Radiation-induced amorphization of Ce-doped Mg2Y8(SiO4)6O2 silicate apatite

Abstract

Ce-doped Mg 2 Y 8 (SiO 4) 6 O 2 silicate apatite (Ce=0.05 and 0.5) were irradiated with 1 MeV Kr 2+ ion beam irradiation at different temperatures and their radiation response and the cation composition dependence of the radiation-induced amorphization were studied by in situ TEM. The two Ce-doped Mg 2 Y 8 (SiO 4) 6 O 2 silicate apatites are sensitive to ion beam induced amorphization with a low critical dose (0.096 dpa) at room temperature, and exhibits significantly different radiation tolerance at elevated temperatures. Ce concentration at the apatite A I site plays a critical role in determining the radiation response of this silicate apatite, in which the Ce 3+ rich Mg 2 Y 7.5 Ce 0.5 (SiO 4) 6 O 2 displays lower amorphization susceptibility than Mg 2 Y 7.95 Ce 0.05 (SiO 4) 6 O 2 with a lower Ce 3+ occupancy at the A I sites. The critical temperature (T c) and activation energy (E a) change from 667.5±33 K and 0.162 eV of Mg 2 Y 7.5 Ce 0.5 (SiO 4) 6 O 2 to 963.6±64 K and 0.206 eV of Mg 2 Y 7.95 Ce 0.05 (SiO 4) 6 O 2. We demonstrate that the radiation tolerance can be controlled by varying the chemical composition, and enhanced radiation tolerance is achieved by increasing the Ce concentration at the A I site.

Synthesis and in situ ion irradiation of A-site deficient zirconate perovskite ceramics

“…T c is dened as the temperature at which the rate of damage induced equals the rate of recovery from damage under specic irradiation conditions. As previously implemented by various groups, 37,62,63,[67][68][69][70][71][72][73][74][75][76] values of T c were calculated using a nonlinear least squares renement of eqn (1) using several models that can be accessed elsewhere. 77,78…”

Crystal Chemical Substitution at Ca and La Sites in CaLa4(SiO4)3O To Design the Composition Ca1–xMxLa4-xREx(SiO4)3O for Nuclear Waste Immobilization and Its Influence on the Thermal Expansion Behavior

“…Considering the ionic substitution in silicate oxyapatites, a wide variety of rare earth substitutions have been reported. 10,11 In particular, actinides such as U-, Pu-, and Hf-incorporated silicate oxyapatites have been developed to study the extent of radiation damage. 12 As mentioned, the thermal stability of the crystalline host is one of the important factors to be considered in the design of the wasteform composition, as it would encounter heat generated in situ, either by self-heating due to the decay heat of the fission products immobilized in the structural framework 13 or from external factors in which a temperature rise might likely occur under repository conditions.…”

“…Tolerance to a wide range of ionic substitutions leads to extensive compositional variation; therefore, numerous reports on various types of apatite compounds such as hydroxyapatite (HA), fluorapatite (FA), chlorapatite (ClA), and oxyapatite (OA) having phosphate, silicate, vanadate, and arsenate moieties as interconnecting tetrahedra are available. , Oxyapatites have been increasingly studied for various properties. Considering the ionic substitution in silicate oxyapatites, a wide variety of rare earth substitutions have been reported. , In particular, actinides such as U-, Pu-, and Hf-incorporated silicate oxyapatites have been developed to study the extent of radiation damage …”