抄録
The results of the particle size measurements by several methods based on different principles are almost equal to each other as far as these methods are applicable, when the powder is considered to be made of sphere shape particles. However, there are some questions about the particle size measurement of irregular shape particles such as plate or needle like powder. Using mica powders as samples of the thin plate like particles, we compared the results of particle size measurements based on six different principles; optical microscope, sieve, sedimentation balance, photo sedimentation, Coulter counter and Microtrac. The measurement of the particle thickness by the mono-particulate film method2) gave a relation between the thickness and the projected diameter of mica particles classified by microsieves with a high accuracy. From this relation, the volume of the plate like mica particle was obtained and then the sphere equivalent diameter was calculated. We compared the particle size distribution based on this sphere equivalent diameter with the results measured by the other methods.
