Search

Cr doped diamond-like carbon (DLC) coating was deposited on the carburized Ti6Al4V alloy (TA) by magnetron sputtering (MS). The physical and chemical characteristics of Cr doped DLC coating were obtained using scanning electron microscope, energy dispersive spectroscope, Raman spectrometer, X-ray photoelectron spectroscopy and Fourier transform infrared, and the mechanical property and adhesion force were analyzed by nanoindenter and scratch tester. The effects of carburizing treatment on the coefficient of friction (COF) and wear mechanism of Cr doped DLC coatings were investigated on a ball-on-disk tribometer. The results show that the adhesion force and mechanical property of Cr doped DLC coating deposited on the carburized TA are higher than those deposited on the original TA. The average coefficients of friction (COFs) of Cr doped DLC coatings deposited on the original and carburized TAs under the dry-friction condition are 0.157 and 0.143, respectively, showing that the carburizing treatment has the obvious effect of friction reduction for the Cr doped DLC coating. The wear mechanism of Cr doped DLC coating deposited on the carburized TA is combined action of abrasive wear and adhesive wear, which are contributed to the enhancement of mechanical property of Cr doped DLC coating by carburization treatment. Furthermore, the average COFs of Cr doped DLC coatings deposited on the original and carburized TAs under the oil-lubrication condition are 0.152 and 0.131, respectively, which are superior to those under the dry-fiction condition. The carburizing treatment promotes the formation of self-repairing carbonyl of Cr doped DLC coating, and the oil-wet characteristic of Cr doped DLC coating with the aromatic aldehyde of C O as the functional group plays the main role of friction reduction. [ABSTRACT FROM AUTHOR]

Different types of Mo coatings were prepared on the surface of a copper alloy via laser cladding technology in this study to address the problem of low hardness of copper alloy current-carrying friction subsets. Meanwhile, the problems of high reflectivity of copper alloy materials to infrared laser light and mutual insolubility of Cu and Mo were solved by introducing an intermediate layer structure, and the coating process was optimized to obtain a coating with excellent formation. The microstructure, hardness, and interfacial shear bond strength of coatings were tested. Results showed that the Mo coating prepared using a plasma-spheroidized powder had a lower dilution rate and finer and tighter grain growth compared with the Mo coating prepared by crushing agglomerated powder. The coating phase mainly consisted of Mo, Ni 3 Mo, MoO 2 , and Cu 0.81 Ni 0.19. The unfused particles present in the plasma-spheroidized powder coating acted as a second hard reinforcing phase, which could significantly increase the hardness of the coating. Three kinds of coatings exhibited strong bond strength, and coatings prepared from different powders fractured in diverse ways. In sum, the plasma-spheroidized Mo coating prepared using the three-way powder feeding method not only had good formation but also possessed the most excellent mechanical properties. [Display omitted] • High-quality molybdenum coating was prepared by laser cladding on copper alloy. • The effects of different feeding methods and powders on the coating were studied. • A method to measure the shear bond strength of the coating interface was designed. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • In-plane compressive behaviors of graphene-coated honeycombs are first investigated. • Mechanical properties can be significantly reinforced by graphene-coating. • A modified Gibson-Ashby model is developed. Abstract The in-plane compressive behaviors of aluminum (Al) nano-honeycombs (ANHCs) and graphene-coated ANHCs (GANHCs) are investigated by using the molecular dynamics (MD) and theoretical methods. The dependences of their mechanical properties on the crystalline direction and the relative mass density are examined. Our MD simulations show that the tensile strength, tensile energy absorption, in-plane elastic modulus and compressive strength of ANHCs can be significantly reinforced by graphene-coating, whereas the compressive energy absorption capacity of GANHCs until densification is lower than that of ANHCs. A modified Gibson-Ashby model is developed to estimate the in-plane Young's modulus and compressive strength of GANHCs, which shows a good agreement with the MD results. [ABSTRACT FROM AUTHOR]

We have undertaken a systematic study of the effect of Fe 3+ doping on the crystal structure, magnetic, electrical transport and magnetoresistance properties of La 0.67 Sr 0.33 Mn 1−x Fe x O 3 (0≤x≤0.15) polycrystalline coatings prepared by the sol-gel and screen printing method. The X-ray powder diffraction and Reitveld refinement results indicate that the partial substitution of Mn 3+ ions by Fe 3+ ions does not introduce noticeable lattice distortion and structural transition. Magnetic measurements show that Fe 3+ ions significantly lowers the Curie temperature, and the magnetization at low temperatures first increases and then decreases with further Fe 3+ doping. The Fe 3+ doped manganites (x>0.05) are semiconductors with high resistivity, as the consequence of low number of available hopping sites of charge carriers. The most stimulating result obtained is that the magnetoresistance property is greatly enhanced around the percolation threshold (x=0.05) of Fe 3+ ions in this system and the percolative phase separation is responsible for the anomalous behavior. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) nanoarchitectures can improve the performance of electrical energy storage systems. In this paper, combining an improved solvothermal method with calcination treatment, thin layer carbon-coated MoO 2 nanoparticles with the size of 20-50 nm were uniformly dispersed in 3D graphene aerogel (abbreviated as MoO 2 @C-Gas). The hybrid materials were subsequently used as a new-structured anode for lithium-ion batteries (LIBs), yielding high reversible capacity with excellent stable cyclability. We found that the battery with MoO 2 @C-Gas electrode could deliver a discharge capacity of 1515 mAh g −1 at a current density of 80 mA g −1 in the first cycle, and remain at 1113 mAh g −1 over 60 cycles. Furthermore, with the increase of current density, it also exhibited a high rate of capability and good cycling performance. The outstanding performance of the hybrid electrode were attributed to the unique 3D aerogel morphology and the close combination between C@MoO 2 and graphene layers, which could significantly improve the anode's electronic conductivity. [ABSTRACT FROM AUTHOR]

To improve the high-temperature ablation resistance of Nb alloys, multiphase-multilayer ceramic coatings were prepared using a novel strategy combining halide activated pack cementation (HAPC) and liquid plasma-assisted particle deposition and sintering (LPDS) methods. The MoSi 2 , Yb 2 O 3 , and ZrC particles were deposited individually or co-deposited on the NbSi 2 bottom layer to obtain NbSi 2 /SiO 2 –Nb 2 O 5 /MoSi 2 (Mo), NbSi 2 /SiO 2 –Nb 2 O 5 /MoSi 2 -Yb 2 O 3 –SiO 2 (MoYb), NbSi 2 /SiO 2 –Nb 2 O 5 /MoSi 2 -Yb 2 O 3 –ZrO 2 –ZrC (MoYbZr) multilayer ceramic coatings, respectively. Results showed that all three coatings remained intact after propane ablation (1500 °C), exhibiting excellent ablation resistance. For the harsher oxyacetylene ablation environments with higher temperatures (1800 °C), Mo coating suffered from long cracks, bubbling, and localized spalling and MoYb coating sprouted massive cracks without spalling. The oxide scale integrity of the MoYbZr coating was well maintained without cracks, exhibiting excellent resistance to oxyacetylene ablation attributed to the incorporation of Yb 2 O 3 and ZrC. The mass and linear ablation rates of MoYbZr coating were only 0.137 mg/s and 0.196 μm/s after oxyacetylene ablation, which were 25.14 % and 49.61 % lower than that of MoYb coating, and 88.01 % and 75.37 % lower than that of the Mo coating, respectively. The Yb 2 O 3 strengthened the Si–O bonding in the SiO 2 network and increased the viscosity of the SiO 2 scale, thus enhancing the self-healing ability of the oxide scale and slowing down the evaporation of SiO 2. The oxidation products (ZrO 2 with SiO 2) from MoSi 2 and ZrC further reacted to produce ZrSiO 4 , which can inhibit microcrack creation and extension. Micropores in the Zr–Si–O oxide scale mitigated thermal stresses, inhibited crack initiation and extension. The Yb 2 O 3 , Yb 2 SiO 5 , and ZrSiO 4 embedded in the SiO 2 –ZrO 2 scale acted as pinning effects, enhancing the high-temperature structural stability, thereby improving the ablation resistance of the MoYbZr coatings. [ABSTRACT FROM AUTHOR]

● Multifunctional zinc-based acrylate resins for marine antifouling and EM wave absorption were prepared and researched. ● The resins effectively inhibited the growth and adhesion of bacteria (>90%) and algae (optimal: 92.5%). ● The ARZn-x without antifoulants can maintain their antifouling properties for more than 4 months in marine. ● RL min was -40.18 dB at 1.5 mm and 30.55 GHz, and full absorption was achieved in the range of 1.0 ~ 5.5 mm at 18-40 GHz. [Display omitted] Here, we report on the marine antifouling performance and electromagnetic wave absorption (EMWA) properties of multifunctional zinc-based acrylate resins (ARZn-x). Their controlled hydrolysis with varying contents of carboxylic acid groups and ZnO led to formation of new surfaces that contributed to excellent antibacterial activity (>90%) and reductions in algal adhesion (optimal: 92.5%). Marine field tests demonstrated ideal antifouling performance during immersion in seawater for 4 months, and the coatings inhibited the adhesion and growth of biofouling species in marine. Furthermore, the ARZn-x resin coatings exhibited remarkable EMWA performance, with an RL min of − 40.18 dB at 1.5 mm and 30.55 GHz, and full absorption of frequencies ranging from 18 to 40 GHz was achieved with thicknesses ranging from 1.0 to 5.5 mm. These resins provide new approaches to the development of multifunctional materials demonstrating marine antifouling performance and EMWA properties. [ABSTRACT FROM AUTHOR]

The present paper proposes a new method for the preparation of nanofiber coated hybrid yarns. This method requires designing a multi-nozzle jet electrospinning device based on the principle of bubble bursts forming multiple jets to significantly increase the production of nanofibers and to obtain nanofiber bundles based on the principle of conjugated electrospinning. The design allows continuous nanofiber coated hybrid yarns to be obtained through the twisting of a three-dimensional (3D) high-velocity rotational airflow. The mechanism for the formation and bundling of nanofibers was studied, and the airflow field within the nozzle-twisting device was numerically simulated. The airflow forms a 3D high-velocity rotational airflow after it is injected into the twisting chamber from the jet orifice, and takes on the characteristics of a vortex flow. Under the effect of this vortex flow, the nanofibers are evenly twisted around the filament yarn and coated onto its surface, with the fibers oriented in the same direction as the twist direction. This airflow twisting process significantly improves the mechanical properties of the nanofiber hybrid yarn. [ABSTRACT FROM AUTHOR]

Gradient environmental barrier coatings (EBCs) were fabricated via atmospheric plasma spraying to deposit Yb 2 Si 2 O 7 -Yb 2 SiO 5 onto a laser-sculpted SiC substrate, with varying mass ratios. Experimental results reveal that the gradient coating exhibited remarkable integrity, showing no signs of cracking even after exposure to 90% H 2 O-10% O 2 (g) water vapor corrosion at 1300 ℃ for 100 h. Besides, the thickness of the thermally grown oxide (TGO) layer was minimal (18.53 ± 1.08 μm) compared to 75Yb 2 Si 2 O 7 -25Yb 2 SiO 5 single layer EBCs (24.93 ± 1.62 μm) with similar integrity under water vapor environment for 100 h. The superior performance of the gradient coating against water vapor corrosion can be attributed to the outmost layer containing more Yb 2 SiO 5 with excellent vapor corrosion resistance, while the innermost layer primarily comprises Yb 2 Si 2 O 7 , providing significant damage resistance and resilience to thermal shock. These favorable attributes make the gradient coating a promising candidate for EBC application in aerospace. [ABSTRACT FROM AUTHOR]

Abstract: In order to better understand the adsorption mechanism of chitosan-coated magnetic nanoparticles modified with α-ketoglutaric acid (α-KA-CCMNPs), the removal of Cu2+ by α-KA-CCMNPs from aqueous solution was investigated in a batch system at 18, 35 and 50°C. Different experimental approaches were applied to show mechanistic aspects, such as adsorption isotherms, kinetics and thermodynamics studies. Adsorption equilibrium studies showed that Cu2+ adsorption followed Langmuir model. The kinetics of the interactions was best described by pseudo-second-order mechanism. The thermodynamic parameters (ΔG°, ΔH° and ΔS°) analysis predicted that the adsorption process was strongly dependent on temperature of medium, and spontaneous and endothermic process. The XPS combined with FT-IR spectra revealed that N atom of –NH– group and O atom of carboxyl group in α-KA-CCMNPs coordinated with Cu2+. Experimental results from this study provide data that would be required if this heavy metal adsorption system was to be “scaled up” for industrial application. [Copyright &y& Elsevier]

Abstract: Chemical treatment was used to modify the surface of microarc oxidized (MAO) coating containing Ca and P. And the chemically treated MAO (C-MAO) coating was further heat-treated at 400–800°C. The average roughness of the MAO and C-MAO coatings is about 250nm; further heat treatment improved the roughness of the C-MAO coating. The chemical and heat treatment enhanced the wetting ability of the MAO coating. During SBF immersion, amorphous Ca- and P-containing precipitate (Ca–P) appeared firstly, eventually transforming to crystalline apatites. At the same time, the apatite firstly formed at the concave region on the surface, and then spreads on the whole surface. The induced biomimetic apatite possessed a porous structure on two-scales of micron and nanometer levels. In the interlayer and outlayer of the C-MAO coating, the elements of Ca, P and Ti showed a gradient distribution. In the apatite layer, Ti disappeared basically, and the concentrations of Ca and P did not change obviously. In this work, continuous MG63 cell layer was observed on the surface of the C-MAO coating, which can provide good environment for the cell proliferation. [Copyright &y& Elsevier]

Abstract: The structure, cell response and induction capability for apatite formation of the microarc oxidized (MAO) coating before and after chemical-treatment and subsequent dehydration at 400°C were investigated. The surfaces of the chemically treated MAO (C-MAO) coatings before and after dehydration showed ribbon-like amorphous phase mainly containing Na, Ti and O elements with network morphology. Subsequent dehydration has no pronounced effect on the surface roughness, wetting ability, surface constituents and chemical state of Ti, Na and O of the C-MAO coating. The outer layers of the C-MAO coating before and after dehydration showed Na, Ti and O elements with uniform distributions along the surface depth. Chemical-treatment improves the apatite-forming ability of the MAO coating; however, subsequent dehydration greatly lowers that of the C-MAO coating, since it changed the ability of C-MAO coating to release Na+ ions, which is unfavorable for the formation of Ti-OH groups. The apatite formed on the two coatings contained HPO4 2− and CO3 2− ions. In addition, the dehydration of the C-MAO coating seemed to be unsuitable for the cell proliferation on its surface. [Copyright &y& Elsevier]

Abstract: TiO2-based coating containing amorphous calcium phosphate (CaP) was prepared on titanium alloy by microarc oxidation (MAO). The increase in the EDTA–2Na concentration was unfavorable for the crystallization of TiO2. After heat treatment, the amorphous CaP was crystallized. The thickness of the MAO coatings did not change when heat-treated at 400, 600 and 700°C; while it increased slightly after heat treatment at 800°C due to the crystallization of amorphous CaP and growth of TiO2. No apparent discontinuity between the coatings and substrates was observed at various heat-treatment temperatures, indicating the MAO coatings with good interfacial bonding to the substrate. The heat treatment did not alter the chemical composition of the MAO coating and the chemical states of Ti, Ca and P elements. However, it increased the roughness (Ra) of the MAO coating and improved the wetting ability of the MAO coating. In this work, preliminary investigation of the MG63 cell proliferation on the surface of the MAO and heat-treated MAO coatings was conducted. The MAO coating surface with about Ra=220nm may be suitable for the MG63 cell adhesion and proliferation. The increased roughness of the heat-treated MAO coatings may result in a decrease in the ability for cell adhesion and proliferation. [Copyright &y& Elsevier]

Abstract: Biomimetic apatite was formed on a microarc oxidized (MAO) anatase-based coating containing Ca and P in a simulated body fluid (SBF). At the process of the SBF immersion (0–96h), the Ca and P of the MAO coating dissolve into the SBF, increasing the supersaturation degree near the surface of the MAO coating, which could promote the formation and growth of apatite. After SBF immersion for 7 days, the surface of the MAO coating was modified slightly. The entire surface immersed for 14 days was covered by an apatite coating. The apatite possesses carbonated structure, controllable crystallinity and pore networks. The results indicate that the MAO coating formed in an electrolyte containing phosphate and EDTA–Ca chelate complex possesses good apatite-forming ability. [Copyright &y& Elsevier]

Abstract: Microarc oxidized (MAO) TiO2-based coatings containing Ca and P on titanium alloy were formed in electrolytes containing nano-hydroxyapatite (nano-HA), calcium and phosphate salts. The effects of HA concentration on the thickness, micropore size and number of the MAO coatings were not pronounced. However, the surfaces of the MAO coatings become rough and the crystallinity of anatase increases with increasing HA concentration. In addition, the Ca and P concentrations on the surfaces of the MAO coatings decrease, since the chelate complex of CaY2− (Y=[2(OOC)NCH2CH2N(COO)2]4−) and phosphate ions are hindered to be incorporated into the MAO coatings by HA. In vitro experiments indicate that the apatite-forming abilities of the MAO coatings decrease with increasing HA concentration. Furthermore, with increasing HA concentration, the solubility of Ca and P of the MAO coatings decreases, which could lower the supersaturation of the SBF with respect to apatite near the surfaces of the MAO coatings, further leading to the decreased apatite-forming ability. The results indicate that the HA addition in the electrolytes has an important effect on the structure and in vitro bioactivity of the MAO coatings. [Copyright &y& Elsevier]

A Cr–DLC coating was deposited on nitrided Ti6Al4V alloy (TA) by magnetron sputtering (MS) using CrN as an interlayer. The characterization processes of obtained coating were performed on scanning electron microscopy (SEM), energy dispersive spectroscope (EDS), X-ray diffraction (XRD), Raman spectroscopy and transmission electron microscopy (TEM), and the hardness and bonding strength were also measured by nanoindentation and scratch testers. The electrochemical corrosion performances of TA, nitrided TA and Cr–DLC coating in 3.5% NaCl solution were systematically investigated using an electrochemical workstation, and the corrosion mechanisms were discussed in detail. The results show that the amorphous carbon atoms are uniformly distributed on the in–situ grown Cr–DLC coating, and the CrN interlayer plays an important connection role between the Cr–DLC coating and the nitrided TA. After the electrochemical corrosion test, the O mass fraction on the Cr–DLC coating is lower than those on the TA and nitrided TA, and the nitrided TA is effectively protected from electrochemical corrosion. The Cr–DLC coating presents the smallest corrosion current density i corr and the largest polarization resistance R p among the TA, nitrided TA and Cr–DLC coating, showing the outstanding electrochemical corrosion resistance. Meanwhile, the capacitive arc radius, impedance | Z | and phase angle of Cr–DLC coating are also the maximum, exhibiting that its electrochemical corrosion resistance is higher than the TA and nitrided TA. [Display omitted] • Plasma nitriding is used for the TA to overcome the property mismatch with the Cr–DLC coating. • The Cr–DLC coating is deposited on plasma nitrided TA by employing CrN interlayer. • The Cr–DLC coating on the nitrided TA presents the excellent corrosion resistance. • The decrease of interface capacitance C c improves the corrosion resistance of Cr–DLC coating. [ABSTRACT FROM AUTHOR]

Dissipation of heat efficiently from a hot object via radiation while minimizing the inward heat conduction is the key requirement of radiation thermal protection. In this study, a Ca‐Cr co‐doped Y3NbO7 coating with lamellar porous structure is fabricated, which shows an ultra‐low thermal conductivity (<0.7 W m−1 K−1) and near‐unity emissivity (>0.9) across a broad wavelength range of ≈1–24 µm. This record high emissivity to thermal conductivity ratio (≈1.3) is experimentally and theoretically revealed from a multi‐scale perspective. The diffusoin‐mediated thermal conduction feature of niobates combined with lamellar porous structure of the coating reduces its thermal conductivity to an impressive 0.5 W m−1 K−1 at 25 °C, surpassing the theoretical amorphous limitation of 0.72 W m−1 K−1. Experiments and FDTD calculation results demonstrate that the intrinsic emissivity dips at shallow extinction wavelengths (1 and 8 µm) and strong phonon‐polariton resonances wavelengths (>13 µm) can be effectively compensated by the multiple scattering/absorption and gradual modulation of conical shape/effective refractive index induced by surface micro‐protrusion structures, respectively. Furthermore, the coating exhibits robust mechanical and thermal stability with a high bonding strength (18.3 MPa) and thermal expansion coefficient (≈11 × 10−6 K−1 at 1200 °C) comparable to YSZ, showing great potential in the radiation thermal protection field. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs) for temperature regulation have been proven to be promising for passive radiative heat dissipation. However, it remains a considerable challenge to assemble a CNTs layer in situ while simultaneously achieving horizontal electrical conductivity, vertical electrical insulation, and radiative heat dissipation. Herein, plasma pretreatment was employed to functionalize CNTs in an aqueous solution, thus improving their dispersion capability. Subsequently, a liquid-plasma-assisted particle deposition and sintering (LPDS) technology was proposed to prepare a dual-layer coating with an Al 2 O 3 -P 2 O 5 -SiO 2 -In 2 O 3 glass system embedded with crystalline indium tin oxide (ITO) as the porous bottom layer and ITO-CNTs as the top layer on the aluminum alloy surface. The results show that plasma pretreatment significantly increases the deposition amount of ITO nanoparticles and functionalized CNTs on the coating surface, resulting in the transition from a single-layer composite coating to a dual-layer coating. The surface micro-/nano hierarchical structure favors strong absorptance/emittance, exhibiting a high infrared emittance of 0.94 (3-20 μm) and high solar absorptance of 0.92 (0.2-2.5 μm). Meanwhile, the surface balance temperature of the dual-layer coating is about 392 K, which is 146 K lower than that of aluminum alloy. Furthermore, the top conductive ITO-CNTs layer contributes to the low surface resistivity of 3.46×102 Ω, while the glass phase of the bottom layer ensures vertical electrical insulation with a volume resistance of 4.20×107 Ω. The process provides a new path for preparing thermal control coatings with anti-static function. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, the LPDS-coating charactered by the volcanic-like surface with micropores is synthetized on Nb alloys through halide activated pack cementation (HAPC) combined with a liquid-plasma-assisted particle deposition and sintering (LPDS) technology. Results show that the mass gain of NbSi 2 /Nb 2 O 5 -SiO 2 /HfC-HfO 2 coated sample (6.38 mg/cm2) is only 46% compared to NbSi 2 coated sample (13.8 mg/cm2) and holds the lowest oxidation rate (0.367 mg2·cm−4·h−1) during the isothermal oxidation process after 100 h at 1200°C. Besides, this multilayer coating also exhibits an enhanced oxyacetylene ablation resistance (the lowest mass ablation rate of −0.106 mg/s and a linear ablation rate of −0.333 μm/s) compared with NbSi 2 coating and NbSi 2 /Nb 2 O 5 -SiO 2 coating. Such superior high-temperature oxidation/oxyacetylene ablation resistance of multilayer coating are mainly ascribed to HfC oxygen-consuming phase combined with the oxide scale's high-temperature stability provided by the HfSiO 4 -HfO 2 -SiO 2 skeleton. • NbSi 2 /Nb 2 O 5 -SiO 2 /HfC-HfO 2 multilayer coating is designed to enhance the high-temperature oxidation/ablation resistance. • HfC particle is introduced into multilayer coating by a simple LPDS technique. • A dense oxygen diffusion barrier layer is formed by introducing HfC particle for retarding the oxide rate of coating. • HfSiO 4 -SiO 2 skeleton processes a large stress damage tolerance, exhibiting a strong high-temperature stability. [ABSTRACT FROM AUTHOR]

The emergence of single crystal nickel-rich cathode materials preparation offsets the poor cycle performance of traditional ternary cathode materials, with an efficient enhancement of the energy density. Despite all this, the stability of single crystal Ni-rich materials is still hard to fully meet the commercial requirements. We select La and Co elements for co-coating single crystal cathode materials by an efficient method, La 2 Li 0.5 Co 0.5 O 4 coating layer with a thickness of about 5 nm is successfully formed on the single crystal nickel-rich samples. The coating layer effectively protect nickel-rich materials from the corrosion of electrolyte and retain a high Li-ion conductivity during charge/discharge processes. Besides, the part of residual lithium reacts with La and Co, forming La 2 Li 0.5 Co 0.5 O 4 coating layer, and decorates the materials surface. Eventually, the single crystal NCM811 with 2 wt% La 2 Li 0.5 Co 0.5 O 4 coating affords a terrific cyclic stability after 200 cycles. The capacity retention is 81.15% at 1 C with voltage range of 2.8–4.3 V, obtaining an 18% performance improvement compare with that of pristine material. Moreover, the rate performance and first charge/discharge efficiency are improved to a certain extent. The co-coating process with La and Co is a competitive approach to modify the performance of single crystal nickel-rich cathode materials and contribute to the commercial application of the NCM811 materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • Integration of thermal regulation and friction reduction functionalities in a nanocomposite coating for electronic packaging. • Inspired by Camponotus ants, coatings with hierarchical micro/nanostructures were developed for efficient radiative cooling and friction reduction. • Utilization of PEO for rapid and eco-friendly coating fabrication, offering potential for large-scale production of multifunctional radiative cooling materials. • Achieving high infrared emissivity and substantial reduction in LED temperature (21.5 °C), alongside outstanding friction reduction performance. To date, the demand for electronic packaging materials with combined highly efficient heat dissipation and low friction attracts intensive attention. There have been hardly any reports of coatings that provide simultaneous radiative cooling, thermal conduction, and friction reduction properties. In the present work, a novel biomimetic nanocomposite coating is gown on the titanium alloy substrate. The coating consists of a TiO 2 ceramic layer adorned with hemispherical protrusions and is enriched with hexagonal boron nitride (h-BN) flakes and CNTs on the surface. The optimal microstructures are determined through Finite Difference Time Domain (FDTD) simulation calculations and then prepared using plasma electrolytic oxidation (PEO). The results show that the hierarchical micro/nanostructures enable the coating to achieve an infrared emissivity of ∼ 0.9 within the 3–14 wavelength range, whilst h-BN and CNTs contribute to the thermal conduction of the TiO 2 -BN/CNTs ceramic coating. The advantage of the biomimetic nanocomposite coating over the bare titanium alloy is that the coating facilitates a reduction in the equilibrium temperature of a 5 W LED by around 21.5 °C. In addition, the coating exhibits outstanding friction reduction performance with a low friction coefficient (COF) of 0.15 over a sliding distance of 94.2 m, benefitted from the lubrication effect of h-BN and CNT. This work introduces a straightforward and environmentally friendly approach to fabricating bifunctional thermal regulation materials. [ABSTRACT FROM AUTHOR]

Black carbon (BC), particularly internally mixed and aged BC, exerts a significant influence on the environment and climate. Black carbon coated by non-absorbing materials shows an enhancement of BC absorption, whereas absorptive coatings on BC can reduce the BC absorption enhancement. In this paper we use the multiple-sphere T-matrix method to accurately model the influence of the absorbing volume fraction of absorbing coatings on the reduction of the absorption enhancement of partially coated BC. The reduction of the absorption enhancement due to the absorbing coating exhibited a strong sensitivity to the absorbing volume fraction of the coating, and no reduction of BC absorption enhancement was seen for BC particles with non-absorbing coatings. We found that coatings with higher absorbing volume fraction, greater coated volume fraction of BC, higher shell/core ratio, and larger coated BC particle size caused stronger reductions of the BC absorption enhancement, whereas the impact of the BC's fractal dimension was negligible. Moreover, the sensitivity of the reduction of absorption enhancement resulting from the ratio of the absorbing coating shell to the BC core increased for coatings with higher absorbing volume fractions, higher coated volume fractions of BC, or larger particle sizes, although this effect was weaker than the sensitivities to size distribution, absorbing volume fraction of coating, and coated volume fraction of BC. Reductions in the absorption enhancements resulting from the absorbing coating for partially coated BC with various size distributions typically varied in the range of 0.0–0.24 for thin coatings with shell/core ratio of 1.5 and between 0.0 and 0.43 for thick coatings with shell/core ratio of 2.7. In addition, we propose an empirical formula relating the reduction of BC absorption enhancement to the absorbing volume fraction of the coating, which could inform a quantitative understanding and further applications. Our study indicates the significance of the absorbing volume fraction of coatings on the absorption properties of BC. [ABSTRACT FROM AUTHOR]

This present work explores initially the feasibility of producing in-situ surface oxidized coating on porous silicon nitride (Si 3 N 4) ceramics. Theoretical prediction identifies the applied conditions of self-sealing strategy and oxidation time required to form dense coating. Experimentally, the porous Si 3 N 4 ceramics with different pore structures were selected to fabricate in-situ oxidized coatings. The phase compositions, microstructures and mechanical properties of the porous Si 3 N 4 ceramics were investigated before and after oxidation. The results show that flat and dense coatings are prevailed in all samples, which consist of amorphous SiO 2 and its precipitates besides dominant Si 3 N 4 phase. The strengthened substrate and strengthening effect of coating are the essential mechanisms associated with the improved mechanical properties. Self-sealing method seems to offer an inexpensive and efficient route to prepare coating on porous Si 3 N 4 ceramics. [ABSTRACT FROM AUTHOR]

Heat dissipation material with programmable anisotropic property is very challenging, yet can realize the controllable thermal diffusion for heating device. In this work, anisotropic Si3N4 ceramics with oriented grains are prepared to adjust and improve the mechanical and thermal properties under the applied stress field by rolling film forming technology. Through the design of the sintering aids in the process of liquid‐phase sintering, the orientation degree of the Si3N4 grains is programmable as well as the mechanical property and the thermal property of the Si3N4 ceramics. As a consequence, the obtained Si3N4 ceramics show significant anisotropy in mechanical properties and thermal conductivity. The typical fracture toughness and thermal conductivity along the grain orientation direction are 10.6 MPa⋅m1/2 and 45.45 W/(m⋅K) while they are 4.5 MPa⋅m1/2 and 66.42 W/(m⋅K) in the direction perpendicular to the oriented grain, respectively. This grain orientation method paves the way for the thermal performance design and the production of programmable heat dissipation material. [ABSTRACT FROM AUTHOR]

Abstract: To form bioactive microarc oxidized (MAO) coatings on titanium, the exploration for introducing various elements into the TiO2-based MAO coatings has been continually noticed. In this work, novel MAO coatings containing Si, Ca and Na (SCN) elements were prepared on titanium. The elemental composition, mechanical properties, corrosion resistance and apatite-forming ability of TiO2-based MAO coatings containing SCN were investigated. The surface hardness, elastic modulus, elastic recovery and corrosion resistance of the MAO coatings containing SCN were improved obviously by increasing the applied voltages. And the effect of applied voltage on the wetting ability of MAO coatings containing SCN is not significant. The current results indicated that the MAO coating containing SCN possesses good apatite-forming ability. The apatite-bonding structure is highly dependent on the chemical reactivity of the materials surface in simulated body fluid. [Copyright &y& Elsevier]

Abstract: Microarc oxidized (MAO) coatings containing Si, Ca and Na elements (SCN) were prepared on titanium. The morphology, phase composition and elemental concentrations of the MAO coating surfaces highly depended on the applied voltages. The MAO coatings containing SCN show an atomic concentration gradient along the coating depth. The chemical states of Ti2+, Ti4+, Ca2+, Si2+ and O2− were observed in all the MAO coatings. The novel cefazolin sodium/chitosan composite films were deposited on the MAO coatings for application in therapy of the inflammation resulting from implanting. The increases of depositing times and cefazolin sodium concentration could increase the accumulative release concentration of cefazolin sodium, and could improve the sustaining-release ability of drug film. Also, the addition of chitosan could improve the sustaining-release ability of drug film, indicated that chitosan is a promising delivery carrier for cefazolin sodium. [Copyright &y& Elsevier]

A magnetic dye affinity adsorbent was prepared by coating the magnetic nanoparticles (MNPs) with chitosan (CS), which significantly decreased the non-specifically adsorbing protein. Following this, Reactive Red 120 (Red 120), chosen as a dye affinity ligand, was immobilized onto the chitosan-coated magnetic nanoparticles (CS-MNPs) to obtain the specific protein adsorption. The prepared functionalized adsorbents were characterized by SEM, FTIR, XRD, VSM, and elementary analysis. Factors influencing the adsorption of bromelain, e.g., initial protein concentration, medium pH, and ionic strength were investigated. The adsorption isotherm fitted the Freundlich model well. The regeneration experiment showed that the affinity superparamagnetic particles were suitable for bromelain adsorption. [ABSTRACT FROM AUTHOR]

Abstract: Sphene/titania composite coatings were fabricated on titanium by a hybrid technique of microarc oxidation (MAO) and heat treatment. The high-applied voltages promote the formation of sphene in the MAO coatings after heat-treatment. Heat treatment could change the surface morphology of the MAO coatings such as roughness, macropores size and density and the thickness of the MAO coatings. Increasing the heat-treatment temperature decreased the atomic concentration ratios of Ti/Si and Ti/Ca of the MAO coatings. The chemical states of Ti4+, Ca2+, Si2+ and O2− were observed on all the coatings. Additionally, Ti2+ was detected in the MAO and heat-treated MAO coatings at 600 and 700°C. The heat-treatment has obvious effect on the chemical states of Si, Ti and O elements due to the formation of sphene and oxidation of TiO phase of the MAO coating, but did not affect that of Ca. In the heat-treated MAO coatings at 800°C (MAO-H8), the titanium surface shows a MAO top layer and oxidized interior layer. A concentration gradient in components in the MAO layer of the MAO-H8 coating was formed. [ABSTRACT FROM AUTHOR]

Abstract: Mesoporous titania coatings (MTCs) with a pore size of 4.75nm were prepared on Ti6Al4V substrates by a sol–gel process, and then irradiated with UV light at room temperature for 2h. The effects of mesoporous structure and UV irradiation on the in vitro bioactivity were investigated. Simulated body fluid (SBF) tests reveal that the MTCs exhibit a high apatite-forming ability, which may be attributed to the following reasons: (i) the BET surface area of the MTCs is ∼190m2/g, resulting in a greater density of Ti–OH groups than that without mesoporous structure; (ii) theoretical analysis reveals that the mesoporous structure can improve the driving force and nucleation rate of apatite precipitation in SBF. As compared with the MTCs, the UV-irradiated coatings do not exhibit any change in phase components and surface morphologies. However, the apatite-forming ability is higher on the UV irradiation coatings than on the MTCs because of the increase of Ti–OH groups and the improvement of wettability after UV irradiation. In addition, the investigation of the MG63 cell proliferation on the both substrates was performed. The results indicate that the MTCs before and after UV irradiation exhibit a good biocompatibility and are fit for the MG63 cell proliferation. [Copyright &y& Elsevier]

PEO coatings on SiC p /Al composites generated in phosphate, silicate, and aluminate electrolytes are compared to reveal the effect of the electrolyte composition on the coating formation process and coating performance. The observed significant disparity in spark discharge highlights the considerable influence of the electrolyte composition on the coating growth of the SiC p /Al composite surface. Within the plasma discharge zone, the local temperature ranges are approximately 6000 K–12000 K for silicate electrolyte, 6000 K–10000 K for aluminate electrolyte, and 4000 K–5000 K for phosphate electrolyte. Regarding spark discharge intensity, silicate electrolyte exhibits the highest discharge, followed by aluminate electrolyte, while phosphate electrolyte displays the weakest discharge. Consequently, the resulting surface porosity reaches up to 9.1% for PEO-Si coating, 6.5% for PEO-Al coating, and 4.9% for PEO-P coating. Phase analysis reveals that coatings generated in aluminate and silicate electrolytes tend to consist of crystalline alumina and mullite, whereas the coating formed in phosphate electrolyte predominantly contains amorphous phases and some crystalline mullite. The electrochemical tests demonstrate that the anti-corrosive ability of the coatings follows the order of PEO-Al > PEO-Si > PEO-P. The electrical insulation protection performance of the three coatings is PEO-Al > PEO-Si > PEO-P under comprehensive consideration. • PEO coatings are formed on the SiC p /Al composite in phosphate, silicate, and aluminate electrolytes, respectively. • The spark discharge intensity follows the order of silicate electrolyte > aluminate electrolyte > phosphate electrolyte. • The considerable influence of the electrolyte composition on the coating growth of the SiC p /Al composite surface. • The corrosion resistance and electrical insulation performance of the coatings ranks as PEO-Al > PEO-Si > PEO-P. [ABSTRACT FROM AUTHOR]

To develop anti-oxidation and high emissivity coatings on Nb alloys for thermal protection systems, the NbSi 2 /SiO 2 -Nb 2 O 5 /MoSi 2 -xYb 2 O 3 (0, 10, 20, and 30 wt%) multilayer coatings are prepared by a two-step method. The NbSi 2 /SiO 2 -Nb 2 O 5 /MoSi 2 -20Yb 2 O 3 coating possesses the smallest oxidation mass gain (4.86 mg/cm2) at 1200 °C for 100 h and is the best oxidation resistance of the four coatings. The appropriate Yb3+ filles the SiO 2 network voids, enhancing the Si-O bond and raising the viscosity of the SiO 2 scale, thus further blocking oxygen diffusion. The coatings with Yb 2 O 3 below 20 wt% achieve an emissivity of ∼0.9 at room temperature and still reach ∼0.7 at 1200 °C, showing excellent radiant thermal protection. • A new type of NbSi 2 /SiO 2 -Nb 2 O 5 /MoSi 2 -Yb 2 O 3 multilayer coating is designed to enhance high-temperature oxidation resistance and high emissivity. • The MoSi 2 and Yb 2 O 3 particles are co-introduced onto the NbSi 2 surface by the liquid plasma-assisted particle deposition and sintering method to construct a multilayer structure. • The appropriate introduction of Yb 2 O 3 changes the viscosity of the silica-based oxide scale, thus enhancing its self-healing ability and improving the oxidation resistance of the coating. • The pre-fabricated SiO 2 -Nb 2 O 5 /MoSi 2 -Yb 2 O 3 layer significantly enhances the high-temperature emissivity of the ceramic coating. [ABSTRACT FROM AUTHOR]

[Display omitted] • A highly compact ceramic coating is formed on SiC p /Al composite surface by PEO. • The coating obtained at +500 V/−80 V (i.e., N80) has high electrical insulation. • The compact coating structure provides a good long-term anti-corrosion ability. • The coatings display a high infrared emissivity value in the waveband of 8–20 μm. PEO coating microstructure on SiC p /Al composites under the influence of negative pulse are comparatively studied. Results show that the cross-sectional porosity is significantly reduced to 5.1%. The electrical insulation performance of coatings initially improves and then declines as the negative voltage rises from 0 V to 120 V, which is attributed that either an excessively low or excessively high negative voltage is insufficient to improve the internal defects of the coating. Among all the coatings, the coating obtained at +500 V/−80 V (i.e., N80) possesses better electrical insulation (with breakdown voltage of 736 ± 15 V, dielectric strength of 16.3 ± 0.3 V/μm, electrical resistivity of 1.51 × 1011 Ω∙cm), better dielectric performance, higher optical band gap value, making it appropriate for usage as electronic packaging or dielectric materials. The impedance modulus at low frequency of N80 coating is two to three times higher than that of N0, N40, and N120 coating, providing a long-term anti-corrosion ability for the substrate, during the 72-hour immersion. Additionally, the coatings display a high infrared emissivity in the waveband of 8–20 μm (>0.9) to achieve good radiation and heat dissipation effect. Thus, a reasonable negative voltage used in coating preparation does effectively diminish internal structural defects, enhancing coating performance. [ABSTRACT FROM AUTHOR]

Abstract: Gd2Zr2O7 ceramic was prepared by solid state reaction at 1650°C for 10h in air, and exhibited a defect fluorite-type structure. Reaction between molten V2O5 and Gd2Zr2O7 ceramic was investigated at temperatures ranging from 700 to 850°C using an X-ray diffractometer (XRD) and scanning electron microscopy (SEM). Molten V2O5 reacted with Gd2Zr2O7 to form ZrV2O7 and GdVO4 at 700°C; however, in a temperature range of 750–850°C, molten V2O5 reacted with Gd2Zr2O7 to form GdVO4 and m-ZrO2. Two different reactions observed at 700°C and 750–850°C could be explained based on the thermal instability of ZrV2O7. [Copyright &y& Elsevier]

• A fractal-patterned coating is designed for superhydrophobicity and passive cooling. • The coating is fabricated by plasma electrolytic oxidation and hydrothermal treatment. • The coating with high emissivity enhances the passive heat dissipation efficiency. • The coating has robust water-repellence, self-cleaning and anti-corrosion properties. Effective surface passive cooling and superhydrophobicity is vital for promoting more flexible application of energy power system for aircraft and aerospace. Here, we experimentally demonstrate a fractal-patterned coating on TA15 titanium alloy for superhydrophobic and passive cooling performance through plasma electrolytic oxidation and hydrothermal treatment successively. The coating exhibits excellent corrosion resistance and self-cleaning properties, largely thanks to the fractal structure and low surface energy. Additionally, the micro-hole's infrared trapping effect and TiO 2 lattice absorption significantly increase the emissivity over the thermal wavelength range. When functioned on a titanium radiator, such a coating can reduce the temperature by as much as 9.3 °C. Therefore, the passive heat dissipation and superhydrophobic multi-functional coatings are expected to be a promising candidate for heat exchange equipment that requires exposure to harsh external environments. [ABSTRACT FROM AUTHOR]

Plasma electrolytic oxidation (PEO) coatings were formed, respectively in three silicate-based, phosphate-based and aluminate-based electrolytes on niobium, with the aim to explore the relationships between electrolyte composition, dielectric breakdown behavior and corresponding corrosion resistance. The initial growth stages of the anodic coatings were studied, and result shows that an impedance falling stage (from about 200 V to 400 V) starts at the emergence of spark discharge accompanied with the surface morphology evolution from compact to porous. The PEO coatings were characterized through electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) methods. Results show the coatings fabricated in (NaPO 3) 6 electrolyte provide the best corrosion resistance. It attributes to the effective thickness of the compact inner layer rather than the entire thickness of the coating that decrease diffusion of corrosion medium. Unlabelled Image • Porous oxide formation at spark occurrence explained coating impedance decrease. • The sustained inner and outer growth of the coating caused impedance rebounding. • Coatings produced in (NaPO 3) 6 electrolyte exhibited the prior corrosion resistance. • The outstanding corrosion resistance depends on inner barrier layers of PEO coating. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A novel superhydrophobic Al 2 O 3 /cerium hexadecanoate double-layer coating was designed. • The composite coating was fabricated by combining plasma electrolytic oxidation and electrodeposition. • The high emissivity double-layer surface enabled a significant LED temperature drop. • The composite coating showed superior self-cleaning, anti-corrosion and adhesion strength. Abstract To enhance the heat dissipation and anti-corrosion performance simultaneously, a superhydrophobic Al 2 O 3 /cerium hexadecanoate (Al 2 O 3 /CH) composite coating with high adhesion strength has been fabricated by plasma electrolytic oxidation and subsequent electrodeposition. The Al 2 O 3 /CH composite coating with a contact angle of 165.5° shows excellent water repelling and self-cleaning ability owing to the micro/nano structure and low surface energy. The composite coating enhances the corrosion potential of pure Al from −0.742 to −0.730 V and lowers the corrosion current density by two orders of magnitude. Thanks to the high emissivity in the wavelength range from 2.5 to 25 μm, the Al 2 O 3 /CH coated sample enables the operation temperature of a 5 W LED to drop approximately by 9.3 °C compared with Al substrate. In addition, the Al 2 O 3 /CH composite coating exhibits higher adhesion strength than that of the CH single layer. Therefore, the superhydrophobic coating is expected to be a promising candidate for heat dissipation and anti-corrosion applications. [ABSTRACT FROM AUTHOR]

α -Cordierite glass-ceramic coating was fabricated on the porous BN/Si 2 N 2 O ceramic by glass-ceramic method. The effect of the heating temperature on the phase composition, microstructure, mechanical properties, water resistance and dielectric properties of the coatings was investigated. A large amount of α -cordierite precipitated from the glass phase when the heating temperature was 1050 °C and the content of α -cordierite in the coating increased with increasing the heating temperature. The resulting α -cordierite glass-ceramic coatings had a good wettability and adhesion with the porous ceramic substrate. The coating/substrate interface was continuous without defects. When the heating temperature was 1050–1200 °C, the resulting coatings possessed positive mechanical properties and good water resistance due to the high densification. And the dielectric constant and loss tangent of the coated samples prepared at 1050–1200 °C were 4.1–4.3 and 0.005–0.01 respectively in the frequency of 21–36 GHz. [ABSTRACT FROM AUTHOR]

In spacecraft, thermal control coatings with anti-static functionality are vital for electronic packages to ensure proper operation of devices and instruments while preventing the reduction of component lifetime due to extreme temperatures or electrostatic discharge. However, simultaneously integrating thermal control and static charge dissipation into one coating remains a huge challenge. Herein, a dual-layer black coating composed of an Al 2 O 3 -In 2 O 3 -P 2 O 5 -SiO 2 glass bottom layer embedded with crystalline indium tin oxide (ITO) and a top layer with ITO and carbon nanotubes (CNTs) as sealed conductive and radiative components grows in situ on the 6061 aluminum alloy surface using a modified PEO method with nanoparticles additive under special parameters, experiencing one-step liquid-plasma-assisted particle deposition and sintering (LPDS) process. During the LPDS process, the addition of CNTs to the electrolyte promotes the deposition and sintering of ITO nanoparticles on the bottom layer, resulting in the transition from a single-layer coating to a dual-layer coating. CNTs with high absorption/emissivity assisted further by the infrared-trapping effect of the micro/nanostructure lead to flat absorber dual-layer coating. The black coating offers both high solar absorptance (~0.93) in the 0.2–2.5 μm waveband and infrared emissivity (~0.94) in the 3–20 μm waveband. Notably, CNTs with high aspect ratio connect the ITO nanoparticles to form a complete conductive channel on the coating surface, thus eliminating in-plane charges. At only 1.27 × 102 Ω, the surface resistivity of the dual-layer coating is five orders of magnitude lower than that of the single-layer Al 2 O 3 coating (1.15 × 107 Ω). Such an all-in-one design provides a feasible and sustainable strategy for anti-static black products in space applications. [Display omitted] • Thermal management and electric shielding are achieved by a modified PEO method. • The potential impact mechanisms of CNTs on the coating formation are proposed. • CNTs and the infrared-trapping effect of structure lead to flat absorber coating. [ABSTRACT FROM AUTHOR]

Plasma electrolytic oxidation (PEO) coatings fabricated on 6061 aluminum alloy under different applied voltages (400 V, 500 V and 600 V) were used to investigate the plasma discharge induced ‘local over-growth’ characteristics across substrate/coating interface. The instant microdischarges across the local plasma channels induce the ‘micro molten pool’ products and then solidify rapidly to form ‘over-growth’ oxides region extending into substrate. A thin bonding layer composed of nanocrystalline and amorphous Al 2 O 3 with a constant thickness of ~600 nm is always forming on the interface. The intact interface structure of the “local over-growth” characteristic patterns was presented perfectly by both microdischarge-sculpted substrate side ‘pits’ and electrochemically detached coating side ‘protrusions’. The patterns demonstrate that the over-growth ‘pits’ and ‘protrusions’ gradually grow up with increasing applied voltage, which is attributed to the larger discharge channels and molten pools caused by the increased size and intensity of plasma discharges. The speculative ‘over-growth’ mechanism of discharge event during plasma electrolytic oxidation process is described. This work provides insights to control ‘over-growth’ characteristics of substrate/coating interface by tailoring electrical parameters or electrolytes composition. And this strategy has a potential application to fabricate micro-nano structure or optimize outstanding performance of PEO coatings. [ABSTRACT FROM AUTHOR]

An Nb 2 O 5 -SiO 2 -Al 2 O 3 /NbSi 2 /Nb 5 Si 3 multilayer coating is fabricated by a two-step method of pack cementation and microarc oxidation. The isothermal oxidation resistances of Nb 2 O 5 -SiO 2 -Al 2 O 3 /NbSi 2 /Nb 5 Si 3 multilayer coated and NbSi 2 /Nb 5 Si 3 coated Nb alloy are investigated at 1250 °C. The results show that the oxidation kinetics of NbSi 2 /Nb 5 Si 3 coated Nb alloy follows a parabolic-like law with the parabolic rate constant k p of 0.79 mg 2  cm −4 h −1 . Whereas the multilayer coated Nb alloy exhibits better oxidation resistance with a lower k p of 0.06 mg 2  cm −4 h −1 for the first 15 h oxidation period, and a comparable oxidation resistance to that of NbSi 2 /Nb 5 Si 3 coated Nb alloy in the following oxidation period. The multilayer coating has successfully retarded the oxidation process, which is attributed to the formation of Al 2 O 3 and glassy SiO 2 within the Nb 2 O 5 -SiO 2 -Al 2 O 3 outer layer. [ABSTRACT FROM AUTHOR]

Ni-rich cathode materials always suffer from serious side reaction and irreversible phase transition leading to capacity fading and thermal instability, which could be improved by surface coating and elemental doping. However, it is difficult and cumbersome to carry on the coating and doping at the same time. Herein, a facile method of bi-functional Ti modification has been employed on LiNi 0.8 Co 0.15 Al 0.05 O 2 to enhance surface and structural stability via heterogeneous layer coating and bulk doping. The mechanism and synergistic effect of Ti modification has been investigated by XRD, XPS, SEM, TEM and the half-cell test in details. The existence of Ti occupancy in Ni site of the transition metal layer has been confirmed. Besides, a 22 nm heterogeneous layer has been detected on the particle surface and the composition has been analyzed. Ti bulk doping can reduce the cation mixing degree, and stabilize the lattice due to the pillar effect and charge compensation. Moreover, the heterogeneous coating layer could protect the cathode particles from hydrofluoric acid attack and reduce the decomposition of electrolyte during cycling. With the synergistic effects of heterogeneous layer coating and bulk doping, NCA-T2 exhibits the highest initial capacities of 162.9 and 182.4 mAh·g −1 at 1C and 0.1C, and the discharge capacity retentions of 1C cycling reach 85.0% after 200 cycles. [ABSTRACT FROM AUTHOR]

Zn metal has been proved to be a promising anode material in aqueous secondary Zn-ion batteries. However, the uncontrollable dendrite growth on Zn anode deriving from uneven Zn deposition during cycling seriously impairs its reliability and limits the service life. Achieving uniform Zn deposition is the key to overcoming the dendritic issue and accelerating the commercial application of aqueous Zn-ion batteries. Herein, a polymer coating with semi-interpenetrating network (s-IPN) structure is designed for the protection of Zn anode in aqueous Zn-ion batteries. Benefiting from the hydrophilic and robust polymer network, uniform Zn deposition and excellent dendrite growth resistance could be realized for the s-IPN polymer coated Zn (s-IPN@Zn) anode. As a consequence, the symmetric cell with s-IPN@Zn shows an ultra-long cycle life of 2370 h at 0.5 mA cm−2, which exhibits significant improvement compared with the unmodified bare Zn anode. Furthermore, the Zn//MnO 2 rechargeable aqueous battery with s-IPN@Zn anode shows more excellent long-cycle stability compared with bare Zn, revealing the effectiveness of this unique s-IPN polymer coating design. • A semi-interpenetrating network polymer coating was prepared in-situ on the Zn anode. • The hydrophilic polymer coating can even out the electric field near the anode. • The unique network structure promotes uniform and dendrite-free Zn deposition. • An ultra-long cycle life was achieved with the network polymer-coated Zn anode. [ABSTRACT FROM AUTHOR]

[Display omitted] • Compared with traditonal spherical feedstocks, saucer-shaped feedstocks are prepared by electrostatic spray method; • The coating achieved by saucer-shaped feedstocks shows a bimodal organization similar to that of nano thermal barrier coatings; • The emissivity of Ca2+-doping YbCrO 3 coatings is above 0.92 in the 1–14 μm band at room temperature; • The emissivity of Ca2+-doping YbCrO 3 coatings decreases with the increasing temperature; • The average emissivity of Ca2+-doping YbCrO 3 coatings at 1–14 μm is still above 0.67 when the temperature reaches 1200 °C. A high infrared emissivity coating with porosity of 16.2 % was deposited on Ni-based alloy by saucer-shaped porous feedstocks using the atmospheric plasma spraying technique. The solid-phase reaction method was employed to synthesize Ca2+-doped YbCrO 3 ceramic powders, and then the saucer-shaped porous feedstocks were obtained by electrostatic spraying accompanied by heat treatment, and the conventional spray drying feedstocks were used as comparison. Compared with the conventional structural coating, the coating achieved by saucer-shaped feedstocks shows higher porosity and surface roughness due to the insufficient melting of the feedstocks with larger diameters in the plasma flame. Therefore, the coating achieved by saucer-shaped feedstocks exhibits a bimodal organization similar to that of nanostructured thermal barrier coatings. Compared with the conventional coating, the coating with new structure shows a higher emissivity value of 0.9460 at 1–14 µm waveband at room temperature due to the higher surface roughness (7.12 μm). Moreover, the average emissivity of coatings with roughness ranging from 0.93 µm to 7.12 µm is all above 0.91. More importantly, although the infrared emissivity of all coatings with different roughness decreases with the increase of temperature, they still remain above 0.77 at 1–14 µm when the temperature reaches 1200 °C. [ABSTRACT FROM AUTHOR]

The application of Ni-rich ternary cathode materials is restricted by the irreversible phase transition and interfacial side reactions during long-term cycling. Herein, a LiTaO 3 coating and Ta5+ doping strategy are simultaneously achieved by a simple solid-phase synthesis. The surface side-reaction and undesired phase transition of LiNi 0.8 Co 0.15 Al 0.05 O 2 (NCA) are effectively restrained by this approach, which utilizes residual lithium to afford the coating. The NCA-LTO 3 (The modified NCA with a LiTaO 3 coating content of 3 wt%) delivers a high reversible capacity of 168.04 at 5 C (140.56 mAh g−1 for NCA), revealing the enhanced rate capability. More importantly, the cycling life could be greatly maintained after 200 cycles with a significant capacity retention of 94.1% (61.2% for NCA) at 1 C. Mechanism analysis indicates that such improvement is ascribed to the coating of conductor LiTaO 3 and doping Ta5+ greatly promoting the Li-ion diffusion and stabilizing the interface of NCA. The study proposes a highly convenient strategy for interfacial optimization of cathode materials toward assisting the large-scale production of high-performance NCA. • The double modification of coating and doping is realized by consuming the residual lithium salt on the surface of NCA material. • After LiTaO 3 coating and Ta5+ doping, the discharge capacity, cycling stability and rate performance are significantly improved. • The double modification improves the structural stability of LiNi 0.8 Co 0.15 Al 0.05 O 2. [ABSTRACT FROM AUTHOR]

Amorphous microarc oxidation (MAO) coating containing Ca, P, Si and Na elements on Ti substrate has been heat treated in different atmospheres (air or argon) to adjust the phase composition, surface structure and bioactivity. After heat treatment in air at 800 °C for 1 h, the coating consists of anatase, rutile and CaTi 4 (PO 4 ) 6 , with almost unchanged microporous surface structure. As for the one treated in argon at 800 °C for 1 h, anatase and rutile are formed on the coating, and the coating surface is covered by flower-like rutile particles. The formation of rutile particles could be attributed to the prior growth of the oxidized β-Ti along the discharge channel caused by the diffusion of incorporated elements. Thanks to the crystallization of TiO 2 and the rise of surface roughness, which provides good sites for apatite nucleation, the MAO coated Ti after heat treatment in argon at 800 °C exhibits good apatite-inducing ability. [ABSTRACT FROM AUTHOR]

A MoSi 2 /SiO 2 -Nb 2 O 5 /NbSi 2 multilayer coating was designed on Nb alloys using halide activated pack cementation (HAPC) and an innovative liquid plasma-assisted particle deposition and sintering (LPDS) method to improve its hot corrosion resistant. The weight gain of MoSi 2 /SiO 2 -Nb 2 O 5 /NbSi 2 coating was 3.204 mg/cm2 after 200 h, which was 85.7% lower than that of NbSi 2 /Nb 2 O 5 -SiO 2 coating, while the life of NbSi 2 coating was restricted only 100 h (20.539 mg/cm2) at 900 °C in Na 2 SO 4 +NaCl salt. This improved performance is attributed to the prefabricated SiO 2 -based barrier layer and MoSi 2 as a Si source to supplement the SiO 2 content, thus effectively alleviating the penetration of oxygen and molten salts. • A new type of MoSi 2 /SiO 2 -Nb 2 O 5 /NbSi 2 multilayer coating is designed to resist hot corrosion. • The multilayer coating is fabricated by combining halide activated pack cementation and an innovative liquid plasma-assisted particle deposition and sintering method. • The MoSi 2 /SiO 2 -Nb 2 O 5 /NbSi 2 multilayer coating shows superior hot corrosion resistance. • The pre-fabricated MoSi 2 /SiO 2 -Nb 2 O 5 layer is a barrier against molten salt and oxygen, in which the MoSi 2 acts as a Si source to consume oxygen and replenish the SiO 2. [ABSTRACT FROM AUTHOR]

One-step liquid-plasma-assisted particle deposition and sintering (LPDS) method was developed to fabricate ZrSi 2 /SiO 2 -Nb 2 O 5 bi-layers on the bottom NbSi 2 layer of halide activated pack cementation (HAPC) treated niobium alloy. The microstructure evolution and isothermal oxidation performance of ZrSi 2 /SiO 2 -Nb 2 O 5 /NbSi 2 coating were investigated at 1200 °C. The single NbSi 2 and SiO 2 -Nb 2 O 5 /NbSi 2 coating were also studied for comparison. The mass gain of ZrSi 2 /SiO 2 -Nb 2 O 5 /NbSi 2 coating after 100 h is only 6.14 mg/cm2, which is significantly lower than that of SiO 2 -Nb 2 O 5 /NbSi 2 (9.42 mg/cm2) and NbSi 2 coating (13.41 mg/cm2), showing a minimal mass gain due to forming the SiO 2 -ZrO 2 -ZrSiO 4 skeleton. Namely, the "Zr peg" fixed SiO 2 scale effectively prevents oxygen from penetrating inwards. • A novel ZrSi 2 /SiO 2 -Nb 2 O 5 /NbSi 2 multi-layer coating is prepared by combining HAPC and LPDS techniques. • A new fabrication strategy of thermal protective coatings by tailoring particles and designing structures is proposed. • The ZrSi 2 /SiO 2 -Nb 2 O 5 /NbSi 2 multi-layer coating shows superior high temperature oxidation resistance. • The ZrSi 2 serves to consume oxygen and also forms a SiO 2 -ZrO 2 -ZrSiO 4 skeleton with a low oxygen diffusion coefficient. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel double-layer nanocomposite coating is prepared via a facile one-step PEO-SDSN technique. • The addition of nanoparticles creates interesting rising and falling changes in current. • A new fabrication strategy of multifunctional coatings by tailoring particles species is proposed. • The instant, dense discharges are induced by Highfield, high temperature and bubbles accumulation. • Such intense discharges significantly improve the growth rate of nanocomposite coating. A novel double-layer structural nanocomposite coating was prepared via one-step plasma electrolytic oxidation-synchronous deposition & sintering of nanoparticles (PEO-SDSN) technique under unique threshold conditions of concentration of added nanoparticles, electrolyte temperature, and applied voltage. The special discharges at the coating/electrolyte interface lead to the directional migration, deposition and sintering of organic (eg. PTFE) or inorganic (eg. SiC) nanoparticles, combined with the dynamic growth equilibrium of bottom oxide layer and outer nanoparticle deposition & sintering layer. Different from traditional PEO, the addition of nanoparticles creates interesting rising and falling changes in current and corresponding discharging characteristics. The underlined formation mechanism of the double-layer coating was detected by OES combined with discharging phenomena and coating structure evolution. Moreover, compared with the single PEO coating, the double-layer structural nanocomposite coating has better comprehensive performances, such as corrosion protection, and low and stable friction coefficient. The PEO-SDSN technique is energy saving, more importantly, it provides a brand-new fabrication strategy for a series of double-layer multifunctional coatings by tailoring the nanoparticles species. Eventually, the potential applications and guiding strategies of double-layer nanocomposite coating are presented. [ABSTRACT FROM AUTHOR]

Microarc oxidation (MAO) coatings have been formed on Ti 2 AlNb alloy in different electrolytes containing NaAlO 2 , Na 2 SiO 3 and (NaPO 3 ) 6 solutions, respectively, to evaluate their phase constituents and high temperature oxidation resistance at 800 °C. The electrolyte compositions have a significant influence on structure and oxidation resistance of MAO coatings on Ti 2 AlNb alloy. MAO coatings formed in the electrolytes of NaAlO 2 and (NaPO 3 ) 6 solutions, respectively, have a better oxidation resistance than the bared Ti 2 AlNb alloy after oxidation at 800 °C up to 150 h. However, the situation is reversed for the MAO coatings formed in a Na 2 SiO 3 electrolyte, which has a similar weight gain to the bared Ti 2 AlNb alloy. A compact oxide barrier interlayer of Ti- and Al-containing oxides is found between the substrate and the MAO coatings formed in the NaAlO 2 solution, which is effective to protect Ti 2 AlNb alloy from the inward diffusion of oxygen and the outward diffusion of metallic elements. [ABSTRACT FROM AUTHOR]

BN/Si 3 N 4 composite ceramics with different BN content were prepared by water-based gel casting process with raw and Y–Al-oxides-coated BN powder, separately. A Y–Al oxides layer with the thickness ranging from dozens to hundreds of nanometers, serving as sintering additives, was coated on the surface of BN particles with the method of precipitation of inorganic salts. As a result, the fluidity of BN/Si 3 N 4 slurry with Y–Al-oxides-coated BN powder was much improved compared to that with raw BN. SEM examination showed the Y–Al-oxides-coated BN particles were homogeneously distributed within the Si 3 N 4 grain boundaries, and BN aggregation was barely detected. The BN/Si 3 N 4 composite ceramic prepared by Y–Al-oxides-coated BN powder showed a better sintering behavior than those prepared by raw BN due to the formation of fine and homogeneous microstructure in it. Compared to the BN/Si 3 N 4 ceramic with 15 vol% raw BN, the density and flexural strength of the ceramic with the same content of surface-coated BN were significantly improved to 8.5% and 67.2%, respectively. [ABSTRACT FROM AUTHOR]