Open AccessArticle
Characterization and Photovoltaic Properties of BiFeO3 Thin Films
Coatings 2016, 6(4), 68; doi:10.3390/coatings6040068 -
Abstract
Bismuth ferrite (BiFeO3) thin films were prepared by a spin-coating method. Crystal structure and optical properties of the BiFeO3 films were evaluated using X-ray diffraction. The lattice constants, crystallite size, and energy gap of BiFeO3 films depended on the
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Bismuth ferrite (BiFeO3) thin films were prepared by a spin-coating method. Crystal structure and optical properties of the BiFeO3 films were evaluated using X-ray diffraction. The lattice constants, crystallite size, and energy gap of BiFeO3 films depended on the concentration of the BiFeO3 precursor solution. BiFeO3/CH3NH3PbI3 photovoltaic devices were fabricated to investigate photovoltaic properties of BiFeO3. Current density–voltage characteristics of the photovoltaic devices showed rectifying behavior, indicating that BiFeO3 worked as an electron transport layer in CH3NH3PbI3-based photovoltaic devices. Full article
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Open AccessArticle
The Microstructure and Wear Resistance of a Copper Matrix Composite Layer on Copper via Nitrogen-Shielded Arc Cladding
Coatings 2016, 6(4), 67; doi:10.3390/coatings6040067 -
Abstract
A TiN and TiN·Ti2Cu reinforced copper matrix composite layer was cladded onto a T3 copper substrate to improve the anti-wear performance of copper products by means of the nitrogen-shielded gas tungsten arc cladding method (N2-GTAC). Better than the traditional
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A TiN and TiN·Ti2Cu reinforced copper matrix composite layer was cladded onto a T3 copper substrate to improve the anti-wear performance of copper products by means of the nitrogen-shielded gas tungsten arc cladding method (N2-GTAC). Better than the traditional preparation method of TiN, the TiN particles in the cladding layer were in situ generated using N atoms of shielding gas and Ti atoms of pre-deposited metal powders. In addition, the composite phase TiN·Ti2Cu occurred in the cladding layer, which also had a positive effect on anti-wearing. As Ti increased, the amount and grain size of TiN·Ti2Cu and TiN increased as a result. The hardness of the cladding layer increased with the increasing amount of reinforced phase generated in the layer. The hardness of the layer reached a maximum of 410 HV, which is nearly 5.1 times greater than that of copper. The TiN·Ti2Cu- and TiN-reinforced phases improved the wear resistance of the cladding layers. The cladding layer with 15 wt % Ti had the longsest launch stage (600 s) and the lowest fiction coefficient (0.56). Full article
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Open AccessArticle
Improving the Performance of Clear Coatings on Wood through the Aggregation of Marginal Gains
Coatings 2016, 6(4), 66; doi:10.3390/coatings6040066 -
Abstract
Remarkable increases in the performance of complex systems can be achieved by a collective approach to optimizing individual factors that influence performance. This approach, termed the aggregation of marginal gains, is tested here as a means of improving the performance of exterior clear-coatings.
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Remarkable increases in the performance of complex systems can be achieved by a collective approach to optimizing individual factors that influence performance. This approach, termed the aggregation of marginal gains, is tested here as a means of improving the performance of exterior clear-coatings. We focused on five factors that influence clear-coating performance: dimensional stability of wood; photostability of the wood surface; moisture ingress via end-grain; coating flexibility and photostability; and finally coating thickness. We performed preliminary research to select effective wood pre-treatments and durable clear-coatings, and then tested coating systems with good solutions to each of the aforementioned issues (factors). Red oak and radiata pine panels were modified with PF-resin, end-sealed, and thick acrylic, alkyd or spar varnishes were applied to the panels. Panels were exposed to the weather and the level of coating defects was assessed every year over a 4-year period. All of the coatings are performing well on PF-modified pine after 4 years’ outdoor exposure. In contrast, coatings failed after 2 years on unmodified pine and they are failing on PF-modified oak. We conclude that our approach shows promise. Future research will build on the current work by developing solutions to additional factors that influence clear-coating performance. Full article
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Open AccessArticle
Corrosion Testing of Thermal Spray Coatings in a Biomass Co-Firing Power Plant
Coatings 2016, 6(4), 65; doi:10.3390/coatings6040065 -
Abstract
Large-scale use of biomass and recycled fuel is increasing in energy production due to climate and energy targets. A 40% cut in greenhouse gas emission compared to 1990 levels and at least a 27% share of renewable energy consumption are set in EU
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Large-scale use of biomass and recycled fuel is increasing in energy production due to climate and energy targets. A 40% cut in greenhouse gas emission compared to 1990 levels and at least a 27% share of renewable energy consumption are set in EU Energy Strategy 2030. Burning fuels with high content of corrosive species such as chlorine and heavy metals causes deterioration of boiler components, shortened lifetime, limited availability of a plant and hence higher maintenance and investment costs and lower thermal and economic efficiency. Coatings can be applied to protect the critical boiler components against high temperature corrosion. In this study, five thermal spray coatings were tested in an actual biomass co-firing boiler for 1300 h with a measurement probe. The coatings were analyzed after the exposure by metallographic means and scanning electron microscope/energy-dispersive X-ray spectroscope (SEM/EDX). The deposits formed on the specimens were analyzed by X-ray fluorescence. At 550 °C, the coatings showed excellent corrosion performance compared to reference material ferritic steel T92. At 750 °C, tube material A263 together with NiCr and NiCrTi had the highest corrosion resistance. To conclude, thermal spray coatings can offer substantial corrosion protection in biomass and recycled fuel burning power plants. Full article
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Open AccessArticle
Structural Study of Silica Coating Thin Layers Prepared from Perhydropolysilazane: Substrate Dependence and Water Penetration Structure
Coatings 2016, 6(4), 64; doi:10.3390/coatings6040064 -
Abstract
The structure of perhydropolysilazane (PHPS)-derived silica (PDS) waterproof thin layers synthesized by curing at 60 °C for 1 h and allowed to stand for 48 h at 20 °C on various kinds of substrates was studied. Neutron reflectivity (NR) analysis suggested that uniform
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The structure of perhydropolysilazane (PHPS)-derived silica (PDS) waterproof thin layers synthesized by curing at 60 °C for 1 h and allowed to stand for 48 h at 20 °C on various kinds of substrates was studied. Neutron reflectivity (NR) analysis suggested that uniform PDS thin layers were synthesized on the substrates, and the density of the layers varied depending on the type of substrate. Additionally, since the change in PDS density is correlated with the pKa value of the OH group on the substrate, it can be suggested that the acidity of the substrate would be one of the main factors determining the density of the coated PDS thin layers. For the water penetration structure study, NR analysis revealed that the depth of water penetration into the PDS layers was below 500 Å, and the hydration number of the SiO2 molecule was estimated to be 8.0–9.0. From these results, we concluded that water penetration occurred by the formation of water-pool structures in the PDS layers, and the randomly formed nano-air holes lead to a reduction in the probability of water penetration into the deep regions of the PDS layers. Full article
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Open AccessArticle
Fabrication of Microalloy Nitrided Layer on Low Carbon Steel by Nitriding Combined with Surface Nano-Alloying Pretreatment
Coatings 2016, 6(4), 63; doi:10.3390/coatings6040063 -
Abstract
Surface mechanical attrition treatment (SMAT) is an effective method to accelerate the nitriding process of metallic materials. In this work, a novel technique named surface nano-alloying (SNA) was developed on the basis of surface mechanical attrition treatment, which was employed as a pretreatment
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Surface mechanical attrition treatment (SMAT) is an effective method to accelerate the nitriding process of metallic materials. In this work, a novel technique named surface nano-alloying (SNA) was developed on the basis of surface mechanical attrition treatment, which was employed as a pretreatment for the nitriding of low carbon steel materials. The microstructure and surface properties of treated samples were investigated by SEM, XRD, TEM and the Vickers hardness test. Experimental results showed that a surface alloying layer (Cr element) of about 10–20 μm in thickness was formed on the low carbon steel sample after the surface nano-alloying treatment. After nitriding for the SNA sample, a complex compound layer composed of Fe2–3N, FeCr and Cr2N phases was fabricated. Moreover, the thickness of this compound layer was about 50 μm. Meanwhile, both the surface hardness and wear resistance of the SNA nitrided sample are better that those of the SMAT nitrided sample. This work offers a new approach for improving the nitriding process of steel materials. Full article
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Open AccessArticle
Development of Mirror Coatings for Gravitational Wave Detectors
Coatings 2016, 6(4), 61; doi:10.3390/coatings6040061 -
Abstract
The first detections of gravitational waves, GW150914 and GW151226, were associated with the coalescence of stellar mass black holes, heralding the opening of an entirely new way to observe the Universe. Many decades of development were invested to achieve the sensitivities required to
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The first detections of gravitational waves, GW150914 and GW151226, were associated with the coalescence of stellar mass black holes, heralding the opening of an entirely new way to observe the Universe. Many decades of development were invested to achieve the sensitivities required to observe gravitational waves, with peak strains associated with GW150914 at the level of 10−21. Gravitational wave detectors currently operate as modified Michelson interferometers, where thermal noise associated with the highly reflective mirror coatings sets a critical limit to the sensitivity of current and future instruments. This article presents an overview of the mirror coating development relevant to gravitational wave detection and the prospective for future developments in the field. Full article
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Open AccessArticle
Influence of Surface Roughness and Agitation on the Morphology of Magnetite Films Electrodeposited on Carbon Steel Substrates
Coatings 2016, 6(4), 62; doi:10.3390/coatings6040062 -
Abstract
In this work, we investigated the effects of surface roughness and agitation on the morphology of magnetite films electrodeposited from alkaline Fe(III)-triethanolamine (TEA) solutions on carbon steel substrates. The surface roughness of the carbon steel substrates was maintained in the range of 1.64–0.06
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In this work, we investigated the effects of surface roughness and agitation on the morphology of magnetite films electrodeposited from alkaline Fe(III)-triethanolamine (TEA) solutions on carbon steel substrates. The surface roughness of the carbon steel substrates was maintained in the range of 1.64–0.06 μm by using mechanical grinding and polishing methods. The agitation speed was set at 0 and 900 rpm during the electrodeposition process. The particle size and surface roughness value of the magnetite films gradually decreased with decreasing substrate roughness. However, the influence of the substrate roughness on the thickness of the magnetite film was negligible. The morphology of the magnetite film fabricated at 900 rpm appeared to be highly faceted compared to that of the magnetite film produced at 0 rpm. The thickness and surface roughness of the magnetite film significantly increased with the agitation speed, which also significantly affected the electrodeposition efficiency. The effects of substrate surface roughness and agitation on the morphology of magnetite films electrodeposited on carbon steel substrates were also discussed. The obtained results provide critical information for the simulation of magnetite deposits on carbon steel pipes in the secondary systems of nuclear power plants. Full article
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Open AccessArticle
Performances and Coating Morphology of a Siloxane-Based Hydrophobic Product Applied in Different Concentrations on a Highly Porous Stone
Coatings 2016, 6(4), 60; doi:10.3390/coatings6040060 -
Abstract
Many polymers, able to confer a hydrophobicity to treated surfaces, have been proposed for the restoration and conservation of civil and monumental buildings. Polysiloxanes, and their precursors, the silanes, have been frequently employed for stone protection. To avoid decay of the treated surfaces,
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Many polymers, able to confer a hydrophobicity to treated surfaces, have been proposed for the restoration and conservation of civil and monumental buildings. Polysiloxanes, and their precursors, the silanes, have been frequently employed for stone protection. To avoid decay of the treated surfaces, the effectiveness and harmlessness of the treatment need to be carefully evaluated before application in the field. In this study, a commercial alkyl-siloxane was tested as a protective treatment on a highly porous stone, starting from water solutions with different contents of the product. The treatments have been devised to try to balance the requirements and the sustainability of the conservative actions. Sustainability, in terms of costs and environmental impact, is regarded as a key factor in the 21st century. Morphological observations of the stone surface, static contact angle and colour measurements, water vapour transmission test, and tests of water absorption were carried out to characterize the untreated and treated stones. A concentration below the minimum level suggested by the manufacturer was still able to act as a good barrier against water. More concentrated solutions produced polymer accumulation and coatings with extended cracks. The properties of the treated stone were affected by the presence of cracks in the coating. Full article
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Open AccessCommunication
Cylindrical Three-Dimensional Porous Anodic Alumina Networks
Coatings 2016, 6(4), 59; doi:10.3390/coatings6040059 -
Abstract
The synthesis of a conformal three-dimensional nanostructure based on porous anodic alumina with transversal nanopores on wires is herein presented. The resulting three-dimensional network exhibits the same nanostructure as that obtained on planar geometries, but with a macroscopic cylindrical geometry. The morphological analysis
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The synthesis of a conformal three-dimensional nanostructure based on porous anodic alumina with transversal nanopores on wires is herein presented. The resulting three-dimensional network exhibits the same nanostructure as that obtained on planar geometries, but with a macroscopic cylindrical geometry. The morphological analysis of the nanostructure revealed the effects of the initial defects on the aluminum surface and the mechanical strains on the integrity of the three-dimensional network. The results evidence the feasibility of obtaining 3D porous anodic alumina on non-planar aluminum substrates. Full article
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Open AccessArticle
Thermally Sprayed Aluminum Coatings for the Protection of Subsea Risers and Pipelines Carrying Hot Fluids
Coatings 2016, 6(4), 58; doi:10.3390/coatings6040058 -
Abstract
This paper reports the effect of boiling synthetic seawater on the performance of damaged Thermally Sprayed Aluminum (TSA) on carbon steel. Small defects (4% of the sample’s geometric surface area) were drilled, exposing the steel, and the performance of the coating was analyzed
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This paper reports the effect of boiling synthetic seawater on the performance of damaged Thermally Sprayed Aluminum (TSA) on carbon steel. Small defects (4% of the sample’s geometric surface area) were drilled, exposing the steel, and the performance of the coating was analyzed for corrosion potential for different exposure times (2 h, 335 h, and 5000 h). The samples were monitored using linear polarization resistance (LPR) in order to obtain their corrosion rate. Scanning electron microscopy (SEM)/energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) were used for post-test characterization. The results showed that a protective layer of Mg(OH)2 formed in the damaged area, which protected the underlying steel. Additionally, no coating detachment from the steel near the defect region was observed. The corrosion rate was found to be 0.010–0.015 mm/year after 5000 h in boiling synthetic seawater. Full article
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Open AccessArticle
Statistical Contact Angle Analyses with the High-Precision Drop Shape Analysis (HPDSA) Approach: Basic Principles and Applications
Coatings 2016, 6(4), 57; doi:10.3390/coatings6040057 -
Abstract
Surface science, which includes the preparation, development and analysis of surfaces and coatings, is essential in both fundamental and applied as well as in engineering and industrial research. Contact angle measurements using sessile drop techniques are commonly used to characterize coated surfaces or
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Surface science, which includes the preparation, development and analysis of surfaces and coatings, is essential in both fundamental and applied as well as in engineering and industrial research. Contact angle measurements using sessile drop techniques are commonly used to characterize coated surfaces or surface modifications. Well-defined surfaces structures at both nanoscopic and microscopic level can be achieved but the reliable characterization by means of contact angle measurements and their interpretation often remains an open question. Thus, we focused our research effort on one main problem of surface science community, which is the determination of correct and valid definitions and measurements of contact angles. In this regard, we developed the high-precision drop shape analysis (HPDSA), which involves a complex transformation of images from sessile drop experiments to Cartesian coordinates and opens up the possibility of a physically meaningful contact angle calculation. To fulfill the dire need for a reproducible contact angle determination/definition, we developed three easily adaptable statistical analyses procedures. In the following, the basic principles of HPDSA will be explained and applications of HPDSA will be illustrated. Thereby, the unique potential of this analysis approach will be illustrated by means of selected examples. Full article
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Open AccessArticle
Cellular Automata Modelling of Photo-Induced Oxidation Processes in Molecularly Doped Polymers
Coatings 2016, 6(4), 55; doi:10.3390/coatings6040055 -
Abstract
The possibility of employing cellular automata (CA) to model photo-induced oxidation processes in molecularly doped polymers is explored. It is demonstrated that the oxidation dynamics generated using CA models exhibit stretched-exponential behavior. This dynamical characteristic is in general agreement with an alternative analysis
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The possibility of employing cellular automata (CA) to model photo-induced oxidation processes in molecularly doped polymers is explored. It is demonstrated that the oxidation dynamics generated using CA models exhibit stretched-exponential behavior. This dynamical characteristic is in general agreement with an alternative analysis conducted using standard rate equations provided the molecular doping levels are sufficiently low to prohibit the presence of safe-sites which are impenetrable to dissolved oxygen. The CA models therefore offer the advantage of exploring the effect of dopant agglomeration which is difficult to assess from standard rate equation solutions. The influence of UV-induced bleaching or darkening upon the resulting oxidation dynamics may also be easily incorporated into the CA models and these optical effects are investigated for various photo-oxidation product scenarios. Output from the CA models is evaluated for experimental photo-oxidation data obtained from a series of hydrazone-doped polymers. Full article
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Open AccessArticle
Emulsion Polymerization of Tung Oil-Based Latexes with Asolectin as a Biorenewable Surfactant
Coatings 2016, 6(4), 56; doi:10.3390/coatings6040056 -
Abstract
Bio-based vesicles, with potential application in drug delivery and/or catalyst encapsulation, have been prepared by the free radical emulsion co-polymerization of tung oil, divinylbenzene (DVB), n-butyl methacrylate (BMA), and asolectin in a xylene/water mixture. The free radical polymerization was initiated by di-
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Bio-based vesicles, with potential application in drug delivery and/or catalyst encapsulation, have been prepared by the free radical emulsion co-polymerization of tung oil, divinylbenzene (DVB), n-butyl methacrylate (BMA), and asolectin in a xylene/water mixture. The free radical polymerization was initiated by di-tert-butyl peroxide (DTBP) at 100 °C in a convection oven. Molecular weights of approximately 11,000 Da were measured by Matrix-assisted Laser Desorption/Ionization-Time of Flight (Maldi-TOF) for tung oil-asolectin copolymers, verifying that significant polymerization occurs under the cure conditions employed. The cure of the co-monomer mixture employed in this work was monitored by Dielectric Analysis (DEA), while changes in the Raman spectrum of all co-monomers before and after the cure, along with differential scanning calorimetry (DSC) analysis, have been used to verify the need of a post-cure step and completion of the polymerization reaction. Scanning Transmission Electron Microscopy (STEM) images of the emulsion after polymerization indicate that vesicles were formed, and vesicle size distribution of samples prepared with different amounts of tung oil were determined using a Zetasizer. Full article
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Open AccessReview
Introduction to Advanced X-ray Diffraction Techniques for Polymeric Thin Films
Coatings 2016, 6(4), 54; doi:10.3390/coatings6040054 -
Abstract
X-ray diffraction has been a standard technique for investigating structural properties of materials. However, most common applications in the organic materials community have been restricted to either chemical identification or qualitative strain analysis. Moreover, its use for polymeric thin films has been challenging
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X-ray diffraction has been a standard technique for investigating structural properties of materials. However, most common applications in the organic materials community have been restricted to either chemical identification or qualitative strain analysis. Moreover, its use for polymeric thin films has been challenging because of the low structure factor of carbon and the thin film nature of the sample. Here, we provide a short review of advanced X-ray diffraction (XRD) techniques suitable for polymeric thin films, including the type of analysis that can be done and measurement geometries that would compensate low signals due to low carbon structure factor and the thin film nature of the sample. We will also briefly cover the χ-pole figure for texture analysis of ultra-thin film that has recently become commonly used. A brief review of XRD theory is also presented. Full article
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Open AccessArticle
Fullerene-Based Electron Transport Layers for Semi-Transparent MAPbBr3 Perovskite Films in Planar Perovskite Solar Cells
Coatings 2016, 6(4), 53; doi:10.3390/coatings6040053 -
Abstract
In this study, four kinds of structures—[6,6]-phenyl-C61-butyric acid methyl ester (PCBM), PCBM/fullerene (C60), C60/bathocuproine (BCP), and PCBM/C60/BCP—were used as electron transport layers, and the structure, and optical and electronic behaviors of MAPbBr3 perovskite layers
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In this study, four kinds of structures—[6,6]-phenyl-C61-butyric acid methyl ester (PCBM), PCBM/fullerene (C60), C60/bathocuproine (BCP), and PCBM/C60/BCP—were used as electron transport layers, and the structure, and optical and electronic behaviors of MAPbBr3 perovskite layers after annealing treatments were observed. The experimental results indicate that PCBM/C60 bi-layer structure is acceptable for MAPbBr3 planar perovskite solar cells due to electron step transporting. Low-temperature annealing is suitable for smooth and large grain MAPbBr3 films. The semi-transparent yellow C60/PCBM/MAPbBr3/PEDOT:PSS/ITO glass-structure solar cells exhibit the best performance with a power conversion efficiency of 4.19%. The solar cells are revealed to be suitable for application in building integrated photovoltaic (BIPV) systems. Full article
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Open AccessArticle
Machining Duplex Stainless Steel: Comparative Study Regarding End Mill Coated Tools
Coatings 2016, 6(4), 51; doi:10.3390/coatings6040051 -
Abstract
The difficulties in the machining of duplex stainless steel are well known. However, research on this matter is rather limited. Suppliers offer quite different cutting tools for the same raw material, with end mills of two, three or even four knives and a
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The difficulties in the machining of duplex stainless steel are well known. However, research on this matter is rather limited. Suppliers offer quite different cutting tools for the same raw material, with end mills of two, three or even four knives and a huge number of distinct coatings, some of them under commercial brands, making it difficult to assess the advantages they offer. Furthermore, there is a remarkable difference among the several types of duplex stainless steel available nowadays on the market. The present work intends to assess the machining performance of different tools, analyzing the behavior and wear mechanisms with two different cutting lengths, keeping constant the machining trajectory. Some other parameters were also kept constant, such as cutting speed, depth of cut and cutting width, as well as feed per tooth. The machining process was carried out under lubricated conditions, using an emulsion of 5% oil in water. Tools provided with a different number of teeth and surface coatings were tested, analyzing the wear behavior of each cutting length using scanning electron microscopy, trying to identify wear performance and how each coating contributes to increased tool life. The surfaces produced were also analyzed by means of profilometry measurements, correlating tool wear and part surface roughness. This comparative study allows determining the advantages of different tools relative to others, based on coatings and tool geometry. Full article
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Open AccessArticle
Synthesis of Covalently Cross-Linked Colloidosomes from Peroxidized Pickering Emulsions
Coatings 2016, 6(4), 52; doi:10.3390/coatings6040052 -
Abstract
A new approach to the formation of cross-linked colloidosomes was developed on the basis of Pickering emulsions that were stabilized exclusively by peroxidized colloidal particles. Free radical polymerization and a soft template technique were used to convert droplets of a Pickering emulsion into
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A new approach to the formation of cross-linked colloidosomes was developed on the basis of Pickering emulsions that were stabilized exclusively by peroxidized colloidal particles. Free radical polymerization and a soft template technique were used to convert droplets of a Pickering emulsion into colloidosomes. The peroxidized latex particles were synthesized in the emulsion polymerization process using amphiphilic polyperoxide copolymers poly(2-tert-butylperoxy-2-methyl-5-hexen-3-ine-co-maleic acid) (PM-1-MAc) or poly[N-(tert-butylperoxymethyl)acrylamide]-co-maleic acid (PM-2-MAc), which were applied as both initiators and surfactants (inisurfs). The polymerization in the presence of the inisurfs results in latexes with a controllable amount of peroxide and carboxyl groups at the particle surface. Peroxidized polystyrene latex particles with a covalently grafted layer of inisurf PM-1-MAc or PM-2-MAc were used as Pickering stabilizers to form Pickering emulsions. A mixture of styrene and/or butyl acrylate with divinylbenzene and hexadecane was applied as a template for the synthesis of colloidosomes. Peroxidized latex particles located at the interface are involved in the radical reactions of colloidosomes formation. As a result, covalently cross-linked colloidosomes were obtained. It was demonstrated that the structure of the synthesized (using peroxidized latex particles) colloidosomes depends on the amount of functional groups and pH during the synthesis. Therefore, the size and morphology of colloidosomes can be controlled by latex particle surface properties. Full article
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Open AccessArticle
The Effect of Sintering Oxygen Partial Pressure on a SmBiO3 Buffer Layer for Coated Conductors via Chemical Solution Deposition
Coatings 2016, 6(4), 50; doi:10.3390/coatings6040050 -
Abstract
The application of high-temperature YBa2Cu3O7−δ (YBCO) superconducting material is a considerable prospect for the growing energy shortages. Here, SmBiO3 (SBO) films were deposited on (100)-orientated yttrium-stabilized zirconia (YSZ) simple crystal substrates via the chemical solution deposition (CSD)
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The application of high-temperature YBa2Cu3O7−δ (YBCO) superconducting material is a considerable prospect for the growing energy shortages. Here, SmBiO3 (SBO) films were deposited on (100)-orientated yttrium-stabilized zirconia (YSZ) simple crystal substrates via the chemical solution deposition (CSD) approach for coated conductors, and the effects of sintering oxygen partial pressure on SBO films were studied. The crystalline structures and surface morphologies of SBO films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscope (AFM). The optimized growth temperature, the intensity ratios of the SBO (200) peak to the SBO (111) peak, and the crystallinities of SBO films increased with the sintering oxygen partial pressure. The SEM and AFM images displayed a smooth and well-distributed surface in the argon atmosphere. The subsequent YBCO films with superconducting transition temperatures (Tc = 89.5 K, 90.2 K, and 86.2 K) and critical current densities (Jc = 0.88 MA/cm2, 1.69 MA/cm2, and 0.09 MA/cm2; 77 K, self-field) were deposited to further check the qualities of the SBO layer. These results indicated that sintering oxygen partial pressure had an effect on the epitaxial growth of the SBO buffer layer and YBCO superconducting properties. The experimental results may be a usable reference for the epitaxial growth of YBCO-coated conductors and other oxides. Full article
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Open AccessArticle
Self-Cleaning Mineral Paint for Application in Architectural Heritage
Coatings 2016, 6(4), 48; doi:10.3390/coatings6040048 -
Abstract
A mineral silicate paint has been developed for architectural heritage. To enhance durability, any type of organic additive has been avoided. Potassium silicate was the binder agent intended to give strong adherence and durability to stone and concretes. Incorporation of mainly anatase titanium
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A mineral silicate paint has been developed for architectural heritage. To enhance durability, any type of organic additive has been avoided. Potassium silicate was the binder agent intended to give strong adherence and durability to stone and concretes. Incorporation of mainly anatase titanium dioxide was intended to act both as a white, bright pigment and as a photocatalyst. Reflectivity analyses on the paint in the visible-to-near infrared wavelength region show high solar heat reflection. The self-cleaning activity of the mineral paint was evaluated by the degradation of organic dyes under solar light irradiation. Anatase titania was effective in decomposing organic and airborne pollutants with the solar radiation. The optical properties and self-cleaning activity were compared with the organic binder-based paints and commercial paints. Developed paints possess high stability: since they contain only inorganic components that do not fade with exposure to solar radiation, photocatalytic self-cleaning capability further enhances such stability. Full article
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