Fabrication translucent AlN ceramic under the strong magnetic field

The translucent aluminum nitride (AlN) ceramic was fabricated by pressureless-sintering at 1800 °C for 24 h in the flowing nitrogen atmosphere. The pore and different grains size of the sample was eliminated using CaF2 as the sintering additive. The total transmittance of the sample with 2 wt% CaF2 is enhanced 52.51% at 800 nm, which is 55% higher than that of AlN without CaF2. The grain orientation of the samples was adjusted by the slipping casting under the strong magnetic field. The a, b-axes of AlN are arranged from parallel to the direction of the magnetic field, and the c axis is arranged from perpendicular to the direction of the magnetic field due to magnetic susceptibility anisotropic of the grain. The birefringence phenomenon is reduced by the arrangement of the grains to a certain direction. The Lotgering factor and total transmittance of the texture AlN ceramic fabricated under the 9 T magnetic are up to 73.21% and 63.12% at 800 nm, respectively.