Glass Foils Research Articles

The Reciprocal Relationship Between Art and Occupational Therapy Practice

Susan Burwash, Ph.D., OTR/L, an occupational therapy professor and artist based in Washington State, provided the cover art for the Winter 2017 issue of the Open Journal of Occupational Therapy (OJOT). The featured piece contains Professor Burwash’s signature fauxpals, lampwork glass beads made from molten glass and pure silver foil. Art creates balance between traditional medicine and personal medicine, those meaningful activities that give life purpose. Professor Burwash’s personal medicine is making beautiful things that can be given away.

Crystallisation behaviour during tensile loading of laser treated Fe–Si–B metallic glass

Effect of tensile loading on crystallisation behaviour of as-cast and laser thermal treated Fe–Si–B metallic glass foils was investigated. Tensile loading lacked any marked influence on the crystallisation behaviour of as-cast and structurally relaxed laser-treated metallic glass foils. Furthermore, the average crystallite/grain size in partially crystallised laser-treated metallic glass foil was nearly equal to the average crystallite/grain size in the region away from the fracture of the same partially crystallised laser-treated metallic glass foil after tensile loading. However, a significant crystallite/grain growth/coarsening of the order of two and half times was observed in the fractured region compared to the region around it for the laser-treated partially crystallised metallic glass foils. The simultaneous effects of stress generation and temperature rise during tensile loading were considered to play a key role in crystallite/grain growth/coarsening.

Model supporting the use of pressure in the hot slumping of glass substrates for X-ray telescopes.

Thin glass foils are nowadays considered good substrates for lightweight focusing optics, especially for X-ray telescopes. The desired shape can be imparted to the foils by hot slumping, a process that replicates the shape of a slumping mould. During thermal slumping, when the glass and the mould come into contact, ripples in the glass surface appear spontaneously if the thermal expansions are mismatched. In our hot slumping setup, pressure is applied to ease the mould shape replication and to enhance the ripple relaxation. Starting from an existing model developed to explain the ripple formation in hot-slumped glass foils without pressure, we have developed a model that includes the pressure to support our experimental results.

Raman Imaging for LiCoO2 Composite Positive Electrodes in All-Solid-State Lithium Batteries to Investigate State-of-Charge Distributions

All-solid-state batteries show higher safety with low risk of leakage and explosion because of nonflammable inorganic solid electrolytes, which are alternative to conventional organic liquid electrolytes. Bulk-type all-solid-state batteries are constructed by pressing positive and negative electrode layers and a solid electrolyte layer at room temperature. The batteries are capable of having high energy density by adding large amounts of active materials into composite electrodes, which are composed of solid electrolyte particles and active material particles. We have investigated electrochemical performances of bulk-type all-solid-state cells using a LiCoO2 composite positive electrode and a Li2S-P2S5 solid electrolyte.1 Composite positive electrodes have many solid-solid interfaces, and electrochemical reactions at the interfaces have not been studied well. Inhomogeneous reaction may occur in the composite electrodes when solid-solid contact areas are insufficient. To improve cell performance, investigation of state-of-charge (SOC) distributions in the electrodes and fabrication of electrodes showing uniform reaction distributions are important. Raman spectroscopy is a suitable technique for investigating SOC of active materials because Raman spectra are sensitive to the structural changes of active materials during charge-discharge tests. Moreover, Raman mapping technique enables us to obtain SOC distribution maps of composite electrodes. In this study, Raman mapping was carried out for charged and discharged LiCoO2 composite positive electrodes in all-solid-state cells to investigate SOC distributions. A 75Li2S·25P2S5 (mol%) glass and indium foil were used as a solid electrolyte and a negative electrode, respectively. A composite positive electrode was prepared by mixing LiCoO2 particles and 75Li2S·25P2S5 glass particles with 80:20 in weight ratio. All-solid-state cells were charged and discharged with a cut-off voltage of 2.6-4.2 V (vs. Li+/Li) at 25oC under a current density of 0.064 mA cm-2. Raman mapping was conducted for surface parts of composite positive electrodes prepared by an Ar ion-milling technique. There are two strong Raman bands at 486 and 596 cm-1, originating from the E g and A 1g modes corresponding to O-Co-O bending and Co-O stretching, respectively.2 Those peaks of E g and A 1g modes shifted to 470 cm-1 and 582 cm-1 respectively, when the cell was charged to 4.2 V (vs. Li+/Li) and returned to original peak positions after the discharging process. To evaluate SOC of the composite positive electrode, A 1g peak positions were investigated in detail. The mapping image showed that charge-discharge reactions did not proceed uniformly, and inhomogeneous reaction distributions existed at the areas of insufficient contacts between LiCoO2 particles and solid electrolyte particles.3 To achieve uniform electrochemical reactions, a composite positive electrode having sufficient interfaces between LiCoO2 and solid electrolyte particles should be prepared. To increase contact points between them, a composite positive electrode with solid electrolytes with a smaller particle size was fabricated. Raman mapping images of the charged and discharged electrodes suggest that uniform electrochemical reactions are achieved. It is noteworthy that the use of smaller solid electrolyte particles is effective way to obtain uniform reaction distributions for composite positive electrodes in all-solid-state lithium batteries. Acknowledgement This research was financially supported by JST, ALCA-SPRING.

Optimization of laser thermal treatment of Fe–Si–B metallic glass

Fe–Si–B metallic glass foils were laser treated using a continuous wave Nd:YAG laser. Electrical resistivity and ultimate tensile strength of the laser treated foils were evaluated using four point probe method and Instron universal testing machine respectively in order to realize the structural changes during laser treatment. Electrical resistivity increased with laser fluence till the laser fluence of 0.42J/mm2 and then steadily reduced. Ultimate tensile strength remained stable in the laser fluence range of 0.39–0.52J/mm2 and then substantially reduced. The analysis of variance (ANOVA) based statistical analysis for optimization helped to identify the laser processing condition that contributed the most to maximize ultimate tensile strength and minimize the electrical resistivity.

Inactivation effect of dielectric barrier discharge plasma against foodborne pathogens on the surfaces of different packaging materials

Abstract The usefulness of dielectric barrier discharge (DBD) plasma for surface disinfection of the common food packaging materials, namely glass, polyethylene, polypropylene, nylon, and paper foil was evaluated. DBD plasma was generated by applying a pulsed DC voltage of 10 kV and at a power of 208 W. The separation distance between the electrodes was 2.65 mm. On exposure of food pathogens-loaded packaging materials to the plasma, > 4 log/cm2 reduction (99.99%) in viable cell counts of Escherichia coli O157:H7 was observed in 10 min. The other two tested pathogen strains, Salmonella typhimurium and Staphylococcus aureus, were inactivated in the range 3.0–3.5 log/cm2. The inactivation pattern of the pathogens fitted well to the log-linear and tail model. Compared to unexposed packaging materials, no significant (p > 0.05) changes in the surface temperatures, optical characteristics, tensile strengths, and strain-induced deformation were observed for the DBD plasma-exposed materials. Therefore, the DBD plasma can be used to disinfect surfaces of different food packaging materials harboring moderate levels of bacterial contaminants without adversely affecting their physicomechanical properties. Industrial relevance Traditionally, dry heat, steam, UV light and chemicals like ethylene oxide and hydrogen peroxide have been used as surface sterilants and disinfectants for packaging materials in the food industry. However, certain limitations have motivated the search for new approaches. Cold plasma technology is an emerging, green process for surface sterilization. The DBD plasma was found to be effective in reducing the bacterial food pathogens on different food packaging materials. As the technology is simple and scalable, it can be readily applied industrially.

Raman Mapping for LiCoO2 Composite Positive Electrodes in All-Solid-State Lithium Batteries Using Li2S-P2S5 Solid Electrolytes

All-solid-state batteries with nonflammable inorganic solid electrolytes, an alternative to conventional inflammable organic liquid electrolytes, are widely studied as next generation batteries with low risk of leakage and explosion. Bulk-type batteries use composite electrodes of active materials and solid electrolytes. Solid electrolytes play a role of delivering Li ions to active materials. Bulk-type batteries are capable of having high energy density by adding large amounts of active materials into composite electrodes. We have investigated the electrochemical performance of bulk-type all-solid-state cells using a LiCoO2 composite positive electrode and a Li2S-P2S5 solid electrolyte [1]. Composite electrodes can be fabricated by mixing LiCoO2 particles and solid electrolyte particles. There are many solid-solid interfaces in composite electrodes. It is important that electrochemical reactions at LiCoO2-electrolyte solid-solid interfaces are clarified to improve the cell performance. Raman microscopy is one of the useful methods for investigating the reactions because of its feature of high spatial resolution and surface sensitivity. Raman spectral changes of composite electrodes are closely related to the structural changes of active material during charge-discharge cycling. In this study, Raman spectroscopy was carried out for LiCoO2 composite positive electrodes in all-solid-state cells before and after the charge-discharge process. Moreover, Raman mapping was conducted to evaluate state-of-charge (SOC) distributions of each active material in the electrodes. The 75Li2S·25P2S5 (mol%) glass and indium foil were used as solid electrolyte and a negative electrode, respectively. A composite positive electrode was prepared by mixing LiCoO2 particles and 75Li2S·25P2S5 glass particles (80:20 wt.%). All-solid-state cells were charged and discharged with a cut-off voltage of 2.6-4.2 V (vs. Li+/Li) at 25 oC under a current density of 0.064 mA cm-2. Raman spectra were obtained for the surface part of composite positive electrodes prepared by an Ar ion-milling technique. There are two strong Raman peaks at 486 and 596 cm-1, originating from the E g and A 1g modes of oxygen vibration in LiCoO2, respectively. Those peaks shifted to the lower wavenumber side and their intensity decreased after the initial charging process. After the discharging process, those peaks returned to the original positions. Mapping images showed charge-discharge reactions did not proceed uniformly at the areas of insufficient contacts between LiCoO2 particles and solid electrolyte particles [2]. Our approaches to fabricate composite positive electrodes having uniform charge-discharge reactions will be demonstrated. Acknowledgement This research was financially supported by JST, ALCA-SPRING.

Transport stability of pesticides and PAHs sequestered in polyethylene passive sampling devices.

Research using low-density polyethylene (LDPE) passive samplers has steadily increased over the past two decades. However, such research efforts remain hampered because of strict guidelines, requiring that these samplers be quickly transported in airtight metal or glass containers or foil wrapped on ice. We investigate the transport stability of model pesticides and polycyclic aromatic hydrocarbons (PAHs) with varying physicochemical properties using polytetrafluoroethylene (PTFE) bags instead. Transport scenarios were simulated with transport times up to 14days with temperatures ranging between -20 and 35°C. Our findings show that concentrations of all model compounds examined were stable for all transport conditions tested, with mean recoveries ranging from 88 to 113%. Furthermore, PTFE bags proved beneficial as reusable, lightweight, low-volume, low-cost alternatives to conventional containers. This documentation of stability will allow for more flexible transportation of LDPE passive samplers in an expanding range of research applications while maintaining experimental rigor.

OBTAINING ZnO IMMOBILIZED OVER DIFFERENT SUBSTRATES BY HYDROTHERMAL TREATMENT FOR PHOTOCATALYSIS APPLICATION

The aim of this work is to systematically explore the effect of the synthesis conditions of ZnO structures, immobilized on different substrates by hydrothermal treatment, in its photocatalytic activity. A circumscribed central composite design of experiments was used to analyze the effects of reagents stoichiometry, reaction time and temperature, covering a wide range of these variables. The substrates used were etched glass, copper and zinc foils. The photocatalytic activity of the as-obtained ZnO samples was evaluated through photocatalytic degradation of rhodamine B (RhB) in aqueous solution under UV irradiation. Zinc foils presented the best immobilized film quality and the maximum dye removal was 80% in one hour of UV exposure.

Manufacturing an active X-ray mirror prototype in thin glass.

Adjustable mirrors equipped with piezo actuators are commonly used at synchrotron and free-electron laser (FEL) beamlines, in order to optimize their focusing properties and sometimes to shape the intensity distribution of the focal spot with the desired profile. Unlike them, X-ray mirrors for astronomy are much thinner in order to enable nesting and reduce the areal mass, and the application of piezo actuators acting normally to the surface appears much more difficult. There remains the possibility to correct the deformations using thin patches that exert a tangential strain on the rear side of the mirror: some research groups are already at work on this approach. The technique reported here relies on actively integrating thin glass foils with commercial piezoceramic patches, fed by voltages driven by the feedback provided by X-rays, while the tension signals are carried by electrodes on the back of the mirror, obtained by photolithography. Finally, the shape detection and the consequent voltage signal to be provided to the piezoelectric array will be determined by X-ray illumination in an intra-focal setup at the XACT facility. In this work, the manufacturing steps for obtaining a first active mirror prototype are described.

Dynamic crystallization during non-isothermal laser treatment of Fe–Si–B metallic glass

Fe–Si–B metallic glass foils were subjected to non-isothermal laser treatment to induce crystallization, and the effect of laser fluence on crystallite size was investigated. Temperature, and corresponding heating and cooling rates generated during laser processing of metallic glass were estimated using multiphysics computational models. Estimation of the onset and arrest temperatures of crystallization was based on the results obtained using the thermal model. Crystallite size was measured with the aid of x-ray diffraction and transmission electron microscopy. The fraction of crystallization was estimated with a differential scanning calorimetry. Crystallite size increased with laser fluence in the initial stages and saturated later within the laser fluence range (0.6–0.9 J mm−2) explored in the current efforts. The fraction of crystallization steadily increased with the increase in laser fluence. Unlike conventional processes, in the present situation the dynamic effects during laser processing dominated the crystallization and growth process. Rapid heating rates during laser processing led to a shift in the onset of crystallization temperature to a higher level. Faster cooling rates prematurely arrested the crystallite growth yielding much finer crystallite sizes.

Mechanically induced waves in metallic glass foils

The response of vitrified metallic arc foils under normal load is studied. Application of normal load on an initial arc shaped vitrified metallic foil is followed by multiplication of the initial arc. A sinusoidal mathematical expression can be used for the description of the produced harmonic undulations. The number of the formed waves increases as the displacement increases. Therefore, this undulatory behavior of the vitrified foils can be exploited as a flat spring with multiple spring constants. For comparison crystalline foils were tested. The enormous elastic region of vitrified alloys allows this undulatory response to occur extensively while plastic deformation is unavoidable when crystalline foils are used. Exploiting the metallic glass characteristics, the predefined extrema positions of the formed undulations and the mechanical characteristics of the vitrified foils a new type of electromechanical switch is suggested.

Tensile behavior of laser treated Fe-Si-B metallic glass

Fe-Si-B metallic glass foils were treated with a linear laser track using a continuous wave Nd-YAG laser and its effect on the overall tensile behavior was investigated. Microstructure and phase evolutions were evaluated using X-ray diffraction, resistivity measurements, and transmission electron microscopy. Crystallization fraction was estimated via the differential scanning calorimetry technique. Metallic glass foils treated with the lower laser fluences (<0.49 J/mm2) experienced structural relaxation, whereas higher laser fluences led to crystallization within the laser treated region. The overall tensile behavior was least impacted by structural relaxation, whereas crystallization severely reduced the ultimate tensile strength of the laser treated metallic glass foils.

Room Temperature Oxide Deposition Approach to Fully Transparent, All-Oxide Thin-Film Transistors.

A room temperature cathodic arc deposition technique is used to produce high-mobility ZnO thin films for low voltage thin-film transistors (TFTs) and digital logic inverters. All-oxide, fully transparent devices are fabricated on alkali-free glass and flexible polyimide foil, exhibiting high performance. This provides a practical materials platform for the low-temperature fabrication of all-oxide TFTs on virtually any substrate.

Development of mirrors made of chemically tempered glass foils for future X-ray telescopes

Thin slumped glass foils are considered good candidates for the realization of future X-ray telescopes with large effective area and high spatial resolution. However, the hot slumping process affects the glass strength, and this can be an issue during the launch of the satellite because of the high kinematical and static loads occurring during that phase. In the present work we have investigated the possible use of Gorilla glass (produced by Corning), a chemical tempered glass that, thanks to its strength characteristics, would be ideal. The un-tempered glass foils were curved by means of an innovative hot slumping technique and subsequently chemically tempered. In this paper we show that the chemical tempering process applied to Gorilla glass foils does not affect the surface micro-roughness of the mirrors. On the other end, the stress introduced by the tempering process causes a reduction in the amplitude of the longitudinal profile errors with a lateral size close to the mirror length. The effect of the overall shape changes in the final resolution performance of the glass mirrors was studied by simulating the glass foils integration with our innovative approach based on glass reinforcing ribs. The preliminary tests performed so far suggest that this approach has the potential to be applied to the X-ray telescopes of the next generation.

Structural And Optical Properties Of VOx Thin Films

Abstract VOx thin films were deposited on Corning glass, fused silica and Ti foils by means of rf reactive sputtering from a metallic vanadium target. Argon-oxygen gas mixtures of different compositions controlled by the flow rates were used for sputtering. Influence of the oxygen partial pressure in the sputtering chamber on the structural and optical properties of thin films has been investigated. Structural properties of as-sputtered thin films were studied by X-ray diffraction at glancing incidence, GIXD. Optical transmittance and reflectance spectra were recordedwith a Lambda 19 Perkin-Elmer double spectrophotometer. Thickness of the films was determined from the profilometry. It has been confirmed by XRD that the deposited films are composed mainly of V2O5 phase. The estimated optical band gap of 2.5 eV corresponds to V2O5.

Characterization, shear strength and corrosion resistance of self joining AISI 304 using a Ni Fe–Cr–Si metallic glass foil

This work studied the microstructure of the interlayer formed after self joining of AISI 304 stainless steel, using a commercial metallic glass foil as the joining element and its effect on the shear and corrosion resistances at the interface zone. Different joining times and temperatures were used varying from 25 to 90min, and 800°C, 900°C and 1000°C, respectively. The joining process induced an inter-diffusion of alloy elements from the steel to the amorphous foil, conveying to the formation of intermetallics and second phases at the joining interphase, as was observed by SEM. The residual porosity at the joining zone was reduced as both, the bonding time and temperature increased. The mechanical behavior of the bonded samples was evaluated by shear tests presenting a maximum value of 108MPa for joints produced at 900°C for 60min, however the shear test presented values higher that 75MPa for the temperature vary from 850°C to 1000°C and time of 45min. Fractures occurred on the interlayer, indicating a strong relationship between the microstructure of the interface and the mechanical strength of the joints. Electrochemical tests in 3.5wt.% NaCl solution presented pitting corrosion at room temperature under conditions of open circuit potential in the form of preferential dissolution.

Laser perforated ultrathin metal films for transparent electrode applications

Transmittance and conductivity are the key requirements for transparent electrodes. Many optoelectronic applications require additional features such as mechanical flexibility and cost-efficient fabrication at low temperatures. Here we demonstrate a simple method to fabricate high performance transparent electrodes that is based on perforation of thin silver layers using picosecond laser pulses. Transparent electrodes have been characterized optically and electrically in order to determine the influence of specific surface coverage. Special attention was paid to maintaining sufficient conductivity in the metal-free areas. As a result, transmittance of a much higher bandwidth was achieved as compared to unpatterned metal films. Transparent electrodes have been fabricated on glass and plastic foil, as well as wafer-based silicon heterojunction solar cells, demonstrating their applicability for most relevant cases.

Nile Blue and Nickel Organometallic Dyes Applied in Dye-sensitized Solar Cells

Solar cells (Gratzel cells) have been highly regarded due to their extremely efficient and low-cost process of converting sun light into electricity. In this work screen printed electrodes were fabricated by spraying organic and organometallic dyes on glass and flexible aluminum foil. These solar cells were prepared based on three dyes, namely nickel Di thiocyanato bis(triphenyl phosphine), nickel Dimethylglyoxime and Nile blue, and the performance of these dye-sensitized solar cells (DSSC) has been experimentally evaluated. The solar cells were fabricated using thin TiO 2 films; these films were characterized by FTIR. The dyes were characterized using UV–Vis and typical J-V and P-V curves of the cells. The best performance was obtained for the mixture of nickel Dithiocyanatobis (triphenyl phosphine) and Nile blue with an open circuit voltage (Voc) of 976 mV using an incident irradiation of 100 mW cm -2 at 25 oC.

Ultrasonic Welding of Fe<sub>78</sub>Si<sub>9</sub>B<sub>13</sub> Metallic Glass

The solid bonds of multi-layer Fe78Si9B13metallic glass foils have successfully been produced by ultrasonic welding technology. The interface of weld joints was investigated by Optical micrograph (OM), scanning electron microscope (SEM) observation, micro-area X-ray diffraction (micro-XRD) and differential scanning calorimetry (DSC) analysis. The results demonstrate that no visible interface and defects were observed and the amorphous structure was maintained. The thermal properties of the joined metallic glasses were the same as that of the parent metallic glass. The formation of joining metallic glasses was attributed to the superplastic flow and the thermal stability at elevated temperatures in the supercooled liquid state. Ultrasonic welding as tack welding proposes an effective method for the preparation of bulk metallic glasses (BMGs) and lays the foundation for its future applications.