Highly Texturing β‐Sialon Via Strong Magnetic Field Alignment

Abstract

This paper reports the texturing behavior of β‐sialon by strong magnetic field alignment (SMFA) during slip casting, followed by reaction pressureless sintering, using either α or β‐Si3N4, Al2O3, and AlN as the starting materials. It is found that the β‐Si3N4 crystal exhibits a substantially stronger orientation ability than the α‐Si3N4 crystal regardless of the Si3N4 raw powders in the magnetic field of 12 T. The β‐raw powder produces a highly a, b‐axis‐oriented β‐Si3N4 green body with a Lotgering orientation factor of up to 0.97. During sintering, the β‐raw powder allows the a, b‐axis‐oriented β‐sialon to retain the Lotgering orientation factor similar to and even higher than that of β‐Si3N4 in the green body. In contrast, the α‐raw powder leads to a faster transformation rate of α/β‐Si3N4 to β‐sialon but a substantially lower texture in β‐sialon. The results indicate that the use of the β‐raw powder is more efficient for producing highly textured β‐sialon via SMFA than that of the α‐raw powder as well as the prolonged sintering.