In this study, a novel and interesting method to grow β-Si3N4 whiskers was developed using thermal decomposition of Si3N4 and large pores introduced intentionally during liquid phase sintering. The pore size, pore vol%, pore morphology and nitrogen pressure were chosen as experimental variables to find proper conditions for growing whiskers. In this experiment, commercial α-Si3N4, Al2O3 and Y2O3 were selected as starting materials, and polymer beads with average diameters of 100 and 200 μm were used as pore formers to make intentional pores in the sintered sample. A polyvinyl film was also used to make a film type of pore. β-Si3N4 whiskers grew well on the inside of pores in the case of a low vol% of pores, 14 and 27 vol% or closed pores of a film shape, but not for a high vol% of pore, 39 and 50 vol% or open pores of a film shape. The variation of pore size, pore morphology and nitrogen pressure did not have any influence on whisker growth.

Keywords: Si3N4 whiskers, Thermal decomposition, Sintering, Open pores, Closed pores.