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To achieve the expected level of sensitivity of third-generation gravitational-wave (GW) observatories, more accurate and sensitive instruments than those of the second generation must be used to reduce all sources of noises. Amongst them, one of the most relevant is seismic noise, which will require the development of a better isolation system, especially at low frequencies (below 10 Hz), the operation of large cryogenic silicon mirrors, and the improvement of optical wavelength readouts. In this framework, this article presents the activities of the E-TEST (Einstein Telescope Euregio Meuse-Rhine Site & Technology) to develop and test new key technologies for the next generation of GW observatories. A compact isolator system for a large silicon mirror (100 kg) at low frequency ( < 10 Hz) is proposed. The design of the isolator allows the overall height of the isolation system to be significantly compact and also suppresses seismic noise at low frequencies. To minimize the effect of thermal noise, the isolation system is provided with a 100 kg silicon mirror which is suspended in a vacuum chamber at cryogenic temperature (25–40 K). To achieve this temperature without inducing vibrations to the mirror, a radiation-based cooling strategy is employed. In addition, cryogenic sensors and electronics are being developed as part of the E-TEST to detect vibrational motion in the penultimate cryogenic stage. Since the commonly used silicon material is not transparent below the wavelengths typically used in the 1 µ m range for GW detectors, new optical components and lasers must be developed in the range above 1500 nm to reduce absorption and scattering losses. Therefore, solid-state and fiber lasers with a wavelength of 2090 nm, matching high-efficiency photodiodes, and low-noise crystalline coatings are being developed. Accordingly, the key technologies provided by E-TEST serve crucially to reduce the limitations of the current generation of GW observatories and to determine the technical design for the next generation. [ABSTRACT FROM AUTHOR]

The properties of optical coatings play an important role in precision experiments. Gravitational-wave detectors not only require the highest quality coatings but also ones with relatively large diameters. Coatings made with amorphous material can be scaled up easily but for now exhibit relatively high thermal noise characteristics. Crystalline coatings show great promise in terms of their thermal noise properties but cannot easily scale up to the needed sizes. In this paper we explore the possibility of a piecewise coating that includes both amorphous and crystalline material. Specifically, we estimate the scattering losses of such a piecewise coating as a function of the mismatch in the interface between the two coatings. The calculation should be taken as a lower limit to the total losses, as other surface imperfections will play an important role in the final result, but are not considered here. Finally, we present a measurement of the scattering losses from a piecewise coating, to showcase the challenges of realizing such a design. [ABSTRACT FROM AUTHOR]

Perovskite nanocrystals (NCs) feature adjustable bandgap, wide absorption range, and great color purity for robust perovskite optoelectronic applications. Nevertheless, the absence of lasting stability under continues energization, is still a major hurdle to the widespread use of NCs in commercial applications. In particular, the reactivity of red-emitting perovskites to environmental surroundings is more sensitive than that of their green counterparts. Here, we present a simple synthesis of ultrathin ZrO2 coated, Sr2+ doped CsPbBrI2 NCs. Introducing divalent Sr2+ may significantly eliminate Pb° surface traps, whereas ZrO2 encapsulation greatly improves environmental stability. The photoluminescence quantum yield of the Sr2+-doped CsPbBrI2/ZrO2 NCs was increased from 50.2% to 87.2% as a direct consequence of the efficient elimination of Pb° surface defects. Moreover, the thickness of the ZrO2 thin coating gives remarkable heat resistance and improved water stability. Combining CsPbSr0.3BrI2/ZrO2 NCs in a white light emitting diode (LED) with an excellent optical efficiency (100.08 lm W−1), high and a broad gamut 141% (NTSC) standard. This work offers a potential method to suppress Pb° traps by doping with Sr 2+and improves the performance of perovskite NCs by ultrathin coating structured ZrO2, consequently enabling their applicability in commercial optical displays. [ABSTRACT FROM AUTHOR]

Group IV elements and their oxides, such as Si, Ge, Sn and SiO have much higher theoretical capacity than commercial graphite anode. However, these materials undergo large volume change during cycling, resulting in severe structural degradation and capacity fading. Al2O3 coating is considered an approach to improve the mechanical stability of high-capacity anode materials. To understand the effect of Al2O3 coating directly, we monitored the morphology change of coated/uncoated Sn particles during cycling using operando focused ion beam–scanning electron microscopy. The results indicate that the Al2O3 coating provides local protection and reduces crack formation at the early stage of volume expansion. The 3 nm Al2O3 coating layer provides better protection than the 10 and 30 nm coating layer. Nevertheless, the Al2O3 coating is unable to prevent the pulverization at the later stage of cycling because of large volume expansion. [ABSTRACT FROM AUTHOR]

Group IV elements and their oxides, such as Si, Ge, Sn and SiO have much higher theoretical capacity than commercial graphite anode. However, these materials undergo large volume change during cycling, resulting in severe structural degradation and capacity fading. Al2O3 coating is considered an approach to improve the mechanical stability of high-capacity anode materials. To understand the effect of Al2O3 coating directly, we monitored the morphology change of coated/uncoated Sn particles during cycling using operando focused ion beam–scanning electron microscopy. The results indicate that the Al2O3 coating provides local protection and reduces crack formation at the early stage of volume expansion. The 3 nm Al2O3 coating layer provides better protection than the 10 and 30 nm coating layer. Nevertheless, the Al2O3 coating is unable to prevent the pulverization at the later stage of cycling because of large volume expansion. [ABSTRACT FROM AUTHOR]

A multi-component category of an alloy containing very specific properties revolutionized the area of material science and the present engineering era. Laser cladding, a technique for surface coating, enhances surface quality and modifies properties using advanced coating technologies. In current trends, Laser cladding is mainly used in equipment and machine parts for enhancing surface properties, repairing damaged parts and surface coating caused by its advantages such as small heat-affected zone, low substrate damage, low dilution rate and exceptional metallurgical material bonding among coating and used substrate. Laser cladding improves substrates’ mechanical and various functional-specific properties, ensuring a high-quality balance between mechanical and surface attributes. The research society was able to investigate laser-cladding HEAs coatings because of the superior attributes of HEAs compared to ordinary alloys. This paper reviews current developments in laser-cladding HEAs coatings and the application of laser-cladding technology to HEAs materials. The laser cladding high-entropy alloy coatings have potential applications in corrosion, wear, and oxidation resistance, as well as their respective substrates. Cladded coatings composed of HEAs materials are measured to have shown potential applications in recent technology, opening exciting possibilities for the future. The study also discusses current trends and future prospects.

This research examines the performance of epoxy, ceramic, and graphene coatings on stainless steel 316 in a producer gas environment, focusing on corrosion and erosion resistance. This research aimed to identify the most effective coating for applications in harsh gasification environments. In this research, various analyses, including microstructural examination, hardness and weight measurements, FESEM analysis, and EDAX analysis, were conducted to evaluate the performance of the coatings. The producer gas was passed on to all the coated samples for a period of 100 h. The significant findings include the superior corrosion and erosion resistance of ceramic-coated stainless steel, as evidenced by low weight fluctuations, maintained hardness levels, and elemental stability. Graphene coatings exhibit high hardness but increased porosity, raising concerns about durability, while epoxy coatings are vulnerable to gas-induced structural alterations. The inclusion rating analysis underscored the ceramic coatings’ ability to preserve consistent material properties. Overall, ceramic coatings have emerged as the preferred option for gasification environments due to their structural resilience, inclusion integrity, and elemental stability. Considering the inclusion integrity, mechanical strength, weight stability, and elemental stability, ceramic-coated stainless steel 316 samples exhibit better resistance toward producer gas influence. This research contributes valuable insights for material selection in applications exposed to harsh gasification environments, emphasizing the importance of coating selection for long-term durability and performance.

This study added Zn, Zr and Ca as alloying elements of magnesium alloy (ZKX500) and produced fine grain structure by extrusion process. After 2 h of homogenization, abnormal grain growth was avoided, stress relief, improvement of stability and reduction of element segregation are achieved. In addition, application of phosphate coating on homogenized ZKX500, the mechanism of coating degradation and mechanical properties after degradation were accomplished and determined that the corrosion resistance of ZKX500 can be enhanced by homogenization and phosphate coating. To further enclose clinical-applying condition, ZKX500 screw undergoes 2 h of homogenization and phosphate coating, then immersed in simulated body fluid (SBF). The degradation rate of ZKX500 screw meets application requirement, which demonstrated homogenization and phosphate coating improved degradation behavior and mechanical properties of ZKX500 screws and exhibited its potential of clinical application.

The susceptibility of magnesium alloys to corrosion has hindered the wide application of magnesium alloys. A natural green method was proposed in this study to prepare a corrosion-resistant film layer whose main substance is MgO on the magnesium alloy substrate by a two-step hydrothermal method combining water steaming and annealing treatment. The morphology, composition, structure and corrosion resistance of the coating were investigated by SEM, FTIR, XRD and electrochemical methods. The results showed that the prepared coating has excellent corrosion resistance, reducing corrosion current by about four orders of magnitude compared with the bare Mg alloy substrate, and the corrosion potential and corrosion rate are also increased in different degree.

This study was conducted to investigate the effect of the ultrasonic field on the preparation of amorphous/crystalline Fe-based coatings. For this purpose, Fe _86.3 Si _5.9 B _3.2 Cr _4.6 (wt%) powder was deposited on GTD-111 superalloy substrate with and without ultrasonic field by selective laser melting method. After coating, the corrosion behavior, microstructure, and hardness of the amorphous coating were investigated. The results showed that in conditions without ultrasonic vibration, the growth of grains starts in columnar form. At the same time, the use of an ultrasonic field inhibits columnar growth and creates equiaxed grains. In addition, the ultrasonic field increased the amorphous phase by 34.5%. This is attributed to the increased solidification rate caused by the cavitation effect. The experimental results of corrosion show that the self-corrosion current density of 6.83×10 ^−7 A⋅cm ^2 is obtained due to the refinement of the microstructure and the increase of the amorphous phase. The wear results showed that the increase in the amorphous phase, as well as the decrease in the grain size, reduction in the grain ratio, and the increase in the tendency to equiaxed grains when using the ultrasonic field, reduce the coefficient of friction by 97%.

The aim of the current research is to examine the tribological, corrosion and mechanical properties of AISI 316L stainless steel without and with Al _2 TiO _5 surface coating. AISI 316L is selected for the study, owing to its extensive usage in power plant and marine members that are usually subjected to wear, fatigue and corrosion either separately or in a combinatorial mode from mild to severe intensities. Al _2 TiO _5 coating is provided to components to improve their tribological, corrosion and mechanical properties. Being a ceramic material, Al _2 TiO _5 coating is expected to improve the properties under consideration. The coated specimens are analyzed by considering two factors viz. ‘speed of rotation of job’ and ‘axial speed of the spray gun’, applying Taguchi L _4 array. Coating of Al _2 TiO _5 on AISI 316L substrate increased the corrosion resistance, coefficient of friction and micro-hardness, however the wear rate and fatigue life decreased. Twenty times reduction in wear rate is recorded with the coating of Al _2 TiO _5 on the base material when compared to the uncoated counterpart. The wear rate has also decreased by 16% with the increase in coating thickness from 300 to 375 μ m. The fatigue life of the coated specimens reduced by around 12% while their corrosion resistance increased by 20% when compared to the uncoated specimens.

Using alkali-activated slag to prepare coatings is an alternative solution for concrete repair and protection. However, shrinkage cracking limits the application of alkali-activated slag, which also increases the risk of coating peeling. Graphene dispersions (content of 0.2%, 0.4%, 0.6% and 0.8%) were added to the alkali-activated slag coatings. The drying time, apparent circumstance (thicknesses of 1 mm, 2 mm, 3 mm and 5 mm) and the tensile bond strength with 1 mm thickness coating were determined. The mechanism of action was analyzed in terms of both product and interfacial properties. The experimental results showed that the graphene dispersion would shorten the drying time of the coatings. The drying time was reduced by 57.1% (from 116 min to 52 min). Moreover, the graphene dispersion improves the cracking of the coating. The larger the coating thickness is, the better it improves the cracking effect. The surface cracking of the coating with 5 mm thickness was reduced by 60.7% (from 1.6751% to 0.6583%). Graphene can significantly improve the bond strength of the coating. When the graphene content is 0.8%, the bonding strength with a thickness of 1 mm is 0.502 MPa at 7 days and 1.577 MPa at 28 days. The bond strength increased by 280.3% and 175.2%, respectively, XRD, FTIR and SEM analysis showed that the increase in bond strength was caused by two factors. (1) Graphene can promote the generation of zeolite phase in alkali-activated slag. This is conducive to enhancing the interlayer adhesion of the coating itself. (2) Graphene is beneficial to reduce the pores in the transition zone between the coating and the substrate and enhance the contact area between the coating and the substrate and makes the transition zone denser.

The effect of operating gas temperature and powder type on microstructure and mechanical characteristics of cold spraying coatings deposited on EZ33A-T5 magnesium alloy was studied. Three aluminum-based cold spraying powder mixtures Al + Zn, Al + Al _2 O _3 and Al + Zn + Al _2 O _3 were used for the investigation. Deposition was performed using D423 low-pressure cold spray system at operating gas pressure of 1.0 MPa and different temperatures –300 °C, 450 °C, and 600 °C. The coatings microstructure was investigated with optical and scanning electron microscopy. Mechanical properties of the coatings were characterized through standard test methods for adhesion and cohesion strength, and standard test methods for Vickers hardness of thermal spray coatings. The results demonstrate that with increasing initial gas temperature at spraying nozzle inlet from 300 °C to 600 °C, an increase in the porosity of the coatings of all investigated powder mixtures can be observed. Microstructure characterization showed an increase in porosity from 2.3% to 4.1% for Al + Zn powder mixture, from 2.1% to 3.5% for Al + Al _2 O _3 powder mixture, and from 2.5% to 5.6% for Al + Zn + Al _2 O _3 powder mixture. The minimum porosity was obtained at 450 °C for all investigated powder mixtures. Adhesion and cohesion strength and microhardness of coatings were reach their maximum value at 450 °C. The best performance was obtained for Al + Al _2 O _3 powder mixture: coating adhesion—31.9 MPa (was limited by the bonding strength of the glue), cohesion—93.5 MPa, microhardness—81 HV _0.15 . The influence of Al _2 O _3 particles in the powder mixture on the above-mentioned parameters was also established. The results show that the presence of ceramic particles in powder mixtures can positively effect porosity level and mechanical characteristics.

We have prepared an ultra-thin flexible transparent conductive electrode with high folding endurance composed of randomly arranged silver nanowires (AgNWs) embedded in polydimethylsiloxane (PDMS). A simple preparation method was performed to connect a glass substrate coated with a AgNW network and a glass substrate coated with PDMS. The glass substrate was then removed after the PDMS solidified, and the AgNW–PDMS composite film was peeled off. Moreover, the problem of the high contact resistance caused by the random arrangement of AgNWs was solved by the local joule heat generated by applying voltage to both sides of the AgNW–PDMS composite structure to weld the overlapping AgNWs. The sheet resistance ( R _s ) of AgNW–PDMS composite films with different AgNW deposition concentrations decreased by 46.4%–75.8% through this electro-sintering treatment. The embedded structure of the AgNW–PDMS composite ensures better voltage resistance and environmental stability under high temperature and humidity conditions compared with a AgNW network attached to a glass substrate. Additionally, the substrate-free, excellent elasticity and high resilience characteristics resulted in the R _s value of the same composite electrode only increasing by 2.9 ohm sq ^−1 after folding four times. The advantage of the metal thermal conductivity makes the joule heat generated by electric injection rapidly diffuse and dissipate in the AgNW-based transparent heater with faster response time and smaller voltage drive than indium tin oxide.

In search to meet technological demands, material studies as well as techniques to process them have been increasing worldwide, thus seeking to unite lower processing costs, the best properties of the materials involved, reuse of resources and more sustainable means. Thus, the development of new materials, coatings and composites have stood out in the market. For this work, we fetch the development and characterization of polyamide 6 composite coatings with quasicrystalline AlCuFe fillers, recycled through the spin coating technique , since that little is known about the interaction between these two materials, which have excellent isolating properties, and little is observed about the use of this technique to produce coatings with metallic loads. The recycled AlCuFe quasicrystalline alloy was manufactured by conventional induction casting. Polyamide 6 coatings with quasicrystalline particles were developed with additions of 0, 1, 3 and 5 (% vol.) quasicrystal, via Spin Coating technique. Thermogravimetric analyses (TG), differential scanning calorimetry (CSD), average roughness (RA), contact angle, surface energy and scanning electron microscopy (SEM) were performed to characterize this material. Being observed an increase in the thermal stability of the composite, reduction in average roughness (Ra) and surface energy values, with increase in quasicrystal fraction in the polymer matrix. In addition to hydrophobicity and oleophilic character of the samples with the addition of quasicrystalline loads. It can be concluded, in general, that the Spin Coating technique is effective in the production of polyamide composite coatings 6 with recycled quasicrystals, presenting interesting surface properties with potential for further studies in innovative applications, such as semiconductors and surface coatings.

Bioactive hydroxyapatite (HA) coating is applied on a commercially pure Ti by electrophoretic deposition (EPD). Optimizing the coating structure is necessary to obtain a stable layer and the best corrosion protection. The EPD was conducted at a constant voltage of 20, 30, and 40 V for 30 min in a HA/DMF (dimethylformamide) suspension. Uniform HA layers with a Ca/P ratio of 1.82 were successfully deposited on the Ti surface. The layers, which consisted of HA grains with the size of 1–5 μ m, exhibited a gradual increase in thickness of 32, 50, and 60 μ m with formation voltage. For the biomedical application, the suitable coating thickness was at least 50 μ m. The high compaction of HA grains deposited at 30 V led to an order magnitude higher polarization resistance and ten times lower corrosion current density relative to the other specimens. The porous HA layer formed at 20 V, and the presence of cracks in the 40 V-coating led to a lower corrosion resistance relative to the 30-V coating. The 20 V- and 30 V-coatings remained intact and triggered the deposition of HA during immersion in simulated body fluid for 28 days, while the 40 V-coating dissolved into the solution. The optimum EPD voltage for depositing a stable HA coating with reasonable coating thickness and the best corrosion resistance was 30 V.

Wear due to sliding is an inevitable problem in many engineering applications. Protective surface coating is usually used to mitigate this problem. The development in this field is continuous and consistent. There are many types of coatings according to their compositions and the deposition methods. One of the coatings with the most promising properties, such as the hardness, is the Diamond-Like Carbon (DLC) coating. The tribological properties of this coating generated by Plasma-Assisted Chemical Vapor Deposition (PACVD) and applied on bearing steel 52100 ASTM are not available. In this study, the wear resistance of the DLC coating applied to bearing steel 52100 ASTM, was evaluated. The coating method employed was PACVD, which is regarded as one of the most distinctive coating techniques due to the unique tribological properties imparted to the coating. The pin-on-disc tribometer was used to examine the coefficient of friction and mass losses for samples of (steel disc against steel ball) and (DLC coated disc against DLC coated ball) under constant sliding velocity and constant sliding distance with four different loads (2, 5, 10 and 20 N) that results in maximum contact pressure below and higher than the maximum shear stress of the bearing steel. The wear coefficient was calculated using Archard’s equation based on the experimental results. It was found that the DLC coating may result in significant reduction, reaching 93.5%, in weight loss and 83% in COF at low contact pressure (less than the maximum shear stress). However, at high contact pressure (equals to or higher than the maximum shear stress) the weight loss and the COF for the DLC coating are higher than those of the bearing steel. This behavior indicates that the DLC coated pair may not be suitable at high loads. The wear coefficient is calculated for each testing condition and it is found to be affected by the applied load. The average wear coefficient for the DLC coating is provided which can be used with the Archared wear model to predict the wear rate within the range of the parameters used in this study.

The popularity of coated aluminum is gaining significant attention in numerous sectors in the industry due to its specific strength, corrosion resistance, and recyclability. However, because of friction, its lifetime reduces which causes a billion-dollar loss every year to our property. Many types of research are going around the world on how friction and wear loss can be reduced. This research focuses on the tribological study of coated aluminum in different conditions in the experiments, lubricant is used to find its efficiency, and coating materials have also its self-lubricating properties. Both reciprocating motion of pin and simultaneous motion of pin and disc applied. The combined effects of lubrication and motions are correlated with the reduction of tribological properties to a certain extent. The velocity of both pin and disc is also varied. Applied loads are changed in different experiments as well. Roughness analysis has also been done to observe the effect of lubricant, motion, and applied load on the surface of the specimens. SEM, EDX, XRD, and FTIR tests are also performed to check the morphology of the specimens. The experiments show that comparatively less friction and wear are in at lubricated, reciprocating, and less velocity of pin and disc conditions. Less coefficient of friction is observed at higher applied load but less wear is produced at lower applied load. The Machine Learning (ML) approach is used to detect patterns automatically in datasets and create models to predict future data or other outcomes.

The content of river cement and sand in our country is relatively high, and the surface of hydraulic machinery in hydropower stations is often subject to fatigue damage and erosion. This topic is mainly used to solve the problem of abrasion and corrosion of hydraulic machinery coatings. UV curable polyurethane acrylate (PUA) can be quickly solidified into film and directly coated on the surface of hydraulic machinery with excellent anti-wear, adhesion properties and low cost. In this work, a hyperbranched polyester synthesized by the stepwise reaction of trimethylolpropane (TMP) and dimethylolpropionic acid (DMPA) was as a ‘nucleus’, and the polyurethane prepolymer was obtained by grafting IPDI and PTMG (C Schüll, H Frey, 2013 Grafting of hyperbranched polymers: from unusual complex polymer topologies to multivalent surface functionalization, Polymer , 54, 5443–5455). The UV-curing hyperbranched polyester polyurethane acrylate (PUA-1) was prepared by capping with HEA (Xu, W, Wang, W, Hao, L, Zhao, W, Liu, H, Wang, X 2020 Effect of generation number on properties of fluoroalkyl‐terminated hyperbranched polyurethane latexs and its films. J. Appl. Polym. Sci. , e49215). Another UV-curing hyperbranched polyester polyurethane acrylate (PUA-2) was prepared as comparison by using TDI and PTMG as the main raw materials. Fourier Transform Infrared Spectrometer, ^1 H-nuclear magnetic resonance spectroscopy, Gel Permeation Chromatography, thermogravimetric analysis and dynamic thermomechanical analysis were used to characterize its structure and properties. The wear rate of the two hyperbranched polyesters measured by the underwater steel ball method is below 3%, The swelling rate of PUA-1 is between 250%–300%, and the swelling rate of PUA-2 is around 260%, indicating that PUA-2 has better solvent resistance than PUA-1, and the internal structure of the film is more dense. TG analysis showed that the thermal stability of the two materials was good.

Black phosphorus (BP) is a semiconductor material with excellent optical properties. To explore a more convenient method for preparation bulk BP and facilitate new applications of BP in engineering field, we used a single-zone tube furnace to fabricate bulk BP using tin and iodine as mineralisers. Further, a BP slurry with a uniform particle size was prepared by cutting the bulk BP in a solvent. BP coatings with different thicknesses were prepared, and their photo-thermal conversion properties were evaluated. The characterisation and test results showed that the BP coating was superimposed by BP flakes with an estimated plane size of ∼10 μ m. The infrared absorptivity of the BP coatings was 87.83%–92.48%. The results clearly indicated that the BP coatings exhibit photo-thermal conversion properties that can be exploited for various applications.

IN625 coatings applied by selective laser melting show high resistance at high temperatures but the creep behavior of such coatings is not well understood. In this paper, the microstructure and creep behavior of this coating applied to Rene80 alloy under different heat treatment conditions, were investigated by a small punch creep test. The results show that coating application in the form of solution heat treatment + coating + aging heat treatment leads the maximum creep life of about 135 h. In cast-coated specimens, liquation cracks due to incomplete solution of γ - γ ′ eutectic, γ ′ phase, Cr-Mo boride, and MC carbide in heat affected zone reduced the creep life by about 63 h. In these samples, unlike the heat treatment sample, which experienced inter-granular creep failure, the failure occurred exactly from the coating-substrate interface.

In braking systems, which consist of dry sliding lining against a pearlitic cast-iron disc, disc wear has a significant impact on the overall wear rate. In this work, dynamometer tests were conducted to find out the friction and wear behaviour of 20NiCrBSi-WC12Co cermet coating accumulated on the cast-iron disc by High velocity oxy-fuel spraying (HVOF) and the findings were compared with those of the uncoated disc. Braking tests of the coated and uncoated discs were performed on a full-scale brake dynamometer, which was designed in line with the SAE-J2430 Brake Effectiveness Procedure. Microhardness values, surface properties, scanning electron microscopy (SEM) analysis, energy dispersive x-ray (EDX) and x-ray diffraction (XRD) analysis of the discs were evaluated. As a result of these analyses, it was found out that cermet coating had a much higher microhardness and abrasion resistance with the combination of hard WC phase and mild Ni matrix compared to the conventional disc. The coated disc exhibited stable braking effectiveness with lower surface contact temperature. At the same time, this coating results in longer service life by reducing abrasive wear on the brake disc surface and a lower lining wear rate, reducing particle matter emissions to the environment.

The multi-walled carbon nanotubes (MWCNTs) have drawn great attention due to their exceptional mechanical, physical, thermal and electrical properties. The MWCNTs as the reinforcements significantly improved the properties of materials. However, the major challenges in composites containing CNTs are the poor wettability and poor interfacial bonding between matrix and CNTs. In this study, the used MWCNTs have a diameter of 8–10 nm and 1.5 μ m in length. MWCNTs are purified in HNO _3 : H _2 SO _4 , sensitized in Sn solution and activated in Pd solution at 90 °C, and coated with the Nickel and Cobalt elements using an electroless coating method. The holding time in the bath is 15, 30 and 60 min, and the bath concentration is also changed. The coatings are characterized by Scanning Electron Microscopy (SEM) equipped with electron dispersive spectrum (EDS), elemental mapping, x-ray diffraction (XRD), Raman spectroscopy, Transmission Electron Microscopy (TEM) and Fourier Transform Infrared (FTIR) spectrometer. The results showed that the Ni and Co coating layers are successfully formed on the surface of MWCNTs. The deposition rate is affected by the holding time and the bath concentration. The optimal results are obtained at the holding time of 60 min in the C concentration sample.

In this paper, near infrared (NIR) absorbing dye and fluorane dye (FD) was successfully encapsulated into microcapsules with NIR light responsive performance. The NIR responsive microcapsules are able to be utilized in information recording and anti-counterfeiting fields. Specifically, the factors effecting on synthesis of NIR responsive microcapsules were studied in detail. Microcapsules with an average particle size of 0.2 ∼ 0.5 μ m were prepared by adjusting the mass ratio of shell/core material, the viscosity of oil phase and the mass ratio of water/oil (W/O) phase. It was found that the preferred reaction condition was the feeding mass ratio of shell/core materiel at 1:2 and the W/O phase mass ratio of 2:1. When the feeding mass ratio of NIR absorbing dye and FD is 1/10, the NIR responsive microcapsules have the best coloration performance. Then the NIR responsive microcapsules were coated on aluminum substrate and scanned by 808 nm near-infrared laser, the image precision reached 20 μ m.

In this paper, WC-10Co4Cr coating was prepared on the surface of LC9 aluminum alloy by high velocity air-fule (HVAF) process. And a thermal deformation method was developed to enhance the coating properties. Experimental results show that, during the process of thermal deformation, the increase of temperature and deformation amount could improve the microhardness of coating surface. With temperature of 480 °C and deformation amount of 16% (0.8 mm), the microhardness reached the maximum value of 1349 HV0.3, which increased nearly 20% compared with that of specimen (1137 HV0.3) without compressive deformation. Besides, the strengthening effects of thermal deformation temperature and deformation amount on the bonding strength of coating were obvious. With deformation temperature of 450 °C and deformation amount of 8% (4 mm), the bonding strength reached the maximum critical load of 188 N, which was 17.5% higher than that of initial state.

Environmental issues such as particulate matter (PM) have become more and more serious because of their detrimental effects on human health. The development of an effective way to remove PM is in high demand. In this study, a graphene oxide (GO) membrane with a large specific surface area and a continuous pore structure was prepared via a coating method. The morphology, composition and structure of the GO membrane were characterized by scanning electron microscopy (SEM), an energy dispersive spectrometer (EDS), X-ray diffraction (XRD), FT-IR spectra, X-ray photoelectron spectra (XPS) and Raman spectroscopy. The removal efficiency for PM and the influence of pollutant concentration and wind velocity on the GO membrane were studied. As a result, when the wind velocity was 0.1 m s ^−1 , the PM _2.5 removal efficiency of the GO membrane exhibited the highest efficiency (99.46%) with a low pressure drop (7 Pa) and a high quality factor (QF) of 0.75 Pa ^−1 . The GO membrane maintained a high adsorption performance for a long time. The GO membrane removal efficiency was more significant when the import concentration was higher and the wind velocity was lower. In particular, SEM and EDS clearly revealed that the PM _2.5 was successfully captured by the GO membrane. The preparation of the GO membrane involves a simple and pollution-free process, which provides a new way to deal with air pollution.

Performance of stainless steel 17-4 PH as the orthodontic bracket can be improved by titanium dioxide (TiO _2 ) coating. In order to produce a good quality of the coating layer, the substrate had to be smooth and free from any contaminants. The electropolishing method was used to clean bracket’s surface from oxides substances which formed during sintering by reducing its surface roughness. Bath temperature and electropolishing time were varied to 30 °C and 70 °C, for 15 and 25 min, respectively. Those differences in electropolishing condition would affect the final surface’s roughness of the substrate. The atmosphere during PVD was controlled using oxygen and argon gases with the flowing rate ratio of 10:90 sccm and 50:50 sccm, and these gases would affect TiO _2 coating mechanical properties. The lowest roughness of 0.99 μ m and the highest roughness of 2.85 μ m were obtained after electropolishing. The coating quality on the substrates with different roughness was assessed through coating adhesivity on the substrate by micro Vickers qualitatively. The results showed that the TiO _2 coating layer on the substrate with a lower roughness had better adhesivity rather than on the substrate with higher roughness.

Development of nanostructured high velocity oxy-fuel (HVOF) coatings with low porosity, high strength and increased wear resistance is still in its infancy. Combining nanoparticles with conventional microscale powders are increasingly being investigated to use with feedstock materials for thermal spray processes. Accordingly, this work investigates the addition of nano-Al _2 O _3 particles on the microstructure and erosion wear of NiCrSiB HVOF coating in a stainless steel (AISI 304) substrate. Particle analysis of the NiCrSiB feedstock was conducted and the maximum allowable addition of Al _2 O _3 nanoparticles have been identified using the ‘mass mixture ratio’ model considering both the particle size and density. Consequently, two cases are considered and their performance analysed: a maximum allowable case of 1.4 wt%, followed by a 0.17 wt% addition of nano-Al _2 O _3 with NiCrSiB. Scanning Electron Microscope (SEM), Energy Dispersive Spectroscopy (EDS) and x-ray Diffraction (XRD) analysis were employed to inform the microstructure, material composition and phase spectrum of the resulting coatings. Subsequently, the nanostructured coating was exposed to both a pull-off adhesion strength test and hot air jet (450 °C) hard particle erosion to characterise its performance. It was found that the microhardness of the HVOF NiCrSiB coating improved from 576 HV _0.3 to 748 HV _0.3 with the addition of 1.4 wt% nano-Al _2 O _3 . Furthermore, the nanostructured coating also exhibited high erosion resistance at a 90° erodent impact angle. The increase in erosion wear resistance was due to the increase in the hardness as a result of the nano-Al _2 O _3 addition.

In this work, woven jute fibres were subjected to ecofriendly and chemical treatments (alkali, benzoylation and sodium bicarbonate) and PLA coating in order to improve the adhesion with epoxy thereby improvement in the performances of their composites. Treated and coated jute fibres reinforced epoxy composites were prepared by hand lay-up technique keeping constant 30 wt% of fibres content in the each composite. Mechanical properties (i.e. tensile, flexural and impact) and dynamic mechanical properties (i.e. storage modulus, loss modulus, damping and glass transition temperature) of prepared composites were studied. The outcomes from the experimental results suggested that benzoyl chloride treated and PLA coated jute composite exhibited the best performance as compared to other all the composites. There were 21%, 40.6% and 27.5% improvement in tensile strength, flexural strength and impact strength respectively for this composite as compared to that of untreated jute fibre reinforced composites. Moreover, storage and loss modulus of jute composites were also significantly enhanced by treatment and coating. The present developed composites can be used for medium strength application in the field of automobile, building and construction and packaging.