Investigation of the Vacuum Sintering Kinetics of the Optical Luminescent Ceramic Y3–xScxAl5O12:Cr

The intent of this work is to investigate the influence of scandium occupying dodecahedral and octahedral positions of the garnet crystal lattice on the aspects of vacuum sintering of the optical ceramic Y_3–xSc_xAl_2–ySc_yAl₃O₁₂:Cr as well as on its optical and luminescent properties. As part of this investigation, YSAG:Cr optical luminescent ceramic was produced for the first time from ceramic powders of metastable compositions with a high content of scandium in the dodecahedral position. The compositions considered were described by the general formula Y_3–xSc_xAl_2–ySc_yAl₃O₁₂, where 0.12 ≤ x ≤ 1.50 and 0.08 ≤ y ≤ 1.00 p.u. [physical units] with total scandium content 0.12 – 1.70 p.u. The following investigations of YSAG:Cr ceramic samples were conducted: x-ray diffractometry, measurement of the shrinkage kinetics of ceramic compacts using dilatometry, and investigation of the morphology and elemental composition of the ceramic surface by means of scanning electron microscopy. The spectra of light transmission and luminescence were measured. It was shown that ceramic made from compositions with scandium content predominating in the dodecahedral positions reach maximum density at lower temperatures compared to compositions containing a larger amount of scandium in the octahedral positions. It was found that as the sintering temperature of YSAG:Cr ceramic increases, compositions with a high content of scandium in the dodecahedral position become unstable.