Effect of Nd3+ ions on porosity of SiO2-doped 0-4 at% Nd3+:Y3Al5O12 laser ceramics on different stages of reactive sintering

The evolution of the pore structure of ceramics 0-4 at% Nd3+:Y3Al5O12 at the initial and intermediate stages of sintering was studied by the nitrogen physical adsorption. It was shown that the maximum decrease in the specific surface area (by 70 divided by 83 %) and the total volume of nanopores (by 84 divided by 92 %) at the sintering temperature range of 1100-1500 degrees C is observed for systems with (Nd3+) = 1 divided by 2 at%. The nonlinear nature of the effect of neodymium on the formation of the Nd3+:Y(3)Al(5)O(12 )microstructure is established, which is explained by the presence of several competing mechanisms, the magnitude of which varies differently with the activator concentration. Differences in the pore structure and transparency of ceramics 1-4 at% Nd3+:Y3Al5O12 at the final sintering stage are shown. A possible reason for the slowdown in densification of samples with (Nd3+) >= 3 at% is a decrease in diffusion mobility in the cationic sublattice of garnet. 1.2 at% Nd3+:Y3Al5O12 laser ceramics obtained by reactive sintering at 1750 degrees C for 10 h are characterized by a residual porosity of 0.0009 and 0.0026 vol% with an average pore size of 182 and 161 nm, respectively.