Alpha-Decay Effects in (241)~AmiDoped Gadolinium Zirconate

摘要

Sample of zirconate ceramic with a composition corresponding to formula Gd_(1.7)~(241) Amo.3Zr_2O_7 was synthesized by heat-treatment of mechanically activated and compacted in pellet oxide mixture at 1500 °C for 30 min. The (/values on XRD pattern of the sample soon after synthesis (D = 7.9xl0~(15) ot-decays/g or 0.001 dpa) demonstrated fluorite structure with the most intensive peak with rfm =3.042 A (a = 5.269 A) and very weak diffuse reflections due to (/-pyrochlore. At a dose of 7.9xl0~(17) oc-decays/g or 0.11 dpa the reflections were broadened by approximately 20% and their relative intensity slightly reduced. At higher doses all the weak superstructure reflections disappeared and the growth in intensity and narrowing of the main reflection occurred. Lattice parameters increased with the dose and reached 5.343 A (dm = 3.085 A) at a dose of 4.6x10~(18) α-decays/g or 0.42 dpa. At a dose of 5.5xl0~(18) a-decays/g or 0.78 dpa positions of reflections were shifted to lower (d-spaces (d_111i value reduced to 3.071 A) and the half-width of the major reflection was 67% of initial. For the (241)~Am-doped Gd-zirconate the structure recovery rate exceeds disordering rate and no amorphization occurred at doses higher than -0.2-0.3 dpa.