Varying the Granulometric Composition of an Electrofused-Corundum-Based Ceramic with a Porcelain Binder to Control its Open Porosity and Strength

Resumo

A study is made of a strong porous ceramic based on granular mixes of a filler—electrofused corundum with particle sizes of 2 – 3 and 0.5 mm (95 wt.% of the mix) — and a porcelain binder (5 wt.%). Several mixes were prepared with different values for the 2 – 3 mm/0.5 mm ratio of filler-particle sizes: 0/95, 35/60, 40/55, 45/50, 50/45, and 95/0. The specimens were pressed at pressures of 25, 50 and 100 MPa and fired at temperatures of 1350 and 1450°C. The sintered specimens ranged from 19 to 143 MPa in ultimate flexural strength and 17 to 26% in open porosity. The results are attributed to the formation of a framework in the semifinished product along with regions outside the framework. The new porous permeable ceramic is promising for use in the form of filters and supports for ceramic membranes.