Kr2+辐照导致的Ca8LnNa(PO4)6F2(Ln=La,Nd和Sm)磷灰石结构陶瓷材料的非晶转变

采用传统固相烧结法成功制备出磷灰石结构材料Ca₈LnNa（PO₄）₆F₂（Ln=La，Nd和Sm），并通过常规X射线衍射（X-ray diffraction，XRD）进行表征确定三种样品都为单一相。在室温条件下用800 keVKr2+对三种样品进行辐照实验，辐照后的样品利用掠入射X射线衍射（grazing incidence X-ray diffraction，GIXRD）进行表征获取其表面辐照损伤层的结构信息。发现在实验辐照剂量范围内（1.0×1014~7.0×1014cm-2）三种样品都发生了从晶体结构到非晶结构的转变，不过三种样品的抗辐照非晶性能却有差异，抗辐照非晶能力大小关系是Ca₈LaNa（PO₄）₆F₂ > Ca₈NdNa（PO₄）₆F₂ > Ca₈SmNa（PO₄）₆F₂。这是由于在Ca₈LnNa（PO₄）₆F₂中，当镧系核素半径越小时，将有更大概率占据Ca（2）位置与F形成比Ca-F更弱的离子键。因此，镧系核素半径越小，辐照下将有更多的点缺陷保留下来，更容易发生非晶相变。

Amorphization of Ca8LnNa(PO4)6F2(Ln=La,Nd and Sm) Apatite Ceramics Induced by Kr Ion Irradiation

The apatite structure material Ca₈LnNa(PO₄)₆F₂(Ln=La, Nd and Sm) were successfully synthesized by the solid state reaction method, and the single phase was confirmed by normal X-ray diffraction(XRD). Three kinds of samples were irradiated with 800 keV Kr2+ at room temperature, then the irradiated samples were characterized by grazing incidence X-ray diffraction(GIXRD) to identify the structures of irradiation layer. Crystalline to amorphization phase transition was observed in these three kinds of samples within the irradiation dose (1.0×1014~7.0×1014 cm-2). However, the abilities to resist amorphization of the three samples are different, the relationship of the ability to resist amorphization is Ca₈LaNa(PO₄)₆F₂ > Ca₈NdNa(PO₄)₆F₂ > Ca₈SmNa(PO₄)₆F₂. The ion radius of the lanthanide nuclides in Ca₈LnNa(PO₄)₆F₂ are more smaller, more lanthanide nuclides will occupy the Ca(2) positions and form ionic bonds with F. Meanwhile, the ionic bonding between lanthanide nuclides and Ca are weaker than Ca-F. Therefore, the ion radius of the lanthanide nuclides are more smaller, the more point defects will remain under irradiation, and the crystalline to amorphous phase transition is more likely to occur.