SrAl2Si2O8 Ceramic Matrices for 90Sr Immobilization Obtained via Spark Plasma Sintering-Reactive Synthesis

Abstract In the present study, an original spark plasma sintering-reactive synthesis (SPS-RS) method for mineral-like ceramic materials based on SrAl2Si2O8 feldspar-like skeleton structure was used for the first time, promising solid-state matrices for reliable immobilization of high-energy 90Sr. The method is based on the “in-situ” reaction of a mixture of SrO, Al2O3 and SiO2 oxides when heated by a unipolar pulsed current under compacting pressure. The phase and elemental composition structure were studied. The dynamics of the consolidation of the reaction mixture of oxides was studied in the range of 900-1200 °C. The study found the temperature of the high-speed (minutes) SPS-RS formation of single-phase SrAl2Si2O8 composition ceramic in the absence of intermediate reaction products with a relative density of up to 99.2% and compressive strength up to 145 MPa and a strontium leaching rate of 10-4 g/cm2·day.