Comparison of Physical Properties of Different Compositions of Alumina/Lanthanum Hexaaluminate Ceramic Composite.

Abstract

The aim of this study was to prepare four different composition of Alumina/Lanthanum Hexaaluminate powder. Four different compositions ranging from 10 to 80 vol % of Lanthanum Hexaaluminate were prepared. To prepare the Alumina-Lanthanum Hexaaluminate ceramic composite, stable aqueous Alumina slurry was needed to prepare. Thus, selection of electrolyte was made after comparing Darvan and tri-ammonium Cytrate. Darvan was chosen as an electrolyte to prepare stable aqueous Alumina slurry. The effect of pH on zeta potential was also studied.
After preparation of Alumina-Lanthanum Hexaaluminate ceramic composite powder, pellets of approximately 0.7gram for each composition were made by applying 4 Ton pressure for 120 seconds. The pellets were then sintered at 16500C in chamber furnace. The soaking time was kept for 4 hours. Then the bulk density, aparent porosity and strength were compared after calculation of dry weight, soked weight, suspended weight. The results revealed that bulk density increased with increasing vol % of LHA content and aparent porosity decreased with increasing vol% of LHA content. The strength also increased with increasing vol% of Lanthanum Hexaaluminate.