Some Aspects of Liquid-Phase Sintering of Alumina

摘要

An analysis of the interfacial energies associated with a solid-liquid system showed that the possibiity of complete wetting of a liquid in a solid microstructure is not necessarily associated with complete wetting at the solid-liquid-vapor interface. This was investigated using a CaO-Al sub 2 O sub 3 -SiO sub 2 glass on single crystal and polycrystalline aluminas. The absence of complete penetration of grain boundaries was observed in only one alumina, and was attributed to the presence of MgO in solid-solution changing the interfacial energies of the alumina. The observation of complete penetration at long times was also shown to be dependent on the volume of liquid available. The wetting behavior of the glass alumina system was extended to sintering, using two types of alumina. The type of alumina was found to have the greatest effect on sintering. With one of the aluminas, it was shown that surface treatments which increase gamma /sub ss/ can lead to enhanced liquid phase sintering. It was also shown that reactions between the solid and liquid which form a solid product are determined to sintering. 30 figures, 2 tables. (ERA citation 07:054396)