Mechanisms of Oxide Whisker Growth

Whiskers are of interest for toughening polycrystalline ceramics. Nonoxide whiskers are available commercially but can oxidize and lose their effectiveness at high temperatures in oxidizing atmospheres. The availability of oxide whiskers would offer the potential of high toughness and oxidation resistant ceramic composites. Data are presented for the growth of ternary oxide whiskers of 3Al2O3-2SiO2, 9Al2O3-2B2O3, and 2Al2O3B2O3 in an HC1 atmosphere. The possible mechanisms controlling the growth of these whiskers are examined.