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What is Fisher Number according to ASTM B 330 Standard Test Method for Fisher Number of Metal Powders and Related Compounds using a fisher sub sieve sizer/average particle size analyzer?

February 9, 2012 admin Uncategorized

Fisher number a calculated  value equated to an average particle diameter, assuming all the particles are spherical and of uniform size.

HMK-22 Fisher Sub Sieve Sizer/Average Particle Size Analyzer

Overview
HMK-22 Fisher Sub-Sieve Sizer/Average Particle Size Analyzer (FSSS) uses air permeability to fast determine the average particle size of powders. It complete meets international standard ISO 10070 Metallic powders Determination of envelope-specific surface area from the measurements of the permeability to air of a powder bed under steady-state flow conditions and ASTM B 330 Standard Test Method for Fisher Number of Metal Powders and Related Compounds. HMK-22 is a necessary testing method in productions and research fields such as magnetic materials, powder metallurgy, refractory metal, special ceramics, tungsten materials, hard metal, nonferrous metal, nonmetal, chemical industries, building materials, national defense function material, etc.

Manufacturer
-AimSizer is one of the world leading manufacturer of Fisher Sub-Sieve Sizer/Average Particle Size Analyzers
-HMK-22 Fisher Sub-Sieve Sizer meets ASTM and ISO International Standards.

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FAQs of BET Surface Area and Pore Size Analysis

November 17, 2011 admin Uncategorized
1. adsorption
  enrichment of the adsorptive at the external and accessible internal surfaces of a solid.
   
2. physisorption
  weak bonding of the adsorbate, reversible by small changes in pressure and temperature.
   
3. adsorptive
  measuring gas to be adsorbed.
   
4. adsorbent
  solid which adsorbs the measuring gas.
   
5. adsorbate
  enriched adsorptive at the surface of the adsorbent.
   
6. surface area
  area of the external surface of a solid plus the internal surface of its accessible macro and masopores.
   
7. adsorption isotherm
  relation between the quantity of adsorbate and the equilibrium pressure of the adsorptive at constant temperature.
   
8. Principle
  The method specified involves the determination of the amount of adsorbate or adsorptive gas required to cover the external and the accessible internal pore surfaces of a solid with a complete monolayer of adsorbate. This monolayer capacity can be calculated from the adsorption isotherm using the BET equation. Any gas may be used, provided it is physically adsorbed by weak bonds at the surface of the solid (van der Waals forces), and can be desorbed by a decrease in pressure at the same temperature.Nitrogen at its boiling point (about 77 K) is usually the most suitable adsorptive. if the sensitivity of the instrument when using nitrogen is insufficient for low surface areas, adsorptives of heavier molecules or of vapour pressure lower than nitrogen, e.g. krypton, may be used. The results of measurements with different adsorptives may deviate from each other because of different molecular areas, different accessibilities to pores and different measuring temperatures.

The adsoptive gas is admitted to the sample container which is held at a constant temperature. The amounts adsorbed are measured in equilibrium with the adsorptive gas pressure p and plotted against relative pressure, p/p0, to give an adsorption isotherm. Adsorption isotherms may be obtained by volumetric, gravimetric, calorimetric or spectroscopic measurement or by the carrier gas method using continuous or discontinuous operation.
   
9. Volumetric method
  In order to determine the adsorption isotherm volumetrically by the discontinuous method, known amounts of adsorptive are admitted stepwise into the sample container. At each step, adsorption of the gas by the sample occurs and the pressure in the confined volume falls until the adsorbate and the adsorptive are in equilibrium. The adsorbed volume may be compensated by the introduction of calibrated inicrements of gas so that the pressure remains constant. The amount of gas adsorbed is the difference between the amount of gas admitted and the amount of gas filling the dead volume (free space in the sample container, including connections), which is determined by application of the general gas equation. The various volumes of the apparatus and their temperatures should be taken into account.The dead volume must be determined before or after the measurement of the adsorption isotherm. The calibration is done volumetrically using helium at the measuring temperature. It should be noted that some materials may absorb helium. In this case, corrections can be made after measuring the helium isotherms. During sample measurement and determination of the dead volume, it is recommended that the liquid level in the cooling bath be maintained, unless otherwise compensated, at least 50 mm above the sample and constant to within 1 mm. The determination of the dead volume may be avoided using difference measurements, i.e. by means of reference and sample tubes connected by a differential transducer.

In the continuous volumetric measurement, the amount of admitted adsorptive may be calculated from the pressure difference and the duration of the gas flow through a calibrated capillary or metering valve.

http://www.aimsizer.com

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AimSizer offers quality universal test machine

November 13, 2011 admin Uncategorized

Aimsizer starts cooperation with reputed Chinese manufacturer of universal test machine.The universal test machine subcontractor supplies represents the best quality in China.

http://www.aimsizer.com/Laser_Diffraction_Particle_Size_Analyzers.html

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Aimsizer Presents China Quallity Tumbler Screening Machine/Tumbler Screener

November 13, 2011 admin Uncategorized

Aimsizer starts cooperation with reputed Chinese manufacturer of tumbler screening machines.The tumbler screener our subcontractor supplies represents the best quality in China.

For more please visit us at: http://www.aimsizer.com/Hmk18TumblerScreeningMachine.html

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Hall Flowmeter/Flow Meter Apparatus-Stand and horizontal vibration-free base.

November 11, 2011 admin Uncategorized

For Hall flowmeter/Flow Meter, in order to support the Hall Funnel rigidly,Aimsizer supplies a stand and horizontal vibration-free base in the standard AS-300 Hall Flowmeter.

http://www.aimsizer.com/As_300_Hall_Flow_Meter_overview.html

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Welcome to AimSizer’s Blog

June 24, 2011 admin Uncategorized

AimSizer is a leading China manufacturer in instrumentation of particle characterization.Based on years of experience and devotion to research of particle size analyzers AimSizer convinces more and more users worldwide.

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Hello world!

June 24, 2011 admin Uncategorized

Welcome to WordPress. This is your first post. Edit or delete it, then start blogging!

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