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AS 4784:2003 pdf free

AS 4784:2003 pdf free.Sample preparation for particle size analysis – Dispersing procedures for powders in liquids
The following normative document contains provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent edition of the normative document indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards.
Sampling shall comply with the requirements specified in ISO 8213, unless a method specified in a national standard or mutually agreed upon by the analyst and client takes precedence. Sample preparation shall always be done consistently so that repeated preparations based on replicate samples of a batch of powder (which was carefully mixed before being sampled or subdivided into samples) give closely comparable results.
Sprinkle the dry powder on a microscope slide and examine it using an optical microscope at x 200 magnification or other suitable magnification. Put a cover glass over the powder on the microscope slide and tap the cover glass lightly with a spatula (take care to avoid breaking the cover glass) to see how easy it is to crush the clumps. Note the approximate size range of the clumps that are not broken up by such crushing. If the majority of the particles are smaller than 1 μm, use a transmission or scanning electron microscope to observe and characterize the particles.
Note whether the surfaces of the fundamental particles are spherical or crystalline, smooth or rough, porous or nonporous. Determine whether all the sizes of particle have the same morphology. If the particles are very rough or porous, obtain an experimental measure of the volume-specific surface area (m2/kg). If this value is large compared to the area computed for spheres with the powder’s particle size distribution then an unusually large amount of dispersing agent (compared to a similar size distribution of spherical nonporous particles) may be required to stabilize the dispersion.AS 4784 pdf free download.

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