Filtering properties of highly porous materials prepared from iron powders with nonspherical particles

Abstract

We have shown that the method for preparing the initial powder has an effect on the permeability of the porous material. Other conditions being equal, the permeability is somewhat lower in specimens prepared from reduced powder than with fluidized and spherical powder. However, the possibility of using reduced powder to make components with a higher porosity and hence with a higher permeability makes use of this powder desirable. An increase in porosity of the material from 30 to 55% leads to an increase in permeability from 0.6 to 11.0 liter/min·cm2 for a pressure drop of 0.3 kg/cm2. A change in thickness of the specimen from 0.5 to 3 mm reduces the permeability by a factor of 2.5–6, and a change in the particle size from 60 to 110μ increases the permeability by more than 1.3- to 1.6-fold. A comparison of filters with the same degree of purification, made from spherical and nonspherical powders, shows that they have approximately the same transmission capacity. The data obtained for the filtering capacity of a porous material as a function of the particle size of the powder, the wall thickness, and pressure drop can serve as a basis for selecting the characteristics of a material as a function of the actual design requirements.