Changes in marriage the oil surface, which is a wetting process. Be able to see through the glass tube powder preliminary dispersed in the dispersion liquid A medium powder disappeared and numerous black specks. But the dispersion is light oil, low viscosity, low boiling point, is not suitable dispersion medium, and then uses the heavy base oil replacement.

Since the original particles of Nd-Fe-B powders of a few microns, and its density is a big gap with the oil medium density under gravity, it is bound to free settlement, according to estimates, only when the original particle size less than 0.1¼m, particles will be subject to the significant role of the Brownian motion is suspended in the oil medium.

After analyzing Nd-Fe-B powder reunion and its uneasy dispersion, the metal powder supplier begins efficiency feasible dispersion experimental program. Decentralized operating procedures determined by experiments, combined with a metallographic microscope and image analyzer on the scattered sample particle size, distribution and morphology were observed and compared with the imported test equipment detected. The test results show that the quantitative detection method has the advantages of economical and practical, easy to operate, sample dispersion and high accuracy test results. Source:http://www.mhcmp.com