This study reviews the migration behaviour of selenium in polycrystalline SiC, which acts as the main diffusion barrier in the coated fuel particles for Very High Temperature Reactors. Se ions of 200 keV were implanted into polycrystalline SiC wafers to a fluence of 1 × 10¹⁶ cm⁻² at three temperatures, which were room temperature, 350 °C and 600 °C. The implanted samples were annealed at temperatures ranging from 1000 to 1500 °C in steps of 100 °C for 10 h. The migration of implanted Se was monitored by Rutherford backscattering spectrometry (RBS) while structural and morphological changes were monitored by Raman spectroscopy and scanning electron microscopy (SEM). Implantation of Se at room temperature amorphized the near surface region of the SiC substrates, while in samples implanted above the critical amorphization temperature the crystal structure was retained with some radiation damage. Annealing at 1000 °C resulted in the recrystallization of the amorphized SiC layer. In the case of room temperature implantation, the broadening of the implanted Se profile in RBS spectra was observed to occur after annealing at 1300 °C and became significant with an increase in annealing temperature. This broadening was accompanied by a peak shift towards the surface and loss of implanted Se. No broadening was observed in samples implanted above the critical amorphization temperature, but the peak shift towards the surface began after annealing at 1300 °C in samples implanted at 350 °C and 600 °C.

这项研究综述了硒在多晶SiC中的迁移行为，这是超高温反应堆涂层燃料颗粒中的主要扩散阻挡层。将200 keV的离子注入多晶SiC晶片中，注量为1×10 ¹⁶ cm ^-2在室温，350°C和600°C的三个温度下。将植入的样品在1000至1500°C的温度范围内以100°C的步长退火10 h。通过Rutherford背散射光谱（RBS）监测注入的Se的迁移，同时通过拉曼光谱和扫描电子显微镜（SEM）监测结构和形态变化。室温下注入硒使SiC衬底的近表面区域非晶化，而在高于关键非晶化温度注入的样品中，晶体结构得以保留，并受到一定程度的辐射损伤。在1000℃下退火导致非晶SiC层的再结晶。如果是室温植入，观察到在1300°C退火后，RBS光谱中注入的Se分布变宽，并且随着退火温度的升高而变得显着。这种变宽伴随着朝向表面的峰移动和注入的Se的损失。在高于临界非晶化温度的情况下注入的样品中未观察到展宽，但是在以350°C和600°C注入的样品中在1300°C退火之后，开始向表面移动。