共查询到20条相似文献,搜索用时 62 毫秒
1.
D.Q. Peng X.D. Bai Q.G. Zhou X.Y. Liu R.H. Yu D.L. Zhang 《Journal of Nuclear Materials》2004,324(1):71-75
In order to study the influence of cerium ion implantation on the aqueous corrosion behavior of zirconium, specimens were implanted with cerium ions with a fluence ranging from 1 × 1020 to 1 × 1021 ions/m2 at about 150 °C, using a MEVVA source at an extracted voltage of 40 kV. The valence and element penetration distribution of the surface layer were analyzed by X-ray photoelectron spectroscopy (XPS) and auger electron spectroscopy (AES) respectively. The potentiodynamic polarization technique was employed to investigate the aqueous corrosion resistance of zirconium in a 1N H2SO4 solution. It was found that there was a remarkable improvement in the aqueous corrosion behavior of zirconium implanted with cerium ions compared with that of the as-received zirconium. The corrosion resistance improvement of the cerium-implanted zirconium is probably due to the addition of cerium oxide dispersoid into the zirconium matrix and oxidization protection. 相似文献
2.
J.A. Valdez I.O. Usov J. Won M. Tang R.M. Dickerson G.D. Jarvinen K.E. Sickafus 《Journal of Nuclear Materials》2009,393(1):126-220
Room temperature ion irradiation damage studies were performed on a ceramic composite intended to emulate a dispersion nuclear fuel. The composite is composed of 90-mole% MgO and 10-mole% HfO2. The as-synthesized composite was found to consist of Mg2Hf5O12 (and some residual HfO2) particles embedded in an MgO matrix. X-ray diffraction revealed that nearly all of the initial HfO2 reacted with some MgO to form Mg2Hf5O12. Ion irradiations were performed using 10 MeV Au3+ ions at room temperature over a fluence range of 5 × 1016-5 × 1020 Au/m2. Irradiated samples were characterized using both grazing incidence X-ray diffraction (GIXRD) and transmission electron microscopy (TEM), the latter using both selected-area electron diffraction (SAED) and micro-diffraction (μD) on samples prepared in cross-sectional geometry. Both GIXRD and TEM electron diffraction measurements on a specimen irradiated to a fluence of 5 × 1020 Au/cm2, revealed that the initial rhombohedral Mg2Hf5O12 phase was transformed into a cubic-Mg2Hf5O12 phase. Finally, it is important to note that at the highest ion fluence used in this investigation (5 × 1020 Au/m2), both the MgO matrix and the Mg2Hf5O12 second phase remained crystalline. 相似文献
3.
S. Prakash Parthiban E.K. Girija P.K. Kulriya F. Singh A. Tripathi D. Kanjilal T.P. Singh S. Narayana Kalkura 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2008,266(6):911-917
The effect of swift heavy ion irradiation on hydroxyapatite (HAp) ceramic - a bone mineral was investigated. The irradiation experiment was conducted using oxygen ions at energy of 100 MeV with three different fluences of 1012, 1013, 1014 ions/cm2. The irradiated samples were characterized by glancing angle X-ray diffraction (GXRD), atomic force microscopy (AFM), dynamic light scattering (DLS), photoluminescence spectroscopy (PL), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX). GXRD confirmed incomplete amorphisation of HAp with increase in fluence. There was considerable reduction in particle size on irradiation leading to nanosized HAp (upto 53 nm). PL studies showed emission in the visible wavelength region. The irradiated samples exhibited better bioactivity than the pristine HAp. 相似文献
4.
Yingmin Liu Yan Chen Yuren Wang 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2008,266(6):894-898
MeV Au irradiation leads to a shape change of polystyrene (PS) and SiO2 particles from spherical to ellipsoidal, with an aspect ratio that can be precisely controlled by the ion fluence. Sub-micrometer PS and SiO2 particles were deposited on copper substrates and irradiated with Au ions at 230 K, using an ion energy and fluence ranging from 2 to 10 MeV and 1 × 1014 ions/cm2 to 1 × 1015 ions/cm2. The mechanisms of anisotropic deformation of PS and SiO2 particles are different because of their distinct physical and chemical properties. At the start of irradiation, the volume of PS particles decrease, then the aspect ratio increases with fluence, whereas for SiO2 particles the volume remains constant. 相似文献
5.
M. BalajiM. Manivel Raja K. AsokanD. Kanjilal T.R. RajasekaranD. Pathinettam Padiyan 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2011,269(10):1088-1093
Effects of 150 MeV Ni11+ swift heavy ion (SHI) irradiation on copper ferrite nanoparticles have been studied at the fluences of 1 × 1011, 1 × 1012, 1 × 1013, 1 × 1014 and 5 × 1014 ions/cm2. The XRD pattern shows the irradiation fluence dependant preferential orientation. Scanning electron microscope analysis displays fine blocks of material for pristine while partial agglomeration on irradiation. Notably, a large number of holes are present at the fluence of 5 × 1014 ions/cm2. The magnetization measurements performed in these samples exposes that the coercivity and remanence magnetization value increases due to the magnetocrystalline anisotropy up to the fluence of 1 × 1013 ions/cm2. At 1 × 1014 ions/cm2 fluence, the induced thermal energy overcomes the magnetocrystalline anisotropy constant and causes a decrease in coercivity and remanence values. The saturation magnetization decreases up to the fluence of 1 × 1013 ions/cm2 and then it increases for further irradiation. The change of crystalline orientation observed from XRD, the creation of holes from SEM and the change in magnetic properties are discussed on the basis of electro-phonon coupling and it invokes the thermal spike theory. 相似文献
6.
T. Sonoda M. Kinoshita M. Sataka K. Yasunaga 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2010,268(19):3277-3281
In order to understand the properties of ion tracks and the microstructural evolution under accumulation of ion tracks in UO2, 100 MeV Zr10+ and 210 MeV Xe14+ ions irradiation examinations have been done at a tandem accelerator facility of JAEA-Tokai, and it has been observed the microstructure by means of a transmission electron microscope (TEM) and a scanning electron microscope (SEM) in CRIEPI.Comparison of the diameter of ion tracks between UO2 and CeO2 under irradiation with 100 MeV Zr10+ and 210 MeV Xe14+ ions at room temperature clarify that the sensitivity on high density electronic excitation of UO2 is much less than that of CeO2. By the cross-sectional observation of UO2 under irradiation with 210 MeV Xe14+ ions at 300 °C, elliptical changes of fabricated pores that exist till ∼6 μm depth and the formation of dislocations have been observed in the ion fluence over 5 × 1014 ions/cm2. The drastic changes of surface morphology and inner structure in UO2 indicate that the overlapping of ion tracks will cause the point defects, enhance the diffusion of point defects and dislocations, and form the sub-grains at relatively low temperature. 相似文献
7.
K.R. Nagabhushana C. Pandurangappa P.K. Kulria 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2008,266(8):1475-1479
Al2O3 thin films find wide applications in optoelectronics, sensors, tribology etc. In the present work, Al2O3 films prepared by electron beam evaporation technique are irradiated with 100 MeV swift Si7+ ions for the fluence in the range 1 × 1012 to 1 × 1013 ions cm−2 and the structural properties are studied by glancing angle X-ray diffraction. It shows a single diffraction peak at 38.2° which indicates the γ-phase of Al2O3. Further, it is observed that as the fluence increases up to 1 × 1013 ions cm−2 the diffraction peak intensity decreases indicating amorphization. Surface morphology studies by atomic force microscopy show mean surface roughness of 34.73 nm and it decreases with increase in ion fluence. A strong photoluminescence (PL) emission with peak at 442 nm along with shoulder at 420 nm is observed when the samples are excited with 326 nm light. The PL emission is found to increase with increase in ion fluence and the results are discussed in detail. 相似文献
8.
S. Tobbeche A. BoukhariR. Khalfaoui A. Amokrane C. BenazzouzA. Guittoum 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2011,269(24):3242-3245
Cr/Si bilayers were irradiated at room temperature with 120 keV Ar, 140 keV Kr and 350 keV Xe ions to fluences ranging from 1015 to 2 × 1016 ions/cm2. The thickness of Cr layer evaporated on Si substrate was about 400 Å. Rutherford backscattering spectrometry (RBS) was used to investigate the atomic mixing induced at the Cr-Si interface as function of the incident ion mass and fluence. We observed that for the samples irradiated with Ar ions, RBS yields from both Cr layer and Si substrate are the same as before the irradiation. There is no mixing of Cr and Si atoms, even at the fluence of 2 × 1016 ions/cm2. For the samples irradiated with Kr ions, a slight broadening of the Cr and Si interfacial edges was produced from the fluence of 5 × 1015 ions/cm2. The broadening of the Cr and Si interfacial edges is more pronounced with Xe ions particularly to the fluence of 1016 ions/cm2. The interface broadening was found to depend linearly on the ion fluence and suggests that the mixing is like a diffusion controlled process. The experimental mixing rates were determined and compared with values predicted by ballistic and thermal spike models. Our experimental data were well reproduced by the thermal spikes model. 相似文献
9.
A. Quentin I. Monnet B. Lefrançois 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2009,267(6):980-982
ZnAl2O4 spinels have been irradiated with several ions (Ne, S, Kr and Xe) at the IRRSUD beamline of the GANIL facility, in order to determine irradiation conditions (stopping power, fluence) for amorphisation. We observed by transmission electron microscopy (TEM) that with Xe ions at 92 MeV, individual ion tracks are still crystalline, whereas an amorphisation starts below a fluence of 5 × 1012 cm−2 up to a total amorphisation between 1 × 1013 and 1 × 1014 cm−2. The coexistence of amorphous and crystalline domains in the same pristine grain is clearly visible in the TEM images. All the crystalline domains remain close to the same orientation as the original grain. According to TEM and X-ray Diffraction (XRD) results, the stopping power threshold for amorphisation is between 9 and 12 keV nm−1. 相似文献
10.
Ram Prakash R.J. Choudhary D.M. Phase 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2008,266(8):1242-1246
Thin films of Fe3O4 have been deposited on single crystal MgO(1 0 0) and Si(1 0 0) substrates using pulsed laser deposition. Films grown on MgO substrate are epitaxial with c-axis orientation whereas, films on Si substrate are highly 〈1 1 1〉 oriented. Film thicknesses are 150 nm. These films have been irradiated with 200 MeV Ag ions. We study the effect of the irradiation on structural and electrical transport properties of these films. The fluence value of irradiation has been varied in the range of 5 × 1010 ions/cm2 to 1 × 1012 ions/cm2. We compare the irradiation induced modifications on various physical properties between the c-axis oriented epitaxial film and non epitaxial but 〈1 1 1〉 oriented film. The pristine film on Si substrate shows Verwey transition (TV) close to 125 K, which is higher than generally observed in single crystals (121 K). After the irradiation with the 5 × 1010 ions/cm2 fluence value, TV shifts to 122 K, closer to the single crystal value. However, with the higher fluence (1 × 1012 ions/cm2) irradiation, TV again shifts to 125 K. 相似文献
11.
M. Shirai K. Tsumori M. Kutsuwada K. Yasuda S. Matsumura 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2009,267(10):1787-1791
We have investigated morphology change of FePt nanogranular films (FePt)47(Al2O3)53 under irradiation with 210 MeV Xe ions. Here, electron tomography technique was extensively employed to clarify three-dimensional (3D) structure in irradiated specimens, in addition to conventional transmission electron microscopy (TEM) techniques such as bright-field observation and scanning TEM energy dispersive X-ray spectroscopy (STEM-EDX) analysis. The ion irradiation induces the coarsening of FePt nanoparticles with elongation along the beam direction. Electron tomography 3D reconstructed images clearly demonstrated that when the fluence achieves 5.0 × 1014 ions/cm2, well-coarsened FePt balls have been formed on the irradiated surface, and the particles in the film interior have been deformed into rods along the ion trajectory. The alloy particles become inhomogeneous in composition after prolonged irradiation up to 1.0 × 1015 Xe ions/cm2. The particle center is enriched with Pt, while Fe is slightly redistributed to the periphery. 相似文献
12.
Thickness and MeV Si ions bombardment effects on the thermoelectric properties of Ce3Sb10 thin films
S. Güner S. Budak R. Amaral Minamisawa D. Ila 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2008,266(8):1261-1264
The three single layer Ce3Sb10 thin films were grown on silicon dioxide and quartz (suprasil) substrates with thicknesses of 297, 269 and 70 nm using ion beam assisted deposition (IBAD) technique. The high-energy cross plane Si ion bombardments with constant energy of 5 MeV have been performed with varying fluence from 1 × 1012, 1 × 1013, 1 × 1014, 1 × 1015 ions/cm2. The Si ions bombardment modified the thermoelectric properties of films as expected. The fluence and temperature dependence of cross plane thermoelectric parameters that are Seebeck coefficient, electrical and thermal conductivities were determined to evaluate the dimensionless figure of merit, ZT. Rutherford backscattering spectrometry (RBS) enabled us to determine the elemental composition of the deposited materials and layer thickness of each film. 相似文献
13.
The modifications of the mechanical properties of cubic (yttria-stabilized) zirconia induced by swift heavy ion irradiation are investigated. Polycrystalline pellets were irradiated at room temperature with 940 MeV Pb ions at the GANIL accelerator in Caen at fluences ranging from 5 × 1011 to 4 × 1013 cm−2. The microhardness and the fracture toughness of irradiated YSZ were studied by Vickers micro-indentation. Although YSZ is damaged by irradiation, an increase of the microhardness and fracture toughness with increasing ion fluence is observed. A strengthening of YSZ, associated with residual compressive stresses induced in the surface layer by irradiation, explain these results. 相似文献
14.
V. GokulakrishnanS. Parthiban E. ElangovanK. Ramamurthi K. JeganathanD. Kanjilal K. AsokanR. Martins E. Fortunato 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2011,269(16):1836-1840
Indium oxide thin films deposited by spray pyrolysis were irradiated by 100 MeV O7+ ions with different fluences of 5 × 1011, 1 × 1012 and 1 × 1013 ions/cm2. X-ray diffraction analysis confirmed the structure of indium oxide with cubic bixbyite. The strongest (2 2 2) orientation observed from the as-deposited films was shifted to (4 0 0) after irradiation. Furthermore, the intensity of the (4 0 0) orientation was decreased with increasing fluence together with an increase in (2 2 2) intensity. Films irradiated with maximum fluence exhibited an amorphous component. The mobility of the as-deposited indium oxide films was decreased from ∼78.9 to 43.0 cm2/V s, following irradiation. Films irradiated with a fluence of 5 × 1011 ions/cm2 showed a better combination of electrical properties, with a resistivity of 4.57 × 10−3 Ω cm, carrier concentration of 2.2 × 1019 cm−3 and mobility of 61.0 cm2/V s. The average transmittance obtained from the as-deposited films decreased from ∼81% to 72%, when irradiated with a fluence of 5 × 1011 ions/cm2. The surface microstructures confirmed that the irregularly shaped grains seen on the surface of the as-deposited films is modified as “radish-like” morphology when irradiated with a fluence of 5 × 1011 ions/cm2. 相似文献
15.
Sharmistha Bagchi Shahid Anwar 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2010,268(10):1601-1606
Present study reports effect of swift heavy ion irradiation on structural and magnetic properties of sputtered W/Co multilayer structures (MLS) having bilayer compositions of [W(10 Å)/Co(20 Å)]5BL and [W(20 Å)/Co(20 Å)]5BL. These MLS are irradiated by 120 MeV Au9+ ions up to fluence of 1 × 1013 ions/cm2. X-ray reflectivity (XRR), wide-angle X-ray diffraction (WAXD), cross-sectional transmission electron microscopy (X-TEM) and magneto optical Kerr effect (MOKE) techniques are used for structural and magnetic characterization of pristine and irradiated MLS. Analysis of XRR data using Parratt’s formalism shows a significant increase in W/Co interface roughness. WAXD and X-TEM studies reveals that intra-layer microstructure of Co-layers in MLS becomes nano-crystalline on irradiation. MOKE study shows slight increase in coercivity at higher fluence, which may be due to increase in surface and interface roughness after recrystallization of Co-layers. 相似文献
16.
Yuan Gao Tengfei Yang Sha Yan Yugang Wang Dixon T.K. Kwok Yanwen Zhang 《Journal of Nuclear Materials》2011,413(1):11-15
Magnetron sputtered Cu/W multilayer samples with individual layer thicknesses from 2.5 to 50 nm were irradiated by 50 keV He+ ions at ion fluences from 7 × 1020 to 6 × 1021 m−2 at room temperature. Evolution of the interfacial structure during irradiation is monitored by X-ray diffraction and cross-sectional transmission electron microscopy. Moreover, radiation responses on the individual layer thickness and He+ ion irradiation fluence are revealed. The highly morphological stability of the multilayered structure suggests that the interfacial structure and grain boundary can serve as sinks for radiation-induced defects. 相似文献
17.
Rahul Singhal Amit Kumar S. Mohapatra D.K. Avasthi 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2008,266(14):3257-3262
Modifications of the C70 molecule (fullerene) under swift heavy ion irradiation are investigated. C70 thin films were irradiated with 120 MeV Au ions at fluences from 1 × 1012 to 3 × 1013 ions/cm2. The energetic ion impacts lead to the destruction of the C70 molecule. To investigate the stability of C70 fullerene, the damage cross-section and radius of the damaged cylindrical zones are evaluated by fitting the evanescence of C70 vibration modes recorded by Raman spectroscopy. Conductivity measurements together with Raman and optical absorption studies revealed that an irradiation fluence of 3 × 1013 ions/cm2 results in complete amorphization of the carbon structure of the fullerene molecules. 相似文献
18.
Sanju Rani N.K. Puri M.C. Bhatnagar 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2008,266(9):1987-1992
Swift heavy ion irradiation has been successfully used to modify the structural, optical, and gas sensing properties of SnO2 thin films. The SnO2 thin films prepared by sol-gel process were irradiated with 75 MeV Ni+ beam at fluences ranging from 1 × 1011 ion/cm2 to 3 × 1013 ion/cm2. Structural characterization with glancing angle X-ray diffraction shows an enhancement of crystallinity and systematic change of stress in the SnO2 lattice up to a threshold value of 1 × 1013 ions/cm2, but decrease in crystallinity at highest fluence of 3 × 1013 ions/cm2. Microstructure investigation of the irradiated films by transmission electron microscopy supports the XRD observations. Optical properties studied by absorption and PL spectroscopies reveal a red shift of the band gap from 3.75 eV to 3.1 eV, and a broad yellow luminescence, respectively, with increase in ion fluence. Gas response of the irradiated SnO2 films shows increase of resistance on exposure to ammonia (NH3), indicating p-type conductivity resulting from ion irradiation. 相似文献
19.
L.Q. Zhang C.H. Zhang J. GouL.H. Han Y.T. YangY.M. Sun Y.F. Jin 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2011,269(23):2835-2839
Photoluminescence (PL) spectrum, in conjunction with X-ray photoelectron spectroscopy (XPS) is used to evaluate the surface damage of GaN layer by highly-charged Xeq+ (18 ? q ? 30), Arq+ (6 ? q ? 16) and Pbq+ (q = 25,35) ions. The intensity of PL emission of GaN layer, including near band-edge peak and yellow luminescence, decreases with increasing fluence and charge state of the incident ions. Finally the PL emission is completely quenched after irradiation to high fluences at high charge state. A new peak at 450 nm appeared in PL spectra of the specimens irradiated with Xe18+, Ar6+ and Ar11+, indicating that radioactive recombination within donor-acceptor pairs (DAPs) during irradiation. After irradiation, XPS spectra show N deficient or Ga rich on GaN surface and XPS spectra of Ga3d core levels indicate spectral peak evidently shifts from a Ga-N to Ga-Ga and Ga-O bond. The relative content of Ga-N bond decreases and the content of Ga-Ga bond increases with the increase of ion fluence and ion charge state. The binding energy of Ga3d5/2 electron corresponding to Ga-Ga bond of the irradiated GaN film is found to be smaller than that of metallic Gallium (Ga0), which can be attributed to irradiation damage. 相似文献
20.
Polycrystalline pellets of the sesquioxide Dy2O3 were irradiated at cryogenic temperature with Kr++ ions to a fluence of 1 × 1020 Kr/m2. The crystal structure of the irradiated Dy2O3 was observed to change from a cubic, so-called C-type rare-earth sesquioxide structure to a monoclinic, B-type rare-earth sesquioxide structure upon ion irradiation. This transformation is accompanied by a decrease in molecular volume (or density increase) of approximately 9%. 相似文献