Fisher particle size of tungsten powder and its measuring methods

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Fisher particle size of tungsten powder

Tungsten powder is a kind of polygon metal powder that has silver gray appearance, of which the particle size ranges between 0.6-30micron and can be mainly divided into three particle sizes: coarse particle size, middle particle size and fine particle size. The particle size of tungsten powder often refers to the Fisher particle size which is same with the average particle size of tungsten powder measured by testing the steady flow air permeating method with the help of Fisher sub-sieve sizer under the constant air velocity and pressure.

This method can only accurately measure the transmittance when the air passes the powder aggregate, but it cannot accurately measure the real particle size of powder. However, the specific area and average particle size that are measured by this method can be used to control the technological process and the quality of products.

tungsten metal powders

Measuring the Fisher particle size of tungsten powder

Fisher particle size of tungsten powder can be measured byFisher sub-sieve sizer.

When measuring, the best porosity should be found first before measuring the particle size of tungsten metal powder. Gradually debulk the tungsten powder sample in the repression structure composed by the rack and hand wheel of Fisher sub-sieve sizer beginning with high porosity. According to different compressibility of powder, take the different porosity intervals from 0.005 to 0.05 and start the operation when the sample altitude curve is compressed into appropriate porosity. Measure the particle size immediately when it is compressed and do not stop until it cannot compress. Take the corresponding porosity average value of two adjacent and proximate particle size value as the best porosity. Afterwards, take out another tungsten powder sample, measure it under the best porosity, use the data that obtained at this moment as the final reports, thus the tungsten powder Fisher particle size can be obtained.

Notes:

Specific area: it refers to the gross area of unit mass substance, which can be divided into external specific area and internal specific area. Its national standard unit is m2/g.

Porosity: it refers to the proportion between the inside material hole and the total volume in the non-coherent materials. It includes real porosity and closed void fraction.