Study on fabrication of highly textured ceramics by colloidal processing in a strong magnetic field

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We intend to systematically clarify the requirement for fabricating highly textured ceramics through colloidal processing in a strong magnetic field. The following points were examined in details ; (1) highly dispersion of fine particles, (2) in-situ observation and theoretical consideration of particle alignment in a strong magnetic field, and (3) effect of particle shape and size on the degree and direction of orientation. We examined Al_2O_3 and TiO_2 as ceramics where the magnetic susceptibility of c-axis is larger than that of a,b-axis, and Si_3N_4 and HAP where the magnetic susceptibility of ab-axis is larger than that of c-axis. To obtain one-directional alignment the direction of applied magnetic field and/or rotation magnetic field is very important. Furthermore we succeeded to fabricate textured MAX phase ceramics such as Nb_4AlC_3 and Ti_3SiC_2. Especially textured Nb_4AlC_3 shows highest bending strength and fracture toughness among reported ones in ceramics.