Secondary Ion Research Articles

Characterization of silicon-based chromium (VI) replacement coatings by using time-of-flight secondary ion mass spectrometry and salt spray tests

This paper proposes an innovative approach in characterization of silicon-based chromium (VI) replacement coatings on an Al substrate by using, salt spray tests and time-of-flight secondary ion mass spectrometry (ToF-SIMS) performed in profile mode by a gas cluster ion beam source (GCIB). While salt spray tests highlight the difference in anticorrosion behaviour, ToF-SIMS provides molecular information on the entire coating and even down to the interface with the Al substrate. ToF-SIMS revealed Si2O2+ and SiOAl + fragments which both contribute to understanding the differences in the anticorrosion performance which are found in the salt spray tests. Si2O2+ moieties relate to the cross-linking density of the coating and subsequently determines the barrier properties. SiOAl+ originates from the interface and characterizes the actual “conversion” of Al at the interface by the deposited layer. The differences in the profile of Si2O2+ and SiOAl + explained the respective anticorrosion performance. From the tested coatings PCT161 showed the highest intensity for both Si2O2+ and SiOAl + while simultaneously performing the best results in the salt spray test. These observations highlight that Si2O2+ and SiOAl + fragments are good indicators of anticorrosion performance and are confirmed by salt spray tests. Moreover, PCT161 and PCT146 are true conversion coatings capable of replacing chromium-based systems.

HIDALGO: A FUN object from the earliest epoch of the solar system’s history

Chemical and isotopic measurements of HIDALGO, a stoichiometrically pure hibonite inclusion found in the matrix of the Dar al Gani 027 meteorite, were conducted by secondary ion mass spectrometry to investigate its origin and evolution. HIDALGO is characterized by large mass-dependent isotope fractionations in O, Ca, and Ti, as well as large negative anomalies in neutron-rich 48Ca and 50Ti, making it the newest member of the HAL-type FUN inclusions. The highly fractionated Ca and Ti isotopes but unfractionated Mg isotopes are consistent with HIDALGO being a residue from an extensive evaporation event, during which large fractions of initial Ca and Ti, and essentially all the initial Mg, in the precursor material were lost. HIDALGO appears to have incorporated live 26Al at a higher level than other HAL-type inclusions, but still at a lower amount compared to the Solar System’s initial 26Al abundance typically found in non-FUN CAIs. Interestingly, the inferred 10Be abundance in HIDALGO is comparable to the values observed in the majority of CV3 CAIs but ∼ 2.5 times higher than those in HAL-type samples. HIDALGO’s unusual 26Al/27Al and 10Be/9Be ratios, together with the 48Ca-50Ti anomalies, can be best explained by the formation of its precursor material in the isotopically heterogeneous solar nebula. Finally, large 7Li excesses correlating with Be/Li were found in HIDALGO, a behavior that can be interpreted as due to in-situ decay of live 7Be. Charged particle spallation of initially Li-free HIDALGO can simultaneously account for the inferred 7Be abundance and the measured Li elemental concentration. The consistency between the measurement and spallation calculation results provides support for the prior existence of 7Be in HIDALGO, possibly produced by irradiation close to the Sun

Achievable hole concentration at room temperature as a function of Mg concentration for MOCVD-grown p-GaN after sufficient annealing

Relationship between the hole concentration at room temperature and the Mg doping concentration in p-GaN grown by MOCVD after sufficient annealing was studied in this paper. Different annealing conditions were applied to obtain sufficient activation for p-GaN samples with different Mg doping ranges. Hole concentration, resistivity and mobility were characterized by room-temperature Hall measurements. The Mg doping concentration and the residual impurities such as H, C, O and Si were measured by secondary ion mass spectroscopy, confirming negligible compensations by the impurities. The hole concentration, resistivity and mobility data are presented as a function of Mg concentration, and are compared with literature data. The appropriate curve relating the Mg doping concentration to the hole concentration is derived using a charge neutrality equation and the ionized-acceptor-density [ ] (cm−3) dependent ionization energy of Mg acceptor was determined as = 184 − 2.66 × 10−5 × [ ]1/3 meV.

Gemini cationic surfactant of 1, 3-bis (dodecyl dimethyl ammonium chloride) propane as a novel excellent inhibitor for the corrosion of cold rolled steel in HCl solution

Gemini surfactants have become the research focus of novel excellent inhibitors because of their special structure (two amphiphilic moieties covalently connected at head group by a spacer) and excellent surface properties. It is proved by theoretical calculations that 1, 3-bis (dodecyl dimethyl ammonium chloride) propane (BDDACP) molecules can perform electron transfer with Fe (110). And it has a small fraction free volume, thus greatly reducing the diffusion and migration degree of corrosive particles. The potentiodynamic polarization curve showed that coefficients of cathodic and anodic reaction less than 1 and polarization resistance increased to 1602.9 Ω cm−2 after added BDDACP, confirming that BDDACP significantly inhibited the corrosion reaction by occupying the active site. The electrochemical impedance spectrum of imperfect semi-circle shows that the system resistance increases and double layer capacitance after added BDDACP. Weight loss tests also confirmed that BDDACP forms protective film by occupying the active sites on steel surface, and the maximum inhibition efficiency is 92 %. Comparison of the microscopic morphology showed that steel surface roughness was significantly reduced after added BDDACP. The results of time-of-flight secondary ion mass spectrometry show that steel surface contains some elements from BDDACP, which confirms the adsorption of BDDACP on steel surface.

Gamma‐ray‐induced modification of poly(ethylene terephthalate) and polypropylene solid materials with halogen‐containing olefins for X‐ray CT image contrast enhancement

AbstractIt is known that X‐ray CT of organic polymer materials usually provides low‐contrast images because of the low X‐ray absorption of these materials. In this paper, we describe a new method to enhance the contrast of X‐ray CT images of organic polymer materials. We demonstrate that gamma‐ray irradiation of poly (ethylene terephthalate) (PET) fibers in dichloromethane containing 2‐bromoethyl methacrylate, 2‐chloroethyl methacrylate, or 4‐bromostyrene results in the grafting of halogen‐containing oligomeric chains onto the PET fibers. Focused ion beam scanning electron microscopy (FIB‐SEM) and time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS) analyses revealed a homogeneous distribution of bromine atoms within the 2‐bromoethyl methacrylate‐modified PET fibers, not only on the surface. This uniform incorporation translated to a significant improvement in X‐ray CT image contrast compared with pristine fibers. Similar treatment of polypropylene pellets also enhanced the contrast of their X‐ray CT images. This is a new simple and effective method to enhance the X‐ray CT image contrast and potentially applicable to various polymer materials including polymer composites and porous polymer materials, readily allowing the observation of their 3D microstructures finely.

Unraveling the composition of each atomic layer in the MXene/MAX phase structure - identification of oxycarbide, oxynitride, and oxycarbonitride subfamilies of MXenes.

MXenes, the largest known family of 2D materials, are known for their complicated structure consisting of many different elements. Their properties can be finely tuned by precise engineering of the composition of each atomic layer. Thus it is necessary to further develop the secondary ion mass spectrometry (SIMS) technique which can unambiguously identify each element with atomic precision. The newly established protocol of deconvolution and calibration of the SIMS data enables layer-by-layer characterization of MAX phase and MXene samples with ±1% accuracy. Such precision is particularly important for samples that consist of several different transition metals in their structure. This confirms that most MXenes contain a substantial amount of oxygen in the X layers, thus enabling the identification of oxycarbide, oxynitride, and oxycarbonitride subfamilies of these materials. It can also be applied for under- and over-etched samples and to determine the exact composition of termination layers. Generally, the SIMS technique may provide invaluable support in the synthesis and optimization of MAX phase and MXene studies.

Effects of different soda loss measurement techniques on brownstock quality

The efficiency of the kraft recovery plant, bleaching process, and paper machine are affected when black liquor carryover from the brownstock washers is not controlled well. Measuring soda loss within a mill can vary from using conductivity, either in-situ or with a lab sample of black liquor filtrate squeezed from the last stage washer, to measuring absolute sodium content with a lab sodium specific ion probe or spectrophotometer. While measuring conductivity has value in tracking trends in black liquor losses, it is not an acceptable method in reporting losses in absolute units, typically in lb/ton of pulp. This is further complicated when trying to benchmark soda loss performance across a fleet of mills with multiple washer lines. Not only do the testing methods vary, but the amount of bound soda on high kappa pulps can be significant. This variability creates inconsistent results, and studies are needed to understand the effect of different testing methods on the pulp quality. In this study, soda loss is expressed as sodium sulfate (Na2SO4). Four different methods to measure soda content in pulp off commercial brownstock washers were studied: full digestion (FD), washing soaking overnight and washing (WSW), soaking in boiling water and stirring 10-min (SW-10), and squeeze-no wash (Sq). Total, washable, and bound sodium sulfate calculations were determined for each soda content measuring technique using inductively coupled plasma-optical emission spectroscopy (ICP-OES). Results showed bound and washable sodium sulfate amounts significantly depend on which soda measurement technique was used. In addition, the soda results were correlated with the pulp kappa numbers. As the kappa number increases, bound soda increases, regardless of the soda measurement method used. Impacts of high sodium sulfate in brownstock are also discussed.

Alkali cation stabilization of defects in 2D MXenes at ambient and elevated temperatures

Transition metal carbides have been adopted in energy storage, conversion, and extreme environment applications. Advancements in their 2D counterparts, known as MXenes, enable the design of unique structures at the ~1 nm thickness scale. Alkali cations have been essential in MXenes manufacturing processing, storage, and applications, however, exact interactions of these cations with MXenes are not fully understood. In this study, using Ti3C2Tx, Mo2TiC2Tx, and Mo2Ti2C3Tx MXenes, we present how transition metal vacancy sites are occupied by alkali cations, and their effect on MXene structure stabilization to control MXene’s phase transition. We examine this behavior using in situ high-temperature x-ray diffraction and scanning transmission electron microscopy, ex situ techniques such as atomic-layer resolution secondary ion mass spectrometry, and density functional theory simulations. In MXenes, this represents an advance in fundamentals of cation interactions on their 2D basal planes for MXenes stabilization and applications. Broadly, this study demonstrates a potential new tool for ideal phase-property relationships of ceramics at the atomic scale.

Enhancement of anti-oxidation and tensile strength of nanotwinned Cu foils by preferential Ni electrodeposition

In this study, Ni was employed to enhance the mechanical properties of nanotwinned copper (NT-Cu) foils due to its excellent oxidation resistance and compatibility with Cu. The tensile strength of the NT-Cu foils was enhanced 12.6 % (752.8 to 847.3 MPa) by Ni co-electrodeposition. During the electroplating, it was found that Ni ions inhibited the Cu growth, causing the reduction potential (overpotential) to shift in the negative direction. It resulted in a reduced deposition rate and decreased the twin spacing of the foils. Additionally, Ni ions acted as impurities for the grain refinement. Time of flight secondary ion mass spectrometry (TOF-SIMS) results indicated that Ni atoms were deposited on the top and bottom of the foils due to the limiting current density of Ni. The NT-Cu-Ni exhibited low roughness and performed superior resistance to oxidation compared to the NT-Cu. X-ray photoelectron spectroscopy (XPS) was also utilized to characterize the oxidation of the Cu (Ni) alloys. These mechanisms contributed to high strength, low resistivity, and excellent oxidation resistance of the NT-Cu-Ni foils for future battery materials.

Microwave-assisted Facile Synthesized Carbon Dots as "on-off-on" Fluorescence Probes for Mercury and Iodine Ions in Bio-samples and Cell Imaging.

A kind of nitrogen and sulfur co-doped CDs (N, S-CDs) was facilely synthesized using thiourea and citric acid as precursors, which established an "on-off-on" fluorescence probe to sequential detecting mercury and iodine ions inside water and biology samples. Under 360nm excitation, CDs emit blue fluorescence with an optimal emission peak of 425nm (on). The fluorescence of CDs experiences a significant quenching effect upon interaction with Hg2+ ions due to the electron transfer between CDs and Hg2+. This quenching effect is subsequently recovered upon the addition of I- owing to the formation of complexes between Hg2+ and I-. The probe exhibits high selectivity and sensitivity toward Hg2+ and I- with broad linearity in the range of 5-50μM and 15-60μM, respectively, and a low detection limit of 14.336nM and 38.213nM, respectively. The constructed fluorescence probe N, S-CDs has been successfully applied to the detection of Hg2+ and I- in water and biological samples with great recoveries. More importantly, the bioimaging study demonstrated that N, S-CDs are suitable for live monitoring in biological imaging scenarios of Hg2+ and I- in living cells.

BreathXplorer: Processing Online Breathomics Data Generated from Direct Analysis Using High-Resolution Mass Spectrometry.

Nontargeted breath analysis in real time using high-resolution mass spectrometry (HRMS) is a promising approach for high coverage profiling of metabolites in human exhaled breath. However, the information-rich and unique non-Gaussian metabolic signal shapes of real-time HRMS-based data pose a significant challenge for efficient data processing. This work takes a typical real-time HRMS technique as an example, i.e. secondary electrospray ionization high-resolution mass spectrometry (SESI-HRMS), and presents BreathXplorer, an open-source Python package designed for the processing of real-time exhaled breath data comprising multiple exhalations. BreathXplorer is composed of four main modules. The first module applies either a topological algorithm or a Gaussian mixture model (GMM) to determine the start and end points of each exhalation. Next, density-based spatial clustering of applications with noise (DBSCAN) is employed to cluster m/z values belonging to the same metabolic feature, followed by applying an intensity relative standard deviation (RSD) filter to extract real breath metabolic features. BreathXplorer also offers functions of (1) feature alignment across the samples and (2) associating MS/MS spectra with their corresponding metabolic features for downstream compound annotation. Manual inspection of the metabolic features extracted from SESI-HRMS breath data suggests that BreathXplorer can achieve 100% accuracy in identifying the start and end points of each exhalation and acquire accurate quantitative measurements of each breath feature. In a proof-of-concept study on exercise breathomics using SESI-HRMS, BreathXplorer successfully reveals the significantly changed metabolites that are pertinent to exercise. BreathXplorer is publicly available on GitHub (https://github.com/HuanLab/breathXplorer). It provides a powerful and convenient-to-use tool for the researchers to process breathomics data obtained by directly analysis using HRMS.

ND70 Series Basaltic Glass Reference Materials for Volatile Element (H2O, CO2, S, Cl, F) Measurement and the C Ionisation Efficiency Suppression Effect of Water in Silicate Glasses in SIMS

We present a new set of reference materials, the ND70‐series, for in situ measurement of volatile elements (H2O, CO2, S, Cl, F) in silicate glass of basaltic composition. The materials were synthesised in piston cylinders at pressures of 1 to 1.5 GPa under volatile‐undersaturated conditions. They span mass fractions from 0 to 6% m/m H2O, from 0 to 1.6% m/m CO2 and from 0 to 1% m/m S, Cl and F. The materials were characterised by elastic recoil detection analysis for H2O, by nuclear reaction analysis for CO2, by elemental analyser for CO2, by Fourier transform infrared spectroscopy for H2O and CO2, by secondary ion mass spectrometry for H2O, CO2, S, Cl and F, and by electron probe microanalysis for CO2, S, Cl and major elements. Comparison between expected and measured volatile amounts across techniques and institutions is excellent. It was found however that SIMS measurements of CO2 mass fractions using either Cs+ or O− primary beams are strongly affected by the glass H2O content. Reference materials have been made available to users at ion probe facilities in the US, Europe and Japan. Remaining reference materials are preserved at the Smithsonian National Museum of Natural History where they are freely available on loan to any researcher.

Mechanically Robust Current Collector with Gradient Lithiophilicity Induced by Spontaneous Lithium Ion Diffusion for Stable Lean-Lithium Metal Batteries.

Lean-lithium metal batteries represent an advanced version of the anode-free lithium metal batteries, which can ensure high energy density and cycling stability while addressing the safety concerns and the loss of energy density caused by excessive lithium metal. Herein, a mechanically robust carbon nanotube framework current collector with gradient lithiophilicity is constructed for a lean-lithium metal battery. Using the physical vapor deposition method, precise prelithiation of a carbon nanotube framework is achieved, eliminating its irreversible capacity, retaining the porous structure in the framework, and inducing the gradient lithiophilicity formation due to spontaneous lithium ion diffusion. The lithiophilic gradient and three-dimensional porous structure are characterized by time-of-flight secondary ion mass spectrometry (TOF-SIMS), scanning transmission electron microscopy (STEM), and corresponding electron energy loss spectroscopy (EELS), which enables the preferential deposition of lithium ions at the bottom of the carbon nanotube framework, thereby avoiding lithium losses associated with dead lithium. As a result, in the LiFePO4 full cell with an ultralow N/P ratio of 0.15, the initial Coulombic efficiency increases from 77.75 to 95.07%. Collaborating synergistically with the ultrathin (1.5 μm) lithium metal, serving as a gradual lithium supplement, the full cell with an N/P ratio of 1.43 demonstrates an 86% capacity retention after 500 cycles at 1C, far surpassing the copper-based counterparts (0.9%).

SIMS analysis of the degradation pathways of methylammonium lead-halide perovskites

This study employed time-of-flight secondary ion mass spectrometry (TOF-SIMS) to investigate degradation pathways at the nanoscale, utilizing its capacity for in-depth chemical and structural analysis through various methods, including depth profiling and 3D analysis. A key focus is the matrix effect in ToF-SIMS, which alters secondary ion yields based on the sample matrix composition, influencing species identification and quantification. We show that this effect can be used to enhance the resolution of ToF-SIMS beyond its traditional limits, allowing for detailed imaging of the degradation process. Our findings indicate that the initial formation of PbI2 phases, a crucial step in the degradation pathway triggered by environmental factors, can be traced and visualized. By investigating the sputtering yields and secondary ion formation, we reveal the nonlinear sputtering regimes present in MAPI, contributing to our understanding of the mechanisms driving perovskite degradation. The application of this enhanced analytical technique paves the way for improved degradation studies.

Zircon Internal Deformation and Its Effect on U-Pb Geochronology: A Case Study from the Himalayan High-Pressure Eclogites

Zircon, with a chemical formula of ZrSiO4, is a widely used mineral for determining the crystallization age of igneous rocks. It is also used to constrain the timing of metamorphic events from its overgrowth or recrystallized domains. Furthermore, detrital zircon grains can provide information on the sedimentary provenance. Due to the trace amounts of uranium (parent) which decays into its daughter element (Pb), it is a prime geochronometer for the majority of magmatic and metamorphic rocks. With high-precision analytical instruments, such as TIMS, SIMS, and LA-ICP-MS, huge amounts of geochronological and trace element data from zircon have been generated around the globe to date. Target domains within zircon grains are analyzed to extract geochemical and geochronological records using spatially resolved techniques such as ion probes or laser ablation coupled with mass spectrometry. Before any such analysis, the zircon grains are examined for internal structures, growth zoning, and the presence of tiny inclusions. However, many researchers analyze multiple domains within single zircon grains for U-Pb isotope analysis with little regard for their internal structures, particularly crystallographic orientations. Hence, they may obtain mixed ages with variable discordance, leading to imprecise interpretation especially when the growth domains are not well-identified. Particularly, zircon grains that contain multi-growth domains or have local internal deformations within a single grain may not produce geologically meaningful age results if the analyses are conducted on mixed domains. This study presents a brief review on zircon geochronology, how to identify and visualize micro-deformations in metamorphic zircons through the EBSD analysis, and the effects of micro-deformation on age results. Examples from a case study conducted on zircons hosted in the Himalayan high-pressure eclogites are presented that show intra-grain plastically deformed domains and their effects on the corresponding age results.

Sputtering yield increase with fluence in low-energy argon plasma-tungsten interaction

The increase of tungsten sputtering yield with fluence was investigated during plasma (≤100 eV) irradiation. This analysis focused on the combined effects of surface binding energy and surface morphology caused by Ar retention. As post-mortem analysis, Ar concentration was measured with SIMS (Secondary Ion Mass Spectroscopy) and TDS (Thermal Desorption Spectroscopy). The Ar concentration saturated at 21 % of W number density during the sputtering process. The corresponding change in surface morphology causes a change in the local ion incident angle, which leads to a sputtering yield increase of 10 %. The increased Ar concentration leads to a decrease in surface binding energy and a change in surface morphology which increases W sputtering yield from 0.02 to 0.03 by ion energy 80 eV. Over time, W sputtering yield reaches saturation as a function of saturated Ar concentration. This result implies that the synergistic role of Ar concentration and surface morphology on sputtering yield. This sputtering yield enhancement occurs more seriously in the realistic condition of plasma-facing materials that face low-energy plasma.

A study on the surface responses and degradation mechanisms of epoxy-amine coating subjected to UV accelerated weathering and hygrothermal ageing using ToF-SIMS and FTIR analysis

Epoxy amine coatings were subjected to hygrothermal ageing and accelerated weathering conditions that is comprised of neutral salt spray test and UV accelerated degradation condition. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and Fourier Transform Infrared Spectroscopy (FTIR) were employed to study the surface responses and spectral variation of epoxy amine coatings subjected to different ageing conditions. As a result, principal component analysis (PCA) of ToF-SIMS positive ion spectra illustrated that principal component 1 (PC1) has collected information on a variation of surface responses caused by accelerated weathering and hygrothermal ageing conditions as compared to fresh epoxy amine coatings. On the other hand, principal component 2 (PC2) has distinguished the different surface responses generated on epoxy amine coatings that were subjected to UV accelerated degradation conditions and those that were not. FTIR analysis has demonstrated the hydrolysis and photooxidation of epoxy amine coatings from the growth of two absorption bands at 1709 cm−1 and 1650 cm−1, indicating the formation of carbonyl-containing groups such as ketones, aldehydes, phenyl formates, imine or tertiary amides. This comprehensive analysis provides significant insights into the degradation mechanisms of epoxy amine coatings subjected to corrosion under insulation (CUI) and/or artificial weathering (AW) environment. Understanding these mechanisms is pivotal for industries reliant on epoxy coatings, such as oil and gas, ensuring enhanced performance and extended lifespan of their products under varying environmental conditions. The findings also contribute to the broader field of materials science by offering methodologies and analytical approaches that can be applied to other polymeric coatings and materials.

Copper Deposited on Reduced Titania as Catalyst for the Production of CH4 from Sunlight and Air

AbstractAtmospheric CO2 and H2O adsorbed on the photocatalyst surface undergo sunlight‐assisted conversion to solar products that bridge the gaps between artificial and natural photosynthesis. Herein, we report a Lewis acid‐base interaction derived photocatalyst, Cu deposited on reduced titania, that harvests CO2 and H2O from the air and transforms them to CH4. Photocatalyst surface studies confirm that coordinately unsaturated Cu atoms and oxygen vacancies are formed that facilitate CO2 and H2O adsorption. The mechanistic studies, combined with tandem secondary ion mass spectroscopy and isotopic labelling, confirm the CH4 origin from atmosphere‐adsorbed CO2 and H2O. The contributing factors to photocatalyst instability are explored. We expect that this study will have an impact on the widespread application and economic viability of photocatalytic CO2 reduction.

Probing the Solid-Electrolyte Interface in Lithium Ion Batteries with Time-of-Flight Secondary Ion Mass Spectrometry

Probing the Solid-Electrolyte Interface in Lithium Ion Batteries with Time-of-Flight Secondary Ion Mass Spectrometry

Deployment of Magnetic Sector Secondary Ion Mass Spectrometry Technology on Focused Ion Beam Instruments: From the Initial Concept Idea to the Analytical Add-On System

Deployment of Magnetic Sector Secondary Ion Mass Spectrometry Technology on Focused Ion Beam Instruments: From the Initial Concept Idea to the Analytical Add-On System