ASTM C1070-01(R2020) pdf free download

ASTM C1070-01(R2020) pdf free download.Standard Test Method for Determining Particle Size Distribution of Alumina or Quartz by Laser Light Scattering
1. Scope
1.1 This test method covers the determination of particle size distribution of alumina or quartz using laser light- scattering instrumentation in the range from 0.1 to 500 µm. 1.2 The procedure described in this test method may be applied to other nonplastic ceramic powders. It is at the discretion of the user to determine the method’s applicability. 1.3 This test method applies to analysis using aqueous dispersions. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.5 Quartz has been classified by IARC as a Group I carcinogen. For specific hazard information in handling this material, see the supplier’s Material Safety Data Sheet. 1.6 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. Summary of Test Method
3.1 A sample dispersed in an aqueous medium is circulated through the path of a light beam. As the particles pass through the light beam, the particles scatter light at angles inversely proportional to their size and with an intensity directly propor- tional to their size. Detectors collect the scattered light which is converted to electrical signals and analyzed in a micropro- cessor. The signal is converted to size distribution using Fraunhofer diffraction or Mie scattering, or a combination of both. The scattering information is then processed, assuming the particles to be spherical, using algorithms or models proprietary to the particular instrument manufacturer. Calcu- lated particle size distributions are presented as equivalent spherical diameters.
4. Significance and Use
4.1 It is important to recognize that the results obtained by this method or any other method for particle size distribution utilizing different physical principles may disagree. The results are strongly influenced by the physical principles employed by each method of particle size analysis. The results of any particle sizing method should be used only in a relative sense, and should not be regarded as absolute when comparing results obtained by other methods. 4.2 Light scattering theory that is used for determination of particle size has been available for many years. Several manufacturers of testing equipment have units based on these principles. Although each type oftesting equipment utilizes the same basic principles for light scattering as a function of particle size, different assumptions pertinent to applications of the theory and different models for converting light measure- ments to particle size may lead to different results for each instrument. Therefore, the use of this test method cannot guarantee directly comparable results from the various manu- facturers’ instruments. 4.3 Manufacturers and purchasers of alumina and quartz will find the method useful to determine particle size distribu- tions for materials specifications, manufacturing control, and research and development.
5. Interferences
5.1 Air bubbles entrained in the circulating fluid will scatter light and then be reported as particles. Circulating fluids do not require degassing, but should be bubble-free upon visual inspection. 5.2 Re-agglomeration or settling of particles during analy- ses may cause erroneous results. Stable dispersions shall be maintained throughout the analyses. To determine if stability is present, make multiple runs on the same sample and observe if the distribution stays the same throughout the analysis. If the distribution gets coarser, then agglomeration is occurring. If the distribution gets finer, there exists the possibility of material settling. Dispersion properties may be altered by changing dispersants, use of ultrasonic energy prior to or during analyses, and change ofpumping speed during analyses. 5.3 Insufficient sample loading may cause electrical noise interference and poor data repeatability. Excessive sample loading may cause excessive light attenuation and multiple scattering, thereby resulting in erroneous particle size distribu- tions. The size distribution will have a tendency to be finer than actually exists.