β-Si3N4 whiskers prepared by heating a mixture of B2O3 and α-Si3N4

Heating a mixture of α-Si3N4 and B2O3 at 2150 °C for 1 min under N2 at a pressure of 0.85 MPa was found to generate β-Si3N4 plate whiskers with widths of ∼10 µm, thicknesses of ∼0.2 µm and lengths greater than 2 mm. Boron nitride powder, β-Si3N4 platelet grains and a small amount of α-SiC grains were also obtained. Single crystal X-ray diffraction demonstrated that the whiskers were elongated in the c-axis direction and additional tests indicated elastic deformation of the whiskers.