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Photoelectrochemical (PEC) water splitting has attracted strong interest as sustainable technology by converting solar energy into hydrogen. The semiconductor photoelectrodes play an important role to increase the solar‐to‐hydrogen conversion efficiency. Bismuth vanadate (BiVO4) is an excellent candidate as a photoanode material for PEC water oxidation because of its visible light absorption, suitable band edge location, high stability and low cost. However, BiVO4 alone may undergo short carrier diffusion length, rapid recombination of photo‐induced charge carriers and photocorrosion. The heterojunction strategy established by combining two or more materials has provided an outstanding technique to address these issues. This Review focuses on recent important works with respect to BiVO4 heterojunction photoanodes for PEC water oxidation reactions, including interface junction and surface functional junction formation. Additionally, challenges faced and prospects for future research on BiVO4 heterojunction photoanodes in the field of solar‐to‐hydrogen conversion are proposed. [ABSTRACT FROM AUTHOR]

A highly regioselective reaction of 2-indolylmethanols with enamides has been developed at room temperature by using AlCl3 as a catalyst. A wide range of hybrids (40 examples) of indoles and enamides were obtained in moderate to good yields (up to 98% yield). This transformation represents the efficient way to introduce biologically important indoles and enamides skeleton into structurally complex hybrids. [ABSTRACT FROM AUTHOR]

The effect of applied load on the tribological behaviors of single DLC coating and DLC/Cr 3 C 2 –NiCr duplex coating was explored in the paper experimentally, and the role of cermet interlayer on the duplex coating tribological behavior was analyzed from the perspective of carbonaceous transfer film formation. Results proved that the duplex coating wear rate under 20 N was the lowest, about 1/6 of that of the single coating. The existence of Cr 3 C 2 –NiCr interlayer can prevent the top DLC film from being damaged in high load friction, reduce the fluctuation and vibration of the friction interface, and help the friction-induced graphitized carbonaceous transfer film to maintain on the friction counterpart, thus realizing the low-friction of the duplex coating. Furthermore, the critical conditions under which the friction-induced carbonaceous transfer film of a single coating maintains on the friction counterpart are explored by designed experiments. Results show that the carbonaceous transfer film derived from the single coating can only maintain on the friction counterpart under conditions of low load, low sliding frequency, and high humidity, which indirectly confirms the excellent tribological performance of the duplex coating. [ABSTRACT FROM AUTHOR]

Flow chemistry technology innovatively integrates the traditional independent experimental operation processes, speeds up reaction rates and, especially, can be applied in special reactions that are hazardous or under difficult reaction conditions, being beneficial for the development of green chemistry and laboratory automation. In flow chemistry, the application of traditional pipeline microreactors is usually limited by blockage, corrosion and difficult maintenance. The micro/nanomaterials-based microreactors for flow chemistry are supposed to solve these problems. Herein, we report a novel solid–liquid composite microreactor (BiOBr@ILG-microspheres) with ionic liquid compartments based on ionic liquid gel microspheres (ILG-microspheres) and a typical photocatalyst, BiOBr. The BiOBr@ILG-microspheres show high photodegradation performance, which is attributed to the enrichment of organic substrates by the ILG-microspheres, the efficient charge transfer microenvironment of the internal ionic liquids (ILs), and the flower-like heterostructure of the microspheres that hosts abundant active sites. Furthermore, the BiOBr@ILG-microspheres are embedded in a poly(vinyl alcohol) (PVA) hydrogel to build a multi-liquid phase membrane, which exhibits promising performance in removing pollutants continuously from flowing water with an ∼100% removal rate of ciprofloxacin for a long time, due to the synergic effect of the enrichment and catalytic degradation of the pollutants by the BiOBr@ILG-microspheres. This work provides a new research strategy for constructing liquid compartment microreactors with a synergistic effect of extraction–catalysis using the novel developed ILG-microspheres, which will attract widespread interest because it is in accordance with the concept of green chemistry. [ABSTRACT FROM AUTHOR]

In this study, experimental analysis and finite element modeling (FEM) were employed to investigate the microstructure and mechanical properties of duplex coatings composed of a Cr 3 C 2 –NiCr interlayer and a top AlCrN film in comparison with these of a single AlCrN film. Results showed a significant improvement in the adhesive strength, load-bearing capacity, H/E, and H3/E2 ratios, and hardness of the AlCrN/Cr 3 C 2 –NiCr duplex coatings compared to the single AlCrN film, especially the wear resistance that increased by nearly eight times under heavy loads. Moreover, FEM analysis revealed that the duplex design reduced the stress concentration area on the surface of AlCrN film and kept it far away from the contact interface during load-bearing. [ABSTRACT FROM AUTHOR]

WC/a-C nano-multilayers with different modulation ratio (WC:a-C) ranging from 1:10 to 1.5:1 were deposited by fixing a-C individual layer thickness and tailoring WC individual layer thickness. The effect of modulation ratio on mechanical and tribological performance of WC/a-C nano-multilayers were investigated. Superior mechanical and tribological properties were simultaneously achieved at modulation ratio of 1:1.2. In addition to the improvement of mechanical properties, the improved tribological properties should also be attributed to the friction-induced formation of a WO 3 -rich transfer film under an appropriate WC individual layer thickness, which combing the graphitized worn film surface constructed an intrinsically weak-interacting sliding interface (WO 3 /C interface). Also, graphitized carbon is an essential coadjutant for the formation of WO 3 -rich transfer film. [ABSTRACT FROM AUTHOR]

Recently, flight control of unmanned aerial vehicles (UAVs) in non-global positioning system (GPS) environments has become increasingly important. In such an environment, visual sensors are important, and their main roles are self-localization and obstacle avoidance. In this paper, the concept of a multi-camera UAV system with multiple cameras attached to the body is proposed to realize high-precision omnidirectional visual recognition, self-localization, and obstacle avoidance simultaneously, and a two-camera UAV is developed as a prototype. The proposed flight control system can switch between visual servoing (VS) for collision avoidance and visual odometry (VO) for self-localization. The feasibility of the proposed control system was verified by conducting flight experiments with the insertion of obstacles. [ABSTRACT FROM AUTHOR]

[Display omitted] • Highly stable perovskite nanocrystals in water were obtained by modifing wool keratin (WK) and crosslinking agent (PAPI). • CPB/WK-PAPI nanocrystals show excellent photoluminescence retention over time even after 512 days (>40 %). • Portable, low cost, and visualize test strips for amines were successfully made from these nanocrystals. Perovskite nanocrystals (PNCs) have emerged as promising candidates for fluorescent probes owing to their outstanding photoelectric properties. However, the conventional CsPbBr 3 (CPB) NCs are extremely unstable in water, which has seriously limited their sensing applications in water environment. Herein, we present a powerful ligand engineering strategy for fabricating highly water-stable CPB NCs by using a biopolymer of wool keratin (WK) as the passivator and the polyaryl polymethylene isocyanate (PAPI) as the cross-linking agent. In particular, WK with multi-functional groups can serve as a polydentate ligand to firmly passivate CPB NCs by the ligand exchange process in hot toluene; and then the addition of PAPI can further encapsulate CPB NCs by the crosslinking reaction between PAPI and WK. Consequently, the as-prepared CPB/WK-PAPI NCs can maintain ∼ 80 % of their relative photoluminescence (PL) intensity after 60 days in water, and they still maintain ∼ 40 % of their relative PL intensity even after 512 days in the same environment, which is one of the best water stabilities compared previously reported polymer passivation methods. As a proof-of their application, the portable CPB/WK-PAPI NCs-based test strips are further developed as a fluorescent nanoprobe for real-time and visual monitoring amines and food freshness. Among various amine analytes, the as-prepared test strips exhibit higher sensitivity towards conjugated amines, achieving a remarkable detection limit of 18.3 nM for pyrrole. Our research not only introduces an innovative strategy involving natural biopolymers to enhance the water stability of PNCs, but also highlights the promising potential of PNCs for visually and portably detecting amines and assessing food freshness. [ABSTRACT FROM AUTHOR]

Tribological behaviors of three typical kinds of diamond‐like carbon (DLC) films (a‐C, a‐C:Cr, and a‐C:H) in sulfuric acid and sodium hydroxide solutions were investigated. The a‐C film showed the lowest stable coefficients of friction (COF) in both sulfuric acid and sodium hydroxide solutions but the worst wear resistance in sulfuric acid solution. The a‐C:H film showed the highest COF in sulfuric acid solution and the best wear resistance in both sulfuric acid and sodium hydroxide solutions. The a‐C:Cr film exhibited superior comprehensive tribological performance in sulfuric acid solution, while in sodium hydroxide solution, high COF and very poor wear resistance was observed. What is more, friction and wear mechanism was revealed by investigating the friction‐induced material evolutions on the sliding surface. [ABSTRACT FROM AUTHOR]

Zinc oxide (ZnO) has been widely acknowledged as a highly effective photocatalyst for the degradation of organic pollutants. In this study, we presented silver nanoparticles (AgNPs) embedded ZnO foam photocatalyst (Ag−ZnO) on glass substrates by the chemical bath in‐situ co‐deposition method. Our findings demonstrat that at low Ag‐loading content, metallic Ag0 NPs are embedded within the ZnO foam, while at high Ag‐loading content, they accumulates increasingly from inside to the surface of the foam. With the increase of AgNPs loading from 0.1 mM to 1.5 mM, the absorption of Ag−ZnO foams in the visible light region gradually enhances. The photocatalytic degradation efficiency of rhodamine B (RhB) is the highest in Ag−ZnO foams when the Ag loading concentration reaches 0.8 mM, suggesting an optimal content of Ag for enhanced performance. This trend is attributed to the photo‐induced charge transfer behavior of Ag−ZnO samples. The AgNPs embedded inside the ZnO foam enhance the separation of photo‐induced charges and prevent their recombination. As a result, Ag−ZnO(0.8 mM) foam with more photo‐induced holes participate in the photocatalytic reaction, leading to a remarkably high photocatalytic activity. [ABSTRACT FROM AUTHOR]

Duplex coating consisting of a Cr 3 C 2 -NiCr interlayer and a top DLC film was prepared using the high-velocity oxyfuel (HVOF) spraying and a closed field unbalanced magnetron sputtering (CFUBMS). The electrochemical behaviors of the Cr 3 C 2 -NiCr/DLC duplex coatings in 3.5 wt% NaCl solution was investigated by comparing it with a single DLC film and a single Cr 3 C 2 -NiCr coating. Then the role of cermet interlayer on the anticorrosion mechanism of the duplex coatings was explored. Results showed that introducing the cermet interlayer increased the surface roughness of DLC films without changing its microstructure. In the dynamic potential polarization test, duplex coatings maintained high surface integrity even after corrosion, and corrosion only occurs in localized areas. The inclusion of an interlayer avoided substrate corrosion caused by penetrating cracks and therefore provided excellent corrosion resistance. • The top DLC film covers the pores of the Cr 3 C 2 -NiCr coating. • The corrosion occurs the island boundaries, but duplex coating remains dense surface. • Oxide of Cr and Ni protects the coating system from diffusion of corrosive ions. [ABSTRACT FROM AUTHOR]

Effects of carbide content on the mechanical and tribological properties of DLC/Cr 3 C 2 –NiCr duplex coatings were systematically investigated. Results revealed that cermet coating with high carbide content provided strong support for the top DLC film by bearing most of the contact stress, thus improving its hardness, load-bearing capacity, and adhesion strength. The increased carbide content increased the contact and shear stresses on duplex coating during the friction process, intensifying the graphitization of the top DLC film but inhibiting the formation of a graphitized transfer film on the counterpart, thus slightly increasing its friction coefficient. However, the predominant wear mechanism changed from high-efficiency abrasive wear to low-efficiency adhesive wear for low to high carbide content, superior wear resistance was thereby achieved. [Display omitted] • Effects of carbide content on mechanical and tribological properties of duplex coatings was systematically studied. • Contact stress distribution in duplex coatings during the load-bearing process was clarified by FEM analysis. • Tribological mechanisms were revealed from many aspects of energy description, phase transition and contact mechanics. [ABSTRACT FROM AUTHOR]

Fluorinated graphene oxide (FGO) was successfully prepared in this paper, and the chemical structure of FGO was characterized. A series of polyimide (PI) composite films with different content of FGO was prepared by in situ polymerization. Because of the homogeneous dispersion of FGO and the strong interfacial interaction between FGO and the PI matrix, the resulting composite films that contained FGO exhibited effects of mechanical properties, thermal properties and dielectric properties that were even better than the pure PI. Furthermore, due to the hydrophobic properties of FGO, the water absorption of the composite films were reduced. The result showed when the 0.6 wt.% FGO was filled into the PI, the tensile strength was increased about 66.3%, the decomposition temperature was increased from 540∘C to 570∘C, and the dielectric constant (Dk) decreased with the increasing content of FGO, and a Dk value of 2.28 was achieved when the content of FGO was 1.0 wt.%. The FGO was obtained from graphite by modified Hummers method, and the FGO/PI composite material was prepared by in-situ polymerization. Due to the special properties of FGO, the FGO/PI composite material has more excellent mechanical and thermal properties, and greatly reduces its dielectric constant and water absorption performance. The successful preparation of FGO/PI composite material promotes its potential application value and expands its application fields. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Inverted perovskite solar cells (PerSCs) are a highly promising candidate in the photovoltaic field due to their low‐temperature fabrication process, negligible hysteresis, and easy integration with Si‐based solar cells. A cathode interlayer (CIL) is necessary in the development of inverted devices to reduce the trap density and energy barrier between the electron transport layer (ETL) and the electrode. However, most CILs are highly thickness‐sensitive due to low conductivity and poor film‐forming. In this study, we report on a self‐doping perylene imide‐based ionene polymer (PNPDIN) used as CIL material to modify electrode in inverted PerSCs. PNPDIN exhibits high conductivity and a good solubility in polar solvent, which results in an improved power conversion efficiency (PCE) from 10.05% (device without a CIL) to 16.97%. When the blend of PNPDIN and Bphen was used as a mixed CIL, the PCE of PerSCs can be further increased to 21.28% owing to the excellent morphology and matched energy level. More importantly, the PCE of the device is highly tolerant to the thickness of the mixed CIL, which benefited from the high conductivity of PNPDIN. This development is expected to provide an excellent mixed CIL material for roll‐to‐roll processing efficient and stable inverted PerSCs. [ABSTRACT FROM AUTHOR]

A novel nanomultilayered architecture was developed through magnetron sputtering to simultaneously achieve excellent mechanical and tribological properties in TiB 2 /a-C film. Structural optimization was conducted by adjusting the modulation period from 1 to 10.5 nm. Film hardness and toughness were significantly improved and reached the optimal value at Λ = 6.6 nm. Combination of a sufficient number of heterointerfaces and appropriate individual layer thickness played a key role in hardening and toughening. The internal stress increased linearly with the increase in modulation period, which may be related to the reduction in the number of interfaces. Furthermore, a low friction coefficient of about 0.1 was achieved in the steady state at Λ ≤ 6.6 nm due to the formation of a uniform and compact transfer film on the worn ball surface. The improved mechanical performance and the presence of an effective transfer film resulted in an outstanding anti-wear performance at Λ = 6.6 nm. [ABSTRACT FROM AUTHOR]

[Display omitted] • Friction-induced reconstruction behavior of sliding interface and low friction mechanism of WC/a-C films are studied. • Moisture and oxygen are two essential factors for the formation of a WO 3 -rich transfer film. • Intrinsically weak interaction of the WO 3 /C interface is the origin of low friction. Tungsten carbide reinforced amorphous carbon (WC/a-C) films exhibit significantly lower coefficient of friction (COF) than typical a-C films in the atmospheric environment; thus, they are promising candidates for use as solid lubricants. However, the low friction mechanism of WC/a-C films remains poorly understood. Here, we revealed that the friction-induced formation of WO 3 -rich transfer film changed the real sliding interface between the initial friction pair materials into an interface between a WO 3 -rich transfer film and carbon-rich worn film surface (WO 3 /C interface). First-principles calculations indicated that the WO 3 /C interface showed weaker interactions than the C/C interface of the a-C film under the same conditions, particularly when the dangling carbon bonds at the sliding interface were not completely passivated. This resulted in a reduced COF of the WO 3 /C interface. Thus, friction-induced reconstruction of the sliding interface to an intrinsically weak-interacting interface is proposed as a new path to further improve the tribological performance of a-C-based films. [ABSTRACT FROM AUTHOR]

Nanomultilayered WC/a-C coatings with modulation period raning from 1.3 to 11.5 nm were successfully fabricated using unbalanced magnetron sputtering process and the evolution of their microstructure, mechanical and tribological properties with the modulation period were systemically investigated. It has been demonstrated that the columnar structure in WC/a-C nanomultilayers originates from the surface irregularities of intermediate Cr/WC/C layer and the column diameter is correlated with the initial Cr layer thickness in this intermediate stage. Hardening and toughening through the nanomultilayer structure design have been achieved and particularly pronounced when the modulation period ranges from 5.8 to 10 nm. The enhanced hardness and fracture toughness are mainly attributed to dislocation/crack pinning effect from the thin individual layer and the heterointerfaces between WC and a-C layers. It is also found that the more heterointerfaces, the lower internal stress. What's more, the WC/a-C nanomultilayers with small modulation period (≤5.8 nm) exhibit low COF about 0.05 and good wear resistance due to the interfacial sliding between a WO 3 -rich tribofilm and a carbon-rich wear surface; once the modulation period above 5.8 nm, it fails to build up such a low friction interface between the tribopairs, which combining with the high intrinsic friction caused by its own structure characteristics result in high COF about 0.18–0.2 and poor wear resistance. [ABSTRACT FROM AUTHOR]

Nanocomposite WC/a-C coatings were successfully fabricated using a magnetron sputtering process, and post-deposition annealing was conducted in vacuum for 1 h at the annealing temperatures ranging from 100 to 500 °C. The changes in coating structure, internal stress, hardness, toughness, friction coefficient and wear have been investigated to assess the effects of annealing on microstructure, mechanical and tribological properties of the WC/a-C coatings. The results show that the nanocrystalline WC partially decays to metastable WC when annealing at 300-500 °C and no graphitization of amorphous carbon matrix starts up to 500 °C. This structural change results in a slightly increased hardness and an improved toughness as well as a gradually decreased internal stress. In addition, the time for the annealed coatings to achieve a low steady friction coefficient decreases with the increase of annealing temperature. An optimized tribological property with low friction coefficient of about 0.06 and enhanced wear resistance of the WC/a-C coating is obtained by annealing at 400 °C. Friction reduction and wear resistance caused by annealing can be attributed to the friction-induced WO-rich tribofilm which slides against a thin carbon-rich layer on the coating surface resulting in a low friction, and the partition effect of the stationary WO-rich tribofilm combining with the improved mechanical properties generates a high wear resistance. [ABSTRACT FROM AUTHOR]

Nanocomposite WC/a-C coatings with variable contents of tungsten carbide (WC 1− x ) and amorphous carbon (a-C) were successfully fabricated using a magnetron sputtering process. The microstructure, mechanical properties and tribological behaviors of the as-fabricated coatings were investigated and compared. The results showed that the “superlattice coating” feature of an alternating multilayer structure with a-C and WC 1− x nanocrystallites layers on the nanoscale was formed. These multilayer superlattice structures led to diminished residual stress and improved the strength of the adhesion to the substrate. The WC/a-C coating with W 5.43 at.% exhibited low friction coefficients of 0.05 at 25 °C and 0.28 at 200 °C. This significant improvement in the tribological performances of the WC/a-C coating was mainly attributed to the superior “superlattice” microstructure and the formation of a continuously compacted tribofilms, which was rich in graphitized carbon at 25 °C and dominated by the friction triggered WO 3 at 200 °C. Moreover, the WC/a-C coating with W 5.43 at.% achieved optimal anti-wear properties at 25 °C due to the synergistic combination of the enhancement effects of the WC 1− x nanoparticles and the partition effect from the transfer film that restricted direct contact of the steel ball with the coating and thus prevented further intense wear. The accelerated wear of the WC/a-C coating with the increase of the WC phase content at 200 °C might be due to the combination of oxidation wear and abrasive wear that originated from the WC 1− x phase. [ABSTRACT FROM AUTHOR]

Titanium alloys are characterized by poor tribological performance, and their conventional use has been restricted to non-tribological applications. Surface films and surface texturing are effective methods to improve the tribological properties of sliding surfaces. In this study, the patterns of micro-dimples with different densities and diamond-like carbon (DLC) films were fabricated on the surface of titanium alloy by laser surface texturing and magnetron sputtering, respectively. The effects of dimple densities and DLC phase transformation on the tribological behavior of the titanium alloy under dry friction and liquid lubrication conditions were investigated. The results showed that DLC film with appropriate dimple area density (44%) are effective in enhancing reducing-friction property of titanium alloy substrate because of the entrapment of wear particles in the dimples and dimple-induced graphitization during sliding motions, while the 24% textured specimen exhibited outstanding wear resistance. [ABSTRACT FROM AUTHOR]

Developinghigh surface area nanostructured electrodes with rapidcharge transport is essential for artificial photosynthesis, solarcells, photocatalysis, and energy storage devices. Substantial researchefforts have been recently focused on building one-dimensional (1D)nanoblocks with fast charge transport into three-dimensional (3D)hierarchical architectures. However, except for the enlargement insurface area, there is little experimental evidence of fast electrontransport in these 3D nanostructure-based solar cells. In this communication,we report single-crystal-like 3D TiO2branched nanowirearrays consisting of 1D branch epitaxially grown from the primarytrunk. These 3D branched nanoarrays not only demonstrate 71% enlargementin large surface area (compared with 1D nanowire arrays) but alsoexhibit fast charge transport property (comparable to that in 1D singlecrystal nanoarrays), leading to 52% improvement in solar conversionefficiency. The orientated 3D assembly strategy reported here canbe extended to assemble other metal oxides with one or multiple componentsand thus represents a critical avenue toward high-performance optoelectronics. [ABSTRACT FROM AUTHOR]

Abstract: Different sizes of ZnWO4 photocatalysts were synthesized by a hydrothermal method. The as-prepared sample shows highly efficient photocatalytic activity for the degradation of RhB under UV irradiation, which significantly vary with the increase of the hydrothermal temperatures. Surface photovoltage spectrum (SPS), field-induced surface photovoltage spectrum (FI-SPS) and surface photovoltage transient (TPV) techniques are used to investigate the detailed photoinduced charge transfer behavior. Results indicate that the ZnWO4 synthesized at 413K possess the largest BET surface area and the abundant donor surface states which are assumed to inhibit the recombination of the photogenerated electron–hole pairs, and thus a significant enhancement in the reaction rate is observed. [Copyright &y& Elsevier]

• The introduction of Cr 3 C 2 -NiCr interlayer significantly extends the life of the CrN film at 550 °C. • The duplex coating exhibits superior high temperature oxidation resistance. • Top CrN film effectively improves hot corrosion resistance of Cr 3 C 2 -NiCr coating. • Chlorine-induced corrosion in uncovered holes is the main reason of top CrN film failure. In this study, an optimized duplex coating, consisting of a thick Cr 3 C 2 -NiCr interlayer and a top CrN film, were designed and deposited by HVOF and PVD. And then hot corrosion behaviors were systematically investigated, and corresponding corrosion mechanisms are discussed in detailed. Results showed that the thickness of the oxide scale of duplex coating is approximately one-tenth that of the Cr 3 C 2 -NiCr coating. Due to the formation of Cr 2 O 3 oxide film, the CrN/Cr 3 C 2 -NiCr duplex coating exhibits superior hot corrosion resistance. However, chlorine-induced corrosion in uncovered holes is the main cause of local failure of duplex coating. [ABSTRACT FROM AUTHOR]

• Textured DLC films were in-situ deposited by masking substrate with metallic meshes. • Covered region became concave part while exposed region became protruding part. • In-situ surface texturing improved film hardness, elastic modulus and lipophilicity. • DLC-T52% reached the lowest COF and wear rate under dry and lubricated conditions. Surface texturing is emerging as one of the viable means that can be applied to improve the tribological properties of diamond like carbon (DLC) films. In this study, textured DLC films were in-situ fabricated by masking the substrate with metallic meshes during the deposition process. The tribological behaviors of the textured DLC films with micro-dimples densities of 39%, 52% and 58% were studied and compared with that of the un-textured DLC films under dry friction and liquid lubrication conditions. The results showed that the textured DLC films with micro-dimples density of 52% exhibited the lowest average coefficient of friction (COF) and wear rate both under dry friction and liquid lubrication conditions. The improved tribological performance of the textured DLC films with optimum micro-dimples density (52%) under dry friction could be attributed to the friction-induced graphitization of the textured layer and entrapment of wear debris in the micro-dimples. Under liquid lubrication condition, the micro-dimples played the double role of wear debris and lubricating oil reservoirs, then the graphitized textured layer on the worn surface combined with the liquid lubrication film formed a solid-liquid duplex lubricating, thus achieving significantly lower friction and wear. [ABSTRACT FROM AUTHOR]

Pickering emulsion and TiO 2 are subtle assembled by one-step gelation to form the gel sphere with strong adsorption and high catalytic activity. The gel sphere solve the difficulty recovery of powder catalysts, enhance the stability of the Pickering emulsion, and can be used as column filler to build flow photocatalytic systems. • A hierarchical (IL/W) Pickering emulsion gel spheres was designed and fabricated. • The static and flow catalysis systems based on gel spheres were built. • The flow catalysis system exhibited ~100% removal efficiency of 2-naphthol. • Synergistic effect between adsorption and charge transfer was revealed and proved. Pickering emulsion-based photocatalysis is considered to be a promising system due to its large active surface area and water/oil spatial separation capability for enrichment of substrates and products. In this work, a novel hierarchical structure composed of calcium alginate gel sphere wrapped ionic liquid-in-water Pickering emulsion with TiO 2 in the water phase, which are stabilized by graphene oxide, is prepared via a facile one-step emulsion gelation method. Such subtle combination of Pickering emulsion, hydrogel and TiO 2 with a multi-stage solid-liquid assemblage structure shows enhanced degradation activity of 2-naphthol into small molecular alkanes under simulated solar irradiation. The photodegradation activity is attributed to the ionic liquid as adsorption medium for 2-naphthol, and the high-efficient charge separation at graphene oxide/TiO 2 interface superior to that of pure TiO 2. More importantly, the as-prepared millimeter-sized assembled gel spheres can be directly used as the column filler to construct continuous flow photocatalytic system, maintaining the promising performance in removing pollutants from water with ~100% remove ability of 2-naphthol on stream. A charge transfer mechanism of the photocatalyst is proposed, i.e. photogenerated charges are separated in TiO 2 /graphene oxide p-n heterostructure at the interface of Pickering emulsion droplets. [ABSTRACT FROM AUTHOR]

• Steel was coated with Fe-based amorphous coating (AMC) by detonation spraying • This technique worked well: the coating was thick, hard, smooth, and dense • We performed nanoindentation creep tests on the Fe-based AMC • Viscoplastic and anelastic creep responses varied with indentation loading rate • There were two kinds of anelastic creep, corresponding to two relaxation processes A very thick (∼1 mm) coating of Fe-based amorphous material was applied to a Q235 steel substrate by detonation spraying. The rate-dependent anelastic and viscoplastic deformations of the coating were investigated through nanoindentation creep experiments with loading rates of 0.1∼5 mN s−1; the results were analyzed using the Maxwell-Voigt model with two Kelvin units. Creep deformation in the Fe-based amorphous coating was found to be sensitive to loading rate; the nanohardness, creep-stress exponent, and viscosity lessened with increased loading rate during viscoplastic deformation. The presence of two characteristic peaks in the relaxation-time spectrum shows that the anelastic deformation was related to the activation of two types of defects. Low loading rates promoted the activation of defects in the soft region with long relaxation times; larger loading rates promoted the activation of defects in the hard region with shorter structural relaxation times, allowing plastic deformation. This resulted in lower creep resistance at higher loading rates. [ABSTRACT FROM AUTHOR]

Super-thick diamond-like carbon (DLC) film is a potential protective coating in corrosive environments. In the present work, three kinds of DLC films whose thickness and modulation periods are 4 µm and 3, 21 µm and 17 and 21 µm and 7, respectively, were fabricated on stainless steel. The effect of different thickness and modulation periods on corrosion and tribocorrosion behaviour of the DLC-coating stainless steel was investigated in 3.5 wt% NaCl aqueous solution by a ball-on-flat tribometer equipped with a three-electrode electrochemical cell. The DLC-coating stainless steel served as a working electrode, and its OCP and potentiodynamic polarization were monitored before and during rubbing. The wear-corrosion mechanism of the DLC films was investigated by SEM. The results showed that the increasing thickness can prolong significantly lifetime of DLC films in NaCl aqueous solution. In particular, the modulation period has a significant impact on the tribocorrosion resistance of the DLC super-thick films. The study suggested that the increasing thickness of compressive stress layer could suppress film damage by reducing crack propagation rate. Thus, the super-thick DLC film with thickness of 21 µm and 7 periods presented the best tribocorrosion resistance among all studied films. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

To promote the application of Fe-based amorphous coating (AMC)-protected magnesium alloys in fretting wear conditions, a Fe-based AMC with a thickness of about 164 μm was deposited on AZ31B magnesium alloy substrate by detonation spraying. The microstructure and fretting wear behaviors against GCr15 counterpart ball in different frequencies of the Fe-based AMC were studied in detail. The results show that the Fe-based AMC has a substantially complete amorphous structure, the porosity and surface hardness are ≤1.2 vol %, and 764.7 ± 37.5 Hv 0.1 , respectively. Therefore, the Fe-based AMC presents excellent fretting wear resistance, and its wear rate is almost 1/10 of that of AZ31B magnesium alloy, and 1/5 of that of high-velocity oxygen-fuel sprayed 316L stainless steel coating on AZ31B magnesium alloy substrate. The fretting wear behavior of Fe-based AMC was found to be sensitive to the fretting frequency: as the frequency increases from 5 to 100 Hz, the average steady-state friction coefficient increases from 0.77 to 1.07, but the wear rate exhibits an anomalous phenomenon, decreasing from 5.26 × 10−5 mm3N−1m−1 to 3.47 × 10−5 mm3N−1m−1. The improvement in wear rate is mainly attributed to the formation of an oxygen-rich river-like friction layer on the worn surface as the transient contact temperature increases with frequency, effectively suppressing delamination wear. Additionally, the occurrence of high transient frictional temperatures at high frequencies leads to evident crystallization within the coating, accompanied by the formation of nanocrystals, oxide films, and a large area river-like friction layer consisting of debris-compacted layers, which strengthens the Fe-based AMC. Consequently, the wear mechanism changes from delamination wear and abrasive wear at low frequencies to oxidative wear and adhesive wear at high frequencies, resulting in superior fretting wear resistance of the Fe-based AMC at high frequencies. • The synergistic effect of crystalline and oxidized phases increase the average microhardness of the worn surface. • The friction coefficient is positively correlated with fretting wear frequency, while the wear rate is opposite. • The wear mechanism transitions from delamination and abrasive wear to adhesive wear and oxidative wear. [ABSTRACT FROM AUTHOR]

The regular structure provided by two-dimensional (2D) structural colloidal crystals is widely accepted to provide an ideal template that ensures that plasmonic bimetallic composite nanostructures are uniform. Herein, we report an effective method for fabricating bimetallic Au–Ag composite films loaded on the surfaces of 2D polystyrene@polyacrylic acid (PS@PAA) colloidal crystals. PS@PAA particles coated with uniform Ag particle layers (AgFON) were produced by a simple and effective sputtering-deposition technique, after which the galvanic replacement (GR) reaction was used to produce a bimetallic (Au–Ag)FON composite film at the liquid/solid interface in aqueous HAuCl4. The morphology and relative contents of the bimetallic (Au–Ag)FON composite film can be regulated by changing the kinetic factors that control the GR reaction, including the concentration and pH of the HAuCl4 solution, and the reaction time. We demonstrated that the fabricated bimetallic (Au–Ag)FON composite has localized surface plasmon resonance (LSPR) properties that can be regulated by varying the composite structure and Ag/Au composition. On the one hand, the regular 2D colloidal crystal structure provides an ideal template for preparing Au–Ag composite films, which ensures that the optical signals of plasmonic Au–Ag composite films are reproducible. On the other hand, the synergy between Ag and Au in the bimetallic alloy composite film ensures stable and tunable LSPR performance. Furthermore, the prepared 2D ordered (Au–Ag)FON Au–Ag bimetallic material is expected to be used in sensing and catalysis applications. [ABSTRACT FROM AUTHOR]

To supply wear-resistant coatings on AISI 310 austenitic stainless steel for harsh industry applications, Ni3Al intermetallic compound coatings were prepared by high-velocity oxygen fuel (HVOF) spraying. Ni3Al coatings were deposited under different oxygen/fuel ratios of 4.45, 4.89 and 5.34. The phase structure, microstructure, mechanical and tribological properties of the coatings at 25 °C were investigated firstly. As a result, the HVOF oxygen/fuel ratio of 4.89 was chosen to get the best physical properties of an average porosity 1.0 vol.%, thickness 290 μm, hardness 527 ± 16 HV, friction coefficient 0.75 and wear rate 1.74 × 10− 5 mm3/(N·m). Then tribological tests across a wide temperature range from 25 to 800 °C were carried out on the optimized coating: the coating presented the highest anti-friction and wear resistance at 600 °C, a continuous and dense oxide layer comprised of NiO, Ni2O3, Al2O3 and NiAl2O4 was formed and acted as a solid lubricant, and contributed a relatively low friction coefficient of 0.57 and wear rate of 8.91 × 10− 5 mm3/(N·m). The wear mechanisms were mainly tribo-oxidation wear and slight abrasive wear. [ABSTRACT FROM AUTHOR]

A simple and sensitive electrochemical cholesterol biosensor was fabricated based on ceramic-coated liposome (cerasome) and graphene quantum dots (GQDs) with good conductivity. The cerasome consists of a lipid-bilayer membrane and a ceramic surface as a soft biomimetic interface, and the mild layer-by-layer self-assembled method as the immobilization strategy on the surface of the modified electrode was used, which can provide good biocompatibility to maintain the biological activity of cholesterol oxidase (ChOx). The GQDs promoted electron transport between the enzyme and the electrode more effectively. The structure of the cerasome-forming lipid was characterized by Fourier transform infrared (FT-IR). The morphology and characteristics of the cerasome and GQDs were characterized by transmission electron microscopy (TEM), zeta potential, photoluminescence spectra (PL), etc. The proposed biosensors revealed excellent catalytic performance to cholesterol with a linear concentration range of 16.0 × 10−6–6.186 × 10−3 mol/L, with a low detection limit (LOD) of 5.0 × 10−6 mol/L. The Michaelis–Menten constant (Km) of ChOx was 5.46 mmol/L, indicating that the immobilized ChOx on the PEI/GQDs/PEI/cerasome–modified electrode has a good affinity to cholesterol. Moreover, the as-fabricated electrochemical biosensor exhibited good stability, anti-interference ability, and practical application for cholesterol detection. [ABSTRACT FROM AUTHOR]

A top DLC film was deposited on the surface of Cr 3 C 2 -NiCr coated 38CrMoAl steel substrate, and the effect of Cr 3 C 2 -NiCr cermet interlayer thickness on the mechanical and tribological properties of the duplex coating was investigated by experimental analysis and finite element modeling (FEM). Results shown that, compared with single DLC film, the load-bearing capacity and tribological performance of DLC/Cr 3 C 2 -NiCr duplex coating were significantly improved, especially its anti-wear performance was nearly ten times higher than that of the single DLC film. Moreover, the duplex coating with an optimum cermet interlayer thickness of 100 μm showed the best comprehensive performance. FEM analysis also shown that the presence of Cr 3 C 2 -NiCr cermet interlayer limited the stress concentration area within the interlayer, which made the stress concentration area far away from the interface of DLC film and cermet interlayer, thus improved duplex coating durability. What's more, the cermet interlayer thickness increase resulted in the contact stress on DLC film increase, which contributed to the improvement of its tribological performance. • C100 duplex coating achieved superior mechanical and tribological properties. • C100 duplex coating anti-wear rate is ten times higher than single DLC film. • Stress concentration in C100 is the farthest against film/cermet interlayer interface. • Thickened interlayer increased contact stress and intensified DLC graphitization. [ABSTRACT FROM AUTHOR]

Abstract: Nanosized TiO2 photocatalysts of anatase, rutile and mixed-phase were synthesized through hydrolysis method. The influence of the interface junction between anatase and rutile TiO2 on the photo-generated charge carriers properties were studied by Kelvin probe (KP), surface photovoltage (SPV) and transient photovoltage (TPV) techniques. The KP results revealed that the difference of the surface work function between anatase and rutile might cause the formation of built-in field at the interface in mixed-phase TiO2. The role of the interface junction was further testified through the characteristics of photo-generated charge carriers by SPV and TPV. [Copyright &y& Elsevier]

A Ti 40 Zr 25 Ni 3 Cu 12 Be 20 bulk metallic glass (BMG) is treated by laser shock peening (LSP) with 1, 2 and 30 times, and then the phase structure, thermal, mechanical and tribocorrosion behaviors of the Ti-based BMG after LSP processing were studied in detail. The results demonstrate that although LSP did not significantly alter the phase structure of the Ti-based BMG, it facilitated rejuvenation and induced residual compressive stress within the BMG, thereby introducing internal structural heterogeneity. This heterogeneity promoted the generation of a substantial amount of free volume in the LSP-processed BMG specimens, leading to a marked improvement in plasticity and resistance to crack propagation. Consequently, the LSP-1 specimen exhibited higher surface microhardness (7.1 GPa) and plasticity, making it both plastic and tough and mitigating fatigue peeling wear caused by brittleness during reciprocating sliding wear. The average tribocorrosion volume loss rate of the LSP-1 specimen decreased by approximately 11 % to 5.73 × 10−4 mm3 N−1 m−1 (400 mV). However, excessive LSP resulted in elevated surface roughness (552.9 nm) and rejuvenation (ΔH relax = 3.68 J g−1), rendering the surface of LSP-2 specimens more susceptible to pitting and significantly reducing their tribocorrosion resistance. • Ti 40 Zr 25 Ni 3 Cu 12 Be 20 bulk metallic glass is treated by laser shock peening. • Rejuvenation and residual compressive stress are introduced on BMG. • The nanohardness and plasticity of BMG was promoted by laser shock peening. • The tribocorrosion resistance of Ti-based BMG can be optimized by LSP. [ABSTRACT FROM AUTHOR]

• A highly conductive and solvatochromic poly(ionic liquid) ionogel was prepared. • The e-skin based on P(AAm-IL) ionogel can visually detect chemicals. • LiTf can enhance the mechanical and electrical properties of P(AAm-IL) ionogel. • An e-skin with electro-optical dual response to visually detect strain was fabricated. The biological skins exhibit various fascinating visual functions, such as turning red in response to strain, whitening upon hydrogen peroxide stimulation, and changing color in accordance with the environment (octopus). Inspired by these phenomena, two kinds of multifunctional visualized electronic skin (e-skin) were designed and fabricated based on a novel poly (ionic liquid) ionogel. Herein, we reported a transparent and conductive poly (ionic liquid) ionogel (P(AAm-IL)) by photopolymerizing acrylamide (AAm) with 1-vinyl-3-butylimidazolium tetrafluoroborate (ionic liquid, IL) in ethylene glycol (EG). Interestingly, P(AAm-IL) displays a solvatochromic phenomenon, and typical hydrogen-bonding acceptor solvents like acetone, methanol, and nitromethane induce a whitening effect in it. Based on this ionogel, we fabricated multifunctional strain sensors integrated with the visualized chemical sensing ability. The discoloration mechanism of the chemical sensing was detailed studied. Furthermore, by combining the P(AAm-IL) ionogel with Lithium trifluoroethane sulfonate (LiTf), the blend P(AAm-IL)-Li ionogel exhibits enhanced stretchability (>4300 %), higher conductivity (1.44 × 10−2 S·m−1), good transparency (>80 %) as well as wide operating temperature range (−20 to 80 °C). A sandwich-structured e-skin (Polypyrrole/PAAm-IL-Li/CsPbBr 3 -TPU) exhibiting both electro-optical dual response to strain was successfully fabricated. The luminescent e-skin not only exhibits highly sensitive electrical responses but also demonstrates visible fluorescence changes in response to external strain variations. These multifunctional visualized e-skins demonstrate great potential for applications in chemical environmental monitoring robotics, wearable electronic devices, and human–computer interaction. [ABSTRACT FROM AUTHOR]

• A series of solvent additives 1,8-diiodooctane (DIO), 1-chloronaphthalene (CN), 1-phenylnaphthalene (PN), 1-methylnaphthalene (MN) were used to effectively control the morphology and transport properties of a kind of pristine perylene diimide dimer (Bis-PDI-T-EG) films. • The PCE of PerSCs based on the 1-methylnaphthalene doped Bis-PDI-T-EG electron transport layer increase by 18% compared to the reference device without solvent additives. It could be further improved by adding 0.05 wt% graphene together with 0.05 v/v% 1-methylnaphthalene, and the hysteresis effect was reduced. Perylene diimide derivatives (PDIs) are a kind of very promising non-fullerene electron transport material for organic-inorganic perovskite solar cells (PerSCs), owing to their excellent photoelectric properties and low-cost synthesis. However, their tendency to form aggregates strongly influences the film morphology and transport properties. Herein, we provided a simple way to tune the morphology and transport properties of PDIs by solvent additive engineering. A series of solvent additives (1,8-diiodooctane, 1-chloronaphthalene, 1-phenylnaphthalene, 1-methylnaphthalene) was investigated for their role in the morphology and transport property of PDI dimer (Bis-PDI-T-EG) film as well as on the photovoltaic performance of PerSCs. Among these four solvent additives, 1-methylnaphthalene (MN) was found one of the best additive that possesses good adjusting ability to control both morphological and electrical properties of Bis-PDI-T-EG film. The fabricated PerSCs with optimized Bis-PDI-T-EG + 0.05 v/v% MN electron transport layer (ETL) displayed the best power conversion efficiency (PCE) of 14.96%. The performance of PerSCs was further improved by adding 0.05 wt% graphene together with 0.05 v/v% MN, and the maximum PCE of 15.11% was achieved. [ABSTRACT FROM AUTHOR]

The pure MoS 2 coating always performs high friction coefficient and short service life when used in high humidity or after long-time storage in humid atmospheric environment. In this study, the MoS 2 /Pb-Ti composite and MoS 2 /Pb-Ti multilayer coatings are deposited to improve the corrosion resistance in 3.5 wt% NaCl solution and tribological performance in high humidity condition. The electrochemical impedance spectra and salt spray test shown that the MoS 2 /Pb-Ti composite and multilayer coatings can inhibit the permeation of oxygen and other corrosive elements, thus resulting a high corrosion resistance. Furthermore, compared with pure MoS 2 coating, the tribological performance of the MoS 2 /Pb-Ti composite and multilayer coatings is also improved significantly owing to the high mechanical properties and compact structure. Moreover, the heterogenous interfaces in MoS 2 /Pb-Ti multilayer coating play an important role to improve the corrosion resistance and tribological performance of coatings. Overall, the dual-doping and multilayer construction are promising approaches to design the MoS 2 coatings as the environmentally adaptive lubricants. [ABSTRACT FROM AUTHOR]

Boron carbide doped DLC coating can combine the property superiority of these two materials to create high-performance carbon-based coating, while the final property of the composite coating is strongly dependent on the proportion of coating components. The aim of this study was to investigate the effect of boron carbide content on the mechanical and tribological properties of the magnetron sputtered B 4 C/a-C coatings, as well as the relevant low friction mechanism. It was found that both the carbon matrix and introduced boron carbide were amorphous and the composite coating exhibited typical columnar structure. Appropriate doping of boron carbide significantly enhanced coating hardness, toughness as well as the adhesion strength and carrying ability, and all of them reached the optimal value when the B concentration was 2.92 at.%. It was also found that the B 4 C/a-C coating with B 2.92 at.% exhibited the lowest steady friction coefficient about 0.05 and highest wear resistance at 20% RH. None of boric acid was formed on the sliding interface under the tested humidity range. Thus, the improved tribological properties were mainly attributed to the enhanced mechanical properties and friction-induced formation of an intact graphitized carbon transfer layer on the counterpart under specific humidity condition. [ABSTRACT FROM AUTHOR]

A ternary Ti-25Al-17 Nb coating (89.5 vol. % O phase and 4.3 vol. % α 2 phase) was fabricated from the pre-alloyed powder by in-situ laser synthesis. The powder was laser scanned to form α 2 phase at high temperature and subsequently precipitated primary Ti 2 AlNb phase (O phase) in an acicular structure; while the secondary fine acicular O phase was squeezed due to the expansion of α 2 phase with induced some edge dislocations and mixed dislocations. The dense and hard Al 2 O 3 film gradually replaced the loose and porous TiO 2 oxide film as an oxygen diffusion barrier, thereby reducing the possibility of brittle oxide formation and significantly increasing the wear resistance and oxidation resistance, results in an excellent wear resistance at 800 ℃. [Display omitted] • Ti2AlNb-based alloy coating with 89.5 % O-phase was synthesized by laser in-situ cladding on Ti-6Al-4V. • TEM indicates that O phase precipitates from α2 phase and satisfies (001)O//(0001)α2 orientation. • EBSD indicates that secondary O phase grains was restrained and distributed in the deformed region. • O-based coating exhibits good wear resistance at 800 °C profit from dense and hard Al2O3 film. [ABSTRACT FROM AUTHOR]

The Fe-based amorphous amorphous coating with a thickness of 150 μm was prepared by detonation spraying. Under a constant strain rate (0.01 s−1 and 0.50 s−1) and a holding time of 50 s, the Fe-based amorphous coatings were subjected to room temperature nanoindentation creep tests with the penetration depth varying from 50 nm to 500 nm, then the depth-dependent creep deformation mechanism of Fe-based amorphous coating during nanoindentation tests were investigated in detail. The results show that the creep responses of coating obviously depend on the indentation penetration depth (h p) and the indentation load rate, i.e., the creep displacement of coating increases with the increase of h p and loading strain rate. This is mainly due to the rapid increase in the shear transition zone volume of the coating as the h p increases, making it easier for the shear band to be excited to nucleate, and results in an obvious creep deformation. Moreover, at high strain rates, the initiation rate of the free volume in the amorphous coating far exceeds its annihilation rate, resulting in a large amount of excess free volume in the amorphous coating, which makes it easier to excite multiple shear bands in the amorphous coating and cause creep plastic deformation. • Fe-based amorphous coatings were deposited by detonation spraying. • The amorphous coating displays a very significant indentation size effect. • Lager shear transition zone volume induces the multiple initiations of shear bands. • Free volume is more likely to accumulate and promote creep at high strain rates. [ABSTRACT FROM AUTHOR]

Sintering behavior is one of the most important indicators correlated to the service behaviors for thermal barrier coatings (TBCs). 5 different La 2 Zr 2 O 7 (LZO)/YSZ double ceramic layer (DCL) combination TBCs are subjected to gradient thermal cyclic tests under the surface temperature of 1150 °C, aiming to elucidate the service behaviors of the DCL TBCs under relative low temperature. The failure of DCL TBCs is the cracking of top coat along in-plane direction, the 8YSZ TBCs showed an vertical cracking after 2200 cycles, and the stress state transferred from tensile about 250 MPa to compressive of −60 MPa. The pure 8YSZ is superior to the DCL TBCs for the long-term application at relative low temperature. Sintering induced the competition of cracking driving force and resistance dominates the cracking of TBCs, the formation of vertical cracks released the stress of the 8Y TBCs system to a large extent and the lifetime was extended. • 8YSZ TBCs is still shows outstanding performance under 1200 °C, a moderate sintering may contribute to the cracking resistance and promote the formation of vertical cracks which is beneficial for extending the TBCs thermal cyclic test lifetime. • La 2 Zr 2 O 7 /YSZ double ceramic layer (DCL) thermal barrier coatings showed an inferior thermal cyclic performance compared with the 8YSZ TBCs when subjected to the surface temperature of 1150 °C thermal gradient cyclic test. • The formation of vertically cracks is beneficial the releases of stress boosted by sintering and thermal mismatch, the stress state of 8YSZ TBCs transferred from tensile to compressive after 2200 thermal cyclic tests. [ABSTRACT FROM AUTHOR]

Abstract: Carbon-doped ZnO microspheres were prepared through a facile hydrothermal process. The characterizations for the physicochemical properties of prepared samples under different calcination temperatures were carried out on X-ray diffraction analysis, scanning electron microscopy, X-ray photoelectron spectroscopy, UV–vis diffuse reflectance spectra, Raman spectroscopy and photocurrent spectra. C-doped ZnO under 500°C calcination exhibited the superior UV-activated room-temperature gas sensing activity for the detection of ethanol. The result of transient photovoltage suggested that the presence of sp2 carbon-type structures could improve the separation extent and restrain the recombination of the photoinduced electron–hole pairs, which increase the number of photoinduced oxygen ions on the surface of C-doped ZnO and enhancing of gas sensing activity. [Copyright &y& Elsevier]

Abstract: The magnetic mixed hemimicelles solid-phase extraction (MMHSPE), based on the adsorption of cation surfactant octadecyltrimethylammonium bromide (OTMABr) onto magnetite nanoparticles (Fe3O4 NPs) to form mixed hemimicelles, was proposed for the preconcentration of several sulfonamides (SAs) compounds including sulfamethoxazole (SMX), sulfamethoxydiazine (SMD), sulfadimethoxine (SDM) and sulfaquinoxaline (SQX) from environmental water samples. This method avoided the time-consuming column-passing process of loading large volume samples in traditional SPE through the rapid isolation of OTMABr-coated Fe3O4 NPs with an adscititious magnet. Mixed hemimicelles formed on the surface of Fe3O4 NPs by OTMABr showed great adsorptive tendency towards analytes. The OTMABr-coated Fe3O4 NPs adsorbents were easy to be prepared, low cost and environmentally friendly. A comprehensive study on the adsorption conditions such as the amount of the surfactant, the solution pH, the desorption condition and the maximum extraction sample volume were optimized. A concentration factor of 1000 was achieved by the extraction of 500mL of environmental water samples using MMHSPE. Detection limits obtained for SMX, SMD, SDM and SQX were 0.026, 0.024, 0.033 and 0.030μgL−1, respectively. Good recoveries (70–102%) with low relative standard deviations (1–6%) were achieved in analyzing spiked water samples. Low concentration of SQX was found in hospital primary and final sewage effluent sample. [Copyright &y& Elsevier]

Si-doped diamond-like carbon (Si/DLC) films appear very attractive due to their superior mechanical and tribological properties and chemical inertness. In the present work, Si/DLC films with silicon concentration from 1.64 to 15.32 at.% were fabricated on 304 stainless steel by adjusting Si target current using unbalanced magnetron sputtering system. The microstructure, surface morphology and mechanical properties of the films with different Si concentration, as well as the tribological and electrochemical properties of the films under HCl corrosive environment were systematically investigated. Results showed that Si doping increased the sp3 C C content, hardness, and elastic modulus of as-fabricated films, lowered the residual stress, but deteriorated the adhesion strength. At the same time, the appropriate Si concentration was conducive to low surface roughness and dense microstructure. The Si/DLC films presented good tribological performances in 1 M HCl solution, including low friction coefficient and wear rate. The degradation of tribological properties was attributed to the synergistic effect of less solid lubrication, declined adhesion strength, worse resistance to elastic and plastic deformation. The wear mechanism was mainly dominated by abrasive wear. Furthermore, the Si/DLC film with 15.32 at.% Si provided the best corrosion resistance, which benefited from its dense structure, higher thickness, and the highest sp3 C C content. [Display omitted] • The Si/DLC films with various Si concentrations were fabricated by UBMS technology. • The Si/DLC films showed favorable tribological behaviors in 1 M HCl solution. • The Si/DLC film with 15.32 at.% Si exhibited the best corrosion resistance. [ABSTRACT FROM AUTHOR]

Fe-based amorphous coating is deposited on invar steel substrates using detonation spray and then through the cryogenic cycling (CCT) treatment from 0 to 60 cycles with the interval 10 cycles. Effects of CCT on microstructure, thermal properties, mechanical and tribological properties were investigated. It was found that, all the coated samples with CCT are still well bonded with the invar steel substrate, except for the surface of C60 appears local cracks. Moreover, it also found that although CCT did not significantly change the phase structure of the amorphous coating, CCT promoted the rejuvenation behavior in the amorphous coating, which also led to the heterogeneity of the internal structure. Attributed to this heterogeneity, it promotes the generation of a large amount of free volume in the amorphous coating, which results in a significant change in the toughness and resistance to crack propagation of the amorphous coating. And after 50 CCT cycles, the amorphous coating has undergone an obvious ductile-brittle transition, which has the highest fracture toughness K IC and plastic work W p value. The COF and wear rate of coatings increased initially, then followed by a decrease, but then again increased with the increase of CCT cycles. The 50-cycles coatings exhibited the lowest COF (0.60) and wear rate (0.56 × 10−5 mm3N−1 m−1). The wear mechanism of all the samples is mainly delamination wear with oxidative wear, but the degree of delamination wear is obviously different, showing a trend corresponding to the tribological behavior of the amorphous coating. Therefore, the CCT method could be an effectively strategy to ameliorate the toughness and then enhance the wear performance of the Fe-based amorphous coating. • Fe-based amorphous coatings were deposited by detonation spraying. • The coated samples were treated by cryogenic thermal cycling from 0– 60 cycles. • The cryogenic thermal cycling treated samples undergo a brittle-tough transition. • C50 coatings exhibit the best friction and wear properties. [ABSTRACT FROM AUTHOR]

Duplex coating, composing of a thick Cr 3 C 2 -NiCr interlayer and a top CrN film, were deposited by high velocity oxy-fuel (HVOF) and arc ion plating technologies, and the microstructure, mechanical properties and thermal shock resistance of the duplex coating were investigated compared to those of the single CrN film, as well as tribological behaviors at elevated temperatures. Results showed that the duplex coating exhibited high surface hardness, H / E and H 3/ E 2 ratios, load-bearing capacity and adhesive strength due to the supporting of the Cr 3 C 2 -NiCr interlayer, which contributed to improve the wear properties of duplex coating sliding against Al 2 O 3 ball. At 25 °C, the duplex coating had a higher friction coefficient and a relatively low wear loss, and the main wear mechanism was abrasive wear. As the temperature increased to 350 °C, the top CrN film of duplex coating was worn out totally. The severe mismatch of coefficient of thermal expansion (CTE) between Cr 3 C 2 -NiCr interlayer and substrate that might have a negative impact on wear resistance of duplex coating at high temperature. In addition, a large number of debris produced due to oxidation peeling of the coatings were compacted to form a thick transfer film during the sliding process, resulting in badly adhesive wear. The wear mechanisms were adhesive and oxidation wear accompanied with abrasive wear at high temperature (from 150 °C to 550 °C). • The CrN/Cr 3 C 2 -NiCr duplex coatings are fabricated by PVD/HVOF. • Duplex coatings show superior mechanical properties than single PVD film. • Cr 3 C 2 -NiCr interlayer significantly improves wear resistance of CrN film at 25 °C. • Mismatch of CTE in duplex coating and friction induced oxidation results in severe wear above 150 °C. [ABSTRACT FROM AUTHOR]