Effect of environmental impurities on the microstructure and sinterability of alumina ceramics

The effect of volatiles present in the kiln atmosphere on the sinterability and microstructure of alumina ceramics was studied. The experiments were so designed that the volatile impurities generated from the respective salts of Na, Cu, Zn, Ni, Cr and Fe were allowed to act on pure alumina ceramics. The properties studied included porosity, density, fired shrinkage, microhardness, power factor, loss factor, volume resistivity and dielectric strength. Scanning Electron Microscopy was used for the characterization of the resulting microstructures. The results when compared with the corresponding properties of alumina ceramics fired under a pure environment have been presented