Nuclear Backscattering Spectrometry Research Articles

Quantitative Lithiation Depth Profiling in Silicon Containing Anodes Investigated by Ion Beam Analysis

The localisation and quantitative analysis of lithium (Li) in battery materials, components, and full cells are scientifically highly relevant, yet challenging tasks. The methodical developments of MeV ion beam analysis (IBA) presented here open up new possibilities for simultaneous elemental quantification and localisation of light and heavy elements in Li and other batteries. It describes the technical prerequisites and limitations of using IBA to analyse and solve current challenges with the example of Li-ion and solid-state battery-related research and development. Here, nuclear reaction analysis and Rutherford backscattering spectrometry can provide spatial resolutions down to 70 nm and 1% accuracy. To demonstrate the new insights to be gained by IBA, SiOx-containing graphite anodes are lithiated to six states-of-charge (SoC) between 0–50%. The quantitative Li depth profiling of the anodes shows a linear increase of the Li concentration with SoC and a match of injected and detected Li-ions. This unambiguously proofs the electrochemical activity of Si. Already at 50% SoC, we derive C/Li = 5.4 (< LiC6) when neglecting Si, proving a relevant uptake of Li by the 8 atom % Si (C/Si ≈ 9) in the anode with Li/Si ≤ 1.8 in this case. Extrapolations to full lithiation show a maximum of Li/Si = 1.04 ± 0.05. The analysis reveals all element concentrations are constant over the anode thickness of 44 µm, except for a ~6-µm-thick separator-side surface layer. Here, the Li and Si concentrations are a factor 1.23 higher compared to the bulk for all SoC, indicating preferential Li binding to SiOx. These insights are so far not accessible with conventional analysis methods and are a first important step towards in-depth knowledge of quantitative Li distributions on the component level and a further application of IBA in the battery community.

On the Development of a Method for Determining the Concentration of Hydrogen in Materials Based on Nuclear Backscattering Spectrometry

Metal hydrides and their alloys are widely used in nuclear power engineering and are regarded as promising hydrogen accumulators. Due to the nature of materials used in reactors, nondestructive methods are required to determine the concentration of hydrogen and its content in hydrides under the influence of a harsh environment. In this paper, a technique based on nuclear backscattering spectrometry is proposed, which allows determination of the hydrogen content in a sample at a depth of up to 100 μm. The profiles of the hydrogen distribution in Al, Mg, Ti, Zr, and their hydrides are measured. Estimation of the radiation damage to the sample is performed using the example of polymer impregnation of the protective coating.

Investigation of Plasma Gradient Coatings with a Top Hafnium-Oxide Layer by Nuclear Backscattering Spectrometry

Investigation of Plasma Gradient Coatings with a Top Hafnium-Oxide Layer by Nuclear Backscattering Spectrometry

Formation and investigation of nanocomposite gradient coating with upper layer of hafnia

Nanostructured hafnia films and gradient coatings NiCoCrAlY – (7YSZ + NiCoCrAlY) – 7YSZ – (7YSZ + 9YSH) – 9YSH were deposited by low pressure plasma spraying using a supersonic nozzle creating Prandtl-Meyer expansion fan. The coatings have been analyzed by scanning electron microscopy, nuclear backscattering spectrometry (NBS), XRD analysis, scratch testing, thermal analysis and thermal insulation testing. The coating structure are characterized by the mixture of lamellar and nanostructured regions composed of nanoparticle with sizes of 0.02–0.04 μm. Profiling of the coatings elemental composition by NBS method has indicated the presence of transition zones of the mixed composition at the layers boundaries. Synchronous thermal analysis has showed stability of the 9YSH coating structure at temperatures up to 1200 °C and a tiny exothermic process around 1400 °C. In thermal insulation test the thermal conductivity of gradient coatings ceramic layers was estimated as the range of 0.2–0.7 W/m·K at temperatures of 1200–2700 °C. The gradient coating with thickness of 150 μm reduced the heat flow to the cooling system to 0.34 from the initial one.

Investigation of zirconia plasma electrolytic oxidation coatings by nuclear backscattering spectrometry

Zirconia coatings of a thickness up to 110 μm were obtained by plasma electrolytic oxidation (PEO) in silicate-alkaline and silicate-hypophosphite electrolytes. Layer-by-layer structure and total porosity of the coatings were investigated using proton nuclear backscattering spectrometry (NBS). The PEO coating obtained in the first electrolyte has a thick transition layer with decreasing oxygen content with the depth increasing. The coating formed in the second electrolyte has a thick layer of zirconia and a thin transition layer. When analyzing the NBS spectra, the thickness is determined without taking porosity into account (so called mass thickness). The total porosity of the coatings was evaluated by determining the difference between their geometric and mass thicknesses: 15 and 22%, respectively. The critical load of disruption is higher for the PEO coating formed in the silicate-hypophosphite electrolyte.

Study of Plasma Electrolytic Oxidation Coatings on Aluminum Composites

Coatings, with a thickness of up to 75 µm, were formed by plasma electrolytic oxidation (PEO) under the alternating current electrical mode in a silicate-alkaline electrolyte on aluminum composites without additives and alloyed with copper (1–4.5%). The coatings’ structure was analyzed by scanning electron microscopy, X-ray microanalysis, X-ray photoelectron spectroscopy, nuclear backscattering spectrometry, and XRD analysis. The coatings formed for 60 min were characterized by excessive aluminum content and the presence of low-temperature modifications of alumina γ-Al2O3 and η-Al2O3. The coatings formed for 180 min additionally contained high-temperature corundum α-Al2O3, and aluminum inclusions were absent. The electrochemical behavior of coated composites and uncoated ones in 3% NaCl was studied. Alloyage of aluminum composites with copper increased the corrosion current density. Plasma electrolytic oxidation reduced it several times.

Study of hafnium-oxide coatings by means of nuclear backscattering spectrometry

Single-layer coatings made of hafnium oxide and double-layer structures with an intermediate nickel layer, the total thickness of which is 70 μm, are obtained via plasma spraying with a supersonic jet in a rarefied atmosphere. A nozzle extension capable of implementing a Prandtl–Meyer expansion fan is used to generate nanostructured coatings. The coatings are investigated via the nuclear backscattering of spectrometry 7.6 MeV protons, scanning electron microscopy, X-ray microanalysis, and X-ray diffraction. The studies of the surface and transverse microsection of the coatings indicate that they comprise not only deformed particles of the sprayed powder with sizes of greater than 20 μm but also layers and conglomerates of nanoparticles with sizes of 30–60 nm. Depth profiling of the elemental composition performed by means of the nuclear backscattering spectrometry of protons demonstrates that transition layers exist at the interface between the substrate and coating layers characterizing the average size of the coating microparticles. A comparison of thicknesses defined by two methods allows estimation of the overall porosity of the hafnium-oxide layer. In accordance with X-ray diffraction data, the cubic and monoclinic phases of hafnium oxide with a high fraction of the amorphous component are formed in the coating.

Investigation of the structure of carbon-ceramic composite using of electron microscopy and nuclear backscattering spectrometry

The structure and composition of carbon-ceramic composite FEBUS reinforced with carbon fibers based on viscose, as well as its precursors, are studied using the methods of scanning electron microscopy with energy dispersion analysis and nuclear backscattering spectrometry of 7.5 MeV protons. It is shown that impregnation of the composite precursor with Si (up to ∼30 at %) scarcely leads to siliconizing of the reinforcing fibers. With the stoichiometry of SiC taken into account, the fraction of the carbide component in the composite reaches ∼40%; the remaining ∼60% is the carbon component.

Study of the structure of ceramic-polymer functional coatings via nuclear backscattering spectrometry

Coatings prepared by the microarc oxidation (MAO) of aluminum alloys AMg-3 and V-95 with subsequent filling with poly-p-xylylene by vapor-phase polymerization on a surface are studied. It is found that filling with the polymer makes it possible to reduce the through porosity of MAO coatings by a factor of more than 5. It is shown that nuclear backscattering spectrometry with 7.5 MeV protons is an efficient and nondestructive method for measuring the composition and thickness of layered ceramic-polymer coatings.

Study of nanostructured coatings prepared by low-pressure plasma spraying with a supersonic jet

Zirconia coatings on copper prepared by the low-pressure plasma spraying of a ZrO2 + 5% Y2O3 powder through a mesh mask exhibit high resistance and low thermal conductivity in tests in the nitrogen plasma stream of a plasmatron. Data on the coating structure and its changes during thermal testing derived by scanning electron microscopy, X-ray diffraction analysis, and nuclear backscattering spectrometry are discussed.

Investigation of zirconia coatings obtained under plasma action in electrolytes

The results of experiments on the production of zirconia (ZrO2)-based thermal barriert coatings on copper substrates under plasma action in electrolytes on preliminary applied zirconium layers are represented. Structural-morphological investigations by scanning electron microscopy, X-ray analysis, and nuclear backscattering spectrometry showed that micro-arc oxidation (MAO) makes it possible to produce Zr-ZrO2 coatings with a thermal barrier ZrO2 layer with a thickness of more than 100 μm, which is separated from the substrate of the base by a dense MAO barrier layer and a nonoxidized zirconium layer.

The study of zirconium alloy coatings produced by microarc oxidation using Rutherford and nuclear backscattering spectrometry

The effect of the electrolyte composition during microarc oxidation of the E110 zirconium alloy on the corrosion resistance of coatings is investigated using proton Rutherford backscattering spectrometry, nuclear backscattering spectrometry, and other methods.

The study of ceramic-like oxide coatings on zirconium produced by plasma treatment in electrolytes

Ceramic-like oxide coatings on zirconium with a thickness of up to 300 μm produced by plasma treatment in an electrolyte demonstrate high thermal resistivity and low thermal conductivity during high-temperature testing in a plasmatron in a plasma flow. Data on the structure of coatings and its changes during thermal testing obtained using the methods of scanning electron microscopy, X-ray diffraction analysis, and nuclear backscattering spectrometry are discussed.

A comparative study of TiN and TiC: Oxidation resistance and retention of xenon at high temperature and under degraded vacuum

Dense TiN and TiC samples were prepared by hot pressing using micrometric powders. Xenon species (simulating rare gas fission products) were then implanted into the ceramics. The samples were annealed for 1 h at 1500 °C under several degraded vacuums with PO2 varying from 10−6 to 2×10−4 mbars. The oxidation resistance of the samples and their retention properties with respect to preimplanted xenon species were analyzed using scanning electron microscopy, grazing incidence x-ray diffraction, Rutherford backscattering spectrometry, and nuclear backscattering spectrometry. Results indicate that TiC is resistant to oxidation and does not release xenon for PO2≤6×10−6 mbars. When PO2 increases, geometric oxide crystallites appear at the surface depending on the orientation and size of TiC grains. These oxide phases are Ti2O3, Ti3O5, and TiO2. Apparition of oxide crystallites is associated with the beginning of xenon release. TiC surface is completely covered by the oxide phases at PO2=2×10−4 mbars up to a depth of 3 μm and the xenon is then completely released. For TiN samples, the results show a progressive apparition of oxide crystallites (Ti3O5 mainly) at the surface when PO2 increases. The presence of the oxide crystallites is also directly correlated with xenon release, the more oxide crystallites are growing the more xenon is released. TiN surface is completely covered by an oxide layer at PO2=2×10−4 mbars up to 1 μm. A correlation between the initial fine microstructure of TiN and the properties of the growing layer is suggested.

Thermal behaviour of xenon in zirconium carbide at high temperature: Role of residual zirconia and free carbon

Transition metal carbides, such as ZrC, are interesting candidates used as structural and fuel cladding materials for the 4th generation Gas cooled Fast Reactors. A study has been carried out to elucidate the role of temperature on the diffusion of xenon in zirconium carbide. For that purpose, zirconium oxycarbide samples (ZrC 0.95O 0.05) have been prepared from powders synthesized by carbothermal route and sintered by Spark Plasma Sintering at 2125 K. Two batches have been studied in order to evaluate the role of the presence of free carbon and zirconia during high temperature annealing. The composition and microstructural features of the sintered samples such as stoichiometry, density and grain size have been determined using complementary analytical techniques such as Nuclear Backscattering Spectrometry, Electron Microscopy and elementary chemical analysis. Ions of 136Xe 2+ have been implanted at an energy of 800 keV corresponding to a mean projected range of 160 nm and at an ion fluence of 10 16 cm −2 corresponding to a maximum concentration of 1 at.%. Thermal annealing has been carried out in a temperature range from 1775 to 2075 K. The xenon distribution profiles have been measured by Rutherford Backscattering Spectrometry before and after the different treatments. The results show that the presence of residual zirconia induces a strong damage of the surface and that pure ZrC sintered specimen display less degradation of the surface and better retention capabilities for xenon.

Examination of medicinal agents by nuclear backscattering spectrometry of protons

It is proposed to exam pelleted medicinal agents by nuclear backscattering spectrometry of protons. The backscattering spectra of 7.8-MeV protons have been measured for such medicinal agents as analginum, aspirin, lizobact, and berlicort, as well as for chalk and starch—examples of a base for forged medicinal agents. The measurement results indicate that proton backscattering spectrometry can be used to detect forged medicinal agents.

Thermally Induced Atomic Transport in Nanometric LaAlON Films on Si

The thermal stability of nanometric lanthanum aluminum oxynitride films on silicon was investigated in vacuum and oxygen. Isotopic enrichment of the films with 15 N and of the annealing atmosphere with 18 O combined with nuclear reaction analysis and Rutherford backscattering spectrometry provides direct evidence of atomic transport starting at 600°C. Oxygen exchange and nitrogen replacement are identified. Interfacial silicon oxide growth takes place as the interfacial N concentration falls below 5 X 10 21 cm -3 . Complementary X-ray photoelectron spectroscopy shows changes in chemical bonding as a function of annealing temperature and ambient.

Application of the particle backscattering methods for the study of new oxide protective coatings at the surface of Al and Mg alloys

Rutherford (1.5 MeV 4He +) and Nuclear (7.7 MeV H +) Backscattering Spectrometry were used for investigation of oxide protective coatings on the surface of Al and Mg alloys obtained by microarc oxidation (MAO). A model of microarc coating formation is proposed. For Mg alloy, the structure of MAO coating with very high corrosion resistance was determined.

Nature of super-lubricating MoS2 physical vapor deposition coatings

MoS2 is a well-known solid lubricant used for space applications. Radio frequency (rf) magnetron sputtered MoS2 films are being used increasingly, due to an ultra-low friction behavior in high vacuum (friction coefficient: ∼0.01). MoS2 coatings with a super-low friction behavior (friction coefficient: ∼0.001) have been recently synthesized in an ultra-high vacuum tribometer equipped with a rf magnetron sputtering device. Physicochemical and structural characterizations of the thin films have been carried out using XPS (x-ray photoelectron spectroscopy) and AES (Auger electron spectroscopy) to determine the extreme surface composition, HRTEM (high-resolution transmission electron microscopy), GXRD (grazing-angle x-ray diffraction) for structural investigations, RBS (Rutherford backscattering spectrometry) for thickness and stoichiometry determination, and NBS (nuclear backscattering spectrometry) for quantitative analysis of oxygen contamination. Indentation tests at nanometric scale have also been performed to compare the mechanical constants (Young modulus, hardness) of the sputtered MoS2 films with the characteristics of molybdenite and to confirm the overall data. The coatings are made of highly pure, stoichiometric MoS2, with a polycrystalline microstructure (grain size on the order of 10 nm). The stoichiometry is MoS1.97±0.10O0.10±0.01. Most of the grains are ‘‘edge-oriented’’ on the substrate surface [relative to their (002) basal planes], with an azimuthal disorder of the other crystallographic directions [(100) and (110)]. Consequently, and by comparison with already published data, the super-low friction regime is found to be associated with the purity and microstructure of the coating.

Nitrogen implantation in iron: Influence of the beam current density and of the chamber residual pressure

Abstract Iron samples were implanted at a fluence of 1017 N+ ions.cm−2 with an energy of 50 keV. The beam current density was varied in the range 6–60 μA.cm−2 as well as the quality of the vacuum in the implantation chamber. Implantations were performed at 150°C to favour the carburization process. Carbon and oxygen contaminations were controlled using nuclear backscattering spectrometry (NBS) with α particles of 5.7 MeV and 7.5 MeV respectively or by using Auger electron spectroscopy (AES). The depth profiles of implanted nitrogen were determined by the 15N(p,αγ) nuclear reaction or by AES when 15N or 14N ions were implanted respectively. Implantation induced chemical phases were characterized using Mossbauer spectroscopy and electron diffraction. It is shown that at 150°C the beam current density which has an influence on the implantation time as well as the contamination carbon content at the surface play an important role in the migration process of nitrogen. Consequently, the nitrogen depth distribut...