Preparation of porous Si3N4 ceramics with unidirectionally aligned channels.

We prepared porous Si 3 N 4 ceramics with highly ordered and unidirectionally aligned channels by the self-organization method using an alginate template. The obtained samples show uniform pore distribution, high cell density, good mechanical strength and hierarchical pore structure. A great number of long fibrous β-Si 3 N 4 grains protrude into channels, and other short length fibrous β-Si 3 N 4 grains interlock within channel walls forming a peculiar hierarchical pore structure. The pore size, thickness of channel walls, cell density, porosity and mechanical properties of the sintered porous Si 3 N 4 ceramics could be controlled by choosing different solid loadings, whereas β-Si 3 N 4 grains growth could be controlled by adopting different sinter temperatures. [ABSTRACT FROM AUTHOR]