EUROFER is a Reduced Activation Ferritic Martensitic (RAFM) steel developed as structural material for future fusion power plants and is considered as first-wall material in recessed areas of DEMO. Recent work has shown a fluence-dependent decrease of the sputter yield for bombardment with deuterium ions in the energy range of 100 to about 500 eV. This decrease was previously attributed to preferential sputtering of the lower mass constituents in EUROFER, such as Fe and Cr, compared to the higher mass alloying elements. This leads to an increase of the surface tungsten concentration. However, it was also observed that, after sputtering, the samples had developed a very rough surface morphology. In this work, the combined influence of surface roughness and W surface enrichment on the sputter yield of EUROFER under bombardment with 200 eV deuterium ions was studied. The influence of surface roughness was determined with the aid of Scanning Electron Microscopy (SEM) and SDTrimSP-3D simulations. W surface enrichment was investigated applying sputter X-Ray Photoelectron Spectroscopy (XPS) depth-profiling and Rutherford backscattering spectrometry (RBS). After bombardment to a fluence of 10²⁴ D m⁻² (at 200 eV per deuterium) a reduction of the sputter yield to 29% ± 5% of the initial value was measured by weight-loss measurements. This reduction is in good agreement with published values. Two distinct surface morphologies, consisting of smooth and spiked surfaces, were observed on the EUROFER sample after sputtering. Based on the experimental results, the combined effect of the two factors, surface roughness and W surface enrichment, is estimated to be responsible for a reduction in the sputter yield to 27% ± 4% of the initial value, which is in excellent agreement with the measured value. Our assessment shows that both surface morphology and W surface enrichment contribute significantly to the reduction of the sputter yield of EUROFER under the given experimental conditions, and are sufficient to fully explain the experimentally observed reduction in the sputter yield.

EUROFER是一种还原活化铁素体马氏体（RAFM）钢，被开发为未来聚变电站的结构材料，被认为是DEMO凹陷区域的第一壁材料。最近的工作表明，在能量范围为100至约500 eV的氘离子轰击下，溅射产量的取决于通量的下降。这种降低以前是由于与较高质量的合金元素相比，EUROFER中较低质量的成分（如铁和铬）的优先溅射。这导致表面钨浓度的增加。然而，还观察到，在溅射之后，样品已形成非常粗糙的表面形态。在这项工作中 研究了在200 eV氘离子轰击下，表面粗糙度和W表面富集对EUROFER溅射产量的综合影响。表面粗糙度的影响借助扫描电子显微镜（SEM）和SDTrimSP-3D模拟确定。使用溅射X射线光电子能谱（XPS）深度分析和卢瑟福背散射光谱（RBS）研究了W表面富集。轰炸后的通量为10²⁴ 毫米^-2（每氘200 eV）通过减重测量将溅射产率降低至初始值的29％±5％。减少量与公布的值高度吻合。溅射后在EUROFER样品上观察到两种不同的表面形态，包括光滑的表面和尖刺的表面。根据实验结果，估计表面粗糙度和W表面富集这两个因素的综合作用可将溅射率降低至初始值的27％±4％，这与测量值。我们的评估表明，在给定的实验条件下，表面形态和W表面富集都可显着降低EUROFER的溅射产量，