Synthesis of the a-Axis Textured Forsterite Aggregate Using Slip Casting in a Strong Magnetic Field

Abstract:

Since crystallographic preferred orientation (CPO) is commonly observed in nature, it is important to understand how physical properties of rocks change with the development of CPO.

For this purpose, we fabricated highly dense and fine grained mineral aggregates with controlling crystal orientation.

Fine forsterite powders were prepared from high purity and fine grained reagents (<100 nm). Such powders were milled by zirconia beads under wet condition with changing milling duration and beads diameter to minimize particle size. To control the surface potential of the particles, we applied various types of polymer modification. The green compact prepared by a slip casting in a high magnetic field (12T) was sintered under vacuum condition.

The resultant materials were analyzed by X-ray powder diffraction (XRD), secondary electron microscopy (SEM) and Electron Backscatter Diffraction (EBSD). The specimen prepared without an exposure to a strong magnetic field exhibited a randomly orientated forsterite grains whereas the specimen exposed to the magnetic field exhibited strong a-axis alignmentparallel to the magnetic direction with random distributions of b and c-axes on the plane perpendicular to the magnetic direction.