Removal Of Film Research Articles

Potentiality of chitosan/titanium oxide nanocomposite for removing iron and chromium from hydrous solutions.

The present study involved the preparation of a nano-polymer based on shrimp wastes as a biodegradable chitosan nanoparticle (Cs) incorporated into titanium oxide nanoparticles (TiO2) in an aqueous medium and carried on the specific polymer to form thin films. The spectroscopic properties of chitosan/TiO2/Polymer thin films were estimated by transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy. The fabricated films were then examined for their potential to eliminate iron (Fe) and chromium (Cr) from solutions. The adsorption efficiency was also evaluated along various contact times. In general, the results illustrated that the heavy metals removal increases with increasing the different ratios of chitosan and TiO2 nanoparticles incorporated in polymer thin films. Removal efficiency increased with an increase in contact time. More than 70% of Fe and Cr ions were removed in the first 30min of contact time using different thin films examined. The maximum removal for metal ions after 90min for the pest thin film (0.08 TiO2) was 97.1 and 88.8% for Fe and Cr, whereas the lowest thin film removal efficiency (PVC) was 29.5 and 8.07% for Fe and Cr, respectively. In conclusion, the fabricated thin film composed of polyvinylidene chloride and chitosan plus 0.08 g titanium oxide nanoparticles had a heavy metal removal capacity three times greater than that of basic polyvinylidene chloride.

A novel approach for the removal of oxide film to achieve seamless joining during hot-compression bonding

The oxide film on the substrate surfaces can severely hinder the bonding quality during hot-compression bonding (HCB). To address the above issue, this investigation proposes a novel approach to enhance bonding quality by removing surface oxide film and encapsulating the interface to be bonded in sequence under vacuum. The principle of the approach was clarified, and an experiment platform used for implementing the approach was designed and developed. By considering 316H stainless steel as a testbed, the key parameter for laser ablation of the oxide films before HCB was determined. The HCB comparative experiments of substrates with or without treatment by the approach were carried out and the effectiveness of the approach was assessed by comparing the quality of bonding joints through interface morphologies and tensile properties. Results showed that a nearly seamless bond without thermal holding was achieved after adopting this approach. Further, it also showed improvement in the tensile properties both in elongation and the ultimate tensile strength (UTS). For instance, when using the proposed approach, the average UTS of 316H stainless steel joints improved from 371.17 MPa to 430.25 MPa whereas the average elongation increased from 26.41 % to 64.04 %. Although this investigation was directed to 316H stainless steel, the suggested approach can be applied to a wide range of other engineering materials to improve the joining quality.

Fabrication of Magnetic Pulse Welding Sheets of Aluminum Alloy and GA Steel Plates Subjected to Film Removal Treatment and Their Welding Property

Fabrication of Magnetic Pulse Welding Sheets of Aluminum Alloy and GA Steel Plates Subjected to Film Removal Treatment and Their Welding Property

Dynamics of deposition and removal of a fluorocarbon film in the cyclic process of plasma-chemical etching of silicon

In situ measurements of the dynamics of deposition and etching of a fluorocarbon film (FCF) during cyclic plasma-chemical etching of silicon using a laser interferometer have been carried out. Direct measurements of the deposition and etch rates, as well as the etch time of the FCF, open up new possibilities for optimizing the cycle procedure. For example, adjusting the etching time of the FCF improves the selectivity of the etching process.

Advanced Nested Coaxial Thin-Film ZnO Nanostructures Synthesized by Atomic Layer Deposition for Improved Sensing Performance

We report a new synthesis method for multiple-walled nested thin-film nanostructures by combining hydrothermal growth methods with atomic layer deposition (ALD) thin-film technology and sacrificial films, thereby increasing the surface-to-volume ratio to improve the sensing performance of novel ZnO gas sensors. Single-crystal ZnO nanorods serve as the core of the nanostructure assembly and were synthesized hydrothermally on fine-grained ALD ZnO seed films. Subsequently, the ZnO core nanotubes were coated with alternating sacrificial coaxial 3D wrap-around ALD Al2O3 films and ALD ZnO films. Basically, the center nanorod was coated with an ALD 3D wrap-around Al2O3 sacrificial layer to realize a nested coaxial ZnO thin-film nanotube. To increase the surface-to-volume ratio of the nested multiple-film nanostructure, both the front and backside of the nested coaxial ZnO films must be exposed by selectively removing the intermittent Al2O3 sacrificial films. The selective removal of the sacrificial films exposes the front and backside of the free-standing ZnO films for interaction with target gases during sensing operation while steadily increasing the surface-to-volume ratio. The sensing response of the novel ZnO gas sensor architecture with nested nanotubes achieved a maximum 150% enhancement at low temperature compared to a conventional ZnO nanorod sensor.

Designable Electrochemiluminescence Patterning for Renewable and Enhanced Bioimaging.

Electrochemical imaging enables an in-depth analysis of the interface heterogeneity and reaction kinetics of single entities. However, electrode passivation during electrochemical reactions decreases the active sites and harms the long-term stability. Here, we introduce a method using laser-induced photothermal effects to restore the electrochemical activity, which is particularly displayed as enhanced micrometric patterns in electrochemiluminescence (ECL) microscopy. By co-localization characterization and X-ray photoelectron spectroscopy, the mechanism of active site regeneration is validated as the removal of the oxide film for restoring the local surface ECL reactivity under laser irradiation. The surface-confined and voltage-dependent features of ECL allows for easy pattern erasure and rewriting, and it shows good reversibility and anti-counterfeiting potential. This approach overcomes the passivation processes, evidently improves the image quality of single biological entities including Shewanella bacteria and cells, and makes the subtle contour structures more distinct. The renewable electrode interface also enhances the ECL signal of model bead-based bioassays. This approach not only showcases precise control in fabricating micron patterns but also holds promise for enhancing the sensitivity in electrochemical immunoassays and bioimaging.

Designable Electrochemiluminescence Patterning for Renewable and Enhanced Bioimaging

Electrochemical imaging enables an in‐depth analysis of the interface heterogeneity and reaction kinetics of single entities. However, electrode passivation during electrochemical reactions decreases the active sites and harms the long‐term stability. Here, we introduce a method using laser‐induced photothermal effects to restore the electrochemical activity, which is particularly displayed as enhanced micrometric patterns in electrochemiluminescence (ECL) microscopy. By co‐localization characterization and X‐ray photoelectron spectroscopy, the mechanism of active site regeneration is validated as the removal of the oxide film for restoring the local surface ECL reactivity under laser irradiation. The surface‐confined and voltage‐dependent features of ECL allows for easy pattern erasure and rewriting, and it shows good reversibility and anti‐counterfeiting potential. This approach overcomes the passivation processes, evidently improves the image quality of single biological entities including Shewanella bacteria and cells, and makes the subtle contour structures more distinct. The renewable electrode interface also enhances the ECL signal of model bead‐based bioassays. This approach not only showcases precise control in fabricating micron patterns but also holds promise for enhancing the sensitivity in electrochemical immunoassays and bioimaging.

Characterization of liquid-thickness distribution in micropores on elastic surface under sliding and pressurizing conditions.

To improve the performance of studless tires on ice surfaces, the mechanism of liquid film removal must be elucidated. In this study, an experimental system is developed to simulate the running conditions of a studless tire, and the microscopic liquid film flow generated between the rubber surface and glass is observed to evaluate the liquid thickness distribution. Liquid film removal by micropores on foamed rubber samples is investigated by visualizing the liquid thickness in the micropores. The proposed system enables variations in the pressure and sliding velocity between the rubber and glass. The liquid thickness in the micropores is measured using laser-induced fluorescence, and the effects of pressure and sliding velocity on the thickness are examined. Water penetrates the micropores on the rubber sample surface, and different liquid thicknesses are obtained for each pore. The amount of liquid penetrating the pores is affected to a greater extent by the sliding velocity than by the pressure. Therefore, liquid penetration is more strongly influenced by the hydrodynamic effect of the increasing inertia of the liquid under high sliding velocities than by the elastic deformation of the pore.

Controlled Spalling of 4H Silicon Carbide with Investigated Spin Coherence for Quantum Engineering Integration.

We detail scientific and engineering advances which enable the controlled spalling and layer transfer of single crystal 4H silicon carbide (4H-SiC) from bulk substrates. 4H-SiC's properties, including high thermal conductivity and a wide bandgap, make it an ideal semiconductor for power electronics. Moreover, 4H-SiC is an excellent host of solid-state atomic defect qubits for quantum computing and quantum networking. Because 4H-SiC substrates are expensive (due to long growth times and limited yield), techniques for removal and transfer of bulk-quality films are desirable for substrate reuse and integration of the separated films. In this work, we utilize updated approaches for stressor layer thickness control and spalling crack initiation to demonstrate controlled spalling of 4H-SiC, the highest fracture toughness crystal spalled to date. We achieve coherent spin control of neutral divacancy (VV0) qubit ensembles and measure a quasi-bulk spin T2 of 79.7 μs in the spalled films.

Solar driven photocatalytic colored co–TixOyNz amorphous film prepared through air plasma treatment of sputtered titanium film

Colored co–titanium oxides and oxynitride amorphous thin film were fabricated through air plasma treatment of sputtered titanium films. Air plasma treatment led to the removal of the passive film that developed on the titanium film surface, and changes in the structural and optical properties of the films. The amorphous nature, grain size, and thickness of the films remained invariant after the treatment process. The surface roughness of the films increased upon plasma treatment. UV-vis spectroscopy study showed the reduction of the bandgap energy of the films after the air plasma treatment and the maximum reduction was found for the thinner film. The 60min air plasma treatment of the thinner film (AD5: film with 5 min deposition time) leads to the changes in bandgap from 4.11 eV to 3.26 eV, and significant Urbach energy values pointed to the formation of defect states. XPS analysis highlighted that the plasma treatment process led to the formation of titanium oxides (TiO2, Ti2O3) and oxynitrides (TiON), accompanied with Ti2+ defect states in the bandgap. The degradation of methylene blue dye solution with plasma-treated film (PT5) as the photocatalyst resulted in 88% degradation efficiency under 240min irradiation of solar simulator. The degradation has also been checked with natural solar illumination and is found to have a 90% degradation efficiency in 480min.

Optimization of laser patterning process for eco-friendly tin-halide perovskite solar module – with a nanosecond green laser

The tin-based perovskite solar cells are promising future eco-friendly photovoltaic technology with increasing efficiency, which relies on fluorine-doped tin oxide (FTO) or indium tin oxide (ITO) as a transparent conducting oxide (TCO) for front contact. In the monolithic module fabrication process interconnections are executed by a series of three scribes with two different lasers 1064 nm and 532 nm. This study aims to simplify the interconnection process in tin-based perovskite solar modules by using a single visible laser source to perform all three scribes. The study uses an inverted device structure of Glass/TCO/ Poly(3,4-ethylenedioxythiophene): Polystyrene sulfonate (PEDOT: PSS)/Formamidinium-tin-iodide (FASnI3)/C60/Bathocuproine (BCP)/Ag and a 532 nm nanosecond pulsed laser source to pattern the ITO and FTO (P1 scribe), the PEDOT: PSS/FASnI3/C60/BCP stack (P2 scribe), and the PEDOT: PSS/FASnI3/C60/BCP/Ag (P3 scribe). The quality of the P1 scribe is assessed by examining the edges, completeness of film removal, cracking, film delamination, and elemental mapping using a stylus profiler, optical microscope, and energy dispersive x-ray spectroscopy. The P1 scribe is completely removed with line widths of 70 µm and 110 µm of ITO and FTO, respectively, without damage to the glass substrate. The profiles are steep, and the electrical isolation is greater than 40 MΩ. The same 532 nm laser is used for P2 and P3 scribes. The ablation of PEDOT: PSS during P2 and P3 scribe is studied by Raman spectroscopy. The results show that the use of a single 532 nm laser source can simplify the patterning process of monolithic tin-based perovskite solar modules, and potentially reduce production costs.

Study on the high temperature wear behavior of TiAlSiN coatings deposited on WC-TaC-Co cemented carbides

This study investigated the high-temperature wear behavior and the failure mechanism of TiAlSiN coating under thermal-mechanical coupling. The results indicate that increased temperature significantly promotes coating oxidation, forming a complete wear-resistant layer. However, coating hardness decreases significantly at elevated temperatures, deteriorating the wear property. Increased load generates higher friction heat and intensifies coating oxidation, but it accelerates oxide film fracture and spalling. Mechanical stress causes oxide film fracture, spalling and removal, while high-temperature oxidation triggers cracks healing, debris connection and oxide film re-formation. Oxide film exhibits a dynamic cycle of formation-breaking-formation in high-temperature wear.

Investigation of laser-assisted micromachining of NiTi SMA bimorph based actuators toward developing optical shutters

Abstract This work explores laser-assisted micromachining for the precision cutting of NiTi shape memory alloy (SMA)-based bimorph in a single-pass laser scan. SMA thin film based optical shutters were developed with this method, which can generate the opening and closing via Joule’s heating rather than mechanical components. NiTi SMA bimorph was fabricated using the e-beam evaporation technique followed by micromachining using a 1064 nm fiber laser. The influence of laser power (LP), laser speed (LS), spot diameter (SP), and laser travel direction on kerf width and heat-affected zone after micromachining was studied using the design of experiments. The optimized parameter for micromachining was at LP 5 W with 5 mm s−1 LS and 50 μm SP. Various shapes were cut at the optimized parameter, including an optical shutter of a diameter of 30 mm. A LS of 6 mm s−1 has produced microchannels in the bimorph due to NiTi film removal only. The SEM analysis of the shutter reveals the formation of refined grains at micromachined edges compared to the center of the actuator. Fabricated optical shutter shows negligible optical transmittance in the 450–700 nm wavelength range.

Effect of grit blasting on fatigue behavior of 2024-T3 aero Al alloy

Aiming at the removal of native oxide film on 2024-T3 Al alloy before plasma electrolytic oxidation, the methods to reduce the fatigue damage caused by grit blasting are explored. Effects of the grit size and pressure on surface roughness, residual compressive stress (RCS), and fatigue life of the Al alloy are studied. Increasing grit size and pressure leads to the increase in the surface roughness and RCS. Based on the theorem of momentum and tool cutting principle, mechanism of the grits on the craters and RCS is revealed. It is found that the angularness of the small-sized grit results in the formation of long scratches. The grit with high kinetic energy induces the large craters and high RCS. The craters are the primary fatigue crack initiation source. Moreover, the craters with long scratch and large height lead to the premature fatigue failure of the grit blasted specimens. However, Fatigue behavior is insignificantly affected by the RCS. The results provide new insights into the fatigue deterioration mechanism and life optimization of the grit blasted samples. Consequently, a parameter optimization scheme for the fatigue life of the grit blasted Al alloy is proposed.

Insight into interaction of electrode particles from spent lithium-ion batteries assisted by pyrolysis

Pyrolysis-assisted dispersion for electrode particles from spent lithium-ion batteries (LiBs) is an extremely effective means to improve subsequent recovery efficiency. The relationship between interaction energy and surface properties of electrode particles has been constructed. The XRD results demonstrated that the mineral phases of both anode and cathode particles, mainly composed of graphite and LiCoO2 respectively, had little changes using a pyrolysis process at 550 ℃ for 30 min. Nevertheless, pyrolysis treatment could remove the organic film of electrode particles to alter the surface properties effectively. With the organic film removal by pyrolysis, the subtraction value on the contact angle of cathode and anode particles was increased from 9.3° to 35.44°, while the difference in charge ability was increased from 0.35 mV to 23.21 mV. The interaction energy calculations also illustrated that the electrostatic repulsion energy and hydrophilic repulsion energy both increased significantly, resulting in the total interaction energy of anode and cathode particles being 1.7 and 3.8 times that before pyrolysis. Furthermore, the total interaction energy, which determined the dispersing of electrode particles in suspension, mainly depended on the hydrophilic force. The findings might propose an alternative means for enhancing particle interaction to improve the recycling efficiency of electrode materials from spent LiBs by flotation.

Remote plasma enhanced cyclic etching of a cyclosiloxane polymer thin film

The continuous evolution of chip manufacturing demands the development of materials with ultra-low dielectric constants. With advantageous dielectric and mechanical properties, initiated chemical vapor deposited (iCVD) poly(1,3,5-trimethyl-1,3,5-trivinyl cyclotrisiloxane) (pV3D3) emerges as a promising candidate. However, previous works have not explored etching for this cyclosiloxane polymer thin film, which is indispensable for potential applications to the back-end-of-line fabrication. Here, we developed an etching process utilizing O2/Ar remote plasma for cyclic removal of iCVD pV3D3 thin film at sub-nanometer scale. We employed in-situ quartz crystal microbalance to investigate the process parameters including the plasma power, plasma duration and O2 flow rate. X-ray photoelectron spectroscopy and cross-sectional microscopy reveal the formation of an oxidized skin layer during the etching process. This skin layer further substantiates an etching mechanism driven by surface oxidation and sputtering. Additionally, this oxidized skin layer leads to improved elastic modulus and hardness and acts as a barrier layer for protecting the bottom cyclosiloxane polymer from further oxidation.

Molecular Interactions in Copper Chemical Mechanical Planarization: A Phenomenological Study

In this study, the molecular interactions occurring during Chemical Mechanical planarization of Copper in Ferric nitrate–Alumina–Benzotriazole system is investigated. This system is characterized by sudden and dramatic transitions in removal rates when experimental parameters such as downforce and concentrations of the slurry components (Benzotriazole, abrasive, oxidizer) are varied. This behavior is interpreted in terms of the three surface kinetic processes viz. Cu dissolution, film formation and film removal by abrasion, that determine the overall removal rate. A phenomenological model incorporating Frumkin isotherm for the adsorption of Benzotriazole molecules and Langmuir isotherm for the adsorption of surfactants/ions is proposed. Mathematical equations relating the rates of film formation, film removal and metal dissolution to the overall removal rates are derived. The model is validated by comparing the model predictions with experimental data. The non-linear equations describing the sudden transitions are shown to exhibit a cusp catastrophe when the interaction parameter exceeds a certain value.

Fabrication of magnetic pulse welding sheets of aluminum alloy and GA steel plates subjected to film removal treatment and their welding property

Fabrication of magnetic pulse welding sheets of aluminum alloy and GA steel plates subjected to film removal treatment and their welding property

Reusing uncured Fiber-reinforced thermoset composite Prepreg waste with water-soluble PVA backing film

One challenge in reusing uncured composite prepreg waste is the removal of the backing film. Ensuring that no backing film remains during the reuse of composite prepreg material is crucial, as the presence of backing film in the laminate can contaminate the part, leading to defects such as delamination. Manual removal of the backing film from the leftover uncured composite prepreg is a labor-intensive task, and ensuring there is no remaining backing film in the prepreg waste can be challenging. To address these issues, the authors implemented a water-soluble polyvinyl alcohol (PVA) film as the backing material for the prepreg, allowing less labor-intensive removal of the PVA backing film by soaking the prepreg in water before reusing. In this study, 20 μm thick 100% PVA film was utilized as backing material for carbon fiber-reinforced thermoset composite prepreg. The performance of the PVA film as a prepreg backing material was assessed, and the process of removing the backing film was demonstrated. To investigate the impact of the backing film removal process on the mechanical properties of the reused prepreg, tensile and double cantilever beam (DCB) tests were conducted. The results indicated that the PVA backing removal and drying processes did not show any significant influence on the tensile properties and interlaminar strength of the reused composite prepreg. Furthermore, this study demonstrated the recycling of the PVA solution used in the backing removal process to produce new PVA film. The application of PVA as a backing film not only simplified the backing film removal for reused prepreg but also established a sustainable closed-loop recycling system for prepreg backing film.

Bio-regeneration for Sodium Silicate Used Sands and its Unattended Monitoring System

Sodium silicate, known for its low cost and non-toxicity, has been considered as a promising option for green foundry in terms of mould sands. However, the utilization of used sodium silicate sands has posed significant challenges. To address the issues of high energy consumption and secondary pollution associated with wet and dry regeneration of sodium silicate used sands, this paper proposes a novel unattended biological regeneration system. The system involves culturing diatoms in an incubator with a solution of sodium silicate used sands. The incubator is equipped with built-in sensors that continuously monitor temperature, illuminance, pH, and water level. The monitoring data is transmitted in real-time to the Yeelink Internet of Things platform via the controller using the TCP/IP protocol. By logging onto the corresponding web page, the experimenter can remotely observe the monitoring data. The results of the experiment indicate that diatoms bloomed five times, and the water pH decreased from 10.2 to 8.2 after 40 days of cultivation. Additionally, the film removal rate of the used sands reached 90.26%.