Reactive SPS of Nd3+:YAG transparent ceramics with LiF sintering additive

1 at% Nd3+:YAG transparent ceramics were obtained for the first time by reactive spark plasma sintering using LiF sintering additive. The effect of the dwell sintering time on the phase composition, microstructure, and transparency of the material obtained at 1475 °C and an external pressure of 60 MPa was studied. It is shown that positive densification dynamics characterize Nd3+:YAG ceramics over the entire sintering (30–60 min). The increase in the isothermal exposure is accompanied by an increase in the average grain size from 8.7 to 12.9 μm and the optical transmission in the visible wavelength range from 48.1 to 71.5%. At the same time, a more balanced structural-phase state of the ceramics is achieved due to the removal of vacancies and a decrease in the contribution of microstresses along the grain boundaries during the evaporation of carbon- and Li-, F-contained components. LiF-doped 1 at% Nd3+:YAG ceramics obtained at 1475 °C/60 min/60 MPa are characterized by average grain size of 12.9 μm, Vickers hardness of 1300 HV, linear optical transmittance 71.5% at λ = 1064 nm, and a residual porosity of 0.001 vol% with an average section pore size of 122 nm.