Scope:

Many manufacturers of testing equipment have units based on the principles described in ASTM C1070. Light scattering theory is important for determination of particle size that has been existing for many years. This method is useful to determine particle size distributions for manufacturing control, materials specifications, research and development for the manufacturer and purchaser.

Test Procedure:

In ASTM C1070, a sample scattered in an aqueous medium is passed through the path of a light beam. As the particle passes through the light beam, they scatter light at angles inversely proportional to their size and having an intensity directly proportional to their size. Detectors collect the scattered light that is converted into electrical signals and examined in a microprocessor. The signal is transferred for size distribution using Fraunhofer diffraction. The scattering information is then processed, assuming the particles to be spherical, using algorithms. Calculated particle size distributions are presented as equivalent spherical diameters.

Specimen Size : 

For ASTM C1070, the index of refraction used should relate to the aqueous media having a refractive index of 1.33.

Data:

Since the ASTM C1070 test method does not include any calculation and equations, the precision of the dispersion is achieved from 0.18 % over 7 μm to 0.01 % at 1 μm.

Conclusion:

ASTM C1070 determines the particle size distribution of quartz or alumina by using laser light scattering instruments that lie in the range from 0.1 to 500 µm.