Investigation of the Microstructure of Fine-Grained YPO4:Gd Ceramics with Xenotime Structure after Xe Irradiation

Abstract

This paper reports on the preparation of xenotime-structured ceramics using the Spark Plasma Sintering (SPS) method. Y0.95Gd0.05PO4 (YPO4:Gd) phosphates were obtained using the sol-gel method. The synthesized powders were nanodispersed and were agglomerated (the agglomerates sizes were 10–50 µm). The ceramics had a fine-grained microstructure and a high relative density (98.67 ± 0.18%). The total time of the SPS process was approximately 18 min. The sintered high-density YPO4:Gd ceramics with a xenotime structure were irradiated with 132Xe+26 ions with 167 MeV of energy and fluences in the range of 1 × 1012–3 × 1013 cm−2. Complete amorphization was not achieved even at the maximum fluence. The calculated value of the critical fluence was (9.2 ± 0.1) × 1014 cm−2. According to the results of grazing incidence X-ray diffraction (GIXRD), the volume fraction of the amorphous structure increased from 20 to 70% with increasing fluence from 1 × 1012 up to 3 × 1013 cm−2. The intensity of the 200 YPO4:Gd XRD peak reached ~80% of the initial intensity after recovery annealing (700 °C, 18 h).