SYNTHESIS OF CERAMIC EUTECTICS USING MICROWAVE PROCESSING

This communication presents preliminary results of using microwave energy in order to melt and re solidify oxide and non oxide refractory ceramic eutectic compositions in an appropriate crucible The Al2O3 -Y3Al5O12 (YAG) (T-m = 1827 degrees C) and B4C TiB2 (T-m = 2310 degrees C) eutectic compositions were melted in a multimode 2 45GHz microwave furnace using a specially designed insulating package based on boron nitride Our experiments demonstrate the stability of eutectic melt temperature (the absence of temperature runaway) and the uniformity of subsequent eutectic microstructure across the sample diameter during the re solidification of big similar to 7cm(3) samples The ability to reach ultra high temperatures (T similar to 2400 degrees C) and prevent the formation of significant thermal gradient across the sample confirms the potential of using microwave energy for processing of directionally solidified refractory ceramic eutectic compositions