Phosphate Ca1/4Sr1/4Zr2(PO4)3 of the NaZr2(PO4)3 structure type: Synthesis of a dense ceramic material and its radiation testing

• High density ceramics with NZP structure were prepared by Spark Plasma Sintering.
• Ceramic materials were irradiated in cyclotron by Xe ions with fluences 6 × 1010 to 1 × 1013 ions/cm2.
• The conditions of transformation from metamict to crystalline state have been found.

The powder of phosphate Ca1/4Sr1/4Zr2(PO4)3 was synthesized by sol–gel processes in the presence of citric acid and ethylene glycol. Ceramic samples were prepared from this powder by Spark Plasma Sintering (SPS), their relative densities were found to be 99.5 ± 0.3% after the isothermal treatment at 860 °С for 3 min.Sintered disc-shaped ceramic samples (d = 10 mm, h = 4 mm) were bombarded at 300 K by 167 MeV Xe26+ ions with fluences ranging from 6 ⋅ 1010 to 1 ⋅ 1013 ions/cm2. It was found that exposure to the highest fluence (1013 ion/cm2) led to a complete amorphization of the irradiated layer. The observed phase transition is ascribed to the formation of amorphous latent tracks via dense electronic excitations. Postradiation heat treatment revealed that the transformation from metamict to crystalline form took place after annealing at T = 200, 300, 400, 500, 600 and 800 °С and t = 3, 13, 11, 5, 17 and 15 h, respectively.