Magnesium oxide ceramics produced by slip casting using aqueous/non-aqueous suspensions

Slurries containing 80 wt-% magnesium oxide in ethanol and in an 80:20 ethanol/water mixture were prepared from high purity magnesium oxide. The slurries were ball milled for 3 h resulting in an average particle size of 1.5 mu m. Casts sintered in the temperature range 1600-1650 degrees C exhibited bulk densities up to 3.52 g cm(-3) (98.2% theoretical), the average linear shrinkage being 11.7%. SEM demonstrated that most of the porosity was intergranular with pronounced grain growth and good grain packing. The use of the ethanol as a slurry medium overcomes the problem of the aqueous solubility of magnesia, while also presenting no evaporation difficulties during milling and casting. BCT/274.