Abstract: The effect of adding nanocrystalline γ-Al₂O₃ powders on the sintering behavior of alumina fibers was investigated. The nanocrystalline
powders will be stuffed into the pores formed from the packing of micron-sized alumina powders when the fiber is extruded. In the case
of 40% nanocrystalline γ-Al₂O₃ in the mixed powders, the relative green density increases from 65% to 80%. The fiber can be
sintered to near theoretical density at relatively low temperature because it is of higher density, narrower pore size distribution and
smaller mean pore size. The diametric shrinkage of the fibers extruded from the nanocrystelline γ-Al₂O₃ is higher than that made
from micron-sized powders. γ-Al₂O₃ phase is transformed to α-Al₂O₃ during sintering process.

Key words: Al₂O₃ fiber, γ-Al₂O₃ nanosized powder, sinter