Editor’s Choice Articles

Background: The success of reconstructive orthopaedic surgery strongly depends on the mechanical and biological integration between the prosthesis and the host bone tissue. Progressive population ageing with increased frequency of altered bone metabolism conditions requires new strategies for ensuring an early implant fixation and long-term stability. Ceramic materials and ceramic-based coatings, owing to the release of calcium phosphate and to the precipitation of a biological apatite at the bone-implant interface, are able to promote a strong bonding between the host bone and the implant. Methods: The aim of the present systematic review is the analysis of the existing literature on the functionalization strategies for improving the implant osteointegration in osteoporotic bone and their relative translation into the clinical practice. The review process, conducted on two electronic databases, identified 47 eligible preclinical studies and 5 clinical trials. Results: Preclinical data analysis showed that functionalization with both organic and inorganic molecules usually improves osseointegration in the osteoporotic condition, assessed mainly in rodent models. Clinical studies, mainly retrospective, have tested no functionalization strategies. Registered trademarks materials have been investigated and there is lack of information about the micro- or nano- topography of ceramics. Conclusions: Ceramic materials/coatings functionalization obtained promising results in improving implant osseointegration even in osteoporotic conditions but preclinical evidence has not been fully translated to clinical applications. Full article

Titanium and its alloys possess several attractive properties that include a high strength-to-weight ratio, biocompatibility, and good corrosion resistance. However, due to their poor wear resistance, titanium components need to undergo surface hardening treatments before being used in applications involving high contact stresses. Laser nitriding is a thermochemical method of enhancing the surface hardness and wear resistance of titanium. This technique entails scanning the titanium substrate under a laser beam near its focal plane in the presence of nitrogen gas flow. At processing conditions characterized by low scan speeds, high laser powers, and small off-focal distances, a nitrogen plasma can be struck near the surface of the titanium substrate. When the substrate is removed, this plasma can be sustained indefinitely and away from any potentially interacting surfaces, by the laser power and a cascade ionization process. This paper presents a critical review of the literature pertaining to the laser nitriding of titanium in the presence of a laser-sustained plasma, with the ultimate objective of forming wide-area, deep, crack-free, wear-resistant nitrided cases on commercially pure titanium substrates. Full article

This study proposed the belt-type microstructure array flexible mold designed hot roller embossing process technology. An extrusion molding system was integrated with belt-type hot roller embossing process technology and, deriving the asymmetric principle as the basis of prediction, designed a belt-type microstructure array hot roller embossing process system. This study first focused on the design and manufacturing of a belt-type hot roller embossing process system (roll to belt-type). It then carried out system integration and testing, along with the film extrusion system, to fabrication microstructure array production. Hot embossing was used to replicate the array of the plastic micro lens as the microstructure mold. The original master mold was fabricated with micro electromechanical technology and the PC micro lens array as the microstructure (inner layer) film using the gas-assisted hot embossing technology. A microstructure composite belt and magnetic belt were produced on the hot roller embossing by an innovated coated casting technique. The forming accuracy of the belt-type microstructure array flexible mold hot roller embossing process and the prediction precision of numerically simulated forming were discussed. The proposed process technology is expected to effectively reduce the process cycle time with the advantages of being a fast and continuous process. Full article

In this study, ZnHAp layers deposited on a Si substrate were obtained by a sol–gel spin-coating procedure. The ZnHAp solutions used to obtain the ZnHAp coatings were investigated by dynamic light scattering (DLS) analysis, ζ-potential, ultrasound measurements, and flame atomic absorption spectrometry (AAS). The average measured hydrodynamic diameter from the DLS analysis, ζ-potential, and ultrasound measurements were analyzed so as to characterize and estimate the stability of the ZnHAp nanoparticles. The AAS results confirmed the presence of zinc in the gels used in the preparation of the ZnHAp layers. The layers were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD results revealed the diffraction peaks of the hexagonal hydroxyapatite in all of the investigated samples. The morphology of the ZnHAp coatings annealed at 500 °C (ZnHAp-500) and 700 °C (ZnHAp-700), which evidenced that no fissures or cracks formed on the surface of the coatings. The biocompatibility assays indicated that the ZnHAp coatings did not present any toxicity towards the HeLa cells. Furthermore, the study regarding the cytotoxicity of the ZnHAp layers against microorganisms emphasized that ZnHAp coatings exhibited an inhibitory effect towards S. aureus bacterial cells and also towards C. albicans fungal cells. Full article

In this paper, the electric and thermoelectric properties of thin films of germanium–gold alloy (Ge–Au) are discussed in terms of choosing the optimal deposition process and post-processing conditions to obtain Ge–Au layers with the best thermoelectric parameters. Thin films were fabricated by magnetron sputtering using the Ge–Au alloy target onto glass substrates at two various conditions; during one of the sputtering processes, the external substrate bias voltage (U_b = −150 V) was used. After deposition thin films were annealed in the atmosphere of N₂ at various temperatures (473, 523 and 573 K) to investigate the influence of annealing temperature on the electric and thermoelectric properties of films. Afterwards, the thermocouples were created by deposition of the NiCrSi/Ag contact pads onto Ge–Au films. In this work, particular attention has been paid to thermoelectric properties of fabricated thin films—the thermoelectric voltage, Seebeck coefficient, power factor PF and dimensionless figure of merit ZT were determined. Full article

Owing to the reducing effect of NH_x radicals and H species produced in (Ar-N₂-H₂) expanding plasma, chemical reactions are promoted in thin metal films in contrast with other plasma treatments where the impinging energetic ions play the main role. Multi layers of Mo, Ti, and their nitrides are used in very recent applications such as supercapacitors or solar cells. They combine the interesting properties of the constituents. This work reports on the formation and the structure of Ti nitrides and Mo silicides in Mo–Ti bilayer films coated on Si wafers exposed to (Ar-N₂-H₂) plasma for 1 to 3 h. Nitrogen diffuses into the surface layers from 400 °C and TiN starts to crystallize from 600 °C. Interdiffusion of Mo, Ti, and Si through Mo–Ti bilayer films gives rise to the formation of Mo–Ti alloys and MoSi₂ of hexagonal structure, which transforms into MoSi₂ of tetragonal structure at longer treatment durations. A 1 h 30 min plasma exposure at 800 °C leads to the formation of three layers of nearly equal thickness with clear interfaces, which consist of TiN and MoSi₂ of nanometric size in the vicinity of the Mo–Ti bilayer film surface. Full article

A LiCoO₂ thin film on a quartz glass substrate was fabricated by a wet process involving heat treatment of a precursor film spray-coated with an aqueous ammonia solution containing LiCH₃COO and Co(CH₃COO)₂. The precursor film formed onto the substrate at 180 °C in air, and was heat treated at 500 °C in air for 0.5 h. The obtained film was spin-coated further with an ethanol-based precursor solution containing identical metal acetates, and heat treated at 500 °C in air for 0.5 h. The X-ray diffraction pattern of the resultant film showed only peaks assignable to the layered-rock-salt LiCoO₂. Raman spectroscopy measurements revealed vibrational modes assignable to layered rock salt LiCoO₂, with minor content of less than 5 mol% of spinel-type Co₃O₄. The field emission scanning electron microscopy images indicated that the resultant film was 0.21 μm thick, had no voids, and was a combination of small rounded grains measuring 18 nm in diameter and hexagonal grains larger than 0.2 μm in length. The Hall effect measurements indicated that the resultant thin film was a p-type semiconductor with electrical resistivity of 35(2) Ω·cm and a carrier concentration and carrier mobility of 8(2) × 10¹⁶ cm⁻³ and 2(1) cm²·V⁻¹·s⁻¹, respectively. Full article

A comparative study between graphene and modified graphene oxide (mGO) on the flame retardancy of graphite doped intumescent flame retardant (IFR) coatings is preliminarily investigated by cone calorimeter (CC), XRD, and SEM, with the final aim of clarifying the interactions between different graphenes and graphite doped coatings (polyester resin-ammonium polyphosphate-urea-pentaerythritol). The CC results determine that graphene exerts an obviously antagonistic effect on flame resistance, evidenced by the increased peak heat release rate (p-HRR) of 56.9 kW·m⁻² for S_D8+graphene (sample coating contains graphite with a particle size of 8 μm and 0.5 wt.% graphene as dopant), which increased by 80.6% compared with S_D8 (coating contains graphite with a particle size of 8 μm); substitution with graphene or mGO imparts an acceleration of fire growth, because graphene inertness improves the viscosity of melting system, evidenced by the cracked appearance and porous structure of S_D8+graphene. However, the higher reactivity of mGO favors the combustion; the barrier effect inhibits the transfer of mass and heat simultaneously, leading to a slight influence on flame retarding efficiency. Full article

Surface-enhanced Raman scattering (SERS) sensors are very powerful analytical tools for the highly sensitive detection of chemical and biological molecules. Substantial efforts have been devoted to the design of a great number of hybrid SERS substrates such as silicon or zinc oxide nanosystems coated with gold/silver nanoparticles. By comparison with the SERS sensors based on Au and Ag nanoparticles/nanostructures, higher enhancement factors and excellent reproducibilities are achieved with hybrid SERS nanosensors. This enhancement can be due to the appearance of hotspots located at the interface between the metal (Au/Ag) and the semiconducting substrates. Thus, in this last decade, great advances in the domain of hybrid SERS nanosensors have occurred. In this short review, the recent advances of these hybrid metal-coated semiconducting nanostructures as SERS sensors of chemical and biological molecules are presented. Full article

Musical instruments are tools for playing music, but for some of them—made by the most important historical violin makers—the myths hide the physical artwork. Ancient violin-making Masters developed peculiar construction methods and defined aesthetic canons that are still recognizable in their musical instruments. Recently, the focus of scientific investigations has been set on the characterization of materials and methods used by the ancient violin makers by means of several scientific approaches. In this work, the merits of synchrotron radiation micro-computed tomography and optical coherence tomography (OCT) for the investigation of complex coatings systems on historical bowed string musical instruments are discussed. Five large fragments removed during past restorations from instruments produced by Jacobus Stainer, Gasparo da Salò, Giovanni Paolo Maggini, and Lorenzo Guadagnini have been considered for a non-invasive insight by tomographic techniques and the results are discussed considering previous micro-invasive investigations. The tomographic approach allows to highlight the micro-morphology of the coating systems and offers preliminary information on the methods that were employed by the ancient Masters to treat the wood and finish the musical instrument. Full article

The well-known bacterial S-layer protein SbpA from Lysinibacillus sphaericus CCM2177 induces spontaneous crystal formation via cooperative self-assembly of the protein subunits into an ordered supramolecular structure. Recrystallization occurs in the presence of divalent cations (i.e., Ca²⁺) and finally leads to producing smooth 2-D crystalline coatings composed of squared (p4) lattice structures. Among the factors interfering in such a process, the rate of protein supply certainly plays an important role since a limited number of accessible proteins might turn detrimental for film completion. Studies so far have mostly focused on high SbpA concentrations provided under stopped-flow or dynamic-flow conditions, thus omitting the possibility of investigating intermediate states, in which dynamic flow is applied for more critical concentrations of SbpA (i.e., 25, 10, and 5 µg/mL). In this work, we have characterized both physico-chemical and topographical aspects of the assembly and recrystallization of SbpA protein in such low concentration conditions by means of in situ Quartz Crystal Microbalance with Dissipation (QCMD) and atomic force microscopy (AFM) measurements, respectively. On the basis of these experiments, we can confirm how the application of a dynamic flow influences the formation of a closed and crystalline protein film from low protein concentrations (i.e., 10 µg/mL), which otherwise would not be formed. Full article

Simple and lithium-doped biological-origin hydroxyapatite layers were synthesized by Pulsed Laser Deposition technique on medical grade Ti substrates. Cytotoxic effects of lithium addition and the biocompatibility of obtained coatings were assessed using three cell lines of human origin (new initiated dermal fibroblasts, immortalized keratinocytes HaCaT, and MG-63 osteosarcoma). Antimicrobial properties of obtained coatings were assessed on two strains (i.e., Staphylococcus aureus and Candida albicans), belonging to species representative for the etiology of medical devices biofilm-associated infections. Our findings suggest that synthesized lithium-doped coatings exhibited low cytotoxicity on human osteosarcoma and skin cells and therefore, an excellent biocompatibility, correlated with a long-lasting anti-staphylococcal and -fungal biofilm activity. Along with low fabrication costs generated by sustainable resources, these biological-derived materials demonstrate their promising potential for future prospective solutions—viable alternatives to commercially available biomimetic HA implants—for the fabrication of a new generation of implant coatings. Full article

Not all sunlight irradiated on the surface of a photovoltaic (PV) module can reach the cells in the PV module. This loss reduces the conversion efficiency of the PV module. The main factors of this loss are the reflection and soiling on the surface of the PV module. With this, it is effective to have both antireflection and antisoiling effects on the surface of PV modules. In this study, the antireflection and antisoiling effects along with the long-term reliability of the silica-based layer easily coated on PV modules were assessed. A silica-based layer with a controlled thickness and refractive index was coated on the surface of a Cu(In,Ga)Se₂ PV array. The array was exposed outdoors to assess its effects and reliability. As a result of the coating, the output of the PV array increased by 3.9%. The environment of the test site was relatively clean and the increase was considered to be a result of the antireflection effect. Moreover, it was observed that the effect of the coating was maintained without deterioration after 3.5 years. The coating was also applied to a silicon PV module and an effect similar to that of the CIGS PV module was observed in the silicon PV module. Full article

The performance of transition metal nitride based coatings deposited by magnetron sputtering, in a broad range of applications including wear-protective coatings on cutting tools and components in automotive engines, is determined by their phase content. The classical example is the precipitation of thermodynamically-favored wurtzite-AlN while alloying TiN with Al to obtain ternary single phase NaCl-structure films with improved high-temperature oxidation resistance. Here, we report on reactive high-power impulse and direct current magnetron co-sputtering (HiPIMS/DCMS) growth of Ti_0.31Al_0.69N and Zr_0.48Al_0.52N thin films. The Al concentrations are intentionally chosen to be higher than theoretically predicted solubility limits for the rock salt structure. The goal is to investigate the effect of the incident Al⁺ energy E_Al⁺, controlled by varying the amplitude of the substrate bias applied synchronously with the Al⁺-rich portion of the ion flux from the Al-HiPIMS source, on the crystalline phase formation. For E_Al+ ≤ 60 eV, films contain predominantly the wurtzite phase. With increasing E_Al⁺, and thus, the Al subplantation depth, the relative fraction of the NaCl structure increases and eventually for E_Al⁺ > 250 eV, Ti_0.31Al_0.69N and Zr_0.48Al_0.52N layers contain more than 95% of the rock salt phase. Thus, the separation of the film forming species in time and energy domains determines the phase formation of Ti_0.31Al_0.69N and Zr_0.48Al_0.52N layers and enables the growth of the cubic phase outside of the predicted Al concentration range. The new film growth concept can be applied to the entire family of multinary transition metal aluminum nitrides, where one of the metallic film constituents is available in the ionized form while the other arrives as neutral. Full article

This study reports the significant mechanistic difference between binary-oxide antibacterial films with the same composition but different microstructures. Binary TiO₂-FeO_x films were found to present a faster bacterial inactivation kinetics under visible light irradiation than each single oxide acting independently. The interaction between the film active surface species and the bacteria within the disinfection period was followed by X-ray photoelectron spectroscopy (XPS) and provided the evidence for a redox catalysis taking place during the bacterial inactivation time. The optical and surface properties of the films were evaluated by appropriate surface analytical methods. A differential mechanism is suggested for each specific microstructure inducing bacterial inactivation. The surface FeO_x plasmon resonance transferred electrons into the conduction band of TiO₂ because of the Schottky barrier after Fermi level equilibration of the two components. An electric field at the interface between TiO₂ and FeO_x, favors the separation of the photo-generated charges leading to a faster bacterial inactivation by TiO₂–FeO_x compared to the bacterial inactivation kinetics by each of the single oxides. Full article

This paper considers the problem of creating a conductive matrix with a framework made of carbon nanotubes (CNTs) for cell and tissue engineering. In silico investigation of the electrical conductivity of the framework formed by T-junctions of single-walled carbon nanotubes (SWNTs) (12, 12) with a diameter of 1.5 nm has been carried out. A numerical evaluation of the contact resistance and electrical conductivity of seamless and suture T-junctions of SWCNTs is given. The effect of the type of structural defects in the contact area of the tubes on the contact resistance of the T-junction of SWCNTs was revealed. A coarse-grained model of a branched SWCNT network with different structure densities is constructed and its electrical conductivity is calculated. A new layered bioconstruction is proposed, the layers of which are formed by natural polymer matrixes: CNT-collagen, CNT-albumin and CNT-chitosan. The energy stability of the layered natural polymer matrix has been analyzed, and the adhesion of various layers to each other has been calculated. Based on the obtained results, a new approach has been developed in the formation of 3D electrically conductive bioengineering structures for the restoration of cell activity. Full article

Mechanical methods to extract undesired graffiti paints on ornamental stones are efficient cleaning methods from an economical point of view. However, effort on the optimization of mechanical cleaning procedures to avoid any damage to the substrate is required for large areas. In this study, two ornamental stones with different composition and texture, and which are commonly used in Spain and Portugal were selected: Granite Vilachán and Limestone Lioz. Moreover, the most common surface finishes were selected-disc-cutting and bush-hammering to simulate the stones found in buildings. Two graffiti spray paints were selected: Blue Ultramarine and Silver Chrome. As cleaning methods, three soft-abrasive blasting procedures: Hydrogommage (mixture of air–water–micro grained silicon abrasive), IBIX (mixture of air–micro grained silicon abrasive), and dry-ice procedure (carbon dioxide ice pellets), were tested at pressure below 0.4 MPa. The methodology for evaluating the effectiveness and harmfulness of each cleaning method was based on stereomicroscopy, scanning electron microscopy, color spectrophotometry, and confocal microscopy. As result, IBIX achieved the highest level of graffiti paint extraction although this method increased the surface roughness. Conversely, cleaning based on dry-ice projection did not achieve a satisfactory extraction of the graffiti, mainly of the blue paint. Dry-ice blasting can induce acid environments and IBIX causes dust emission during the projection. Hydrogommage was the most efficient cleaning method amongst the tested procedures, because it induced the lowest roughness change and although the graffiti extraction was not complete, it achieved the highest removal level. Therefore, the most satisfactory cleaning method was that achieving a satisfactory extraction level, minimal modifications of the surface roughness, an economic suitability, an environmental integration, and lower human health risks. Full article

The automotive painting technique is highly advantageous for coloring solar modules, because it enables the modules to be visually attractive over a large area, numerous colors can be applied, and they are highly durable. Herein, we present a high-performance solar module colored using an automotive painting technique. We coated a dilute automotive pigment, the high-transmittance mica pigment, with a clear coat material on a crystalline Si solar module to generate blue color. Our measurements show that a pigment weight concentration of around 10% with the mica pigment is suitable for painting the solar modules, because it enables visual attractiveness while retaining over 80% of the output power, compared to the original solar module. We believe that the technique proposed herein can considerably increase the installable area of solar modules on a car body. Full article

The application of coating polymers to building materials is a simple and cheap way to preserve and protect surfaces from weathering phenomena. Due to its environmentally friendly character, waterborne coating is the most popular type of coating, and improving its performance is an important key of research. The study presents the results regarding the mechanical and photo-oxidation resistance of some water-based acrylic coatings containing SiO₂ nanoparticles obtained by batch miniemulsion polymerization. Coating materials have been characterized in terms of hydrophobic/hydrophilic behavior, mechanical resistance and surface morphology by means of water-contact angle, and scrub resistance and atomic force microscopy (AFM) measurements depending on silica-nanoparticle content. Moreover, accelerated weathering tests were performed to estimate the photo-oxidation resistance of the coatings. The chemical and color changes were assessed by Fourier-transform infrared spectroscopy (FTIR) and colorimetric measurements. Furthermore, the nanofilled coatings were applied on two different calcareous lithotypes (Lecce stone and Carrara Marble). Its properties, such as capillary water absorption and color modification, before and after accelerated aging tests, were assessed. The properties acquired by the addition of silica nanoparticles in the acrylic matrix can ensure good protection against weathering of stone-based materials. Full article

Poly(phenylene methylene) (PPM) is a thermally stable, hydrophobic, fluorescent hydrocarbon polymer. PPM has been proposed earlier to be useful as a coating material but this polymer was isolated in relevant molar masses only recently, and in large quantities. Accordingly, the preparation of coatings based on PPM and their behavior was explored in this study, with the example of the metal alloy AA2024 as a common substrate for corrosion tests. Coatings free of bubbles and cracks were obtained by hot pressing and application of the following steps: Coating on AA2024 with a layer of polybenzylsiloxane to improve the adhesion between PPM and the metal surface, the addition of polybenzylsiloxane to PPM in order to enhance the viscosity of the molten PPM, and the addition of benzyl butyl phthalate as a plasticizer. Electrochemical corrosion tests showed good protection of the metal surface towards a NaCl solution, thanks to a passive-like behavior in a wide potential window and a very low current density. Remarkably, the PPM coating also exhibited self-healing towards localized attacks, which inhibits the propagation of corrosion. Full article

A Si doped Pt modified aluminide coating was prepared by electroplating and the chemical vapour deposition method. The microstructure and oxidation resistance of the coating were studied, with a single Pt modified aluminide coating as a reference. The results showed that the Si doped Pt modified aluminide coating consisted of singular β-(Ni, Pt)Al phase, and no PtAl₂ phase was detected, which might be due to the fact that the addition of Si retarded the formation of PtAl₂ phase in the outer layer. Si was dissolved in the β-(Ni, Pt)Al phase in the outer layer and might form silicide with refractory elements in the inter-diffusion zone. The Si doped Pt modified aluminide coating possesses a better oxidation resistance than the Pt modified aluminide coating since Si could promote the formation of α-Al₂O₃ and inhibit the diffusion of the refractory elements, reducing the formation of detrimental volatile phase. Full article

The Fe/Zr composite coating was prepared by duplex Fe/Zr ion implantation and deposition to modify the microstructure and corrosion behavior of Mg-5.5 Zn-0.6 Zr (in wt.%, ZK60) alloy. The surface and interface characteristics were investigated using X-ray diffraction (XRD), atomic force microscope (AFM) and scanning electron microscopy (SEM). The results showed that the Fe/Zr composite coating exhibited a bi-layer microstructure of outer Fe-rich layer and inner Zr-rich layer. Multi-phases of α-Fe, ZrO₀.₃₅ and Zr₆Fe₃O were formed on the modified surface. The electrochemical measurements and immersion tests revealed an improvement of corrosion behavior for the surface-modified sample due to the protective effect of Fe/Zr composite coating. Full article

A supersonic plasma sprayed nano-SiC-modified WC/Fe metal–cermet composite coating was remelted with a fibre-pulsed laser at four different laser scanning speeds (100, 150, 200 and 250 mm·min⁻¹) while the other parameters were kept constant. The microstructures, microhardness, and tribological properties of the coatings were analysed by means of SEM (scanning electron microscopy), XRD (X-ray diffractometer), and a friction tester, respectively. The results show that, when the laser scanning speed is 100 mm·min⁻¹, the remelted coating is most dense with regard to the coverage of the substrate. The coating with nano-particles became more smooth, and elements Si and C in the nano-particles reacted with Fe, Ni, or Cr and formed a hard mesophase that enhanced the strength and hardness of the coating. With the increase of laser scanning speed, the hardness of the four coatings increased first and then decreased, and the nano-SiC-modified remelted coating showed a maximum microhardness of about HV_0.51350, and the nano-particles made the coating’s micro-structure finer, at a laser scanning speed of 150 mm·min⁻¹. The friction coefficient and wear rate of the four coatings were 0.58 and 12.01 × 10⁻⁵ mm³/(N·m), 0.21 and 8.50 × 10⁻⁵ mm³/(N·m), 0.62 and 20.04 × 10⁻⁵ mm³/(N·m), and 1.23 and 25.13 × 10⁻⁵ mm³/(N·m). The remelted coating at a laser scanning speed of 150 mm·min⁻¹ exhibits the best wear resistance and its wear mechanism is governed by slight adhesion wear and plastic deformation. Full article

The catalytic behaviour of Ag₂O and Ag doped CeO₂ thin films, deposited by atomic layer deposition (ALD), was investigated for diesel soot oxidation. The silver oxide was deposited from pulses of the organometallic precursor (hfac)Ag(PMe₃) and ozone at 200 °C with growth rate of 0.28 Å/cycle. Thickness, crystallinity, elemental composition, and morphology of the Ag₂O and Ag doped CeO₂ films deposited on Si (100) were characterized by ellipsometry, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and field emission scanning electron microscopy (FESEM), respectively. The catalytic effect on diesel soot combustion of pure Ag₂O, CeO_2, and Ag doped CeO₂ films grown on stainless steel foil supports was measured with oxidation tests. Nominally CeO₂:Ag 10:1 doped CeO₂ films were most effective and oxidized 100% of soot at 390 °C, while the Ag₂O films were 100% effective at 410 °C. The doped films also showed much higher stability; their performance remained stable after five tests with only a 10% initial reduction in efficiency whereas the performance of the Ag₂O films reduced by 50% after the first test. It was concluded that the presence of Ag⁺ sites on the catalyst is responsible for the high soot oxidation activity. Full article

Chromium carbide layers were deposited using liquid-injection metal-organic chemical vapor deposition inside long (0.3 to 1 m) and narrow (8 to 24 mm in diameter) metallic tubes. The deposition was carried out using a molecular single-source, bis(benzene)chromium (BBC), as representative of the bis(arene)metal family diluted in toluene and injected with N₂ as carrier gas. A multicomponent mass transport model for the simulation of the coupled fluid flow, heat transfer and chemistry was built. The kinetic mechanism of the growth of CrC_x films was developed with the help of large-scale experiments to study the depletion of the precursors along the inner wall of the tube. The model fits well in the 400–550 °C temperature range and in the 1.3 × 10² to 7 × 10³ Pa pressure range. The pressure is shown to have a pronounced effect on the deposition rate and thickness uniformity of the resulting coating. Below 525 °C the structure, composition and morphology of the films are not affected by changes of total pressure or deposition temperature. The coatings are amorphous and their Cr:C ratio is about 2:1, i.e., intermediate between Cr₇C₃ and Cr₃C₂. The model was applied to the design of a long reactor (1 m), with a double injection successively and alternatively undertaken at each end to ensure the best uniformity with sufficient thickness. This innovative concept can be used to optimize industrial deposition processes inside long and narrow tubes and channels. Full article

Flake boron nitride (BN) in large yield was successfully synthesized at low temperature from the combustion synthesized precursor. The precursor was prepared by a low-temperature (350 °C) combustion synthesis (LCS) method using nitric acid (HNO₃), urea (CO(NH₂)₂), boric acid (H₃BO₃), and glucose (C₆H₁₂O₆·H₂O) as starting materials. The precursor consists of B₂O₃ and amorphous carbon and the morphology is composed of blocks with average diameters of about 10 μm by statistical methods using SEM at different fields. Then BN was synthesized at 900 °C in NH₃ at a heating rate of 5 °C min⁻¹. The as-prepared BN possesses a flake morphology and high specific surface area up to 936 m² g⁻¹. It also has high density structural defects and abundant –NH₂/–OH groups. The surface groups improve its water wettability and electronegativity, which contributes to the rapid and selective adsorption performance, especially towards the cationic dyes. When 4 mg of the sample was added into a 100 mL RhB solution with an initial concentration of 5 mg L⁻¹, 95% of the RhB was removed within 1 min and the adsorption capacity is 125 mg g⁻¹. Importantly, the sample can be regenerated by heating at 400 °C in air. Full article

The application of nanofibrillated cellulose (NC) films in packaging industry has been hindered by its lack of heat-sealing ability. Incorporation of NC films with the biaxially oriented polypropylene/low density polyethylene (BOPP/LDPE) laminates can take advantage of each material and endow the films with novel functions for food packaging applications. In this study, a coating that consists of NC and nisin was applied onto a cold plasma treated BOPP/LDPE film to fabricate a novel active packaging with an improved oxygen barrier performance and an added antimicrobial effect. The results showed that cold plasma treatment improved the surface hydrophilicity of BOPP/LDPE films for better attachment of the coatings. NC coatings significantly enhanced oxygen barrier property of the BOPP/LDPE film, with an oxygen transmission rate as low as 24.02 cc/m²·day as compared to that of the non-coated one (67.03 cc/m²·day). The addition of nisin in the coating at a concentration of 5 mg/g caused no significant change in barrier properties but imparted the film excellent antimicrobial properties, with a growth inhibition of L. monocytogenes by 94%. All films exhibit satisfying mechanical properties and transparency, and this new film has the potential to be used as antimicrobial and oxygen barrier packaging. Full article

This paper presents the geo-referenced acoustical results obtained throughout the close proximity noise (CPX) technique carried out on different urban sections included within the 2017 strategic noise mapping (Directive 2002/49/CE) in Ciudad Real, a Spanish medium-sized city. The employed methodology quantifies the tire/pavement noise generated in the contact between the tire and the surface of the studied sections. Measurements were carried out in different research campaigns between 2008 and 2015 (medium-term evolution). They give valuable information about the pavement-aging effect on its surface characteristics. Throughout these years, the acoustic situation of these sections has worsened mainly due to surface damage and higher mean profile depth (MPD) values, although the performance does not follow the same pattern in every section. The relationships between measured tire/pavement noise and theoretical environmental noise, just due to the geometric spreading of sound energy, is also studied in order to elaborate a simple rolling noise mapping and to assess the environmental noise evolution. Traffic noise plays the main role in the noise registered within the assessed sections, therefore, CPX assessment could be used by local authorities to take decisions regarding urban planning and traffic management, with the aim of reducing noise exposure from traffic. Full article

Hydrophilic coatings have recently emerged as a new approach to avoiding the adhesion of (bio)organisms on surfaces immersed in water. In these coatings the hydrophilic character is crucial for the anti-fouling (AF) performance. However, this property can be rapidly lost due to the inevitable damages which occur at the surface, reducing the long-term effectiveness of the AF functionality. We report hydrophilic polycarbonate-poly(ethylene glycol) methyl ether (mPEG) polyurethane coatings with tunable hydrophilic properties as well as an excellent and long-term stability in water. The coatings exhibit low protein adhesion values and are able to self-replenish their hydrophilicity after damage, due to the existence of a reservoir of hydrophilic dangling chains incorporated in the bulk. The combination of low T_g and sufficient mobility of the mPEG dangling chains (enabled by chains with higher molecular weight) proved to be crucial to ensure autonomous surface hydrophilicity recovery when the coatings were immersed in water. This coatings and design approach offers new possibilities towards high-performance AF coatings with an extended service life-time which can be used in several major applications areas, such as marine and biomedical coatings, with major economic and environmental benefits. Full article

High-Si-content transition metal nitride coatings, which exhibited an X-ray amorphous phase, were proposed as protective coatings on glass molding dies. In a previous study, the Zr–Si–N coatings with Si contents of 24–30 at.% exhibited the hardness of Si₃N₄, which was higher than those of the middle-Si-content (19 at.%) coatings. In this study, the bonding characteristics of the constituent elements of Zr–Si–N coatings were evaluated through X-ray photoelectron spectroscopy. Results indicated that the Zr 3d_5/2 levels were 179.14–180.22 and 180.75–181.61 eV for the Zr–N bonds in ZrN and Zr₃N₄ compounds, respectively. Moreover, the percentage of Zr–N bond in the Zr₃N₄ compound increased with increasing Si content in the Zr–Si–N coatings. The Zr–N bond of Zr₃N₄ dominated when the Si content was >24 at.%. Therefore, high Si content can stabilize the Zr–N compound in the M₃N₄ bonding structure. Furthermore, the thermal stability and chemical inertness of Zr–Si–N coatings were evaluated by conducting thermal cycle annealing at 270 °C and 600 °C in a 15-ppm O₂–N₂ atmosphere. The results indicated that a Zr₂₂Si₂₉N₄₉/Ti/WC assembly was suitable as a protective coating against SiO₂–B₂O₃–BaO-based glass for 450 thermal cycles. Full article

The aim of this study is to enhance the bioactivity of pure titanium using multiple surface treatments for the application of the implant. To form the biofunctional multilayer coating on pure titanium, anodization was conducted to make titanium dioxide nanotubes, then multi-walled carbon nanotubes were coated using a dipping method after an alkali treatment. The surface characteristics at each step were analyzed using a field emission scanning electron microscope and X-ray diffractometer. The effect of the multilayer coating on the biocompatibility was identified using immersion and cytotoxicity tests. Better hydroxyapatite formation was observed on the surface of multilayer-coated pure titanium compared to non-treated pure titanium after immersion in the simulated body fluid. Improvement of biocompatibility by multiple surface treatments was identified through various cytotoxicity tests using osteoblast cells. Full article

The creation of functional papers requires a specific deposition of chemical moieties at the surface. In particular, water-repellent barrier coatings can be formed by the deposition of (poly(styrene-co-maleimide) nanoparticles filled with different vegetable oils. The analysis of coated paper surfaces by dispersive Raman spectroscopy allows for statistical classification of different coating types and chemical mapping of the lateral surface distribution of the coating components. The Raman spectra were used to quantify the amount of free oil and imide content. The partial least squares model with three principal components (PC) could differentiate between the type of oil (degree of saturation in PC-1), coating thickness (cellulose bands of paper substrate in PC-2), and organic coating phase (styrene, imide in PC-3). The chemical surface maps with average intensities indicate coating inhomogeneities for thin coatings located near the organic coating components, while the presence of free oil acts as a natural binder in between the organic phase and provides a more homogeneous coating. Depending on the type of oil, a higher amount of free oil coincides with lower imide content at the surface. The surface coverage of polyunsaturated oils overlaps relatively well with the areas of organic coating components, as the oil is largely encapsulated. The surface coverage for mono- and unsaturated oils is rather complementary to the organic phase as there are larger amounts of free oil. The latter is confirmed by single wavenumber maps and image processing constructing composite chemical surface maps. Full article

Surface modification procedures by laser techniques allow the generation of specific topographies and microstructures that enable the adaptation of the external layers of materials for specific applications. In laser texturing processes, it is possible to maintain control over the microgeometry and dimensions of the surface pattern through varying the processing parameters. One of the main areas of interest in the field of surface modification treatments is the ability to generate topographies that are associated with specific surface finishes, in terms of roughness, that can improve the manufactured part’s functional capabilities. In this aspect, several types of phenomena have been detected, such as the friction and sliding wear behavior or wetting capacity, which maintain a high dependence on surface roughness. In this research, surface texturing treatments have been developed by laser techniques through using the scanning speed of the beam (V_s) as a control parameter in order to generate samples that have topographies with different natures. Through assessments of surface finish using specialized techniques, the dimensional and geometrical features of the texturized tracks have been characterized, analyzing their influence on the wetting behavior of the irradiated layer. In this way, more defined texturing grooves has been developed by increasing the V_s, which also improves the hydrophobic characteristics of the treated surface. However, due to the lack of uniformity in the solidification process of the irradiated area, some deviations from the expected trends and singular points can be observed. Using the contact angle method to evaluate the wetting behavior of the applied treatments found increases in the contact angle values for high texturing speeds, finding a maximum value of 65.59° for V_s = 200 mm/s. Full article

Two-dimensional (2D) materials, such as graphene and hexagonal boron nitride, are new kinds of materials that can serve as substrates for surface enhanced Raman spectroscopy (SERS). When combined with traditional metallic plasmonic structures, the hybrid 2D materials/metal SERS platform brings extra benefits, including higher SERS enhancement factors, oxidation protection of the metal surface, and protection of molecules from photo-induced damages. This review paper gives an overview of recent progress in the 2D materials-coated plasmonic structure in SERS application, focusing on the fabrication of the hybrid 2D materials/metal SERS platform and its applications for Raman enhancement. Full article

The results of industrial application of an online X-ray fluorescence coating thickness analyzer for measuring the thickness of phosphate coatings on moving steel strips are considered in the article. The target range of coating thickness to be measured is from tens to hundreds of mg/m² in a measurement time of 10 s. The measurement accuracy observed during long-duration factory acceptance test was 10–15%. The coating thickness analyzer consists of two XRF gauges, mounted above and below the steel strip and capable of moving across the moving strip system for their suspension and relocation and electronic control unit. Fully automated software was developed to automatically and continuously (24/7) control both gauges, scanning both sides of the steel strip, and develop and test methods for measuring new coatings. It allows performing offline storage and retrieval of the measurement results, remotely controlling the analyzer components and measurement modes from a control room. The developed XRF coating thickness analyzer can also be used for real-time measurement of other types of coatings, both metallic and non-metallic. Full article

At present, many historical artefacts and furniture are only reconstructed and not restored. They are preserved in terms of material reparation, but their historical value decreases significantly. This work is focused on the comparison of the resistance of high-gloss polyurethane varnish with traditional shellac varnish. The varnishes were applied to oak wood and exposed to interior artificial accelerated ageing in Xenotest. Before and after ageing, cold liquid-resistance tests were performed on the tested specimens and gloss, colour, and adhesion were also evaluated. The structures of the surfaces were also analysed using a confocal laser scanning microscope. As expected, polyurethane varnish was much more durable than shellac varnish. Interestingly, shellac varnish was fairly resistant to water at the beginning, but this resistance was greatly reduced after artificial accelerated ageing. This illustrates the importance of sheltering the shellac treated artefacts in stable temperature-humidity conditions with the least possible effect of solar radiation. Full article

Use of photocatalytic paint-like coatings may be a way to protect building materials from microbial colonization. Numerous studies have shown the antimicrobial efficiency of TiO ${}_2$ photocatalysis on various microorganisms. However, few have focused on easy-to-apply solutions and on photocatalysis under low irradiance. This paper focuses on (a) the antibacterial properties of a semi-transparent coating formulated using TiO ${}_2$ particles and (b) the microscopic investigations of bacterial biofilm development on TiO ${}_2$ -coated building materials under accelerated growth conditions. Results showed significant antibacterial activity after few hours of testing. The efficiency seemed limited by the confinement of the TiO ${}_2$ particles inside the coating binder. However, a pre-irradiation with UV light can improve efficiency. In addition, a significant effect against the formation of a bacterial biofilm was also observed. The epifluorescence approach, in which fluorescence is produced by reflect rather than transmitted light, could be applied in further studies of microbial growth on coatings and building materials. Full article

Above ground indirect detections and random excavations that have applied the past years for buried long distance oil and gas pipelines can only identify some damaged coating locations. Hence, large number of field joint coating (FJC) failures happen unconsciously until they lead to failures of the pipelines. Based on the analysis of magnetic flux leakage (MFL) in-line inspection (ILI) signals, combined with the statistical results of 414 excavations from two different pipeline sections, a new method to identify the failed FJC is established. Though it can only identify FJC failures when there are signs of corrosion on pipe body, it is much more efficient and cost-saving. The concluded identification rule still needs more validations and improvements to be more applicable and accuracy. Full article

Cubic boron nitride (c-BN) films were prepared via radio frequency (RF) magnetron sputtering from a hexagonal boron nitride (h-BN) target in a pure N₂ plasma. The composition and microstructure morphology of the BN films with different deposition times under pure N₂ plasma or mixed Ar/N₂ plasma were investigated with respect to the nucleation and growth processes. The pure-phase c-BN growth window was obtained using pure N₂ gas. The effects of pure N₂ gas on the growth mechanism, structural morphology, and internal compressive stress of the as-synthesized c-BN films were studied. Using pure N₂ gas instead of additional Ar resulted in improved microstructure quality and much reduced compressive stress, suggesting a fundamental strategy for achieving high-quality c-BN films. Full article

Hybrid manufacturing processes that combine additive and machining operations are gaining relevance in modern industry thanks to the capability of building complex parts with minimal material and, many times, with process time reduction. Besides, as the additive and subtractive operations are carried out in the same machine, without moving the part, dead times are reduced and higher accuracies are achieved. However, it is not clear whether the direct material deposition after the machining operation is possible or intermediate cleaning stages are required because of the possible presence of residual cutting fluids. Therefore, different Laser Metal Deposition (LMD) tests are performed on a part impregnated with cutting fluid, both directly and after the removal of the coolant by techniques such as laser vaporizing and air blasting. The present work studies the influence of the cutting fluid in the LMD process and the quality of the resulting part. Resulting porosity is evaluated and it is concluded that if the part surface is not properly clean after the machining operation, deficient clad quality can be obtained in the subsequent laser additive operation. Full article

Thermal management in microelectronic devices has become a crucial issue as the devices are more and more integrated into micro-devices. Recently, free-standing graphene films (GFs) with outstanding thermal conductivity, superb mechanical strength, and low bulk density, have been regarded as promising materials for heat dissipation and for use as thermal interfacial materials in microelectronic devices. Recent studies on free-standing GFs obtained via various approaches are reviewed here. Special attention is paid to their synthesis method, thermal conductivity, and potential applications. In addition, the most important factors that affect the thermal conductivity are outlined and discussed. The scope is to provide a clear overview that researchers can adopt when fabricating GFs with improved thermal conductivity and a large area for industrial applications. Full article

A common belief proposed by Peierls and Landau that two-dimensional material cannot exist freely in a three-dimensional world has been proved false when graphene was first synthesized in 2004. Graphene, which is the base structure of other carbon materials, has drawn much attention of scholars and researchers due to its extraordinary electrical, mechanical and thermal properties. Moreover, methods for its synthesis have developed greatly in recent years. This review focuses on the mechanism of the thermal growth method and the different synthesis methods, where epitaxial growth, chemical vapor deposition, plasma-enhanced chemical vapor deposition and combustion are discussed in detail based on this mechanism. Meanwhile, to improve the quality and control the number of graphene layers, the latest research progress in optimizing growth parameters and developmental technologies has been summarized. The strategies for synthesizing high-quality and large-scale graphene are proposed and an outlook on the future synthesis direction is also provided. Full article

A new family of physical vapor deposited (PVD) coatings is presented in this paper. These coatings are deposited by a superfine cathode (SFC) using the arc method. They combine a smooth surface, high hardness, and low residual stresses. This allows the production of PVD coatings as thick as 15 µm. In some applications, in particular for machining of such hard to cut material as compacted graphite iron (CGI), such coatings have shown better tool life compared to the conventional PVD coatings that have a lower thickness in the range of up to 5 μm. Finite element modeling of the temperature/stress profiles was done for the SFC coatings to present the temperature/stress profiles during cutting. Comprehensive characterization of the coatings was performed using XRD, TEM, SEM/EDS studies, nano-hardness, nano-impact measurements, and residual stress measurements. Application of the coating with this set of characteristics reduces the intensity of buildup edge formation during turning of CGI, leading to longer tool life. Optimization of the TiAlN-based coatings composition (Ti/Al ratio), architecture (mono vs. multilayer), and thickness were performed. Application of the optimized coating resulted in a 40–60% improvement in the cutting tool life under finishing turning of CGI. Full article

Waterborne polyurethane (WBPU)/cerium nitrate (Ce(NO₃)₃) dispersions were synthesized with different defined Ce(NO₃)₃ content. All pristine dispersions were stable with different poly(tetramethylene oxide) glycol (PTMG) number average molecular weights (Mn) of 650, 1000, and 2000. The interaction between the carboxyl acid salt group and Ce(NO₃)₃ was analyzed by Fourier-transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) techniques. Coating hydrophilicity, water swelling (%), water contact angle, leaching, and corrosion protection efficiency were all affected when using different Ce(NO₃)₃ content and PTMG molecular weights. The maximal corrosion protection of the WBPU coating was recorded using a higher molecular weight of PTMG with 0.016 mole Ce(NO₃)₃ content. Full article