Abstract
In this study, we fabricated Aluminum Nitride (AlN) ceramics containing AlN whiskers grown by direct nitridation of Al-Si binary melt. We evaluated their microstructures and thermal conductivities. The samples containing 4 vol% of the AlN whiskers were fully densified at 1650℃ for 10 min using spark plasma sintering (SPS) and Y2O3-CaO-B sintering additives. The microstructures were almost isotropic. This means the whiskers do not work as a seed crystal for the formation of the columnar microstructures, but a sintering additive for promoting the densification at the initial stage of sintering. Si impurity contained in the whiskers is suggested to work as a part of the sintering additives. The thermal conductivity of the sample containing whiskers was around 80 W・m-1・K-1, which is comparable to that of the sample not containing whiskers.
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