Low temperature, transient liquid phase sintering of B₂O ₃-SiO₂-doped Nd:YAG transparent ceramics

B₂O₃-SiO₂ is shown to act as a transient liquid phase sintering aid that reduces the sintering temperature of Nd:YAG ceramics to 1600 °C. 1 at.% Nd_3xY_3-3xAl ₅O₁₂ (Nd:YAG) ceramics were doped with 0.34-1.35 mol% B₂O₃-SiO₂ and sintered between 1100 and 1700 °C. Dilatometric measurements show that B₂O₃-SiO ₂ doping increases the densification rate during intermediate-stage sintering relative to SiO₂-doped samples. B³⁺ content is reduced to <5 ppm in samples heated to 1500 °C, as determined by mass spectrometry. For B₂O₃-SiO₂-doped samples, final stage densification and grain growth follow a more densifying sintering trajectory than SiO₂-doped 1 at.% Nd:YAG ceramics because there is less SiO₂ during final-stage densification. The increased densification kinetics during intermediate-stage sintering lead to highly transparent Nd:YAG ceramics when sintered at 1600 °C in either vacuum or oxygen. Thus, transparent Nd:YAG ceramics can be sintered without the need for expensive refractory metal vacuum furnaces or pressure-assisted densification.