Tensile Strength of Silicon Nitride Whiskers Synthesized by Reacting Amorphous Silicon Nitride and Titanium Dioxide

The tensile strength of α-Si 3 N 4 whiskers synthesized by reacting amorphous Si 3 N 4 and TiO 2 at 1490°C under a N 2 pressure of 700 torr was measured using a microbalance, and the diameter dependence of the strength was investigated. The Si 3 N 4 whiskers had diameters of 0.04 and 0.8 μm and dominant [1011] and [1010] growth directions. Chemical analysis showed that they contained Ti and O impurities. The tensile strength of six Si 3 N 4 whiskers increased from 17 to 59 GPa with decreasing whisker diameter.