Effect of Size Distribution of the Starting Powder on the Pore Size and its Distribution of Tape Cast Alumina Microporous Membranes

Thin disc type pure alumina membranes have been prepared by tape casting technique. Pore size distribution and pore volume have been determined by mercury porosimetry. Initial particle size of the alumina powder and the size distribution are found to have a strong influence on the ultimate median pore size and pore size distribution of the fired membranes. The spread of the particle size distribution of the powders is expressed by ‘quartile ratio’ which represents the size ratio corresponding to the cummulative finer percentages of 75 and 25 in the particle size distribution curve. With higher quartile ratio ( wider particle size distribution ) not only the median pore size increases but also the distribution tends to be bimodal. This is explained on the basis of certain basic sintering behaviors of the fine powders in general. ©