Combined PIXE and SEM study of the behaviour of trace elements in gel formed around implant coated with bioactive glass

Bioactive glasses are used as coating biomaterials to facilitate anchorage of metallic prostheses implanted into the body. The aim of this work is to study the behavior of gel formed in contact with alloys and BVA and BVH bioactive glasses implanted. Cylinders of metallic implants composed by Ti, Al and V, are coated with bioactive glass. Three sheep were implanted for different time length: 3, 6 and 12 months in the femoral epiphysis. Results obtained with particle induced X-ray emission and scanning electron microscopy show that BVA coating induces a better contact between the metallic implant and bone. On the other hand, BVH coating prevents corrosion from the metallic implant.     

高功率脉冲电子束溅射法制备钴-钛多层膜

本文介绍一种利用高功率脉冲电子束溅射法制备金属多层膜的新方法。强脉冲电子束轰击金属靶将产生瞬态高温等离子体,从这种等离子体中飞出的金属离子沉积在附近的衬底上,从而制得Co/Ti系和其他多种金属多层膜。本文报道了对多层膜进行的TEM和AES研究的结果。     

Basic consideration of a nuclear power monitoring system using neutron-induced prompt gamma rays

ABSTRACT

Monitoring only neutron flux in a nuclear reactor core has an advantage of offering reactor power monitoring accuracy. We started the development of a new nuclear instrumentation based on the measurement of prompt gamma rays emitted from metals placed at the neutron flux monitoring positions. The thermal neutron flux at the position of each placed metal piece can be monitored by measuring the prompt gamma rays as the count rate of each energy. The gamma-ray energy range was limited from 6 to 10 MeV to mitigate the interference of environmental gamma rays. Four metals, Ti, V, Ni, and Cu, were chosen as candidates in consideration of their neutron emission rates and self-absorption. In an experiment with a high-purity germanium semiconductor detector, we considered the identification of individual peak energies in an assumed situation where prompt gamma rays were emitted from the four different metals at the same time. Energy resolutions of the peak with the largest energy gap from the nearest energy peak of the other candidate metals were smaller than the gap. Thus, we confirmed that at least one peak for each candidate metal was able to be separated from the peaks derived from other candidate metals.     

Chemical states and thermal stability of hydrogen-implanted Ti and V studied by X-ray photoelectron spectroscopy

X-ray photoelectron spectroscopy (XPS) was applied to the chemical state studies of Ti and V metals bombarded with 8 keV hydrogen ions. The binding energies of the lines for the ion-implanted Ti and V shift from those for the metallic states by 0.3 eV, are consistent with the core-line shifts for the thermally synthesized hydrides such as TiH_1.97 and VH_0.55 The metal 3d-H1s bonding level for the hydrogen implanted Ti appears at ~ 3.5 eV below the Fermi level, which is lower by ~ 2.5 eV than the molecular-orbital energy previously calculated for TiH₂. In the case of the ion-implanted V, however, it appears at ~ 5.0 eV, which is almost equal to the molecular-orbital energy for VH₂. The photopeaks corresponding to the Ti-H and V-H bonds for the ion-implanted samples grew up on raising the annealing temperature up to 550°C and 150°C, respectively. The phenomena are interpreted by means of the thermal diffusion of the implanted hydrogen from bulk to surface.     

Determination of ion fraction and energy analysis of sputtered particles from deuterium bombarded surfaces

Ion energy distributions and sputtering yields have been measured in the presence of various background gases for deuterium, helium and argon ions in the 1–40 keV energy range. Alteration of the surface chemistry of hydride forming metals such as Ti, Y and V by exposure to hydrogen has a significant effect on the charge state of the sputtered particles. Under conditions likely to prevail in plasma devices and possible reactors, the ion/neutral fraction may be drastically increased, reaching ~41% for Ti. Such large ion fractions for metal targets have been previously observed only by sputtering with oxygen ions and present the possibility of improved impurity control in plasma devices. Both gas adsorption and recoil implantation are involved in the mechanism determining the ion fraction of sputtered products.     

Mixed Ne/Ni beams for radiation damage studies on the harwell variable-energy cyclotron

Ion irradiation facilities which use metal ions beams concurrently with beams of He or He+H have been developed extensively in recent years for the simulation of radiation effects which occur in metals during neutron irradiation in fission or fusion reactors. Helium ions are considered necessary to simulate the effect of helium on cavity nucleation and the metal atom is used to create an adequate atomic displacement rate. Many of these dual-beam facilities require the provision of two accelerators, one to produce a gas atom and the other a metal atom beam, and commonly employ low-energy metal ions (eg. 4 MeV ⁵⁸Ni⁺) which have a limited range (0.75 μm) in metals of practical interest. Damage can be created at greater depths by use of high energy ions (eg 45 MeV ⁵⁸Ni) in a cyclotron, but charge-to-mass constraints make it difficult to produce a mixed beam of concurrent He and metal ions. It is noted that the heavier inert gas atom neon has similarities in atomistic behaviour in metals to those of helium and could possibly be used as an analogue for helium. In this report we consider this aspect and show than by suitable matching of $\text{e}\text{m}$ ratio a mixed beam of 15 MeV ²⁰Ne²⁺ and 45 MeV ⁶⁰Ni⁶⁺ can be obtained from the Harwell VEC with gas/metal atom ratios and beam currents that are suitable for use in radiation damage simulation experiments in metals. It is proposed that exploratory studies should be carried out with mixed Ne/Ni beams into nickel to investigate the possibility of using neon as an analogue for helium in radiation damage simulation studies.     

Study by PIXE method of trace elements transferred from prostheses to soft tissues and organs

Some metallic prostheses inserted in human hip undergo physico-chemical modification, a few years after their implantation. Tissues surrounding these prostheses are damaged by metallic element transfer. Surgeons in Clermont-Ferrand Hospital (France) recover tissues of abnormal coloration that were in contact with metallic implants. PIXE technique (particles induced X-ray emission) with a 400 μm proton beam and 3 MeV of energy is an efficient technique to analyze these tissues and to detect elements, which are transferred from prosthesis to tissues. PIXE analyses were carried at the CERI-CNRS Laboratory. We have applied this method to determine qualitatively and quantitatively trace elements migration from metallic implants to surrounding tissues and organs, like kidney, spleen, liver, lymphatic gland and lung.     

Trapping of energetic hydrogen ions in reactive metals

A model is proposed to describe the trapping of a beam of energetic ions of hydrogen isotopes by targets of reactive metals in which the incident ions dissolve exothermically. The model considers the ions free to diffuse inside the metal, and to escape from the surface at a rate determined from the known solubility data.It has been shown that in the case of semi-infinite geometry the trapping efficiency can be expressed in analytic form as a function of dose. However, in the two dimensional case appropriate for beam experiments, radial diffusion becomes important and a numerical solution has been found to be necessary. The model has been compared with experimental results on the trapping of 18 keV deuterons by targets of Nb, Zr, Ti and Pd in the temperature range 230–1000 K and in general good agreement has been obtained.     

Ti-PS nanocomposites by plasma immersion ion implantation and deposition

We synthesize Ti-PS nanocomposites by plasma immersion ion implantation and deposition (PIII&D) technique. Ti nanoparticles at size of 5-15 nm are found in PS matrix. We propose the formation of Ti nanoparticles as a result of the combined effect of ion implantation and ion condensation in PIII&D process. X-ray photoelectron spectroscopy measurements reveal that Ti atoms have three different chemical states, metal, oxide and carbide. While surface Ti atoms are oxidized, embedded Ti atoms keep their metallic states by surrounding PS matrix. We characterize optical absorbance of Ti-PS nanocomposites by UV-VIS measurements. An adsorption peak due to the excitation of localized surface plasmon is found at wavelength 337.5 nm and the fractal nature of Ti-PS nanocomposites broaden absorption wavelength from UV to infrared. In addition, we use a protein assay to measure protein immobilization. It is found that the amount of protein immobilized on Ti-PS nanocomposites is almost twice than that on pristine PS. The enhancement mechanisms are attributed to the increased surface roughness as well as covalent linkages between protein molecules and functional groups on the surface of Ti-PS nanocomposites.     

Effect of metal ions in a heated nitric acid solution on the corrosion behavior of a titanium–5% tantalum alloy in the hot nitric acid condensate

For evaluating the application of titanium and its alloys as components of equipment for storing nitric acid condensate in spent nuclear fuel reprocessing plants, the corrosion behavior of titanium–5% tantalum alloy (Ti–5Ta) in a continuously renewed hot nitric acid condensate, and particularly the effect of metal ions in the heated nitric acid solution, was investigated. Corrosion experiments in an apparatus designed to renew the condensate at regular intervals showed that the corrosion rate of Ti–5Ta in the condensate increased linearly with the nitric acid concentration. The surface morphology of Ti–5Ta coupons after the corrosion experiments indicated uniform corrosion under any condition. The oxide film on the coupons had nearly constant thickness, and it was composed of mainly lower Ti oxides, such as TiO and Ti₂O₃, regardless of the nitric acid concentration in the condensate. The experimental results also showed that the addition of metal ions into the heated nitric acid solution increased the nitric acid concentration in the condensate, which resulted in a higher corrosion rate of Ti–5Ta. The corrosion rate increased noticeably as the valence of the metal ion increased and its ionic radius decreased. This effect of metal ions in the heated nitric acid solution on the corrosion rate of Ti–5Ta in the condensate was evaluated quantitatively based on the Gibbs free energy of hydration of the metal ions, and the calculated corrosion rates of Ti–5Ta in the condensate were found to be in good agreement with the experimental values.     

Plasma immersion ion implantation for metallurgical and semiconductor research and development

Plasma Source Ion Implantation, also termed Plasma Immersion Ion Implantation, is a rapidly developing material modification technique for treating the near-surface regions of various kinds of materials. It makes use of high-energy ions which are accelerated by a high voltage pulse from a plasma which wraps the workpiece to be treated. The ions are implanted into the material causing effects similar to those of conventional beam-line ion implantation. Research and development of plasma immersion ion implantation has focused in two main fields, treatment of metals for improved wear and corrosion performance, and modification of semiconductors. The paper discusses examples from both fields, with nitrogen PIII of steels and aluminum, and modification of thin metal films. From the semiconductor field, trenchwall doping, ultra-shallow doping with boron, and oxygen ion implantation for SIMOX formation is treated.     

用同步辐射X荧光分析法研究兔肝金属硫蛋白中的微量元素

采用同步辐射X荧光分析法（SRXRF）直接测定了兔肝金属硫蛋白（MT)中的金属离子含量，以及经过十二烷基硫酸钠－聚丙烯酰胺凝胶电泳（SDS－APGE）分离后凝胶板中蛋白条带上金属离子的分布。实验结果表明，兔肝MT－1以含锌为主，占总金属含量的97.9%；兔肝MT－2以含锌、镉为主。本工作表明，采用SRXRF技术可实现MT电泳分离后蛋白条带内金属离子分布的原位测定。     

离子液体在金属离子萃取分离中的应用

离子液体作为绿色溶剂是溶剂萃取分离金属离子方面研究的热点.介绍了以离子液体为溶剂时,萃取分离各种金属离子的效果,包括碱金属、碱土金属、过渡金属、稀土及锕系金属,以及核燃料后处理涉及的铀、钚及裂变产物等多种离子,深入探讨了其萃取机理.展望了离子液体取代有毒、易挥发、易造成环境污染的有机溶剂的发展和应用前景.     

Measurement of Anisotropy of Diffusion Coefficient in Plate Cell

Ion-exchange property and thermal stability were studied on four synthetic hydrous metal oxides from the viewpoint of applicability for the processing of liquid radioactive waste. Hydrous titanium (IV) oxide and hydrous niobium (V) oxide, consisting of metal ions having larger ionic potential, possessed large cation-exchange capacities, and showed high affinity for both the transition metal ions and the representative element ions. Hydrous tin (IV) oxide and hydrous zirconium (IV) oxide, consisting of metal ions having smaller ionic potential, were amphoteric ion exchangers possessing large anion-exchange capacities, and showed much higher affinity for the transition metal ions than for the representative element ions. The selectivity series are understood in terms of the formation of a bond partially covalent in character for the transition metals, and the purely electrostatic interaction between anionic exchange sites and unhydrated or hydrated cations for the representative elements. An examination of the effects of heat treatment in air on the ion-exchange properties indicated that the hydrous niobium (V) oxide was the most stable among the four hydrous metal oxides. Even this material, however, was not stable enough to be used under hydrothermal conditions.     

The Production and Acceleration of Metal Ions in the Harwell Variable Energy Cyclotron

The range of ions accelerated by the V.E.C. has recently been extended to metal ions. For example, a 5 to 10 ?A beam of 48 MeV 58Ni6+ is now available and has been used by a customer. This beam has become possible as a result of success in adapting the normal ion source for the production of metal ions. The problem was to add to the ion source a controlled source of metal vapour without increasing the size of the ion source or adding separate oven heaters and controls. This has been achieved by inserting a graphite liner into the existing ion source chimney, the metal being embedded in the liner and out of direct contact with the arc. Provided the arc power exceeds a few kilowatts, the metal becomes molten and the vapour diffuses through the graphite into the arc which then becomes self-sustaining. With nickel (the most widely tested so far), intensity at full radius of between 10 and 20 ?A of 6+ ions and 1?A of 8+ ions is readily obtained and source life averages about 4 hours. Other metals such as cobalt, iron, chromium and copper give similar results.     

Ti-Mo互扩散界面吸氢同位素效应的离子束分析研究

为探究Ti-Mo互扩散对金属吸氢的影响,本文采用离子束分析方法对Ti-Mo薄膜的膜-基互扩散界面的吸氢同位素（H和D）效应进行了研究。通过氩离子刻蚀减薄的方法有效降低了表面碳、氧杂质对样品吸氢的影响。吸氢结果表明,对于表面洁净的样品,氢化后固相中氢或氘的浓度均沿着深度随钼原子含量的增加而减小。在单一气体吸氢实验中,氢原子浓度减小的趋势较氘原子缓慢;而在氢氘混合气体吸氢实验中,当容器中的氢氘压强比p(H2)∶p(D2)≥05∶1时,固体中氘氢浓度之比随钼浓度的增加而降低,但当p(H2)∶p(D2)<05∶1时,氘氢浓度之比随钼浓度的增加而升高。因此,由于Ti Mo界面的互扩散,吸氢出现了显著的氢同位素效应,钼的存在不利于体系对氢同位素气体的吸收。     

Transient field measurements with 80Se ions in glassy metals

Measurements of Transient Magnetic Fields (TF) were performed on ⁸⁰Se(2⁺) ions in amorphous Fe₈₀B₂₀ alloys employing ⁴⁸Ti beams. The motivation was to study the influence of the amorphous structure of the host on the strength of TF, when the 2s-state of probe ions is responsible for the field. The results are compared with those of crystalline Fe, where large attenuations have been observed. The significantly smaller attenuation in the present conditions demonstrates the superiority of metallic glasses for g-factor measurements.     

Ionization probability of secondary ions sputtered from Si(1 1 1) and Ge(1 1 1) surfaces

We have measured the energy distributions of the secondary ions sputtered from the Si(1 1 1) and Ge(1 1 1) surfaces and investigated the ionization probabilities of sputtered Si⁺ and Ge⁺ ions for clarifying their ionization mechanisms. The observed ionization probabilities depend on the velocity of Si⁺ and Ge⁺ ions. This velocity dependence can be successfully analyzed by a theoretical expression, which was proposed originally for the metal surfaces. This implies that the ionization mechanism of Si⁺ and Ge⁺ ions is the same as ions sputtered from the metal surface, i.e., the resonant electron transfer in the high velocity regime and the thermal excitation process in the low velocity regime. The difference in the ionization probability between Si⁺ and Ge⁺ ions is well explained by the difference in the band gap energy.     

Behavior of plasma-sprayed zirconium dioxide ceramic under the thermochemical effect of components of the reactor core melt

Conclusion The investigations have shown that, even though the zirconium dioxide layer sprayed on the metal interacts considerably with molten oxides of other metals (Fe, Ti, Ni), forming a porous loose structure, the saturation zone even with air cooling (not to mention water cooling) of the cold surface does not reach the metal, i.e., a considerable part of the zirconium dioxide remains integral and capable of transmitting large heat fluxes with no substantial damage. That attests to a promising outlook for the construction of a protection refractory layer of both an external and in-reactor core catcher by plasma-spraying ceramic onto a metal substrate. NITs TIV OIVT RAN. Translated from Atomnaya énergiya, Vol. 85, No. 2, pp. 115–119, August, 1998.     

Thick-target Pixe analysis of chromium, copper and arsenic impregnated lumber

Chromium, copper and arsenic (CCA) have for decades been used for wood preservation. Of these elements especially arsenic is very toxic. As CCA impregnated wood is still today used for many construction purposes, a monitoring of these metal ions is of great environmental importance. Thick-target PIXE is a powerful method for the determination of trace metals in wood. The TTPIXE method enabled study of variations of the elemental concentrations in lumber treated with CCA impregnation solution. Distribution patterns were obtained for both naturally occurring elements and elements introduced in the treatment process. During the impregnation process a desorption of e.g. alkali metal ions takes place from the wood. The sensitivity of the method is improved by dry ashing of the samples prior to PIXE analysis. The TTPIXE method was calibrated and validated using international certified reference materials (CRM) based on wood material.