Production of Si3N4 Whiskers in Solid Mixtures through Vapor-Solid Mechanism Using 2MgO 2Al2O3 5SiO2 as Sintering Additives
The production of silicon nitride whiskers in solid mixtures under nitrogen-containing atmospheres was investigated. Green bodies made of micron and nano silicon nitride powders with 2MgO×2Al2O3×5SiO2 as sintering additive were sintered at 1500~1560oC in flowing nitrogen-containing atmospheres. Resultantly whisker-like products were formed on the cold side of the graphite boat. X-ray diffraction analysis indicated that the formed whisker were α–Si3N4. The products were analyzed by transmission electron microscope. The morphologies of the resulting whisker were varied with sintering temperatures and atmospheres. Dislocation structures were observed on the edge of some whiskers. This suggested that the whisker growth proceeded through a vapor-solid (VS) mechanism. The mechanism of whiskers growth at different temperatures and atmospheres was discussed with a thermodynamic calculation based on a database software.
Wei Pan, Jianghong Gong, Chang-Chun Ge and Jing-Feng Li
W. Guo et al., "Production of Si3N4 Whiskers in Solid Mixtures through Vapor-Solid Mechanism Using 2MgO 2Al2O3 5SiO2 as Sintering Additives", Key Engineering Materials, Vols. 280-283, pp. 1227-1230, 2005