A Novel Hot Pressing Flowing Sintering for Preparation of Texturing Ceramics

In this paper, we proposed a novel hot-pressing flowing sintering (HPFS) for texturing ceramics. The perfectly two-dimensional textured Si3N4 ceramics were fabricated by HPFS. The Lotgering orientation factor f(L) for Si3N4 texture was 0.9975. During earlier sintering stage, the specimen flowed along the plane which perpendicular to the hot-pressing direction under pressure, through the controlling of the graphite die movement. The rod-like beta-Si3N4 nuclei was easily to texture during the flowing process, due to the small size of the beta-Si3N4 nuclei and the high porosity of the flowing specimen. As a result, the perfectly two-dimensional textured Si3N4 was obtained. After aligned, the beta-Si3N4 grains grew along the materials flowing direction with little constraint, which accelerated the growth of the grains extensively. So, in addition to texture, the Si3N4 ceramics by HPFS also showed high aspect ratio. The present study indicated that the HPFS would be more simple and low-cost method for texture of Si3N4, compared with conventional hot-forging which contained the sintering and forging.