Control of crystalline texture in polycrystalline alumina ceramics by electrophoretic deposition in a strong magnetic field

Highly crystalline-textured pure dense alumina ceramics were fabricated from spherical alumina powder without any seed particles and sintering additives by electrophoretic deposition (EPD) in a strong magnetic field of 10 T. The crystalline texture was confirmed by x-ray diffraction (XRD) for alumina ceramics deposited at 10 T followed by sintering at 1873 K. The angle between the directions of the magnetic and electric fields (φ_B-E) was altered to control the dominant crystal faces of the α-alumina monoliths. The average orientation angles estimated from the XRD diagram of the samples prepared at φ_B-E = 0°, 45°, and 90° were 16.52°, 45.15°, and 84.90°, respectively. Alumina/alumina laminar composites with different crystalline-oriented layers were also fabricated by alternately changing the φ_B-E layer by layer during EPD in a 10 T magnetic field. It was demonstrated that by using this technique, it is possible to control the crystalline orientation by changing the angle of E versus B during the EPD.