Effects of Helium Implantation and Subsequent Electron Irradiation on Microstructures of Fe-11 wt.% Cr Model Alloy

Helium effects on dislocation and cavity formation of Fe-11 wt.% Cr model alloy are investigated. Single-beam(electron) and dual-beam(He~+/e~-) irradiations are performed at 350℃ and 400℃ using an ultra-high voltage electron microscope combined with ion accelerators. In-situ observation shows that the growth rate of dislocation loops is reduced in the helium pre-injected specimen. The mean size of cavities decreased in the helium preinjected specimen. The possible mechanisms are discussed.     

快重离子辐照引起Ni/SiO2界面原子混合及相变研究

在室温下用308 MeV的Xe离子和853 MeV的Pb离子辐照Ni/SiO2样品, 用卢瑟福背散射和X射线衍射技术对样品进行了分析。 通过分析Ni/SiO2样品中元素成分分布和结构随离子辐照剂量和电子能损的变化, 探索了离子辐照在Ni/SiO2样品中引起的界面原子混合与结构相变现象。 实验结果显示, Xe和Pb离子辐照均能引起明显的Ni原子向SiO2基体的扩散并导致界面附近Ni, Si和O原子的混合。 实验观测到低剂量Xe离子辐照可产生NiSi2相, 而高剂量Xe离子辐照则导致了Ni3Si和NiO相的形成。 根据热峰模型, Ni原子的扩散和新相的形成可能由沿离子入射路径强电子激发引起的瞬间热峰过程驱动。Ni/SiO2 interface were irradiated at room temperature with 308 MeV Xe ions to 1×1012, 5×1012 Xe/cm2 and 853 MeV Pb ions to 5×1011 Pb/cm2, respectively. These samples were analyzed using Rutherford Backscattering Spectrometry (RBS) and X ray diffraction spectroscopy (XRD), from which the intermixing and phase change were investigated. The obtained results show that both Xe and Pb ions could induce diffusion of Ni atoms to SiO2 substrates and result in intermixing of Ni with SiO2. Furthermore, 1.0×1012 Xe/cm2 irradiation induced the formation of NiSi2 and 5.0×1012 Xe/cm2 irradiation created Ni3Si and NiO phases. The diffusion of Ni atoms and the formation of new phase may be driven by a transient thermal spike process induced by the intense electronic energy loss along the incident ion path.     

电子辐照改性PAN/PEO基体凝胶电解质对染料敏化太阳电池性能的提高

采用电子束（EB）对聚丙烯腈/聚氧化乙烯（PAN/PEO）凝胶电解质进行了剂量为13～260 kGy的辐照, 并对辐照改性的电解质组装的染料敏化太阳电池(DSSC)进行了性能测量。 结果表明, 改性后的DSSC的光电转化效率比改性前的高; 并且随EB辐照剂量的增加, DSSC效率先迅速增加(0～65 kGy), 然后缓慢减小(65～130 kGy)直至趋于一个平衡值(130～260 kGy)。 提升DSSC效率的最佳辐照剂量为65 kGy, 此时效率提高了约36%。 对比DSSC短路电流、 开路电压和填充因子随辐照剂量的变化, 发现DSSC效率的提高主要是由短路电流的提高引起的。 测量表明, 辐照改性后的DSSC时间稳定性得到了改善, 并且辐照剂量越高, 稳定性的改善越明显。 In this work, PAN/PEO (polyacrylonitrile/polyethylene oxide) based gel electrolyte was irradiated by electron beam (EB) with dose from 13 to 260 kGy. Then, DSSC (dye sensitized solar cell) was fabricated by the irradiated electrolyte and characterized. The results show that the efficiency of the DSSC fabricated by irradiated electrolyte is promoted comparing with DSSC fabricated by un irradiated electrolyte. And with irradiation dose increasing, the DSSC efficiency increases rapidly at first (0～65 kGy), then, drops down slowly (65～130 kGy), finally trends to a stable value (130～260 kGy). It indicates that there is an optimal irradiation dose, at which the promotion of DSSC efficiency is the highest, approximate 36%. Observed from the change of short circuit current, open circuit voltage and fill factor, short circuit current promotion by EB irradiation is found to be the main reason of DSSC performance promotion. The time stability measurement of the DSSC indicates that EB irradiation on PAN/PEO electrolyte reduces the loss of efficiency and the limiting effects become more apparent as the irradiation dose increases.     

94MeV Xe离子辐照引起的薄膜硅光学带隙变化研究

室温下,用94MeV的Xe离子辐照纳米晶和非晶硅薄膜以及单晶硅样品,辐照量分别为1.0×1011,1.0×1012和1.0×1013ions/cm2。所有样品均在室温下用UV/VIS/NIR光谱仪进行检测分析。通过对比研究了纳米晶、非晶、单晶硅样品的光学带隙随Xe离子辐照量的变化。结果表明,不同结构的硅材料中Xe离子辐照引起的光学带隙变化规律差异显著:随着Xe离子辐照量的增加,单晶硅的光学带隙基本不变,非晶硅薄膜的光学带隙由初始的约1.78eV逐渐减小到约1.54eV,而纳米晶硅薄膜的光学带隙则由初始的约1.50eV快速增大至约1.81eV,然后再减小至约1.67eV。对硅材料结构影响辐照效应的机理进行了初步探讨。     

基于HIRFL 的高温应力材料载能离子辐照实验装置

针对未来先进核能装置候选结构材料在高温和应力等条件下抗辐照性能的评价与快速筛选的需求,基于兰州重离子研究装置( HIRFL ) 可提供的离子束流条件,设计制作了国内第一套高温应力材料载能离子辐照装置。该装置由束流扫描及探测系统、高温系统、应力系统、真空冷却系统和远程控制系统等5 部分组成,可以同时提供高温和拉/ 压应力下材料的离子束均匀辐照件,温区覆盖了室温至1 200 °C范围,拉/ 压应力范围为0 ~1176 N,x-y 方向均匀扫描面积可大于40 mmx40 mm。利用该装置,已经成功进行了多次高温和应力条件下载能离子辐照先进核能装置候选材料的实验研究,并取得了初步成果。In order to expedite the evaluation of properties of irradiated materials and the selection of candidate materials for future nuclear energy systems, we developed a specific ion irradiation equipment installed on the Heavy Ion Research Facility of Lanzhou ( HIRFL ) for materials under high temperature and stress. This equipment consists of ion beam scanning and detector system, high temperature load system, stress load system, water cooling system as well as telecommunication and control system. It can supply a wide range of temperature (from room temperature to 1 200 °C ) and stress ( pull / push from 0 to 1 176 N) simultaneously for materials under ion irradiation. The x-y scanning area with high uniformity is larger than 40 mm40 mm. This is the first suit of ion irradiation equipment made in China that can be used to study co-operating effects of high temperature and stress in an irradiated material. It has been successfully used several times for materials irradiations under high temperatures and stress, which proved that the new equipment has very good performances in experiments.     

T91钢和SIMP钢表面AlOx涂层在600℃静态液态铅铋共晶中的稳定性和腐蚀行为

铁素体/马氏体钢,如T91钢和SIMP钢,被选为第4代铅冷快堆和加速器驱动系统(ADS)的主要候选结构材料.但容器钢与液态铅铋共晶(LBE)在高温下的相容性限制了它们的应用.铁素体/马氏体钢在600℃的LBE中腐蚀严重.为了保护铁素体/马氏体钢免受高温LBE腐蚀,在钢表面制备AlO_x (x <1.5)涂层.本文采用磁控溅射法在T91钢和SIMP钢表面制备了AlO_x涂层.对表面有涂层的T91钢和SIMP钢以及表面无涂层的T91钢和SIMP钢在600℃的饱和氧浓度的LBE中腐蚀300 h和700 h的结果进行比较.结果表明,涂层钢表面的氧化层比无涂层钢表面的氧化层薄,这表明AlO_x涂层可以有效防止铁、铬和氧元素的快速扩散.然而,在LBE中腐蚀700 h后, AlO_x涂层出现裂纹,表面有涂层的T91钢和SIMP钢均遭受到明显的氧化腐蚀,说明该涂层在600℃的LBE中可以在短时间内保护基体免受高温腐蚀.但是涂层在600℃的LBE中不能长时间保持稳定.这可能是由于此次实验条件制备的AlO_x     

250 keV He+ 离子注入钽酸锂改性研究

室温下,将能量为250 keV He+ 离子注入z 切钽酸锂单晶,注量范围5.0x1014~5.0x1016 He+/cm2,应用三维轮廓仪、X射线衍射(XRD)、紫外可见(UV-Vis ) 光学吸收谱对未注入和注入样品进行了表征和分析。分析结果表明,在注量达到5.0x1016He+/cm2 时,样品表面出现大量凸起条纹,同时晶格沿着[001] 方向出现明显肿胀,吸收边则表现出明显的注量相关性。注入样品在空气中放置60 d后,最高注量的样品表面原来凸起的条纹变为细长的裂纹,晶格应变及光学吸收边均出现较大的恢复。讨论了样品表面形貌、晶格应变和光学吸收边与He 行为的关系。The effects of 250 keV He + implantation in the fluence from 5.0x1014 to 5.0x1016 He+/cm2 on lithium tantalate at room temperature were investigated by 3D surface profiler, XRD and UV-Vis optical absorption spectroscopies.The experimental results show that a large number of raised stripes appear on the surface of the sample and the significant lattice swelling occurs along the direction [ 001 ] at the fluence of 5.0x1016 He+/cm2. The dependence of changes absorption edge on the fluences was revealed. After the samples had been exposed to the air for 60 days, the raised stripes on the surface have evolved into narrow cracks. Furthermore, the lattice strain and the optical absorption edge has also recovered dramatically. The relationship between surface morphology, lattice strain, optical absorption edge and behaviorof He-ions was discussed.     

Investigation of PL properties of C-doped SiO2/Si samples after high energy Pb ion irradiation

Amorphous SiO₂ thin films with about 400—500 nm in thickness were thermally grown on single crystalline silicon. These SiO₂/Si samples were firstly implanted at room temperature (RT) with 100 keV carbon ions to 2.0×10¹⁷, 5.0×10¹⁷ or 1.2×10¹⁸ ions/cm², then irradiated at RT by 853 MeV Pb ions to 5.0×10¹¹, 1.0×10¹², 2.0×10¹² or 5.0×10¹² ions/cm², respectively. The variation of photoluminescence (PL) properties of these samples was analyzed at RT using a fluorescent spectroscopy. The obtained results showed that Pb-ion irradiations led to significant changes of the PL properties of the carbon ion implanted SiO₂ films. For examples, 5.0×10¹² Pb-ions/cm² irradiation produced huge blue and green light-emitters in 2.0×10¹⁷ C-ions/cm² implanted samples, which resulted in the appearance of two intense PL peaks at about 2.64 and 2.19 eV. For 5.0×10¹⁷ carbon-ions/cm² implanted samples, 2.0×10¹² Pb-ions/cm² irradiation could induce the formation of a strong and wide violet band at about 2.90 eV, whereas 5.0×10¹² Pb-ions/cm² irradiation could create double peaks of light emissions at about 2.23 and 2.83 eV. There is no observable PL peak in the 1.2×10¹⁸ carbon-ions/cm² implanted samples whether it was irradiated with Pb ions or not. All these results implied that special light emitters could be achieved by using proper ion implantation and irradiation conditions, and it will be very useful for the synthesis of new type of SiO₂-based light-emission materials.     

Modification of Fe/Cu multilayers under 400 keV Xe20+ irradiation

Two kinds of Fe/Cu multilayers with different modulation wavelength were deposited on cleaved Si(100) substrates and then irradiated at room temperature using 400 keV Xe²⁰⁺ in a wide range of irradiation fluences. As a comparison, thermal annealing at 300—900℃ was also carried out in vacuum. Then the samples were analyzed by XRD and the evolution of crystallite structures induced by irradiation was investigated. The obtained XRD patterns showed that, with increase of the irradiation fluence, the peaks of Fe became weaker, the peaks related to Cu-based fcc solid solution and Fe-based bcc solid solution phase became visible and the former became strong gradually. This implied that the intermixing at the Fe/Cu interface induced by ion irradiation resulted in the formation of the new phases which could not be achieved by thermal annealing. The possible intermixing mechanism of Fe/Cu multilayers induced by energetic ion irradiation was briefly discussed.     

Fe/Nb多层膜中离子辐照效应研究(英文)

〗采用磁控溅射技术在Si衬底上沉积Si/\[Fe(10 nm)/Nb(4 nm)/Fe(4 nm)/Nb(4 nm)\]2/ \[Fe(4 nm)/Nb(4 nm)\]4多层膜。 用2 MeV的 Xe离子在室温下辐照多层膜。采用俄歇深度剖析、X射线衍射和振动样品磁强计分析辐照引起的多层膜元素分布、 结构及磁性变化。AES深度剖析谱显示当辐照注量达到1.0×1014 ions/cm2时, 多层膜界面两侧元素开始混合; 当辐照注量达到2.0×1016ions/cm2时, 多层膜层状结构消失, Fe层与Nb层几乎完全混合。XRD谱显示, 当辐照注量达到1.0×1014ions/cm2时, Nb的衍射峰和Fe的各衍射峰的峰位相对于标准卡片向小角方向偏移, 这说明辐照引起Nb基和Fe基FeNb固溶体相的形成;当辐照注量大于1.0×1015 ions/cm2时, 辐照引起非晶相的出现。 VSM测试显示,多层膜的磁性随着结构的变化而变化。 在此实验基础上, 对离子辐照引起界面混合现象的机理进行了探讨。The behavior of the metallic multilayers of Si/\[Fe(10 nm)/Nb(4 nm)/Fe(4 nm)/ Nb(4 nm)\]2/\[Fe(4 nm)/Nb(4 nm)\]4 under 2 MeV Xe ion irradiation has been investigated by depth profile analysis of Auger electron spectroscopy,X ray diffraction and vibrating sample magnetometer. The obtained experimental results show that the inter mixing between Fe and Nb layers occurs in the 1.0×1014 ions/cm2 irradiated multilayer sample which results in the formation of Nb based and Fe based FeNb solid solution. For the samples irradiated to fluence larger than 1.0×1014 ions/cm2, amorphisation is observed, and moreover, the layered structure of the multilayer samples is broken up completely for the samples under 1.0×1016 or 2.0×1016 ions/cm2 irradiation. Vibrating sample magnetometer measurement also reveals that the magnetization of the samples changes with the evolution of the structure of multilayers. Possible mechanism of the modification in Fe/Nb multilayers induced by Xe ion irradiation is briefly discussed.