Electron Beam Modification Research Articles

Electron-Beam-Induced Modification of N-Heterocyclic Carbenes: Carbon Nanomembrane Formation.

Electron irradiation of self-assembled monolayers (SAMs) is a versatile tool for lithographic methods and the formation of new 2D materials such as carbon nanomembranes (CNMs). While the interaction between the electron beam and standard thiolate SAMs has been well studied, the effect of electron irradiation for chemically and thermally ultrastable N-heterocyclic carbenes (NHCs) remains unknown. Here we analyze electron irradiation of NHC SAMs featuring different numbers of benzene moieties and different sizes of the nitrogen side groups to modify their structure. Our results provide design rules to optimize NHC SAMs for effective electron-beam modification that includes the formation of sulfur-free CNMs, which are more suitable for ultrafiltration applications. Considering that NHC monolayers exhibit up to 100 times higher stability of their bonding with the metal substrate toward electron-irradiation compared to standard SAMs, they offer a new alternative for chemical lithography where structural modification of SAMs should be limited to the functional group.

High-current pulsed electron beam modification on microstructure and performance of Cu/CuW diffusion bonding joints

High-current pulsed electron beam modification on microstructure and performance of Cu/CuW diffusion bonding joints

Copper Beam Electron Alloying with Ti Powder

The paper presents the effect of electron beam alloying on the surface of a copper flat bar (M1Ez4) with titanium powder. Due to the quality of the surface after alloying and the obtained properties, the parameters used were given which met the assumed conditions to the greatest extent. The microstructure and mechanical properties as well as the chemical composition of surface-modified electron-beam copper show improved mechanical properties, i.e. hardness and abrasion resistance. This article uses research techniques using scanning electron microscopy and analysis of chemical composition in micro-areas (EDS). In order to examine the properties of the material after electron beam modification, hardness measurements were performed at low loads (HV0.1), abrasion resistance was tested, and conductivity was also measured. As a result of modifying the chemical and phase composition of M1E copper using an electron beam, the hardness increased by 46%, while the conductivity decreased by 16% due to the formation of intermetallic phases during solidification.

Impact of high-current pulsed electron beam modification on element diffusion and performance of Ti6Al4V/AISI 316 L stainless steel diffusion bonded joints

The diffusion bonding process between Ti6Al4V and 022Cr17NiMo2 stainless steel (AISI 316 L SS) was carried out under vacuum conditions, applying a 10 MPa load for 40 min within a temperature range of 800–900 °C. This study investigates the influence of high-current pulsed electron beam (HCPEB) modification on the microstructure at the interface and the shear strength of Ti6Al4V/AISI 316 L SS joints. After HCPEB pretreatment, a well-formed diffusion bond was achieved between Ti6Al4V and AISI 316 L SS at 900 °C. Through calculations, the diffusion coefficient and diffusion activation energy of Fe in the Ti6Al4V section were determined, which demonstrated that Fe exhibits higher diffusion rates in the HCPEB-modified joints. The modified joint, subjected to 900 °C, exhibited a maximum bond strength of 208 MPa, which is attributed to dispersion and solid solution strengthening. Consequently, the implementation of HCPEB modification proves effective in promoting element diffusion and enhancing the mechanical performance of the joints. The presence of abundant crystal defects, including vacancies, dislocations, and grain boundaries (GBs) generated by HCPEB, is believed to be responsible for the observed improvement in diffusion.

Electron beam modification for improving dose uniformity in irradiated objects

Electron beam modification for improving dose uniformity in irradiated objects

The advantages of sub-sampling and Inpainting for scanning transmission electron microscopy

Images and spectra obtained from aberration corrected scanning transmission electron microscopes (STEM) are now used routinely to quantify the morphology, structure, composition, chemistry, bonding, and optical/electronic properties of nanostructures, interfaces, and defects in many materials/biological systems. However, obtaining quantitative and reproducible atomic resolution observations from some experiments is actually harder with these ground-breaking instrumental capabilities, as the increase in beam current from using the correctors brings with it the potential for electron beam modification of the specimen during image acquisition. This beam effect is even more acute for in situ STEM observations, where the desired outcome being investigated is a result of a series of complicated transients, all of which can be modified in unknown ways by the electron beam. The aim in developing and applying new methods in STEM is, therefore, to focus on more efficient use of the dose that is supplied to the sample and to extract the most information from each image (or set of images). For STEM (and for that matter, all electron/ion/photon scanning systems), one way to achieve this is by sub-sampling the image and using Inpainting algorithms to reconstruct it. By separating final image quality from overall dose in this way and manipulating the dose distribution to be best for the stability of the sample, images can be acquired both faster and with less beam effects. In this paper, the methodology behind sub-sampling and Inpainting is described, and the potential for Inpainting to be applied to novel real time dynamic experiments will be discussed.

Electron beam processing of rubbers and their composites

Abstract Electron beam (EB) processing of pristine and filled polymeric materials is considered as one of the most viable techniques in the development of three-dimensional (3D) network structures of polymeric or composite systems with improved physical and chemical properties. The grafting, or the crosslinking process induced by the merging of the macro free radicals generated during the electron beam modification without the aid of any chemical agent or heat, is responsible for the formation of the 3D networks in polymeric systems. Owing to its distinct advantages such as fast, clean and precise, electron beam (EB) radiation technology takes up a vital role in the crosslinking of polymeric compounds. However, during the course of electron beam treatment of polymers, two processes viz., crosslinking and chain scission take place simultaneously, depending on the level of radiation dose used for the processing. The present paper reviews the role of irradiation dose in the presence and absence of radiation sensitizer on the crosslinking and structure formation in a wide variety of soft matrices such as elastomers, latexes, thermoplastic elastomers and their respective filled systems. Notable improvements in mechanical and dynamic mechanical properties, thermal stability, processing characteristics, etc., of the EB processed elastomers and their composites are discussed elaborately in the paper. Specially, the property improvements observed in the EB processed pristine and filled rubbers in comparison to the conventional crosslinking technology are critically reviewed. The level of radiation dose inducing crosslinking in both pristine and filled rubbers, determined by calculating crosslink to scission ratio on the basis of Charlesby–Pinner equation is also discussed in the paper. Finally, the application aspects of electron beam curing technology with special emphasis to cable and sealing industries as developed by one of the authors are highlighted in the paper.

Thermal cycling behavior and stress distribution in TGO layer of MCrAlYX-type coatings via high-current pulsed electron beam modification

In this contribution, NiCoCrAlYSiHf coatings were modified via high-current pulsed electron beam (HCPEB) technique. The surface states (roughness and residual stress) and the microstructures (phase compositions, crystal defects and reactive element distribution) were characterized and analyzed. The coatings were subjected to the thermal cycling test at 1100 °C. The high-temperature service performance of the coatings was evaluated by comparing the oxidation kinetic behavior and the cross-sectional morphologies of the thermally grown oxide (TGO). The stress was measured according to the real TGO morphology after different thermal cycles as a reference for evaluating the thermal cycling oxidation resistance. The experimental results demonstrate that the irradiated coatings achieved a flat remelted surface with rich microscopic plastic deformation and uniformly distributed Y-rich precipitates. These properties ensure the thermostability of the TGO during thermal cycling, hence significantly alleviating the TGO spallation. The modified coating has shown a superior thermal cycling behavior.

Electron-beam modification of nitrile butadiene rubber in the fore-vacuum pressure range

We have studied the modification of nitrile butadiene rubber surface properties by pulsed and by continuous electron beams generated in inert (argon, helium) and in chemically active (oxygen, nitrogen, air) gas atmosphere in the fore-vacuum range of pressure (∼10 Pa). Relative measurements of the wear rate, friction coefficient, and contact (wetting) angle of the sample surfaces before and after beam treatment have been made. We have found that the electron-beam treatment of nitrile butadiene rubber does not result in any significant thermal damage to its surface, and that dependencies of the coefficient of friction and the wear rate on the surface treatment duration have a non-monotonic character. For optimal electron beam treatment conditions, the friction coefficient decreases by a factor of about two.

Duplex surface modification of tool steel - deposition of a WN film and subsequent electron-beam modification

In this study, we demonstrate a combined treatment technique of R18 high-speed tool steel comprising deposition of a WN coating followed by electron-beam surface treatment (EBT). In order to understand the influence of the deposited WN coating on the resultant structure and properties, an uncoated specimen was directly electron-beam treated under the same EBT technological conditions. The structure of the specimens was studied by X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The microhardness was also investigated. The phase composition consisted of a double phase structure of Fe and M6C carbides in both cases. The microstructure was significantly finer in the case of an EBT of the steel with WN coating, leading to a much higher microhardness in comparison with the case without WN.

Comb-like poly(dodecyl methacrylate) modified SiO2 nanoparticles as nanohybrid coatings: Electron beam grafting and tuning superhydrophobic/water-repellent surface studies

The current research focuses on tailoring silica nanoparticles (SiO2NPs) with comb-like poly(dodecyl methacrylate) (PDMA) brushes and tuning coating parameters based on roller coating process for confining surface morphology towards hydrophobic and superhydrophobic including water-repellent surface. Electron beam (EB) induced a simultaneous “graft-from” polymerization of DMA monomer onto vinyl modified SiO2NPs (SiO2NPs-V) was established in an inventive castor oil/ethanol mixed solvent. Functional surface chemistry of SiO2NPs and nanorough surface topography controlled by NPs content and coating thickness mainly influences the hydrophobic/superhydrophobic, water-repellent, and water absorption properties including gloss values, whiteness and yellowness index of coated papers. The papers coated with SiO2NPs-V-PDMA/PVA of 6–10 wt% with the thickness of ~10–14 μm exhibited matt surface and provided superhydrophobic and water-repellent properties. The coated paper has a desirable and stable water contact angle of 152°, low droplet adhesion with lower dynamic tilting angle (<5°), and 5.3-folds reduced water absorption. Our investigation provides compelling evidence that the SiO2NPs-V-PDMA obtained from EB modification and the developed coating formula for roller-based coating process are realistic approaches for hydrophobic/superhydrophobic coatings and printing inks for paper-based industries.

Electron beam modification of the structure and properties of silumins with various silicon concentrations

This work intended to analyse the structure and properties of hypoeutectic silumin treated by a pulsed electron beam. The study has shown that the silumin surface modified by a pulsed electron beam fractures due to the formation and propagation of microcracks along the boundaries of high-speed crystallization cells. In the untreated material (the concentration of silicon in the alloy is irrelevant) microcracks tend to originate and propagate along the phase boundaries between aluminum and silicon. The research has revealed that the plasticity of irradiated AK5M2 silumin is 1.6 higher and the strength is 1.1 lower than these characteristics of the untreated material; the irradiated AK10M2H silumin fractures at higher (by ≈ 30%) applied stress and higher (by 30%) plastic deformation than the untreated material.

Electron beam modification of plasmonic responses of nanoparticles

Electron beam modification of plasmonic responses of nanoparticles

Electrochemical, Tribological and Biocompatible Performance of Electron Beam Modified and Coated Ti6Al4V Alloy

Vacuum cathodic arc TiN coatings with overlaying TiO2 film were deposited on polished and surface roughened by electron beam modification (EBM) Ti6Al4V alloy. The substrate microtopography consisted of long grooves formed by the liner scan of the electron beam with appropriate frequencies (500 (AR500) and 850 (AR850) Hz). EBM transformed the α + β Ti6Al4V mixed structure into a single α’-martensite phase. Тhe gradient TiN/TiO2 films deposited on mechanically polished (AR) and EBM (AR500 and AR850) alloys share the same surface chemistry and composition (almost stoichiometric TiN, anatase and rutile in different ratios) but exhibit different topographies (Sa equal to approximately 0.62, 1.73, and 1.08 μm, respectively) over areas of 50 × 50 μm. Although the nanohardness of the coatings on AR500 and AR850 alloy (approximately 10.45 and 9.02 GPa, respectively) was lower than that measured on the film deposited on AR alloy (about 13.05 GPa), the hybrid surface treatment offered improvement in critical adhesive loads, coefficient of friction, and wear-resistance of the surface. In phosphate buffer saline, all coated samples showed low corrosion potentials and passivation current densities, confirming their good corrosion protection. The coated EBM samples cultured with human osteoblast-like MG63 cells demonstrated increased cell attachment, viability, and bone mineralization activity especially for the AR500-coated alloy, compared to uncoated polished alloy. The results underline the synergetic effect between the sub-micron structure and composition of TiN/TiO2 coating and microarchitecture obtained by EBM.

Comparison of microstructure and oxidation behavior of NiCoCrAlYSi laser cladding coating before and after high-current pulsed electron beam modification

In this study, NiCoCrAlYSi coatings prepared via laser cladding were modified using a high-current pulsed electron beam (HCPEB) technique. The microstructural modifications and the effects that the HCPEB treatment had on the high-temperature oxidation resistance were investigated. Microstructural observations reveal that the cladding coating surface, which was initially porous and composed of dendritic segregations, was totally changed after HCPEB irradiation; specifically, the microstructure became rather dense, and the composition became uniform. The grain refinement and high density of dislocations were obtained in the remelted layer. After oxidation for 100 h, the original coating showed relatively poor oxidation resistance, presented as severe internal oxidation. After HCPEB irradiation, the modified coating samples promoted the rapid formation of a stable, continuous, and slow-growing α-Al2O3 scale, which effectively prolonged the high-temperature life of the cladding coating.

Glycidyl methacrylate functionalized star-shaped polylactide for electron beam modification of polylactic acid: Synthesis, irradiation effects and microwave-resistant studies

A model of acrylate functionalized polyfunctional star-shaped polylactic acid (star-PLLA) was originally proposed for free radical-induced modification of PLA under electron beams (EB) irradiation. The 4-arms star-PLLA was synthesized by ring-opening polymerization and it was further functionalized with glycidyl methacrylate (GMA). The PLA films containing the star-PLLA-GMA additive were EB-irradiated with the absorbed doses of 10–100 kGy. Effects of the star-PLLA-GMA contents and the absorbed doses on the morphologies, pseudo-gel fraction, swelling degree, chemical structure, molecular weight, G-value, thermal stability, crystallinity, and mechanical properties were demonstrated. The star-PLLA-GMA reduced radiation-induced chain scission of PLA under EB irradiation as known from the G-value of the chain scission (Gs) and the pseudo-gel fraction. The PLA properties, i.e., crystallization, thermal and mechanical characteristics, were improved by the addition of the star-PLLA-GMA and EB irradiation process. The EB-irradiated star-PLLA-GMA/PLA also exhibited an evidence of microwave-resistant property. The reactive multi-branched star-PLLA-GMA and EB irradiation are the promising tailoring models for PLA modification towards the development of microwavable bioplastics for food packaging.

МОДИФІКАЦІЯ ТА ПРАКТИЧНЕ ЗАСТОСУВАННЯ П’ЄЗОЕЛЕКТРИЧНИХ ПЕРЕТВОРЮВАЧІВ З РОЗДІЛЕНИМИ ЕЛЕКТРОДАМИ

В роботі наводяться результати удосконалення технології формування струмопровідних електродів п’єзоелектричних елементів та розробка пристроїв з п’єзоелектричної кераміки з розділеними електродами методом, що базується на технології комбінованої електронно-променевої модифікації. Показано перспективу використання методу термовакуумного напилення при отриманні покриттів електродів на виробах з п’єзоелектричної кераміки сорту ЦТС. Особливістю такого комбінованого методу є здійснення його в одному технологічному циклі «термовакуумне осадження – електронно-променева модифікація покриття» за незмінних умов робочого середовища, що виключає утворення хімічних сполук в осаджуваному покритті на проміжному етапі формування наноструктурних утворень. Встановлено, що утворені за запропонованою технологією срібні покриття на п’єзоелектричних елементах є більш рівномірними та однорідними порівняно з покриттями, отриманими у традиційний (промисловий) спосіб. Як практичний результат реалізації запропонованої в статті технології розроблено конструкції пристроїв п’єзоелектроніки на основі елементів із п’єзоелектричної кераміки зі сформованими на їх поверхні розділеними електродами, зокрема багатосекційного п’єзоелектричного перетворювача. Найбільш цікавим у цьому випадку є те, що п’єзоелемент (пружне монолітне тверде тіло) може одночасно мати різні властивості внаслідок технологічних можливостей методу термовакуумного напилення. Зміна розмірів електродів, їх взаємне розташування дають змогу впливати на параметри вихідних сигналів і відкривають широкі можливості для створення п’єзоелектричних перетворювачів для комп’ютерних систем критичного застосування. Основна перевага використання перетворювачів з п’єзокерамічних матеріалів у комп’ютерних системах пов’язана з їх особливою конструкцією, що дає можливість реалізувати принципово різні схеми в одному такому елементі.

Impact of Electronic Radiation on the Morphology of the Fine Structure of the Surface Layer of R6M5 Steel

In recent decades, great efforts have been made to significantly improve the performance characteristics of high-speed steel using various surface hardening techniques. Electron beam modification is engaging because it has an exceptionally high thermal efficiency and can significantly improve steels’ physical and mechanical properties. This work is devoted to researching the fine structure and changing the structural phase state of the surface layer of R6M5 high-speed steel after exposure to an electron beam. Electron beam treatment of steel R6M5 was carried out on a vacuum installation. The structure and phase composition of P6M5 steel samples were studied by transmission electron microscopy. Determined that after electron irradiation, the steel structure as in the initial state consists of martensite, carbides and residual austenite. After electron irradiation, an increase in the volume fraction of lamellar martensite is observed: the fraction of lamellar martensite in the initial state is 80%, and after irradiation, it is ~90% of the total fraction of α′-martensite. The action of the electron beam led to an increase in internal stresses in α′-martensite. Revealed, the value of the scalar dislocation density in R6M5 steel after exposure to an electron beam is higher than in the initial state. A cardinal difference in the state of the material after exposure to an electron beam is the presence of bending extinction contours in all M6C carbide particles.

СИНТЕЗ ЦИНКСУЛЬФИДНЫХ РАДИОЛЮМИНОФОРОВ С ИСПОЛЬЗОВАНИЕМ ЭЛЕКТРОННО-ЛУЧЕВОГО МОДИФИЦИРОВАНИЯ И ИССЛЕДОВАНИЕ ИХ СВОЙСТВ

Synthesized recombination-type zinc sulfide phosphors used in solid-state radioluminescent light sources (SSRLS) are the object of the research. In the course of the study, experimental data were obtained for the first time on the effect of the amount of the incorporated activator on the brightness-spectral characteristics of radioluminescence upon excitation by β-radiation of tritium. Data were obtained on the changes in the radioluminescence parameters under various synthesis conditions, phase composition and electron-beam modification of the crystal structure of the initial phosphors. The results of the work make it possible to find the best light compositions for the use in solid-state radioluminescent light sources

Influence of e-Beam Irradiation on the Physicochemical Properties of Poly(polyol Succinate-co-Butylene Succinate) Ester Elastomers.

The purpose of this research was synthesis and electron beam modification of novel ester elastomers consisting of sugar alcohol–succinic acid block and butylene glycol–succinic acid block. Four different alditols were used in the synthesis—sorbitol, erythritol, xylitol, and glycerol. The materials were irradiated with doses of 50, 100, and 150 kGy in order to determine which dose is the most beneficial. As expected, irradiation of the materials has led to the cross-link density becoming higher and improvement of the mechanical properties. Additionally, the materials were also sterilized in the process. The great advantage of elastomers described in the paper is the fact that they do not need chemical cross-linking agents or sensitizers in order to undergo radiation modification. The following tests were performed on cross-linked poly(polyol succinate-co-butylene succinate) elastomers: quasi-static tensile test, determination of cross-link density, differential scanning calorimetry (DSC), dynamic thermomechanical analysis (DMTA), wettability (water contact angle), and Fourier transform infrared spectroscopy (FTIR). In order to confirm successful synthesis, prepolymers were analyzed by nuclear magnetic resonance spectroscopy (1H NMR and 13C NMR).