Aqueous suspensions of three types of different diameter of alpha-Si3N4 particles with sintering additives were prepared and consolidated by slip casting in 10T. They were sintered in N2 atmosphere at temperatures of 1500-1700℃. The usefulness of the processes has been confirmed through the orientation index evaluated by X-ray diffraction patterns and scanning electron microscope (SEM) images of Si3N4 crystals. The crystal a,b-axis of beta-Si3N4 grains aligned to the magnetic direction. It is also confirmed that the crystalline orientation was improved by addition of -Si3N4 whisker.