Special Issue "Thin Film Fabrication and Surface Techniques"

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Thin Films".

Deadline for manuscript submissions: closed (31 July 2019).

Special Issue Editor

Dr. Alessandro Pezzella
Website
Guest Editor
Department of Chemical Sciences, University of Naples “Federico II”, Complesso Universitario Monte S. Angelo, Via Cintia, I-80126 Naples, Italy
Interests: natural products; melanin pigments; conducting polymers; organic electronics and bioelectronics; biointerfaces; organic chemistry and materials chemistry; protective organic and inorganic coatings; antimicrobial polymer coatings; nanostructured materials; biomimetics; nanocomposites; nanoparticles

Special Issue Information

Dear Colleagues,

Surface modifications using thin film-based coatings is gaining more and more relevance in science and technology and is at the crossroads of physics, chemistry, biology, and medicine. Since the early studies, addressing single metal layer interconnections, the activities connected with thin film fabrication, characterization, and applications have witnessed a great deal of development, involving researchers from academy and industry.

The control of the chemistry and physics at the interface between interacting systems is a major goal and challenge for the development of valuable thin film fabrication protocols. The recent development of nanomanufacturing is impacting both the characteristics and processing techniques of thin films, allowing to expand the scope of such architectures, leading to smart (self)active, multifunctional layers.

This Special Issue, collecting topics from an interdisciplinary viewpoint, is aimed to provide a resourceful background for readers, addressing the design and innovation of surface techniques and thin film fabrication protocols.

Within an organization on two main topics (chemistry and application), special focus will be devoted to post-processing functionalization with the aim to collect the most innovative approaches on the fine control of thin film chemistry.

Both basic research and applications will be covered in dedicated sections, including the tuning of chemical and physical properties of thin film; biocompatibility and bioactivity of functionalized surfaces; deposition technologies; substrate surface preparation techniques; of the development of thin film-based structures/devices; thin film transfer; and large area technologies.

We do believe this collection will stimulate and circulate new ideas on the topic and will contribute to the dissemination of expertise for young investigators, as well as leading experts in the field.

Dr. Alessandro Pezzella
Guest Editor

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Published Papers (23 papers)

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Open AccessArticle
Deposition of Selective Catalytic Reduction Coating on Wire-Mesh Structure by Atmospheric Plasma Spraying
Materials 2019, 12(18), 3046; https://doi.org/10.3390/ma12183046 - 19 Sep 2019
Abstract
A series of catalytic coatings consisting of MnOx-CeO2 and TiO2 support were prepared by atmospheric plasma spraying, which was aimed at the application of selective catalytic reduction (SCR) of NOx. The effect of the load of active [...] Read more.
A series of catalytic coatings consisting of MnOx-CeO2 and TiO2 support were prepared by atmospheric plasma spraying, which was aimed at the application of selective catalytic reduction (SCR) of NOx. The effect of the load of active component on the coating was firstly studied. The results showed that all the coating presented the highest catalytic activity at approximately 350 °C and the coating with the composition of 20MnOx/5CeO2/TiO2 (wt%) achieved the most powerful performance. The coating was then prepared on a wire-mesh structure substrate, which can be easily assembled as a gas filter. The results showed that the specific surface area was greatly increased resulting in the significant improvement of the catalytic activity of the coating. This strategy offered a promising possibility of removing NOx and particulate fliting simultaneously in industrial applications. Full article
(This article belongs to the Special Issue Thin Film Fabrication and Surface Techniques)
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Open AccessArticle
Sustainable, Fluorine-Free, Low Cost and Easily Processable Materials for Hydrophobic Coatings on Flexible Plastic Substrates
Materials 2019, 12(14), 2234; https://doi.org/10.3390/ma12142234 - 11 Jul 2019
Abstract
Zinc oxide nanoparticles (ZnONPs) and stearic acid are herein used for the preparation of hydrophobic coatings with good moisture barrier property on flexible plastic substrates. Fast, high throughput, mild and easy-to-run processing techniques, like airbrushing and gravure printing, are applied for thin films [...] Read more.
Zinc oxide nanoparticles (ZnONPs) and stearic acid are herein used for the preparation of hydrophobic coatings with good moisture barrier property on flexible plastic substrates. Fast, high throughput, mild and easy-to-run processing techniques, like airbrushing and gravure printing, are applied for thin films deposition of these materials. The results of this study indicated that the best hydrophobic coating in terms of water contact angle (115°) is obtained through a two-steps printing deposition of a ZnONPs layer followed by a stearic acid layer. All the deposition procedures proved to be effective in terms of water vapor barrier properties, reaching values of 0.89 g/m2/day, with a 45% reduction with respect to the bare substrate. These preliminary data are very encouraging in the perspective of a low cost and green approach for the realization of functional coatings for packaging applications. Full article
(This article belongs to the Special Issue Thin Film Fabrication and Surface Techniques)
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Open AccessArticle
Electrical and Structural Characteristics of Excimer Laser-Crystallized Polycrystalline Si1−xGex Thin-Film Transistors
Materials 2019, 12(11), 1739; https://doi.org/10.3390/ma12111739 - 29 May 2019
Abstract
We investigated the characteristics of excimer laser-annealed polycrystalline silicon–germanium (poly-Si1−xGex) thin film and thin-film transistor (TFT). The Ge concentration was increased from 0% to 12.3% using a SiH4 and GeH4 gas mixture, and a Si1−xGe [...] Read more.
We investigated the characteristics of excimer laser-annealed polycrystalline silicon–germanium (poly-Si1−xGex) thin film and thin-film transistor (TFT). The Ge concentration was increased from 0% to 12.3% using a SiH4 and GeH4 gas mixture, and a Si1−xGex thin film was crystallized using different excimer laser densities. We found that the optimum energy density to obtain maximum grain size depends on the Ge content in the poly-Si1−xGex thin film; we also confirmed that the grain size of the poly-Si1−xGex thin film is more sensitive to energy density than the poly-Si thin film. The maximum grain size of the poly-Si1−xGex film was 387.3 nm for a Ge content of 5.1% at the energy density of 420 mJ/cm2. Poly-Si1−xGex TFT with different Ge concentrations was fabricated, and their structural characteristics were analyzed using Raman spectroscopy and atomic force microscopy. The results showed that, as the Ge concentration increased, the electrical characteristics, such as on current and sub-threshold swing, were deteriorated. The electrical characteristics were simulated by varying the density of states in the poly-Si1−xGex. From this density of states (DOS), the defect state distribution connected with Ge concentration could be identified and used as the basic starting point for further analyses of the poly-Si1−xGex TFTs. Full article
(This article belongs to the Special Issue Thin Film Fabrication and Surface Techniques)
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Open AccessArticle
A Pragmatic Bilayer Selective Emitter for Efficient Radiative Cooling under Direct Sunlight
Materials 2019, 12(8), 1208; https://doi.org/10.3390/ma12081208 - 12 Apr 2019
Cited by 1
Abstract
Radiative cooling can make the selective emitter cool below ambient temperature without any external energy. Recent advances in photonic crystal and metamaterial technology made a high-efficiency selective emitter achievable by precisely controlling the emitter’s Infrared emission spectrum. However, the high cost of the [...] Read more.
Radiative cooling can make the selective emitter cool below ambient temperature without any external energy. Recent advances in photonic crystal and metamaterial technology made a high-efficiency selective emitter achievable by precisely controlling the emitter’s Infrared emission spectrum. However, the high cost of the photonic crystals and meta-materials limit their application. Herein, an efficient bilayer selective emitter is prepared based on the molecular vibrations of functional nanoparticles. By optimizing the volume fraction of the functional nanoparticles, the bilayer selective emitter can theoretically cool 36.7 °C and 25.5 °C below the ambient temperature in the nighttime and daytime, respectively. Such an efficient cooling performance is comparable with the published photonic crystal and metamaterial selective emitters. The rooftop measurements show that the bilayer selective emitter is effective in the ambient air even under direct sunlight. The relatively low cost and excellent cooling performance enable the bilayer selective emitter to have great potential for a practical purpose. Full article
(This article belongs to the Special Issue Thin Film Fabrication and Surface Techniques)
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Open AccessArticle
P-Type Lithium Niobate Thin Films Fabricated by Nitrogen-Doping
Materials 2019, 12(5), 819; https://doi.org/10.3390/ma12050819 - 11 Mar 2019
Cited by 4
Abstract
Nitrogen-doped lithium niobate (LiNbO3:N) thin films were successfully fabricated on a Si-substrate using a nitrogen plasma beam supplied through a radio-frequency plasma apparatus as a dopant source via a pulsed laser deposition (PLD). The films were then characterized using X-Ray Diffraction [...] Read more.
Nitrogen-doped lithium niobate (LiNbO3:N) thin films were successfully fabricated on a Si-substrate using a nitrogen plasma beam supplied through a radio-frequency plasma apparatus as a dopant source via a pulsed laser deposition (PLD). The films were then characterized using X-Ray Diffraction (XRD) as polycrystalline with the predominant orientations of (012) and (104). The perfect surface appearance of the film was investigated by atomic force microscopy and Hall-effect measurements revealed a rare p-type conductivity in the LiNbO3:N thin film. The hole concentration was 7.31 × 1015 cm−3 with a field-effect mobility of 266 cm2V−1s−1. X-ray Photoelectron Spectroscopy (XPS) indicated that the atom content of nitrogen was 0.87%; N atoms were probably substituted for O sites, which contributed to the p-type conductivity. The realization of p-type LiNbO3:N thin films grown on the Si substrate lead to improvements in the manufacturing of novel optoelectronic devices. Full article
(This article belongs to the Special Issue Thin Film Fabrication and Surface Techniques)
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Open AccessArticle
Morphology and Wear Resistance of Composite Coatings Formed on a TA2 Substrate Using Hot-Dip Aluminising and Micro-Arc Oxidation Technologies
Materials 2019, 12(5), 799; https://doi.org/10.3390/ma12050799 - 08 Mar 2019
Cited by 4
Abstract
Aluminium layers were coated onto the surface of pure titanium using hot-dip aluminising technology, and then the aluminium layers were in situ oxidised to form oxide ceramic coatings, using the micro-arc oxidation (MAO) technique. The microstructure and composition distribution of the hot-dip aluminium [...] Read more.
Aluminium layers were coated onto the surface of pure titanium using hot-dip aluminising technology, and then the aluminium layers were in situ oxidised to form oxide ceramic coatings, using the micro-arc oxidation (MAO) technique. The microstructure and composition distribution of the hot-dip aluminium coatings and ceramic layers were studied by using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The phase structure of the MAO layers was studied using X-ray diffraction. The surface composition of the MAO layer was studied by X-ray photoelectron spectroscopy. The wear resistance of the pure titanium substrate and the ceramic layers coated on its surface were evaluated by using the ball-on-disc wear method. Therefore, aluminising coatings, which consist of a diffusion layer and a pure aluminium layer, could be formed on pure titanium substrates using the hot-dip aluminising method. The MAO method enabled the in-situ oxidation of hot-dip pure aluminium layers, which subsequently led to the formation of ceramic layers. Moreover, the wear resistance values of the ceramic layers were significantly higher than that of the pure titanium substrate. Full article
(This article belongs to the Special Issue Thin Film Fabrication and Surface Techniques)
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Open AccessArticle
A Facile Approach for Preparing Ag Functionalized Nonwoven Polypropylene Membrane to Improve Its Electrical Conductivity and Electromagnetic Shielding Performance
Materials 2019, 12(2), 296; https://doi.org/10.3390/ma12020296 - 18 Jan 2019
Abstract
The commonly used preparation methods of polypropylene functionalization require special equipment to be put into use or take a long time, which limits its application. Therefore, a simple and economical method for preparing silver functionalized nonwoven polypropylene membrane was studied herein. Triethanolamine was [...] Read more.
The commonly used preparation methods of polypropylene functionalization require special equipment to be put into use or take a long time, which limits its application. Therefore, a simple and economical method for preparing silver functionalized nonwoven polypropylene membrane was studied herein. Triethanolamine was first coated on the surface of the polypropylene, and then Ag was deposited on the surface of polypropylene using a continuous reduction reaction of triethanolamine and silver ions. Surface morphology, crystal structure, and surface chemistry during the preparation of Ag functionalized nonwoven polypropylene were investigated. The electrical conductivity, electromagnetic shielding properties, and washing durability of the treated nonwoven polypropylene were also studied. It was found that Ag was uniformly deposited on the surface of the nonwoven polypropylene, and the coating reaction did not change the chemical structure of the polypropylene. The crystallinity and thermal stability of polypropylene were improved after silver coated polypropylene. The washing experiment results showed that the weight gain rate of the treated nonwoven relative to the untreated sample after the 90 min washing ranged from 6.72% to 9.64%. The resistance test results showed that the maximum surface resistivity of Ag coated nonwoven polypropylene was about 1.95 × 105 Ω, which was 64,615 times lower than the original. In addition, the results showed that the maximum electromagnetic shielding effectiveness of the Ag coated nonwoven polypropylene was about 71.6 dB, showing a very good electromagnetic shielding effect. Full article
(This article belongs to the Special Issue Thin Film Fabrication and Surface Techniques)
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Open AccessArticle
Improvement of Electrical Performance in P-Channel LTPS Thin-Film Transistor with a-Si:H Surface Passivation
Materials 2019, 12(1), 161; https://doi.org/10.3390/ma12010161 - 07 Jan 2019
Cited by 1
Abstract
We report the effects of surface passivation by depositing a hydrogenated amorphous silicon (a-Si:H) layer on the electrical characteristics of low temperature polycrystalline silicon thin film transistors (LTPS TFTs). The intrinsic a-Si:H layer was optimized by hydrogen dilution and its structural and electrical [...] Read more.
We report the effects of surface passivation by depositing a hydrogenated amorphous silicon (a-Si:H) layer on the electrical characteristics of low temperature polycrystalline silicon thin film transistors (LTPS TFTs). The intrinsic a-Si:H layer was optimized by hydrogen dilution and its structural and electrical characteristics were investigated. The a-Si:H layer in the transition region between a-Si:H and µc-Si:H resulted in superior device characteristics. Using a-Si:H passivation layer, the field-effect mobility of the LTPS TFT was increased by 78.4% compared with conventional LTPS TFT. Moreover, the leakage current measured at VGS of 5 V was suppressed because the defect sites at the poly-Si grain boundaries were well passivated. Our passivation layer, which allows thorough control of the crystallinity and passivation-quality, should be considered as a candidate for high performance LTPS TFTs. Full article
(This article belongs to the Special Issue Thin Film Fabrication and Surface Techniques)
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Open AccessArticle
A Convenient and High-Efficient Laser Micro-Engraving Treatment for Controllable Preparation of Microstructure on Al Alloy
Materials 2018, 11(11), 2297; https://doi.org/10.3390/ma11112297 - 16 Nov 2018
Abstract
Surface microstructure preparation offers a promising approach for overcoming the shortcomings of Al alloy, such as poor friction resistance, low hardness and weak corrosion resistance to corrosive liquid. Though many methods for the surface microstructure preparation of Al alloy have been developed, it [...] Read more.
Surface microstructure preparation offers a promising approach for overcoming the shortcomings of Al alloy, such as poor friction resistance, low hardness and weak corrosion resistance to corrosive liquid. Though many methods for the surface microstructure preparation of Al alloy have been developed, it is difficult for most of the reported methods to regulate the as-prepared microstructure, meaning that the properties of Al alloy cannot be improved efficiently by the microstructure. Thus, the application of microstructure surface of Al alloy and microstructure preparation technology is severely limited. Aimed at this issue, a simple, convenient, high-efficient, low-cost micro-scale roughness structure construction approach that is suitable for engineering application (laser micro-engraving) was developed. The as-prepared microstructure on Al alloy surface formed by laser micro-engraving was investigated systemically. The morphology and formation mechanism of the microstructure were examined. Meanwhile, the effect of laser parameters on morphology, geometrical dimensions and composition of microstructure was investigated. The results indicate that the morphology of microstructure is affected by the overlap degree of molten pool greatly. When each molten pool does not overlap with others, successive individual pits can be constructed. When each molten pool overlaps with others for one time, successive overlapping pits will form. As the overlap degree of the molten pool further increases (overlapping with others for more than one time), the successive pits can become grooved. Because of the influence of laser beam pulse frequency and scanning speed on the diameter and distance of the molten pools, the morphology and geometrical dimensions of microstructure can vary greatly with laser parameters. As the laser beam scanning speed increases, the geometrical dimensions of as-prepared microstructure reduce significantly. In contrast, with the increase of laser beam pulse frequency, the geometrical dimensions change in a complicated manner. However, the chemical composition of microstructure is slightly affected by laser parameters. More importantly, a relationship model was successfully established, which could be used to predict and regulate the geometrical dimensions of microstructure treated by laser micro-engraving. Controllable preparation of microstructure on Al alloy is realized, leading that specific microstructure can be prepared rapidly and accurately instead of suffering from long-time experimental investigation in the future. Full article
(This article belongs to the Special Issue Thin Film Fabrication and Surface Techniques)
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Open AccessArticle
Substrate Temperature Dependent Properties of Sputtered AlN:Er Thin Film for In-Situ Luminescence Sensing of Al/AlN Multilayer Coating Health
Materials 2018, 11(11), 2196; https://doi.org/10.3390/ma11112196 - 06 Nov 2018
Cited by 1
Abstract
The integrity and reliability of surface protective coatings deposited on metal surface could be in-situ monitored via the attractive luminescence sensing technique. In this paper, we report the influence of substrate temperature on the properties of erbium (Er) doped aluminum nitride (AlN) film, [...] Read more.
The integrity and reliability of surface protective coatings deposited on metal surface could be in-situ monitored via the attractive luminescence sensing technique. In this paper, we report the influence of substrate temperature on the properties of erbium (Er) doped aluminum nitride (AlN) film, which could be applied as a luminescent layer for monitoring the health of multilayered Al/AlN coating. The AlN:Er films were deposited via reactive radio-frequency magnetron sputtering, and the silicon substrate temperature was varied from non-intentional heating up to 400 °C. The composition, morphology, crystalline structure, and dielectric function of the AlN:Er films deposited under these different substrate temperature conditions were studied. These properties of the AlN:Er films show strong correlation with the substrate temperature maintained during film fabrication. The obtained AlN:Er films, without further annealing, exhibited photoluminescence peaks of the Er3+ ions in the visible wavelength range and the strongest photoluminescence intensity was observed for the AlN:Er film deposited with the temperature of substrate kept at 300 °C. The results demonstrated in this work offer guidance to optimize the substrate temperature for the deposition of AlN:Er film for future application of this sensing technique to thin metal components. Full article
(This article belongs to the Special Issue Thin Film Fabrication and Surface Techniques)
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Open AccessArticle
Development of High-Performance Enamel Coating on Grey Iron by Low-Temperature Sintering
Materials 2018, 11(11), 2183; https://doi.org/10.3390/ma11112183 - 04 Nov 2018
Cited by 1
Abstract
In this study, we report on a low-temperature sintered enamel coating with a high-strength bonding and wear-resistance that protected a grey cast iron substrate. The SiO2–Al2O3–B2O3 composited prescription for the enamel coating was modified [...] Read more.
In this study, we report on a low-temperature sintered enamel coating with a high-strength bonding and wear-resistance that protected a grey cast iron substrate. The SiO2–Al2O3–B2O3 composited prescription for the enamel coating was modified by the partial substitutions of SiO2 for B2O3 and alkali metals for Li2O. The optimized enamel coating was prepared by sintering at a relatively low temperature (730 °C) for seven minutes. Due to the composition of both the amorphous and crystalline phases, the enamel coating presented sufficient hardness and excellent wear resistance. The wear volume loss and the specific wear rate of the enamel coating were obviously lower than that of the metal substrate. The enamel coating can effectively improve the service life of the grey cast iron substrate in a complex frictional environment. Full article
(This article belongs to the Special Issue Thin Film Fabrication and Surface Techniques)
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Open AccessArticle
Cold Bonding Method for Metallic Powder Coatings
Materials 2018, 11(11), 2086; https://doi.org/10.3390/ma11112086 - 25 Oct 2018
Abstract
An efficient and simple method for preparing bonded metallic powder coating is in high demand in the paint manufacturing and application industries. The bonding purpose is to keep the mass percentage of metallic pigment consistent between the original and recycled coating powder, which [...] Read more.
An efficient and simple method for preparing bonded metallic powder coating is in high demand in the paint manufacturing and application industries. The bonding purpose is to keep the mass percentage of metallic pigment consistent between the original and recycled coating powder, which aims at solving the problem of recyclability. One possible method capable of realizing this goal is using the binder to cohere metallic pigment with base particles through a cold bonding method. Through this approach, the pre-curing and high-reject-rate problems generally present in thermal bonding can be completely eliminated. In this paper, polyacrylic acid (PAA) and polyvinyl alcohol (PVA) are applied as binders for the bonding process. At various dosages of liquid binder and D.I. water, bonded samples with different bonding effect were prepared. Finally, a good bonding quality with the lowest variance between the mass concentrations of Al flakes in the original powder (before spray) and deposited powder (after spray) 2.94% with PAA as a binder and 0.46% with PVA as a binder was achieved. These results manifest that the cold bonding method is a green and simple approach for preparing the metallic powder coating. Full article
(This article belongs to the Special Issue Thin Film Fabrication and Surface Techniques)
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Open AccessArticle
Effects of Interfacial Passivation on the Electrical Performance, Stability, and Contact Properties of Solution Process Based ZnO Thin Film Transistors
Materials 2018, 11(9), 1761; https://doi.org/10.3390/ma11091761 - 18 Sep 2018
Cited by 3
Abstract
This paper reports low temperature solution processed ZnO thin film transistors (TFTs), and the effects of interfacial passivation of a 4-chlorobenzoic acid (PCBA) layer on device performance. It was found that the ZnO TFTs with PCBA interfacial modification layers exhibited a higher electron [...] Read more.
This paper reports low temperature solution processed ZnO thin film transistors (TFTs), and the effects of interfacial passivation of a 4-chlorobenzoic acid (PCBA) layer on device performance. It was found that the ZnO TFTs with PCBA interfacial modification layers exhibited a higher electron mobility of 4.50 cm2 V−1 s−1 compared to the pristine ZnO TFTs with a charge carrier mobility of 2.70 cm2 V−1 s−1. Moreover, the ZnO TFTs with interfacial modification layers could significantly improve device shelf-life stability and bias stress stability compared to the pristine ZnO TFTs. Most importantly, interfacial modification layers could also decrease the contact potential barrier between the source/drain electrodes and the ZnO films when using high work-function metals such as Ag and Au. These results indicate that high performance TFTs can be obtained with a low temperature solution process with interfacial modification layers, which strongly implies further potential for their applications. Full article
(This article belongs to the Special Issue Thin Film Fabrication and Surface Techniques)
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Open AccessArticle
Effect of Ti Transition Layer Thickness on the Structure, Mechanical and Adhesion Properties of Ti-DLC Coatings on Aluminum Alloys
Materials 2018, 11(9), 1742; https://doi.org/10.3390/ma11091742 - 16 Sep 2018
Cited by 6
Abstract
Multilayers of Ti doped diamond-like carbon (Ti-DLC) coatings were deposited on aluminum alloys by filtered cathodic vacuum arc (FCVA) technology using C2H2 as a reactive gas. The effect of different Ti transition layer thicknesses on the structure, mechanical and adhesion [...] Read more.
Multilayers of Ti doped diamond-like carbon (Ti-DLC) coatings were deposited on aluminum alloys by filtered cathodic vacuum arc (FCVA) technology using C2H2 as a reactive gas. The effect of different Ti transition layer thicknesses on the structure, mechanical and adhesion properties of the coatings, was investigated by scanning electron microscopy (SEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), nanoindentation and a scratch tester. The results showed that the Ti transition layer could improve interfacial transition between the coating and the substrate, which was beneficial in obtaining excellent adhesion of the coatings. The Ti transition layer thickness had no significant influence on the composition and structure of the coatings, whereas it affected the distortion of the sp2-C bond angle and length. Nanoindentation and scratch test results indicated that the mechanical and adhesion properties of the Ti-DLC coatings depended on the Ti transition layer thickness. The Ti transition layer proved favorable in decreasing the residual compressive stress of the coating. As the Ti transition layer thickness increased, the hardness value of the coating gradually decreased. However, its elastic modulus and adhesion exhibited an initial decrease followed by an increasing fluctuation. Among them, the Ti-DLC coating with a Ti transition layer thickness of 1.1 μm exhibited superior mechanical properties. Full article
(This article belongs to the Special Issue Thin Film Fabrication and Surface Techniques)
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Open AccessArticle
Transferred PMN-PT Thick Film on Conductive Silver Epoxy
Materials 2018, 11(9), 1621; https://doi.org/10.3390/ma11091621 - 05 Sep 2018
Cited by 1
Abstract
Approximately 25 μm Pb(Mg1/3Nb2/3)O3–PbTiO3 (PMN-PT) thick film was synthesized based on a sol-gel/composite route. The obtained PMN-PT thick film was successfully transferred from the Silicon substrate to the conductive silver epoxy using a novel wet chemical [...] Read more.
Approximately 25 μm Pb(Mg1/3Nb2/3)O3–PbTiO3 (PMN-PT) thick film was synthesized based on a sol-gel/composite route. The obtained PMN-PT thick film was successfully transferred from the Silicon substrate to the conductive silver epoxy using a novel wet chemical method. The mechanism of this damage free transfer was explored and analyzed. Compared with the film on Silicon substrate, the transferred one exhibited superior dielectric, ferroelectric and piezoelectric properties. These promising results indicate that transferred PMN-PT thick film possesses the capability for piezoelectric device application, especially for ultrasound transducer fabrication. Most importantly, this chemical route opens a new path for transfer of thick film. Full article
(This article belongs to the Special Issue Thin Film Fabrication and Surface Techniques)
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Open AccessArticle
Metal-Based Graphical SiO2/Ag/ZnS/Ag Hetero-Structure for Visible-Infrared Compatible Camouflage
Materials 2018, 11(9), 1594; https://doi.org/10.3390/ma11091594 - 03 Sep 2018
Cited by 3
Abstract
A brand-new approach to realizing visible-infrared compatible camouflage is proposed based on a metal-based graphical hetero-structure (MGHS) SiO2/Ag/ZnS/Ag. For different thicknesses (20, 40, and 60 nm) of color-controlling sub-layer, high-contract and large-span structure colors (yellow, navy, and cyan) were observed due [...] Read more.
A brand-new approach to realizing visible-infrared compatible camouflage is proposed based on a metal-based graphical hetero-structure (MGHS) SiO2/Ag/ZnS/Ag. For different thicknesses (20, 40, and 60 nm) of color-controlling sub-layer, high-contract and large-span structure colors (yellow, navy, and cyan) were observed due to reintroducing constructive interference with a matching intensity of reflected waves. Ultra-low infrared emissivity values of 0.04, 0.05, and 0.04 (with high average reflectance values of 95.46%, 95.31%, and 95.09%) were obtained at 3–14 μm. In addition, the well-performing trisecting-circle structure further indicates that it is feasible to design on-demand compatible camouflage patterns using the easily-prepared MGHS. Full article
(This article belongs to the Special Issue Thin Film Fabrication and Surface Techniques)
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Open AccessFeature PaperArticle
Eumelanin Coating of Silica Aerogel by Supercritical Carbon Dioxide Deposition of a 5,6-Dihydroxyindole Thin Film
Materials 2018, 11(9), 1494; https://doi.org/10.3390/ma11091494 - 21 Aug 2018
Cited by 1
Abstract
Eumelanin integration in silica aerogel (SA) was achieved via supercritical adsorption of 5,6-dyhydroxyindole (DHI) from CO2. Notably, after the supercritical treatment, DHI evolved towards spontaneous polymerization, which resulted in uniform pigment development over the SA. The new material was characterized for [...] Read more.
Eumelanin integration in silica aerogel (SA) was achieved via supercritical adsorption of 5,6-dyhydroxyindole (DHI) from CO2. Notably, after the supercritical treatment, DHI evolved towards spontaneous polymerization, which resulted in uniform pigment development over the SA. The new material was characterized for its morphological and physicochemical properties, disclosing the formation of a eumelanin-like coating, as confirmed by UV–vis and electron paramagnetic resonance (EPR) spectroscopy. Full article
(This article belongs to the Special Issue Thin Film Fabrication and Surface Techniques)
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Open AccessArticle
Microwave-Assisted Rapid Preparation of Nano-ZnO/Ag Composite Functionalized Polyester Nonwoven Membrane for Improving Its UV Shielding and Antibacterial Properties
Materials 2018, 11(8), 1412; https://doi.org/10.3390/ma11081412 - 11 Aug 2018
Cited by 9
Abstract
The cost and efficiency of preparing ZnO/Ag composite functional polyester membrane affect their application, for which a rapid microwave-assisted method was studied for coating ZnO/Ag composite nanoparticles on polyester nonwoven. The surface morphology, crystalline structure, and surface chemistry of the uncoated and coated [...] Read more.
The cost and efficiency of preparing ZnO/Ag composite functional polyester membrane affect their application, for which a rapid microwave-assisted method was studied for coating ZnO/Ag composite nanoparticles on polyester nonwoven. The surface morphology, crystalline structure, and surface chemistry of the uncoated and coated polyester nonwoven was investigated by X-ray diffractometer (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), energy-dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and thermogravimetric (TG), respectively. Washing stability, ultraviolet properties, and antibacterial properties of before and after treatment polyester nonwoven were also investigated. The results indicated that Ag/ZnO composite nanoparticles were successfully deposited on polyester nonwoven surface. The amount of silver nitrate added in reaction has an important effect on the morphology and structure of Ag/ZnO composite on the surface of polyester fiber. The washing experiment results show that the ZnO/Ag composite functional polyester nonwoven fabric prepared by this method exhibits good washing durability after 90 min of washing. The results of UV transmission analysis showed that polyester nonwoven has an obvious increase in ultraviolet resistant properties after Ag/ZnO composite coating. When 0.2 g of silver nitrate was added into 100 mL of the reaction solution, the mean ultraviolet protection factor (UPF) of the treated polyester nonwoven reached a maximum of 219.8. The antibacterial results showed that the coated nonwoven against Escherichia coli and Staphylococcus aureus was about 94.5% and 96.6%, respectively, showing very good antibacterial properties. Full article
(This article belongs to the Special Issue Thin Film Fabrication and Surface Techniques)
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Open AccessArticle
Phase Stability and Properties of Ti-Nb-Zr Thin Films and Their Dependence on Zr Addition
Materials 2018, 11(8), 1361; https://doi.org/10.3390/ma11081361 - 06 Aug 2018
Cited by 2
Abstract
Ternary Ti-Nb-Zr alloys were prepared by a magnetron sputtering method with porous structures observed in some of them. In bulk, in order to control the porous structure, a space holder (NH4HCO3) is used in the sintering method. However, in [...] Read more.
Ternary Ti-Nb-Zr alloys were prepared by a magnetron sputtering method with porous structures observed in some of them. In bulk, in order to control the porous structure, a space holder (NH4HCO3) is used in the sintering method. However, in the present work, we show that the porous structure is also dependent on alloy composition. The results from Young’s modulus tests confirm that these alloys obey d-electrons alloy theory. However, the Young’s modulus of ternary thin films (≈80–95 GPa) is lower than that for binary alloys (≈108–123 GPa). The depth recovery ratio of ternary Ti-Nb-Zr thin films is also higher than that for binary β-Ti-(25.9–34.2)Nb thin film alloys. Full article
(This article belongs to the Special Issue Thin Film Fabrication and Surface Techniques)
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Open AccessArticle
A Novel Method of Synthesizing Graphene for Electronic Device Applications
Materials 2018, 11(7), 1120; https://doi.org/10.3390/ma11071120 - 30 Jun 2018
Cited by 1
Abstract
This article reports a novel and efficient method to synthesize graphene using a thermal decomposition process. In this method, silicon carbide (SiC) thin films grown on Si(100) wafers with an AlN buffer layer were used as substrates. CO2 laser beam heating, without [...] Read more.
This article reports a novel and efficient method to synthesize graphene using a thermal decomposition process. In this method, silicon carbide (SiC) thin films grown on Si(100) wafers with an AlN buffer layer were used as substrates. CO2 laser beam heating, without vacuum or controlled atmosphere, was applied for SiC thermal decomposition. The physical, chemical, morphological, and electrical properties of the laser-produced graphene were investigated for different laser energy densities. The results demonstrate that graphene was produced in the form of small islands with quality, density, and properties depending on the applied laser energy density. Furthermore, the produced graphene exhibited a sheet resistance characteristic similar to graphene grown on mono-crystalline SiC wafers, which indicates its potential for electronic device applications. Full article
(This article belongs to the Special Issue Thin Film Fabrication and Surface Techniques)
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Open AccessArticle
Fabrication of Sputtered Ce/La, La/Ce Oxide Bilayers on AA6061 and AA7075 Aluminum Alloys for the Development of Corrosion Protective Coatings
Materials 2018, 11(7), 1114; https://doi.org/10.3390/ma11071114 - 29 Jun 2018
Cited by 3
Abstract
This work provides a comparative study on the corrosion protection efficiency of Ce, La films as well as Ce/La and La/Ce oxide bilayered coatings deposited onto AA7075 and AA6061 substrates by the radio frequency (RF) magnetron sputtering technique. The coating thickness ranged approximately [...] Read more.
This work provides a comparative study on the corrosion protection efficiency of Ce, La films as well as Ce/La and La/Ce oxide bilayered coatings deposited onto AA7075 and AA6061 substrates by the radio frequency (RF) magnetron sputtering technique. The coating thickness ranged approximately from 12 to 835 nm, which changed with the deposition parameters and substrate composition. The relationship between microstructure, roughness and electrochemical performance is examined. The reactivity and crystallinity of rare earth (RE) films can be tailored by adjusting the sputtering parameters. Sputtered La films with thickness ca. 390 nm and average roughness of 66 nm showed the best corrosion protection properties in chloride medium as determined by potentiodynamic curves and electrochemical impedance spectroscopy (EIS). The method to obtain RE bilayered coatings, i.e., La/Ce or Ce/La as well as the substrate composition and applied power conditioned their inhibition properties. The RE bilayered coatings displayed better barrier properties than Ce films, which were poorer than those featured by La films. Full article
(This article belongs to the Special Issue Thin Film Fabrication and Surface Techniques)
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Open AccessArticle
Structural Coloration of Polyester Fabrics Coated with Al/TiO2 Composite Films and Their Anti-Ultraviolet Properties
Materials 2018, 11(6), 1011; https://doi.org/10.3390/ma11061011 - 14 Jun 2018
Cited by 4
Abstract
Al/TiO2 composite film was successfully deposited on polyester fabrics by using magnetron sputtering techniques. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) were used to examine the deposited films on the fabrics, and the structural colors and anti-ultraviolet property of fabrics were [...] Read more.
Al/TiO2 composite film was successfully deposited on polyester fabrics by using magnetron sputtering techniques. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) were used to examine the deposited films on the fabrics, and the structural colors and anti-ultraviolet property of fabrics were also analyzed. The results indicated that polyester fabrics coated with Al/TiO2 composite films achieved structural colors. The reactive sputtering times of TiO2 films in Al/TiO2 composite films were 10 min, 12 min, 18 min, 20 min, 26 min, 27 min, 30 min and 45 min, respectively, the colors of corresponding fabrics were bluish violet, blue, cyan, green, yellow, yellowish red, orange and blue-green, which was consistent with the principle of the thin film interference. The structure of the TiO2 film in Al/TiO2 composite films was non-crystalline, though the fabrics were heated and maintained at the temperature of 200 °C. The anti-ultraviolet property of the fabrics deposited with Al/TiO2 composite films were excellent because of the effect of Al/TiO2 composite films. Full article
(This article belongs to the Special Issue Thin Film Fabrication and Surface Techniques)
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Open AccessLetter
Investigation of Growth Mechanism of Plasma Electrolytic Oxidation Coating on Al-Ti Double-Layer Composite Plate
Materials 2019, 12(2), 272; https://doi.org/10.3390/ma12020272 - 15 Jan 2019
Cited by 3
Abstract
The aluminum–titanium (Al-Ti) double-layer composite plate is a promising composite material, but necessary surface protection was required before its application. In this paper, plasma electrolytic oxidation (PEO) was employed to fabricate a ceramic coating on the surface of a Al-Ti double-layer composite plate. [...] Read more.
The aluminum–titanium (Al-Ti) double-layer composite plate is a promising composite material, but necessary surface protection was required before its application. In this paper, plasma electrolytic oxidation (PEO) was employed to fabricate a ceramic coating on the surface of a Al-Ti double-layer composite plate. To investigate the coating growth mechanism on the Al-Ti double-layer composite plate, a single-Al plate and a single-Ti plate were introduced for comparison experiments. Results showed that, the composite of Al and Ti accelerated the coating growth rate on the part-Ti portion of the composite plate, and that of the part-Al portion was decreased. Electrochemical impedance spectroscopy analysis indicated that the equivalent circuit of the Al-Ti coating was formed by connecting two different circuits in parallel. The reaction behavior revealed that the electric energy during the PEO would leak from the circuit with the weaker blocking effect, and confirmed that the electric energy distribution followed the law of low-resistance distribution. Finally, the mechanism was extended to the PEO treatment on general metal matrix composites to broaden the application theory of the technology. Full article
(This article belongs to the Special Issue Thin Film Fabrication and Surface Techniques)
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