Ribbon Surface Research Articles

Fabrication of optical gratings through surface patterning of zirconium-based metallic glass by laser irradiation

Periodic lines with intervals ranging from ∼220 μm down to ∼27 μm were fabricated on the surface of Zr55Cu30Al10Ni5 metallic glass ribbon and disk samples by laser irradiation. The X-ray diffraction results indicated that both oxides (monoclinic ZrO2, tetragonal ZrO2) and crystallites (Cu10Zr7, NiZr2) existed together with the amorphous phase on the surface of the laser-patterned metallic glass samples. The energy-dispersive X-ray spectroscopy of a cross section of a disk sample clearly showed that high amounts of aluminum (292% of the nominal composition) and oxygen were present in the laser-irradiated area, suggesting that Al2O3 formed on the surface of the laser-irradiated region. Reflective diffraction spots were observed from the fine grids with a grating period of ∼27 μm, indicating the excellent periodicity and accuracy of the pattern in two dimensions on the surface of the metallic glass substrates. Calculation of the grating period using Bragg's law confirmed that the spots originated from the periodic patterns of the laser-irradiated lines. Along the lines, pairs of ridges and hollows with a height/depth of ∼0.5 μm were observed; such specific morphology generated the diffraction spots as a reflective grating. We observed structural color gradation from the periodic fine grids under a fluorescent light. The present study showed that it is possible to prepare optical gratings on the surface of metallic glasses by laser irradiation more cheaply and easily than by conventional imprinting.

A study on the crystallization behavior of amorphous Ti50Ni25Cu25 shape memory ribbon by X-ray diffraction measurement

XRD spectra from the contact and free surfaces of amorphous Ti50Ni25Cu25 ribbon prepared by melt-spinning technique, crystallized, and aged at 500 °C for different times were collected for intensive investigation. A thin layer of textured grains with a thickness of 1 μm formed at the contact surface, having {100}B2 planes parallel to the ribbon surface during the crystallization process and resulting in an extraordinarily strong (200)B2 diffraction peak from the contact surface. This textured layer was caused by the pre-arrangement of atoms with their easy-growth <100>BCC direction parallel to the maximum temperature gradient perpendicular to the contact surface during the melt-spinning process. On the other hand, equiaxed and randomly orientated grains of about 300 ± 100 nm in size formed at the free surface. During the aging process, when aging time exceeded 15 min, precipitation of TiCu along {100}B2 planes significantly distorted the B2 lattice and thus led to broadening, which decreased the intensity of (200)B2 diffraction. Comparisons of experimental results with reported studies show that the texture developed in Ti50Ni25Cu25 ribbon is highly affected by the thickness and cooling rate.

Rapid Degradation of Azo Dyes by Melt-Spun Mg-Zn-Ca Metallic Glass in Artificial Seawater

Mg-Zn-Ca metallic glass (MG) is effective for degrading azo dyes; however, the related surface evolution and degradation mechanisms are little known. We comparatively investigated the initial surface corrosion morphologies of melt-spun Mg66Zn30Ca4 MG in deionized water and artificial seawater. It was found that the basic corrosion behavior of the MG was the same, except that the corrosion process was accelerated in seawater. The presence of NaCl obviously promotes the formation of nano-ZnO on the surface of ribbons, causing the rapid degradation of azo dyes due to the photocatalytic effect. The degradation efficiency when combined with 3.5 wt % NaCl was over 100 times higher than that without NaCl. This indicates that Mg-Zn-Ca MG ribbons are effective additives for the degradation of azo dyes in seawater.

Interaction of solitons on 2‐dimensional branched π‐electron surface of graphene ribbons

AbstractWe have performed quantum‐mechanical study of charge distribution on the carbon atoms of two‐dimensional conjugated system of the model graphene ribbon. The study shows that charges in the quasi‐two dimensional conjugated system of the graphene ribbon are not localized on separate carbon atoms, but form one‐dimensional solitonic charge waves along zig‐zag sides. There are two solitonic charge waves in the dication or dication due to generation of own soliton by each charge; the first soliton in the acene chain is located on one side while the second one is positioned on the opposite side. The shapes of the solitonic waves in the graphene ribbon are similar to ones in one‐dimensional conjugated systems. Similarly, in the ionic two‐dimensional collective systems of π‐electrons two splitted solitonic levels are generated; lengthening of the chain leads to convergence of the levels. The widening of graphene ribbon (y‐expansion of two‐dimensional conjugated system is accompanied with recession of both solitons to outer sides, so amplitudes of the solitons on the inner sides regularly decrease under widening of the model graphene ribbon; the charges on the inner carbon atoms converge to zero.

Magnetic nanoparticle detection method employing non-linear magnetoimpedance effects

In this work, a sensitive tool to detect magnetic nanoparticles (Fe3O4) based on a non-linear Giant Magnetoimpedance (GMI) effect is presented. The GMI sensor is designed with four nearly zero magnetostrictive ribbons connected in series and was analysed as a function of a constant external magnetic field and exciting frequency. The influence of the magnetic nanoparticles deposited on the ribbon surface was characterized using the first (fundamental) and second (non-linear) harmonics of the magnetoinductive voltage. The results show a clear enhancement of the sensor response in the high magnetic field region (H = 1.5 kA/m) as a consequence of the stray field generated by the magnetic nanoparticles on the GMI ribbons' surface. The highest sensitivity ratios are obtained for the non-linear component in comparison with the fundamental response. The results open a new research strategy in magnetic nanoparticle detection.

Development of Flexible Cell-Loaded Ultrathin Ribbons for Minimally Invasive Delivery of Skeletal Muscle Cells.

Cell transplantation therapy provides a potential solution for treating skeletal muscle disorders, but cell survival after transplantation is poor. This limitation could be addressed by grafting donor cells onto biomaterials to protect them against harsh environments and processing, consequently improving cell viability in situ. Thus, we present here the fabrication of poly(lactic-co-glycolic acid) (PLGA) ultrathin ribbons with "canal-like" structures using a microfabrication technique to generate ribbons of aligned murine skeletal myoblasts (C2C12). We found that the ribbons functionalized with a solution of 3,4-dihydroxy-l-phenylalanine (DOPA) and then coated with poly-l-lysine (PLL) and fibronectin (FN) improve cell attachment and support the growth of C2C12. The viability of cells on the ribbons is evaluated following the syringe-handling steps of injection with different needle sizes. C2C12 cells readily adhere to the ribbon surface, proliferate over time, align (over 74%), maintain high viability (over 80%), and differentiate to myotubes longer than 400 μm. DNA content quantification carried out before and after injection and myogenesis evaluation confirm that cell-loaded ribbons can safely retain cells with high functionality after injection and are suitable for minimally invasive cell transplantation.

Excitation of surface plasmon polaritons by electron beam with graphene ribbon arrays

Graphene has emerged as an alternative material to support surface plasmon polaritons (SPPs) with its excellent properties such as the tight electromagnetic field localization, low dissipative loss, and versatile tunability. Thus, graphene surface plasmon polaritons (GSPs) provide an exciting platform to develop a series of novel devices and systems from the optical band to the terahertz (THz) band. In this paper, theoretical and simulated studies about the excitation of SPPs by an injected electron beam with periodic graphene ribbon arrays deposited on a dielectric medium are presented. The analytical dispersion expression of the GSP mode on the graphene ribbon arrays is obtained by using a modal expansion method along with periodic boundary conditions in the structure. With this result, the dispersion relation, propagation loss, and field pattern of the propagating GSPs for both periodic graphene microribbon arrays and the complete graphene sheet are investigated and analyzed in the THz band. It is shown that the electromagnetic field with a better concentration on the interface can be realized with graphene ribbon arrays compared with the graphene sheet for a given frequency. Besides, the excitation of GSPs by an injected electron beam with graphene ribbon arrays is modeled and implemented by the particle-in-cell simulation based on the finite difference time domain algorithm. GSPs can be excited effectively when the dispersion line of the electron beam and SPPs on the graphene ribbon arrays is matched with each other well. Besides, the dependences of output power on electron beam parameters such as the distance of the electron beam above the graphene ribbon surface and beam voltage are studied and analyzed. Finally, the tunability of graphene conductivity via biased voltage with a ground metal is considered and the tunable excitation of GSPs on the structure with biased drive voltage by the injected electron beam is also realized. The present work can find a lot of potential applications such as low loss plasmonic waveguides, graphene metamaterials, and tunable THz electronic sources.

Crack Propagation in Metallic Glass Ribbon as a Function of the Position of Stress Concentrators

An amorphous metallic ribbon of Fe40Ni40B20 was used for in-situ observation of the crack propagation and shear band formation during tensile tests. Prior to the tensile tests, two holes (with different positions with respect to the tensile axis) were made by laser ablation as stress concentrators. The nucleation and propagation of shear bands on the ribbon surface during tensile tests were analysed with scanning electron microscopy (SEM). At room temperature inhomogeneous plastic deformation of amorphous alloy occurs via the development of primary and secondary shear bands. The influence of the different loading geometry on the topology of shear bands and crack propagation was studied.

Mutual interaction of shear bands in metallic glasses

Shear banding is the main plastic deformation mode in metallic glasses. Even though there are many researches focused on the initiation and propagation of shear bands, the interaction among them has not been systematically studied. Using an atomic force microscope, we investigated the mutual interaction of shear bands at the surface of Cu50Zr50 metallic glass ribbons at the nanoscale. At the sites of the interaction, the propagation direction of one shear band can be changed by the pre-existing one, and the offset is the vector sum of the two bands. Under external stress, one shear band can be decomposed into several tiny bands and more materials could be taken into the deformation zones. Therefore, more energy can be dissipated and the deformation could be more homogeneous for the mutual interaction process. These results are useful for a mechanistic understanding of the evolution and suppression of shear band propagations, as well as the design of metallic glasses with improved plasticity.

Fe-based metallic glass catalyst with nanoporous surface for azo dye degradation

In this work, porous structures were introduced to the surface of Fe-based metallic glass ribbons for the first time by chemical treatment in order to increase the catalytic activity in the degradation of azo dyes. The results show that etching treatment in an HF solution with a volume concentration of 20% for 40 min leads to a porous structure on the FeSiBNb metallic glass with a dramatic increase in the specific surface area by 25 times. The much higher specific surface area of the porous ribbons greatly improves the catalytic activity in the degradation of Direct Blue 15 when compared with as-spun metallic ribbons.

Rapid malachite green degradation using Fe73.5Si13.5B9Cu1Nb3 metallic glass for activation of persulfate under UV–Vis light

In this work, it is the first time to report that Fe73.5Si13.5B9Cu1Nb3 metallic glass having unique atomic structure was employed for activation of persulfate under UV–Vis light. The investigation evaluated the importance of influencing parameters, including dye concentration, persulfate concentration, ribbon dosage and light intensity, on malachite green (MG) dye degradation. The results reveal that 100% dye color removal with a reaction rate of k=0.0849min−1 could be achieved within 30min under specific parameters control. In addition, surface decay behavior of the catalyst also plays a significant effect on the reusability and sustainability. The inclusion of Nb atom in Fe73.5Si13.5B9Cu1Nb3 promotes enrichment of Si atom on the ribbon surface, causing the formation of Si and Nb oxides to further improve the surface stability on both of free and roller-contacted surfaces. The precipitations on reused ribbon surface are confirmed as α-Fe, iron oxide and Si, Nb oxides, revealing a high potential of catalytic reusability for wastewater treatment. The present work will open a new gate for further realizing the high performance of industrial water treatment using metallic glass.

Novel dealloying structures and ageing behaviors of Cu-Zr metallic glass ribbons

Melt-spun Cu64.5Zr35.5 metallic glass ribbons were subject to 250°C annealing for 0.5 to 2h without leading to crystallization. Both the as-spun ribbon and the annealed ribbon were then reserved at room temperature and aged for one month, during which all samples became crystallized and oxidized on the surface. The surface of the aged ribbons tuned into brassy yellow and was featured an unchanged amorphous area and a nano-crystalline area fully decorated with crystallization and oxidation products. The two areas responded differently to the following dealloying process carried out in 0.025M HF. The amorphous area were turned into nanoporous structure, but the dealloyed nano-crystalline area showed more complex morphology, which was composed of micron-sized Cu2O crystals rooted in the nanoporous structure.

Surface aging behaviour of Fe-based amorphous alloys as catalysts during heterogeneous photo Fenton-like process for water treatment

Two novel, multifunctional Fe-based amorphous alloys with the nominal components of Fe78Si9B13 and Fe73.5Si13.5B9Cu1Nb3 exhibit advanced catalytic capability when degrading methyl blue (MB) and methyl orange (MO) dyes. The production rate of hydroxyl radicals (OH) in this work is 5–10 times faster than other Fe-based catalysts. The surface aging behaviour on Fe78Si9B13 and Fe73.5Si13.5B9Cu1Nb3 ribbons shows a significant effect on the dye degradation efficiency and reusability of the catalyst. Results reveal that crystallized α-Fe, iron oxide and SiO2 are gradually precipitated on the surface of the reused Fe78Si9B13 ribbon which ultimately becomes corroded through with holes. However, the inclusion of Nb atoms in the Fe73.5Si13.5B9Cu1Nb3 alloy causes the formation of niobium oxides which overlay the ribbon surface, and tend to reduce the contact area between the Fe and H2O2, thereby decreasing the generation of OH and further reducing the dye degradation efficiency. Tert-butanol is employed for quenching hydroxyl radicals (OH), causing a dramatic reduction in the amount available for degrading the MB and MO molecules. The MB and MO dye degradation and mineralization under UV–vis light are also fully investigated. The findings of this critically important work should form the basis of new research opportunities into the study of amorphous alloy catalysis.

Ultra-sustainable Fe78Si9B13 metallic glass as a catalyst for activation of persulfate on methylene blue degradation under UV-Vis light.

Stability and reusability are important characteristics of advanced catalysts for wastewater treatment. In this work, for the first time, sulfate radicals (SO4∙−) with a high oxidative potential (Eo = 2.5–3.1 V) were successfully activated from persulfate by a Fe78Si9B13 metallic glass. This alloy exhibited a superior surface stability and reusability while activating persulfate as indicated by it being used for 30 times while maintaining an acceptable methylene blue (MB) degradation rate. The produced SiO2 layer on the ribbon surface expanded strongly from the fresh use to the 20th use, providing stable protection of the buried Fe. MB degradation and kinetic study revealed 100% of the dye degradation with a kinetic rate k = 0.640 within 20 min under rational parameter control. The dominant reactive species for dye molecule decomposition in the first 10 min of the reaction was hydroxyl radicals (∙OH, Eo = 2.7 V) and in the last 10 min was sulfate radicals (SO4∙−), respectively. Empirical operating variables for dye degradation in this work were under catalyst dosage 0.5 g/L, light irradiation 7.7 μW/cm2, and persulfate concentration 1.0 mmol/L. The amorphous Fe78Si9B13 alloy in this work will open a new gate for wastewater remediation.

Magnetization distribution in a soft magnetic amorphous alloy ribbon in as-quenched state and efficiency of heat treatment

The effect of heat treatment in air on the formation of magnetic properties has been studied based on the example of soft magnetic Fe77Ni1Si9B13 and Fe81B13Si4C2 amorphous ribbons characterized by positive magneto-striction. The magnetization distribution in the ribbons in the as-quenched state was shown to affect the efficiency of annealing. Under certain conditions, heat treatment, which results in the formation of mainly amorphous state of ribbon surface, is more efficient for samples characterized by high volume of orthogonally magnetized domains. This can be related to high in-plane tensile stresses, which are induced by hydrogen and oxygen atoms introduced into the ribbon surface upon its interaction with atmospheric water vapor.

Oxidation Behavior of Fe-based Amorphous Ribbons

The oxidation behavior of Fe-based amorphous ribbons was tested by annealing at 380 °C in air for different time with heat treatment furnace and analyzed by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The mechanism of oxides formation of the amorphous ribbons was discussed in detail. The results showed that the oxides were mostly B2O2, SiO2 and Fe2O3 or FeO. With the increase of annealing time and holding temperature, the fraction of the oxides on the ribbon surface increased and the size of the oxides became larger due to the generation of new oxides and the coalescence of small oxides. The oxides have different shapes, such as round, rod and needle-shaped. Experimental results also showed that the oxides nucleated at fish scale, air pocket and impurities in priority, and the growth of the oxides was controlled by the diffusion of atoms. With the increase of the distance to the ribbon surface, the oxygen concentration decreased dramatically. Due to the low binding energy of B2O3 and the large diffusion coefficient of B atom, the B element was oxidized firstly compared with other elements. Moreover, the oxidation depths of the B2O3 and SiO2 were larger than that of Fe2O3.

Creation of a sharp cube texture in ribbon substrates of Cu–40% Ni–M (M = Fe, Cr, V) ternary alloys for high-temperature second generation superconductors

The structure and the process of texture formation in ribbons made of Cu–Ni–M (M = Fe, Cr, V) ternary alloys have been studied upon cold rolling deformation to a degree of ~99% and subsequent recrystallization annealing. The possibility of obtaining a perfect cube texture in a thin ribbon made of copper–nickel-based ternary alloys with additives of iron, chromium, and vanadium has been shown, which opens the prospects of the use of these alloys as substrates in the technology of production of tapes of high-temperature second-generation superconductors. Optimal annealing regimes have been determined, which make it possible to obtain a perfect biaxial texture close to single-crystalline one with the content of cube-oriented grains {001}〈100〉±10° more than 99% on the surface of the textured ribbon.

Effect of heat treatment in air and a chemically active environment on the magnetic properties of cobalt-based soft magnetic amorphous alloys

The influence of heat treatment in air on the level of magnetic properties has been studied on the example of a ribbon of an amorphous cobalt-based (Co–Fe–Ni–Cr–Si–B) soft-magnetic alloy with a nearzero saturation magnetostriction. The investigation of the interaction of the ribbon surface with water and water vapor and its influence on the magnetization distribution showed the possibility of applying surface treatment to determine the sign of saturation magnetostriction. The sign of saturation magnetostriction in the initial (quenched) state confirmed the presence of a negative magnetostriction in the ribbon. Based on the results obtained, the dependence of the sign of saturation magnetostriction on the structural state that is obtained upon heat treatment has been revealed.

Transport properties of bilayer graphene nanoribbons with hydrogen adatoms

The transport characteristics of bilayer graphene nanoribbons with hydrogen adatoms in an external static electric field is studied. The adsorption of hydrogen atoms on the surface of bilayer graphene ribbons is considered within the single-impurity periodic Anderson model. The transport coefficients of impurity-doped bilayer graphene ribbons are simulated in the relaxation time approximation. At a constant concentration of hydrogen adatoms, a nonlinear dependence of the transport coefficients on the static electric field strength has been revealed. It is found that the electrical conductivity and the diffusion coefficient of electrons in bilayer graphene ribbons decrease with increasing concentration of hydrogen adatoms.

Floating Silicon Method single crystal ribbon – observations and proposed limit cycle theory

In the Floating Silicon Method (FSM), a single-crystal Si ribbon is grown while floating on the surface of a Si melt. In this paper, we describe the phenomenology of FSM, including the observation of approximately regularly spaced “facet lines” on the ribbon surface whose orientation aligns with (111) crystal planes. Sb demarcation experiments sectioned through the thickness of the ribbon reveal that the solid/melt interface consists of dual (111) planes and that the leading edge facet growth is saccadic in nature, rather than steady-state.To explain this behavior, we propose a heuristic solidification limit cycle theory, using a continuum level of description with anisotropic kinetics as developed by others, and generalizing the interface kinetics to include a roughening transition as well as a re-faceting mechanism that involves curvature and the Gibbs–Thomson effect.