Influence of yttrium dopant on the synthesis of ultrafine AIN powders by CRN route from a sol-gel low temperature combustion precursor

Y-doped ultrafine AIN powders were synthesized by a carbothermal reduction nitridation (CRN) route from precursors of Al2O3, C and Y2O3 prepared by a sol-gel low temperature combustion technology. The Y dopant reacted with alumina and thus forming yttrium aluminate of AlYO3, Al3Y5O12 and Al2Y4O9, which formed a liquid at about 1400 degrees C and promoted the transformation of Al2O3 to AIN and the growth of AIN particles. Compared with the conventional solid CRN process, Y dopant reduced the synthesis temperature by 150 degrees C, and Al2O3 transformed to AIN completely at 1450 degrees C. The content of Y dopant had little effect on the synthesis temperature of AIN whereas it influenced the phase of Y compounds in the products. As the Y/Al molar ratio was in the range of 0.007648-0.022944, the particle sizes of Y-doped AIN powders synthesized at 1450 degrees C were 150-300 nm. Crown Copyright (C) 2013 The Society of Powder Technology Japan. Published by Elsevier B.V. All rights reserved.