Fabrication Process Of Components Research Articles

Feasibility of Building a 3D Battery by Using Triblock Copolymer

Three-dimensional battery designs have emerged as a novel technique to powering micro electromechanical systems and other autonomous devices. These sources of power have the ability to achieve high power density and high energy density while occupying a compact area, despite the fact that there are still less fully functional three-dimensional batteries to date. This article examines the proposed architectures for three-dimensional batteries and the fabrication process of components made for these devices, as well as remaining technical obstacles. Also, defining guidelines for design for three-dimensional architectures and modelling sheds light on the achievable energy density and current uniformity of these architectures. Considerable advances in electrodes and electrolytes fabrication progress for three-dimensional batteries suggest that considerable battery technologies will be demonstrated successfully in the future.

Recent Trends in Additive Manufacturing and Topology Optimization of Reluctance Machines

Additive manufacturing (AM) or 3D printing has opened up new opportunities for researchers in the field of electrical machines, as it allows for more flexibility in design and faster prototyping, which can lead to more efficient and cost-effective production. An overview of the primary AM techniques utilized for designing electrical machines is presented in this paper. AM enables the creation of complex and intricate designs that are difficult or impossible to achieve using traditional methods. Topology Optimization (TO) can be used to optimize the design of parts for various purposes such as weight, thermal, material usage and structural performance. This paper primarily concentrates on the most recent studies of the AM and TO of the reluctance machines. The integration of AM with TO can enhance the design and fabrication process of magnetic components in electrical machines by overcoming current manufacturing limitations and enabling the exploration of new design possibilities. The technology of AM and TO both have limitations and challenges which are discussed in this paper. Overall, the paper offers a valuable resource for researchers and practitioners working in the field of AM and TO of electrical machines.

Outgassing Rates and Compositions of the Released Gases from Optical Fiber Panel and Photocathode Glass Used for Low-light-level Image Intensifiers

To analyze the vacuum failure mechanism of low-light-level image intensifiers in depth, the outgassing rates and compositions of the released gases from optical fiber panel and photocathode glass used for the image intensifiers were investigated by static pressure-rising method and residual gas analysis. The investigation results show that the outgassing rate of the optical fiber panel at a baking temperature of 150°C is only about one order of magnitude higher than that at 23°C, while the outgassing rate of the photocathode glass at 150°C is about two orders of magnitude higher than that at 23°C. As the static accumulation time of gas releasing extends, the outgassing rate of the optical fiber panel linearly increases at 23°C, and it remains basically unchanged at 150°C, while for the photocathode glass, its outgassing rate increases rapidly firstly and then tends to be stable gradually both at 23°C and 150°C. The gas compositions released from the optical fiber panel and photocathode glass at 23°C mainly include H2O, H2, N2/CO and CO2. After experiencing the vacuum baking at 150°C, the releasing ratio of H2O gas from the optical fiber panel decreased just slightly, which indicates that the vacuum baking degassing for the photocathode glass is relatively difficult; by contrast, the releasing ratio of H2O gas from the photocathode glass significantly decreased, and that of H2 gas obviously increased. These results can provide experimental bases for further optimizing the component materials and fabrication process of low-light-level image intensifiers.

A Laser-Processed Carbon-Titanium Carbide Heterostructure Electrode for High-Frequency Micro-Supercapacitors.

Micro-supercapacitors (MSCs) are an important energy storage component for future miniaturized electronic systems, yet their key performance indexes such as high-frequency response, energy density, and cycle life still have a large room to be improved. Herein, a laser-processed carbon-titanium carbide heterostructure (LCTH) electrode is demonstrated, which can excellently address the above key challenges by employing a unique one-step laser-processing fabrication method. Different from the other reported electrode structures, this LCTH electrode shows a heterogeneous structure, featuring the carbon nanofoam layer which provides extremely short ion transport channels and abundant electrochemical active sites, and the underlying titanium carbide layer which can provide excellent electron conductivity and contribute to the pseudo-capacitance. The assembled symmetric supercapacitor can stably work at the voltage window of 3.5V at an ultra-high frequency of approximately 1121.3Hz, exhibiting an ultra-high areal specific energy density of 721 µFV2 cm-2 at 120Hz and a cycle life of 140 000 cycles with capacitance retention of 100.95%, which is superior to most reported MSCs. The as-fabricated MSC is compatible with the contemporary embedded electronic component fabrication processes, which shows significant advantages in large-scale fabrication and system integration, demonstrating a broad prospect for future system-in-package applications.

Fracture tailoring in 3D printed continuous fibre composite materials using the Phase field approach for fracture

Additive Manufacturing is a technology with high potential since it offers a lot of benefits going from lower material waste to flexibility in the component fabrication process. The continuous Carbon Fibre (CF) deposition is an interesting approach since it allows to depose continuous CF bundles following different geometries and avoiding the limitations of current composite manufacturing techniques. Choosing the CF deposition path means also giving the designer the possibility to reinforce areas of the designed component which are subjected to stress concentrations, thus increasing its fracture resistance. In this work, a study on the reinforcement capabilities of this technology is performed, considering different specimen geometries and different geometries for the CF deposition path. Two different geometries are analysed: a V-notch and an Open-Hole specimen, both subjected to tensile loading. To model the fracture scenario, a Phase Field framework is exploited. The V-notch simulation demonstrates the capability of Phase Field to catch both the fracture path and the mechanical response reported in experiments from the literature. In the second part of the paper, the Open Hole Tension test is simulated numerically by means of the same tools described above, taking into consideration different geometries for the reinforcement around the hole. The specimens with different reinforcement geometries show different mechanical responses and crack patterns, thus highlighting the influence of the continuous CF reinforcement geometry on the fracture scenario.

Flexible Ceramic Film Sensors for Free-Form Devices.

Recent technological innovations, such as material printing techniques and surface functionalization, have significantly accelerated the development of new free-form sensors for next-generation flexible, wearable, and three-dimensional electronic devices. Ceramic film sensors, in particular, are in high demand for the production of reliable flexible devices. Various ceramic films can now be formed on plastic substrates through the development of low temperature fabrication processes for ceramic films, such as photocrystallization and transferring methods. Among flexible sensors, strain sensors for precise motion detection and photodetectors for biomonitoring have seen the most research development, but other fundamental sensors for temperature and humidity have also begun to grow. Recently, flexible gas and electrochemical sensors have attracted a lot of attention from a new real-time monitoring application that uses human breath and perspiration to accurately diagnose presymptomatic states. The development of a low-temperature fabrication process of ceramic film sensors and related components will complete the chemically stable and reliable free-form sensing devices by satisfying the demands that can only be addressed by flexible metal and organic components.

The effect of laser surface re-melting on the surface roughness and micro-hardness of selective laser melting (SLM) fabricated Ti-6Al-4V samples

Ti-6Al-4V is favourable due to its exquisite properties for example, low modulus, light weight, excellent strength, and corrosion resistance. Despite the excellent properties of the material, the fabrication process of titanium components is challenging due to the poor final surface quality components caused by non-uniform powder distribution during additive manufacturing (AM) using selective laser melting (SLM) process. SLM process produces fully denser parts with better mechanical properties compared to the bulk materials, although the surface quality is poor. This work aims to study the effect of laser surface re-melting (LSM) on the hardness and surface properties of Ti-6Al-4V alloy. The fabricated Ti-6Al-4V sheet was re-melted by a 3 kW IPG Fiber laser. Microstructural evaluations of the Ti-6Al-4V sheet were characterized using an optical microscope. Micro-hardness and surface roughness measurements were determined by means of an HV Vickers tester under an applied load of 300g and load time of 10s and MarSurf PS1 roughness tester machine respectively. Microstructural evolution and hardness properties were all examined before and after the LSM treatment. The experimental results showed the formation of martensitic structure on the areas treated. Micro-hardness depth profiling results showed an average increase of 15–25% which was higher compared to the average hardness of the as-received. The results indicated that the roughness measurements lowered when both the residence time and irradiance increase. Laser surface re-melting treatment showed an improvement of the microstructural modifications and hardness properties therefore, the process can be used to modify the component’s surface for reliable and best surface finish.

On the interfacial adhesion of fiber metal laminates using surface modified aluminum 7475 alloy for aviation industries – a study

Aluminum-based hybrid laminates are used extensively during the fabrication process of structural components in aviation industries due to its light weight and mechanical properties. A majority of airframe components are usually fitted with adhesion joints and, hence, surface adhesion has a great deal with surface and subsurface properties. To promote adhesion between substrates, various surface activating techniques could be followed. The main objective of this work is to enhance the interfacial adhesion strength between the thin aluminum alloy (AA 7475) and glass fiber. Experimentation was carried out to monitor the increase in the interfacial adhesion, by investigating the change in surface free energy which is influenced by the effect of surface etching. Aluminum sheets were treated using alkali (NaOH), iron (III) sulfate (Fe2(SO4)3) and potassium dichromate (K2Cr2O7). Etching effects were analyzed using water contact angle (WCA), profilometry, scanning electron microscope (SEM images), X-ray diffractometer (XRD) and Fourier transformed infrared spectroscopy (FTIR-ATR). Tensile strength testing was done to evaluate the interfacial adhesion strength. The outcome of experimentation proves that, iron (III) sulfate treated condition laminates have higher tensile strength and it has also increased the interfacial adhesion.

Smart Textile-Integrated Microelectronic Systems for Wearable Applications.

The programmable nature of smart textiles makes them an indispensable part of an emerging new technology field. Smart textile-integrated microelectronic systems (STIMES), which combine microelectronics and technology such as artificial intelligence and augmented or virtual reality, have been intensively explored. A vast range of research activities have been reported. Many promising applications in healthcare, the internet of things (IoT), smart city management, robotics, etc., have been demonstrated around the world. A timely overview and comprehensive review of progress of this field in the last five years are provided. Several main aspects are covered: functional materials, major fabrication processes of smart textile components, functional devices, system architectures and heterogeneous integration, wearable applications in human and nonhuman-related areas, and the safety and security of STIMES. The major types of textile-integrated nonconventional functional devices are discussed in detail: sensors, actuators, displays, antennas, energy harvesters and their hybrids, batteries and supercapacitors, circuit boards, and memory devices.

Enhancing Ductile-mode Cutting of Calcium Fluoride Single Crystals with Solidified Coating

Positive improvements have been observed during machining brittle materials under high hydrostatic pressure, but the techniques to achieve such desirable effects often utilize complex and expensive equipment or tools. This work presents a cost-efficient method to achieve ductile-mode machining of brittle materials at higher uncut chip thicknesses, by the application of a solidified coating on workpiece surface before a machining process. Orthogonal microcutting experiments were conducted on calcium fluoride single crystals oriented with the (111) plane and an increase in critical uncut chip thickness was observed with the solidified coating. The primary cause has been resolved to be mechanical-related and results in a stabilized microcutting process. Transmission electron microscopy provided evidence of slip deformation occurring in the machined subsurface regions and a layer thickness of subsurface damages reduced by ~ 45% under the influence of the solidified coating. In addition, erratic fluctuations in direction of the resultant machining force were subdued with the applied coating, which is proved to be caused by the compressive stresses induced from the sandwiching of the CaF2 material between the tool and the solidified coating. The proposed technique successfully reduces the cost and pollution in the fabrication process of optical components from the use of coolant in an ultraprecision machining process to the time consumed by eliminating the subsurface damage with abrasive slurries in post-machining polishing.

Direct Alcohol‐Fueled Low‐Temperature Solid Oxide Fuel Cells: A Review

AbstractLow‐temperature solid oxide fuel cells (LT‐SOFCs, operating temperature≤600 °C) are advantageous in potential applicability, affordability, and durability compared to conventional SOFCs (operating temperature: 800–1000 °C). Direct operation of LT‐SOFCs on liquid alcohol fuels can further improve their portability as well as accessibility to the fuel. In this review, we overview the results of LT‐SOFCs directly fueled by liquid alcohols that operate at 600 °C and below. Fundamentals regarding operation principles, losses, as well as reactions associated with liquid alcohol‐fueled LT‐SOFCs are presented. The materials, structures, and fabrication processes of cell components, namely anode, electrolyte, and cathode, are mainly reviewed. The electrochemical performances of alcohol‐fueled LT‐SOFCs are also summarized and compared with those of H2‐fueled LT‐SOFCs.

Behavioural Corrosion Mechanism of Hot Worked Mild Carbon Steel Immersed in various Acidic Environments

Heat treatment of metals is an important operation in the final fabrication process of many engineering components. Hot working help to improve the mechanical properties of the affected metals. In this research work, behavioural corrosion mechanism of hot worked mild steel carbon immersed in various acidic environments were evaluated mainly to determine the weight loss and corrosion rate of the material. In evaluating the corrosion rate of the mild steel in acidic environment, weight loss approach was adopted. The coupons were measured prior to immersion and different weight measurements were taken at interval of 24 hours, over the period of 168 hours. The difference in weight between the original weight and the final weight at each 24 hour interval (weight loss), was estimated and used for the calculation of the corrosion rates. The results obtained reveal an increased in weight loss as concentration of acids increases and this resulted to increase in corrosion rate as experienced by coupons immersed in five samples of acid environment used in this research work. Besides, nitric acid proved to be more aggressive, and this was followed by hydrochloric acid, tetraoxosulphate (VI) acid, phosphoric acid, and acetic acid was the least. Therefore, if acid must be used with mild steel, nitric acid should not be used.

Rhodamine-doped nanoporous polymer films as high-performance anti-reflection coatings and optical filters.

We demonstrate a simple and robust procedure for the fabrication of rhodamine-doped nanoporous poly(methyl methacrylate) (PMMA) films, whose optical properties, such as anti-reflection, fluorescence and absorption can be tailored to specific applications. By exploiting phase separation of a binary polymer blend (PMMA and polystyrene), we fabricated foam-like nanoporous films that could be easily and cost-effectively integrated into the fabrication process of optical components. We link film morphology, studied by multifrequency atomic force microscopy (AFM), to the effective refractive index of the films for use as anti-reflection coatings. The film's morphology leads to superior broadband anti-reflection performance compared with homogeneous films. For applications involving optical filters and spectral conversion layers (e.g., for photovoltaic applications), we doped the films with the fluorescent molecule rhodamine, whereby simple variations in the fabrication process enabled us to prepare rhodamine-doped nanoporous PMMA with tunable fluorescence and absorption, without losing the anti-reflective properties. The above combination of optical properties makes the films attractive for a wide range of applications.

Validation of Direct Analysis Real Time source/Time-of-Flight Mass Spectrometry for organophosphate quantitation on wafer surface

Microelectronic wafers are exposed to airborne molecular contamination (AMC) during the fabrication process of microelectronic components. The organophosphate compounds belonging to the dopant group are one of the most harmful groups. Once adsorbed on the wafer surface these compounds hardly desorb and could diffuse in the bulk of the wafer and invert the wafer from p-type to n-type. The presence of these compounds on wafer surface could have electrical effect on the microelectronic components. For these reasons, it is of importance to control the amount of these compounds on the surface of the wafer.As a result, a fast quantitative and qualitative analytical method, nondestructive for the wafers, is needed to be able to adjust the process and avoid the loss of an important quantity of processed wafers due to the contamination by organophosphate compounds.Here we developed and validated an analytical method for the determination of organic compounds adsorbed on the surface of microelectronic wafers using the Direct Analysis in Real Time–Time of Flight-Mass Spectrometry (DART–ToF-MS) system. Specifically, the developed methodology concerns the organophosphate group.

Optimizing the fabrication process and interplay of device components of polymer solar cells using a field-based multiscale solar-cell algorithm.

Both the device composition and fabrication process are well-known to crucially affect the power conversion efficiency of polymer solar cells. Major advances have recently been achieved through the development of novel device materials and inkjet printing technologies, which permit to improve their durability and performance considerably. In this work, we demonstrate the usefulness of a recently developed field-based multiscale solar-cell algorithm to investigate the influence of the material characteristics, like, e.g., electrode surfaces, polymer architectures, and impurities in the active layer, as well as post-production treatments, like, e.g., electric field alignment, on the photovoltaic performance of block-copolymer solar-cell devices. Our study reveals that a short exposition time of the polymer bulk heterojunction to the action of an external electric field can lead to a low photovoltaic performance due to an incomplete alignment process, leading to undulated or disrupted nanophases. With increasing exposition time, the nanophases align in direction to the electric field lines, resulting in an increase of the number of continuous percolation paths and, ultimately, in a reduction of the number of exciton and charge-carrier losses. Moreover, we conclude by modifying the interaction strengths between the electrode surfaces and active layer components that a too low or too high affinity of an electrode surface to one of the components can lead to defective contacts, causing a deterioration of the device performance. Finally, we infer from the study of block-copolymer nanoparticle systems that particle impurities can significantly affect the nanostructure of the polymer matrix and reduce the photovoltaic performance of the active layer. For a critical volume fraction and size of the nanoparticles, we observe a complete phase transformation of the polymer nanomorphology, leading to a drop of the internal quantum efficiency. For other particle-numbers and -sizes, we observe only a local perturbation of the nanostructure, diminishing the number of continuous percolation paths to the electrodes and, therefore, reducing the device performance. From these investigations, we conclude that our multiscale solar-cell algorithm is an effective approach to investigate the impact of device materials and post-production treatments on the photovoltaic performance of polymer solar cells.

Advanced techniques for estimation of the tensile fracture toughness of adhesive joints

Adhesive bonding has become more efficient in the last few decades due to the adhesives developments, granting higher strength and ductility. As a result, adhesives are being increasingly used in industries such as the automotive, aerospace and construction. Thus, it is highly important to predict the strength of bonded joints to assess the feasibility of joining during the fabrication process of components (e.g. due to complex geometries) or for repairing purposes. When using the Finite Element Method with advanced propagation laws, the tensile (Gnc) and shear (Gsc) fracture toughness of adhesive joints must be determined with accuracy. Several conventional methods to obtain Gnc and Gsc exist in the literature, mainly based on Linear Elastic Fracture Mechanics (LEFM). The J-integral technique is accurate to measure these parameters for adhesives with high ductility. In this work, the J-integral is used to obtain Gnc by the Double-Cantilever Beam (DCB) test. An optical measurement method is developed for the evaluation of the crack tip opening and adherends rotation at the crack tip during the test, supported by a Matlab® sub-routine for the automated extraction of these quantities. As output of this work, an optical method that allows an easier and quicker extraction of the parameters to obtain Gnc than the available methods is proposed (by the J-integral technique) and some results are presented regarding joints with different geometry and adherend material.

Advanced techniques for estimation of the tensile fracture toughness of adhesive joints

Adhesive bonding has become more efficient in the last few decades due to the adhesives developments, granting higher strength and ductility. As a result, adhesives are being increasingly used in industries such as the automotive, aerospace and construction. Thus, it is highly important to predict the strength of bonded joints to assess the feasibility of joining during the fabrication process of components (e.g. due to complex geometries) or for repairing purposes. When using the Finite Element Method with advanced propagation laws, the tensile (Gnc) and shear (Gsc) fracture toughness of adhesive joints must be determined with accuracy. Several conventional methods to obtain Gnc and Gsc exist in the literature, mainly based on Linear Elastic Fracture Mechanics (LEFM). The J-integral technique is accurate to measure these parameters for adhesives with high ductility. In this work, the J-integral is used to obtain Gnc by the Double-Cantilever Beam (DCB) test. An optical measurement method is developed for the evaluation of the crack tip opening and adherends rotation at the crack tip during the test, supported by a Matlab® sub-routine for the automated extraction of these quantities. As output of this work, an optical method that allows an easier and quicker extraction of the parameters to obtain Gnc than the available methods is proposed (by the J-integral technique) and some results are presented regarding joints with different geometry and adherend material.

KDP Crystals Grown in Defined Crystallographic Direction

KDP crystals are restrained to grow along (100) direction by a new designed platform. Compared to conventional method, it enables us to grow KDP crystals with higher optical utilization and less labor costs in fabrication process of optical components. The size of the grown crystals is 20×20×10mm3. Its quality has been analyzed by UV-vis spectral, chemical etching and high resolution X-ray diffraction. The FWHM of diffraction curves is 32 and 36 arc s. The transparency measured by UV-vis spectrometer is up to 80%. The results from various characterization studies indicate that the optical quality is almost as same as the conventionally grown crystals.

Adherend thickness effect on the tensile fracture toughness of a structural adhesive using an optical data acquisition method

Adhesive bonding is nowadays a serious candidate to replace methods such as fastening or riveting, because of attractive mechanical properties. As a result, adhesives are being increasingly used in industries such as the automotive, aerospace and construction. Thus, it is highly important to predict the strength of bonded joints to assess the feasibility of joining during the fabrication process of components (e.g. due to complex geometries) or for repairing purposes. This work studies the tensile behaviour of adhesive joints between aluminium adherends considering different values of adherend thickness (h) and the double-cantilever beam (DCB) test. The experimental work consists of the definition of the tensile fracture toughness (GIC) for the different joint configurations. A conventional fracture characterization method was used, together with a J-integral approach, that take into account the plasticity effects occurring in the adhesive layer. An optical measurement method is used for the evaluation of crack tip opening and adherends rotation at the crack tip during the test, supported by a Matlab® sub-routine for the automated extraction of these quantities. As output of this work, a comparative evaluation between bonded systems with different values of adherend thickness is carried out and complete fracture data is provided in tension for the subsequent strength prediction of joints with identical conditions.

鉄系金属ガラス単分散粒子の粘性流動加工による新規マイクロ部品作製プロセスの提案

鉄系金属ガラス単分散粒子の粘性流動加工による新規マイクロ部品作製プロセスの提案