Gelcasting Of Porous Alumina For Particulate Filtering

Abstract

Gelcasting has been an effective route to manufacturing dense as well as porous ceramics, this project attempts at fabricating porous alumina bodies in the form of layer by layer addition by surfactant action.
Meanwhile in the process of fabricating the body several steps or algorithms have been taken care of, initiating with slurry stabilisation, where we obtain an optimum pH, zeta potential, dispersant concentration viz (9.2-66.1mV, 0.5%) combination along with the optimum solid loading for rheology (8:3, alumina:water), we proceed on to fabrication of the gelcasted layers accompanied by a study of porosity introduced in them, solid loading of (7:3, 1:1 alumina:water) have been tried at different surfactant levels of 2.5, 5, 7.5% w/w.
Following the above mentioned steps we have a seamless integration of the layers of varying porosity in different combinations and a mechanical property characterisation of the same which includes compressive and flexural strength analysis is studied.
Finally we prepare the desired porous body with a varying porosity concentration gradient and successfully show its filtering action. Microscopy analysis viz SEM has been done and the individual properties studied. This meanwhile marked the successful attainment of 60% porosity at the lab scale as well as we could manufacture a functionally graded seamlessly integrated monolith where the function is porosity necessary for the desired filtration behaviour.