Neutron diffraction texture analysis for α-Al₂O ₃ oriented by high magnetic field and sintering

We have performed neutron diffraction experiments on highly oriented α-Al₂O₃, obtained by slip casting under a magnetic field and sintering. In order to investigate the magnetic field, B, and sintering temperature, T_sint, dependence of the degree of alignment of the orientation, we used samples treated with systematically varied B up to 12 T and T_sint up to 1600 °C. The degree of alignment of the magnetic easy axis (the hexagonal c-axis) is rapidly enhanced by sintering above 1200 °C, which is coincident with the temperature at which crystal grains start to grow. The angular distribution of the c-axis for the sample sintered at 1600 °C, obtained by ω-scan neutron diffraction profiles, is almost coincident with the probability distribution calculated for the particle size two times larger than that in the starting material. We discuss the orientation process mechanism with sintering in light of the results of this analysis.