共查询到20条相似文献,搜索用时 203 毫秒
1.
研究了碳在铀表面注入、梯度注入、反冲注入及离子束辅助沉积改性工艺。采用俄歇电子谱仪(AES)分析碳改性层沿深度方向的成分分布;采用X射线衍射仪(XRD)分析改性层的结构;通过动电位极化曲线、极限湿热腐蚀实验,比较腐蚀前后样品表面的形貌变化,对改性层抗腐蚀机理进行探索。研究结果表明:几种改性工艺均实现了碳离子在铀表面的注入或沉积,碳离子注入可在铀的表面形成碳化铀;45keV能量辅助轰击沉积碳、50keV能量及梯度能量碳离子注入改性层的抗腐蚀性能较优,先离子溅射沉积再碳离子辅助沉积形成的改性层的抗腐蚀性能最差。改性层腐蚀以点蚀为主,样品的腐蚀呈现在腐蚀点向基体和周围扩展,改性层致密无缺陷的区域则未发生腐蚀。 相似文献
2.
能量为0.6MeV/C荷能碳团簇离子Cn^ (n=2-5)注入到NaCl单晶,利用TRIM程序对碳团簇在NaCl单晶中的射程进行模拟,碳团簇NaCl单晶内存在一定长度的“团簇区域”。光学吸收谱表明:由于团簇区域的存在,不同碳离子团簇辐照产生的缺陷种类浓度都有很大不同,较大团簇会产生V2和V3色心,色心浓度也较大。 相似文献
3.
采用高能氧离子注入同成分铌酸锂(LN)晶体中制备离子注入光波导,对制备的光波导进行(200°C–500°C)不同温度的退火处理。采用常规光谱法对退火后的光波导进行光吸收谱研究。研究发现,氧离子注入后会使LN晶体中的锂离子发生缺失,进一步偏离化学剂量比;随氧离子注入剂量的增加,锂离子缺失的现象会加重。研究还发现离子注入后样品的吸收强度增加,注入剂量增大,其光吸收强度也提高,说明经离子注入后产生的色心点缺陷数目随注入剂量而增加。研究表明,主要的吸收色心缺陷有氧空位、激化子、间隙原子缺陷及反位Nb离子捕获电子等缺陷,由于这些色心缺陷的共同作用,导致了氧离子注入LN晶体的光吸收强度的加强。在实验的退火温度范围内,这些色心缺陷消除程度不显著,在LN晶体采用氧离子注入形成的光波导具有优良的温度稳定性。 相似文献
4.
5.
6.
通过在GIC4117串列加速器前注入器加装注入靶架以及扫描系统,建立了低能负离子注入平台,实现具有"Charge-up free"优点的负离子以及团簇负离子的注入,从而进行了碳及碳团簇负离子注入硅橡胶细胞相容性研究。水接触角测量表明,随着注入剂量增大到3×1015 cm-2,材料表面的水接触角从108.7°减小到103.1°,表面亲水性得到改善。XPS测试表明,随着注入剂量的增加,样品中碳含量逐渐减小,而氧和氮含量逐渐增加。基于上述结果对负离子注入硅橡胶细胞相容性改善的机制进行了讨论,最后在样品上进行了细胞培养实验。结果表明,负离子注入法是一种简单、有效提升硅橡胶细胞相容性的方法。 相似文献
7.
提高铀抗氢化性能的碳氧离子组合注入 总被引:2,自引:0,他引:2
利用离子注入方法,将CO2气体离解后的离子,在不同能量、束流下注入贫铀表面.利用俄歇能谱仪(AES)分析改性层中元素的浓度分布,用低角度X射线衍射仪(GAXRD)分析离子注入层的结构.在t=100℃、p=0.2 MPa条件下,利用铀-氢气体反应测试离子注入C、O后贫铀的铀氢反应孕育期,用扫描电镜(SEM)观察试样氢化反应前后的表面形貌.结果表明注入C、O离子后,形成了结构致密的改性层.在35 kV/8~9 mA/3 h(注入能量/注入束流/注入时间)注入条件下,改性层由UO2和石墨C组成;在65 kV/8~9 mA/3 h和3 kV/80 mA/3 h注入条件下,改性层为UO2和少量UC.UO)2和UC为低氢渗透材料,抑制了氢向基体界面的迁移和渗透,从而降低了氢化物在界面形核和长大的几率,增强了铀抗氢化性能.氢化反应后,空白贫铀试样表面出现较多的蚀坑,并造成大面积脱落,而注入样品的表面仅出现较少孤立的蚀点. 相似文献
8.
9.
硅离子注入聚合物摩擦特性研究 总被引:1,自引:0,他引:1
采用金属蒸汽真空弧(MEVVA)离子注入机引出的Si离子进行了聚酯薄膜(PET)改性研究,注入后的聚酯膜表面结构发生了很大的变化。用透射电子显微镜观察了注入聚酯膜的横截面,结果表明,在注入层形成颗粒的沉积。红外吸收测量揭示这些颗粒为SiC和富集的碳颗粒。这些颗粒增强了注入层表面强化效果。用纳米硬度计测量显示,Si离子注入可明显地提高聚酯膜表面硬度和杨氏模量,从而极大地的增强了表面抗磨损特性。最后讨论了Si离子注入聚酯膜改善特性的机理。 相似文献
10.
11.
12.
13.
N. J. Sack M. Akbulut T. E. Madey 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》1994,90(1-4):451-455
In studies of desorption induced by electronic transitions (DIET) such as electron or photon stimulated desorption, it is important to know whether the desorbing species originate solely from the outermost surface layer, or also from layers beneath the surface. In order to gain better understanding of the charge transfer, elastic scattering, and other inelastic processes involved in this issue, we are currently performing a series of experimental studies of the transmission of low energy ions ( 7 eV) through ultrathin films (submonolayer to multilayer) of condensed gases. Here we report on the first quantitative measurements of the yield, angle, and energy of oxygen ions after transmission through ultrathin films of xenon. In our novel approach, a focused 300 eV electron beam bombards a target at 25 K consisting of an oxidized tungsten (100) crystal with adsorbed overlayers of xenon. In the absence of the xenon, O+ ions desorb in a sharp beam normal to the surface, as measured in a velocity and angle resolving ESDIAD apparatus (electron stimulated desorption ion angular distribution). When Xe layers are present, some oxygen ions penetrate several monolayers of xenon without significant change in energy and angle while others seem to be scattered by large-angle elastic scattering or to be attenuated from the O+ beam. The work presented is the first experimental study of the depth of origin of desorbing ions in DIET processes. 相似文献
14.
N.M. El-Sawy A. El-Hag Ali M.S. Abdel Motlab 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2007,264(2):227-234
Graft copolymerization of (acrylonitrile-co-N-vinylpyrrolidone) AN/NVP binary monomer onto (low density polyethylene) LDPE film was achieved using simultaneous irradiation method. The influence of grafting conditions such as solvent type, comonomer composition and comonomer concentration on the grafting process were investigated. The prepared grafted films were chemically modified into amidoximated form using hydroxyl amine hydrochloride (NH2OH · HCl). The untreated and amidoximated grafted films were characterized by studying their FT-IR spectroscopy, swelling behavior and mechanical properties. The ability of the amidoximated grafted films to adsorbed metal ions such as Cr3+, Ni2+, Cd2+, Ag+ and Pb2+ was evaluated. The parameters that might influence the metal ions adsorption capacity of treated grafted LDPE films such as comonomer compositions, the degree of grafting, the feeding metal ions solution concentration and the pH were discussed. The obtained results illustrate that the amidoximated grafted films could be fruitful in the practical field of water treatment. 相似文献
15.
16.
R.M. Radwan A.M. Abdul-Kader 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2008,266(16):3588-3594
The changes in the optical and electrical properties of polycarbonate (PC) films, bombarded with He and Ar ion beams, have been studied. The PC films were divided into two groups where the first group was bombarded with 130 keV He ions of fluences ranged from 1 × 1014 cm−2 to 2 × 1016 cm−2, while the second one was bombarded with 320 keV Ar of fluences (1 × 1013 cm−2 and 1 × 1015 cm−2). The surface morphology of the unirradiated and irradiated PC films was studied using scanning electron microscopy (SEM) technique. The optical properties of the two groups have been carried out using UV-Vis spectrophotometer and the direct current (DC) electrical conductivity was also performed. The obtained results showed a decrease in the optical energy gap, the optical activation energy and the electrical activation energy with increasing the fluence of both He and Ar ions. Meanwhile, an increase in the DC conductivity was obtained with increasing the fluence of the ions. The bombardment of the PC films with He and Ar ion beams induced formation of carbon clusters near the polymer surface and, also, resulted in scission in the polymer chains. 相似文献
17.
X. Lu J. Ning C.Y. Deng Q. Qiu Yan Ying F. Gou 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2009,267(18):3242-3244
In this study, we have simulated the CH+ ions bombardment on a Si-terminated 3C-SiC (0 0 1) surface using molecular dynamic simulations with a Tersoff-Brenner potentials. The results show that the sputtering yields of Si atoms is more than that of C atoms. With increasing incident energy the uptake of H atoms increases, while the uptake of C atoms decreases. In amorphous layer, a carbon-rich region is observed. In the films, the CH group and SiH group are dominant. Their fractions increase with increasing incident energy, and then decrease. 相似文献
18.
M. Miyakawa M. Hirano T. Kamiya H. Hosono 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2006,250(1-2):155-158
Large enhancement in electrical conductivity from <10−10 S cm−1 to 4 × 10−2 S cm−1 was achieved in polycrystalline 12CaO · 7Al2O3 (p-C12A7) thin films by hot Au+ implantation at 600 °C and subsequent ultraviolet (UV) light illumination. Although the as-implanted films were transparent and insulating, the subsequent UV-light illumination induced persistent electronic conduction and coloration. A good correlation was found between the concentration of photo-induced F+-like centers (a cage trapping an electron) and calculated displacements per atom, indicating that the hot Au+ implantation extruded free O2− ions from the cages in the p-C12A7 films by kick-out effects and left electrons in the cages. These results suggest that H− ions are formed by the Au+ implantation through the decomposition of preexisting OH− ions. Subsequent UV-light illumination produced F+-like centers via photoionization of the H− ions, which leads to the electronic conduction and coloration. 相似文献
19.
P. Mallick Chandana Rath D.K. Mishra D.M. Phase D.K. Avasthi N.C. Mishra 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2010,268(10):1613-1617
NiO nanoparticle films (200 nm thick) grown on Si substrates by pulsed laser deposition method were irradiated by 200 MeV Ag15+ ions. The films were characterized by glancing angle X-ray diffraction, atomic force microscopy and optical absorption spectroscopy. Though electronic energy loss of 200 MeV Ag ions in NiO matrix was higher than the threshold electronic energy loss for creation of columnar defects, films remained crystalline with the initial fcc structure even up to a fluence of 5 × 1013 ions cm−2, where ion tracks are expected to overlap. Irradiation however modified the microstructure of the NiO films considerably. The grain size decreased with increasing ion fluence, which led to reduced surface roughness and increased optical band gap due to quantum confinement. These results correlate well with variation of the power spectral density exponent with ion fluence, which indicate that at high ion fluences, the evolution of surface morphology is governed by surface diffusion. 相似文献
20.
Fa-Min Liu Peng Ding Jian-Qi Li 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2009,267(18):3104-3108
TiO2 thin films were prepared by direct current magnetron sputtering on glass substrates, then were implanted by cobalt ions, and finally annealed at 400 and 500 °C for 50 min, respectively. They were identified as an anatase structure by X-ray diffraction (XRD). Scanning electron microscope (SEM) images showed that the grain sizes of the films grow with increasing annealing temperature. The energy dispersive X-ray (EDX) measurements indicated that the ratio of the cobalt atoms number and total atoms number of cobalt and titanium in the Co-TiO2 films was about 2.51%, and X-ray photoelectron spectroscopy (XPS) results revealed that the cobalt existed in the films as Co2+. The element distribution of cobalt along cross-section of the films was studied by EDX, as the results showed that the cobalt diffused deeply into the films after annealing. The high resolution transmission electron microscopy (HRTEM) images were used to affirm the anatase structure of the Co-TiO2 films, and edge dislocations were further found in the HRTEM images, which could be attributed to the effect of the implantation. 相似文献