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Systematic analysis of discharge processes is needed for a good understanding of the physical mechanism that enables optimal coating deposition, especially pulsed discharges sustained by high voltages and large currents. Owing to the temporal and complex characteristics of the discharge process and relatively simplistic analytical methods, the discharge process and particle evolution in high-power impulse magnetron sputtering (HiPIMS) are still not well understood. In this work, a cylindrical cathode is introduced to restrict the discharge and delay plasma loss, and a global model is established to simulate the discharge on a Cr target in N2/Ar. Particles with different reaction energies appearing successively produce an asynchronous discharge phenomenon, and a series of inflection points corresponding to different physical processes including excitation, sputtering, ionization, and diffusion are observed from the particle density evolution curves. High-precision and time-resolved spectrometry (400 ns) is utilized to monitor the evolution of particles with time, and inflection points predicted by the model are observed experimentally to verify the particle behavior in the HiPIMS discharge. [ABSTRACT FROM AUTHOR]

High-power impulse magnetron sputtering boasts high ionization, large coating density, and good film adhesion but suffers from drawbacks such as low deposition rates, unstable discharge, and different ionization rates for different materials. Herein, a cylindrical cathode in which the special cathode shape introduces the hollow cathode effect to enhance the discharge is described. To study the discharge performance of the cylindrical cathode, a hollow cathode effect modified time-dependent global model is established to fit the discharge current pulses. The simulation results indicate that the cylindrical cathode has relatively large Hall parameters of 24 (700 V) to 26 (1000 V). Compared to the planar cathode, the cylindrical cathode has a larger plasma density as a result of the hollow cathode effect. In addition, the ionization rate and ion return probability increase by about 3.0% and 4.3%, respectively. Particle transport derived from the plasma diffusion model shows that the magnetic field enables further diffusion of ions than atoms, resulting in nearly pure ion deposition on the substrate. The deposition rate and ion current measured experimentally support the simulation model and results, and this model provides a universal platform to simulate plasma systems with similar structures. [ABSTRACT FROM AUTHOR]

Micro-arc oxidation (MAO) is a popular coating technology for aluminum alloys, but the wear resistance and friction properties are limited by the intrinsic properties of the alumina coatings with high friction coefficients. In this work, CePO 4 is identified as a quasi-2D material by the first principle calculation. As a self-lubricating phase, it is firstly formed in situ during the oxidation process and the lubrication mechanism is investigated. Nano-grains of cerium phosphate are formed and imbedded uniformly in the alumina coatings. With increasing Ce contents, the friction coefficients diminish to 0.1–0.15 during the 5-h test without obvious fluctuation. The results reveal the new concept of using self-lubricating additives in MAO oxide on Al alloys to improve the durability and mechanical properties. • CePO 4 is identified as a quasi-2D material and its first attempt in the self-lubrication field is conducted. • Nano CePO 4 grains are produced and imbedded uniformly in alumina coatings, forming a layered fracture. • The friction coefficients diminish to 0.1–0.15 from 0.8 during the 5-h test without obvious fluctuation. • A transformation from abrasive wear to adhesive wear is observed as the content of the lubricating phase increases. [ABSTRACT FROM AUTHOR]

Aluminum alloys are widely used in the aerospace and transportation industries, but the corrosion resistance is insufficient in long-term service especially in the high salinity environment. A ceramic coating composed of ZnO nanoparticles is demonstrated to significantly improve the corrosion resistance of the Al alloys. Owing to the similar chemical activity of Zn and Al, ZnO particles fuse into Al 2 O 3 in the micro-arc during plasma electrolytic oxidation (PEO) rendering the coating compactness. The formation mechanism of the PEO coating is investigated and discussed. The corrosion current of the ZnO modified PEO coating is 4 orders of magnitude less than that of the LY12 substrate. Immersion tests performed in 3.5 wt% sodium chloride show that incorporation of ZnO prevents destruction and dissolution of the PEO coating in the high salinity environment. • The corrosion resistance of the LY12 Al alloy is improved by performing PEO in the electrolyte containing ZnO particles. • The ZnO particles can fuse with multi-phase alumina to form denser PEO coatings. • The ZnO-incorporated coating shows 4 orders of magnitude smaller corrosion currents than the LY12 substrate. [ABSTRACT FROM AUTHOR]

Abstract The high ion energy produced by the substrate bias is essential to the enhancement of the sp3 content in diamond-like carbon (DLC) coatings and adhesion with the substrate. However, excessive ion energy can turn into heat conversely converting sp3 into sp2 undermining the mechanical properties. In this work, pulsed kV bias is applied to increase the carbonous ion energy to increase the sp3 content in DLC coatings and improve the adhesion with the substrate simultaneously while avoiding adverse temperature increase. The high ionized carbonous ions flux is formed by an anode-layer ion source with C 2 H 2 gas and Cr/CrC x /CrC interlayers are introduced between the DLC coating and high-speed steel (HSS) substrate to release the internal stress by high-power impulse magnetron sputtering (HiPIMS). The DLC coatings not only have a large sp3 content, high hardness of 18.5 GPa, a low friction coefficient of 0.12, superior anti-corrosion behaviors,and wear rate of 0.87 × 10−15 m3/N m for 4 h, but also exhibits outstanding adhesion (Lc = 76 N) with the HSS substrate in spite of a DLC coating thickness of 13 μm. Highlights • A novel strategy of pulsed kV bias is used to obtain high ion energy and avoid high temperature in DLC coatings preparation. • The strategy produces both a highest content of sp3 hybridization and high adhesion of 76N, even the DLC thickness is 13 μm. • The DLC coatings show high hardness of >18 GPa, excellent tribological and corrosion resistances. [ABSTRACT FROM AUTHOR]

Abstract Nb-doped TiO 2 (NTO) films have potential to replace indium tin oxide (ITO) as transparent conducting material. However, costly substrates with a specific orientation such as sapphire must be used to avoid formation of the rutile phase and to obtain transparent and conductive NTO films. Furthermore, scaling up is difficult thus hampering commercialization. Herein, in order to control the crystal orientation of TiO 2 , two-step preparation is described. An amorphous NTO film is first prepared on the economical soda-lime glass substrate by low-energy magnetron sputtering and the sample is annealed in Ar with 5 at% H 2 at 400 °C to crystallize the amorphous structure into anatase (101) and anatase (004). The morphology, structure, and optoelectrical properties of the NTO films and relationship with film thickness are studied. The resistivity decreases to 8.1 × 10−4 Ω·cm for a thickness of 320 nm and the average transmittance in the visible region increases monotonically to 73% as the thickness is reduced from 400 nm to 280 nm. The good conductivity and transmittance suggest potential application to smart windows and solar cells. Highlights • NTO films with pure anatase phase were fabricated on the soda-lime glass substrates by a two-step process. • The relationship between the structural, morphological, optical and electrical properties and film thickness was studied. • Low resistivity of 8.1 × 10−4 Ω·cm and excellent transmittance of ~70% in the visible region were obtained. [ABSTRACT FROM AUTHOR]

Abstract The sucker rod pump, an important machine in oil exploration and extraction, normally works in a heavy oil and sand environment in which severe abrasion and erosion occur, especially on oil-well tubings. To improve the service life, DLC coatings with different thicknesses are fabricated on the oil-well tubings and the mechanical, tribological, and anti-corrosion properties are investigated. The results show that the thickness can be compromised with adhesion due to the low stress induced by alternate implantation and deposition at the pulsed high-voltage bias. Compared to severe abrasion of the carbonitriding AISI 1045 oil-well tubing, the thick DLC coatings have good anti-abrasion properties in the heavy oil and sand environment. Moreover, excellent erosion resistance is observed from the DLC-coated samples as exemplified by the small corrosion current density and high corrosion potential. The tests conducted in both simulated and practical working conditions reveal that the service life of the oil-well tubing is significantly improved. Highlights • The behaviors of DLC coatings on oil-well tubing in heavy oil sand environment are studied. • Large DLC thickness can be compromised with adhesion and lead to high load bearing capacity. • The service life of the thick DLC coated oil-well tubing is significantly improved. [ABSTRACT FROM AUTHOR]

The discharge and deposition characteristics of high-power impulse magnetron sputtering using various target materials with different sputtering yields (Cu, Cr, Ti, and C) were analyzed by a plasma global model. The experimental discharge voltages and currents of various target materials were used as the input parameters of the model. The analysis reveals that the ionization fraction of the sputtered species decreases as increasing the sputtering yield, due to the electron temperature was reduced through the cooling effect of sputtered species. However, as the sputtering yield increases, the plasma density under a given discharge power density is increased and the self-sputtering runaway can be fully developed, resulting in a higher fraction of ion density in the form of metal ions in the ion deposition flux. For some high-sputtering yield materials, such as Cu and Cr, this fraction can be up to 95%. [ABSTRACT FROM AUTHOR]

Diamond-like carbon (DLC) coatings have attracted much attention due to their excellent hardness, low friction, and superior corrosion resistance. Unfortunately, the poor adhesion caused by internal stress limits the typical thickness to below 3–5 μm. This paper presents a novel interlayer design and interface engineering and the induced excellent adhesion of thick diamond-like carbon (DLC) coatings on a high speed steel substrate. The interlayer has fundamentally a graded Cr/CrC x /CrC/DLC structure, but various treatments to the hetero-interfaces have been conducted including sequential energetic ion bombardments with Cr at the substrate/Cr interface using high-power impulse magnetron sputtering (HiPIMS) and with C at the CrC/DLC interface using an anode layer ion source. It has been observed that the critical load has been improved from 18 N for a single Cr interlayer to 77 N for a Cr/CrCx/CrC interlayer for thick DLC coatings of 13 μm. Using the same design, a very high critical load of 73 N has been achieved on the ultra-thick DLC coating of 50 μm. This interlayer design has allowed the deposition of a DLC coating that is not only thick but also hard with excellent tribological properties. The DLC coatings have a high hardness of >18 GPa, a low friction coefficient of 0.12 and a low wear rate of (1.7 ± 0.2) × 10 −15 m 3 /N·m. This paper discusses the effect of the ion bombardment of the interlayer on the coating adhesion and the strengthening mechanisms. [ABSTRACT FROM AUTHOR]

By combining the advantages of the thermo-mechanical properties of TiAlN and self-lubricating properties of diamond-like carbon (DLC), a multi-layered TiAlN/DLC coating is fabricated by filtered cathodic vacuum arc and magnetron sputtering. According to the different morphology and mismatch between the physical and chemical properties of TiAlN and DLC, multiple methods are used to study the growth mechanism of crystalline TiAlN and amorphous DLC in the combined system. The morphology evolution depending on the bias is studied and the brittle interface is assessed by scratch experiments. The results show that an interlamination failure occurs at the top of first DLC layer due to the cluster morphology obtained by small bias, however, the failure moves to the interface above the substrate when the clusters are refined by increasing bias. By adopting the stepwise decreased bias, the 4.5 μm thick TiAlN/DLC multi-layer coating is fabricated and does not exhibit interfacial failure at any interface between TiAlN and DLC in the scratch experiments up to a load of 100 N. Excellent adhesion (Lc = 63 N) is also achieved from coatings deposited on high-speed steel with optimized Cr/CrCx/CrC interlayers prepared by high-power impulse magnetron sputtering. [ABSTRACT FROM AUTHOR]

Lead-free solder is widely used in the industry, especially in wave soldering. However, the stainless steel holders used in wave soldering are prone to corrosion by the lead-free solder due to increased reactive wetting. Besides, owing to the high affinity between the holders and solder, they are often used to take solder out of the container. To improve tin repellence and the mechanical properties of the stainless steel holders, Ti/TiC and Ti/TiC/DLC coatings are deposited by filtered cathodic vacuum arc (FCVA) and plasma immersion ion implantation and deposition (PIII&D). The morphology, structure, composition, microhardness, wear resistance, electrochemical properties, and wetting characteristics are investigated systematically. The DLC coating, which has an amorphous structure and I D /I G ratio of about 0.55, further enhances the frictional properties, corrosion resistance, and hydrophobic characteristics of the Ti/TiC structure. The surface-modified holders show excellent tin repellence in wave soldering. [ABSTRACT FROM AUTHOR]

Lead-free solder is increasingly used in the wave soldering but corrosion of the stainless steel holders frequently occurs and produces deleterious effects. To enhance the service life, a Ti/TiC coating is deposited by filtered cathodic vacuum arc (FCVA) on the stainless steel holders. The morphology, structure, composition, microhardness, wear resistance, electron chemical corrosion, and wetting properties against solder are investigated. The results show that not only good frictional properties and corrosion resistance are achieved by the Ti/TiC coatings, but also good tin repelling and hydrophobic characteristics are observed. The Ti/TiC coating provides excellent protection against corrosion of lead-free solder in wave soldering. [ABSTRACT FROM AUTHOR]

An unstable stage is observed from the discharge current during the transition from gas-dominant discharge to the self-sputtering dominant regime in high-power impulse magnetron sputtering (HiPIMS). The phenomenon and the formation mechanism are time dependent and there is a dynamic transition between the two stable stages. The threshold of the high stable discharge is investigated at different pressure and hybrid DC discharge. According to the derivation of the discharge current, the temperature in the discharge is found to play a major role in the dynamic transition at moderate voltage. [ABSTRACT FROM AUTHOR]

The Asian citrus psyllid, Diaphorina citri is the principal vector of the highly destructive citrus disease called Huanglongbing (HLB) or citrus greening, which is a major threat to citrus cultivation worldwide. More effective pest control strategies against this pest entail the identification of potential chemosensory proteins that could be used in the development of attractants or repellents. However, the molecular basis of olfaction in the Asian citrus psyllid is not completely understood. Therefore, we performed this study to analyze the antennal and abdominal transcriptome of the Asian citrus psyllid. We identified a large number of transcripts belonging to nine chemoreception-related gene families and compared their expression in male and female adult antennae and terminal abdomen. In total, 9 odorant binding proteins (OBPs), 12 chemosensory proteins (CSPs), 46 odorant receptors (ORs), 20 gustatory receptors (GRs), 35 ionotropic receptors (IRs), 4 sensory neuron membrane proteins (SNMPs) and 4 different gene families encoding odorant-degrading enzymes (ODEs): 80 cytochrome P450s (CYPs), 12 esterase (ESTs), and 5 aldehyde dehydrogenases (ADE) were annotated in the D. citri antennal and abdominal transcriptomes. Our results revealed that a large proportion of chemosensory genes exhibited no distinct differences in their expression patterns in the antennae and terminal abdominal tissues. Notably, RNA sequencing (RNA-seq) data and quantitative real time-PCR (qPCR) analyses showed that 4 DictOBPs, 4 DictCSPs, 4 DictIRs, 1 DictSNMP, and 2 DictCYPs were upregulated in the antennae relative to that in terminal abdominal tissues. Furthermore, 2 DictOBPs (DictOBP8 and DictOBP9), 2 DictCSPs (DictOBP8 and DictOBP12), 4 DictIRs (DictIR3, DictIR6, DictIR10, and DictIR35), and 1 DictCYP (DictCYP57) were expressed at higher levels in the male antennae than in the female antennae. Our study provides the first insights into the molecular basis of chemoreception in this insect pest. Further studies on the identified differentially expressed genes would facilitate the understanding of insect olfaction and their role in the interactions between olfactory system and biological processes. [ABSTRACT FROM AUTHOR]

Olfactory transduction is a process by which olfactory sensory neurons (OSNs) transform odor information into neuronal electrical signals. This process begins with the binding of odor molecules to receptor proteins on olfactory receptor neuron (ORN) dendrites. The major molecular components involved in olfaction include odorant-binding proteins (OBPs), chemosensory proteins (CSPs), odorant receptors (ORs), gustatory receptors (GRs), ionotropic receptors (IRs), sensory neuron membrane proteins (SNMPs) and odorant-degrading enzymes (ODEs). More importantly, as potential molecular targets, chemosensory proteins are used to identify novel attractants or repellants for environmental-friendly pest management. In this study we analyzed the transcriptome of the flea beetle, Phyllotreta striolata (Coleoptera, Chrysomelidae), a serious pest of Brassicaceae crops, to better understand the molecular mechanisms of olfactory recognition in this pest. The analysis of transcriptomes from the antennae and terminal abdomens of specimens of both sexes identified transcripts from several key molecular components of chemoreception including 73 ORs, 36 GRs, 49 IRs, 2 SNMPs, 32 OBPs, 8 CSPs, and four candidate odorant degrading enzymes (ODEs): 143 cytochrome P450s (CYPs), 68 esterases (ESTs), 27 glutathione S-transferases (GSTs) and 8 UDP-glycosyltransferases (UGTs). Bioinformatic analyses indicated that a large number of chemosensory genes were up-regulated in the antennae. This was consistent with a potential role in olfaction. To validate the differential abundance analyses, the expression of 19 genes encoding various ORs, CSPs, and OBPs was assessed via qRT-PCR between non-chemosensory tissue and antennae. Consistent with the bioinformatic analyses, transcripts for all of the genes in the qRT-PCR subset were elevated in antennae. These findings provide the first insights into the molecular basis of chemoreception in the striped flea beetle. [ABSTRACT FROM AUTHOR]

[Display omitted] • Bio-inertness of Ti has been a long-term shortcoming of the material. • A two-layer hierarchical structure was formed on the surface of 3D printed pure Ti using a one-step MAO approach. • The MTi/Ag/CaP implant showed an excellent long-term antibacterial property and biocompatibility in vitro. • The MTi/Ag/CaP implant showed good osteogenecity and osseointegration in vivo. • The one-step MAO shows potential as a promising approach for the prevention and treatment of IBDs. Infectious bone defects (IBD) remain a major problem in orthopedics in clinical settings. For IBD repair, implants possessing multiple functions such as osseointegration and antibacterial activity are in demand. This study aims to develop a surface-modified titanium (Ti) implant (MTi/Ag/CaP) with osseointegration and antibacterial functions for IBD repair. The pure Ti implant is printed using a selective laser melting technique, and a two-layer hierarchical structure is formed on its surface using a one-step micro-arc oxidation (MAO) approach. The outer layer is an apatite-like material decorated with Ag nanoparticles, whereas the inner layer is porous TiO 2. In vitro experiments show that the MTi/Ag/CaP implant can effectively eliminate and inhibit the adhesion and proliferation of bacteria over a long period time while promoting MG-63 cell adhesion, proliferation, and osteogenic differentiation. In vivo experiments further reveal that the MTi/Ag/CaP implant produces more mineralized bone tissue than non-treated samples and interlocks closely with the bone tissue after 8 weeks. The one-step MAO modification developed in this study is simple, efficient, and environment-friendly, which demonstrates great potential as a promising approach for providing advanced biomedical materials in orthopedic applications, including for the prevention and treatment of IBDs. [ABSTRACT FROM AUTHOR]

The oriental fruit fly, Bactrocera dorsalis, is a devastating fruit fly pest in tropical and sub-tropical countries. Like other insects, this fly uses its chemosensory system to efficiently interact with its environment. However, our understanding of the molecular components comprising B. dorsalis chemosensory system is limited. Using next generation sequencing technologies, we sequenced the transcriptome of four B. dorsalis developmental stages: egg, larva, pupa and adult chemosensory tissues. A total of 31 candidate odorant binding proteins (OBPs), 4 candidate chemosensory proteins (CSPs), 23 candidate odorant receptors (ORs), 11 candidate ionotropic receptors (IRs), 6 candidate gustatory receptors (GRs) and 3 candidate sensory neuron membrane proteins (SNMPs) were identified. The tissue distributions of the OBP and CSP transcripts were determined by RT-PCR and a subset of nine genes were further characterized. The predicted proteins from these genes shared high sequence similarity to Drosophila melanogaster pheromone binding protein related proteins (PBPRPs). Interestingly, one OBP (BdorOBP19c) was exclusively expressed in the sex pheromone glands of mature females. RT-PCR was also used to compare the expression of the candidate genes in the antennae of male and female B. dorsalis adults. These antennae-enriched OBPs, CSPs, ORs, IRs and SNMPs could play a role in the detection of pheromones and general odorants and thus could be useful target genes for the integrated pest management of B. dorsalis and other agricultural pests. [ABSTRACT FROM AUTHOR]

Improving battery capacity and power is a daunting challenge,and in Li-ion batteries positive electrodes often set the limitationon both properties. Layered transition-metal oxides have served asthe mainstream cathode materials for high-energy batteries due totheir large theoretical capacity (∼280 mAh/g). Here we reporta significant enhancement of cathode capacity utilization througha novel concept of material design. By embedding Li(Ni0.5Co0.2Mn0.3)O2in the single wallcarbon nanotube (CNT) network, we created a composite in which allcomponents are electrochemically active. Long-term charge/dischargestability was obtained between 3.0 and 4.8 V, and both Li(Ni0.5Co0.2Mn0.3)O2and CNT contributeto the overall reversible capacity by 250 and 50 mAh/g, respectively.The observed improvement causes significant depolarization withinthe electrodes through the CNT network system. Additionally, the depolarizationprovides the ideal template to understand the solid reaction mechanismof Li(Ni0.5Co0.2Mn0.3)O2by demonstrating well-defined two-stage delithiation kinetics consistentwith first-principle calculations, which would be otherwise impossible.These results deliver new insights on both practical designs and fundamentalunderstandings of battery cathodes. [ABSTRACT FROM AUTHOR]

Abstract: A nanostructured interfacial layer with a graded structure is produced by hybrid high-power pulsed magnetron sputtering–plasma immersion ion implantation and deposition (HPPMS–PIII&D) to improve adhesion of multi-functional coatings. As a demonstration, a ceramic CrN film is prepared on stainless steel together with a Cr interlayer. High-resolution transmission electron microscopy (HR-TEM) reveals the presence of a 40nm thick nanostructured interfacial layer between the Cr interlayer and substrate with gradually changing compositions, and this layer which possesses a dense and pore/void free structure is responsible for the strong film adhesion. The hybrid technology combines the benefits of both the HPPMS and PIII&D enabling fabrication of functional films with the desired properties. The technique and fabrication strategy have many potential applications in photovoltaics, energy storage, tribology, lubrication, aeronautics, and astronautics. [Copyright &y& Elsevier]

Abstract: In order to achieve excellent adhesion between coatings and substrates, PBII&D technique was proposed and used more and more widely to produce hard coatings. Among the metal plasma source, one based on HPPMS technique (HPPMS-PIID) proposed recently seems to have great prospects. The present study aims to develop the difference of CrN films deposited on Si (100) and SU201 stainless steel substrates with PBII&D technique using different metal plasma sources of HPPMS, FCA and DCMS. In contrast to the other two samples, the sample based on HPPMS appears to have dense knitting-like surface and discontinuous columnar structure. The highest intensity of CrN(200) preferential orientation, best adhesion and hardness is obtained by HPPMS plasma source for the highly energetic ion implantation and bombardment, but the C fraction is a little higher since the sputtering of highly energetic ions. [Copyright &y& Elsevier]

Abstract: High power pulsed magnetron sputtering (HPPMS) has attracted much interest due to the large plasma density and high ionization rate of sputtered materials. It is expected to produce a highly ionized C flux from a graphite target but unfortunately, the ionization rate of carbon is still very small and the discharge on a solid carbon target is unstable as well. In this work, a stable discharged chromium target is used in the preparation of chromium-doped diamond-like carbon (Cr-DLC) films in HPPMS in reactive C2H2 gas, but the unstable graphite. The chromium concentration in the Cr-DLC films is limited by surface poisoning due to reactive gas. Less than 2% of Cr is incorporated into the DLC films at C2H2 flow rate of 5sccm or higher. However, as a result of the high ionization rate of the reactive gas in HPPMS, intense ion bombardment of the substrate is realized. The films show a smooth surface and a dense structure with a large sp3 concentration. As the C2H2 flow increase, the sp3 fraction increase and the sp3 to sp2 ratio increase to 0.75at a C2H2 flow rate of 10sccm. Compared to the substrate, the Cr-DLC films have lower friction and exhibit excellent corrosion resistance. [Copyright &y& Elsevier]

Abstract: CrN films with strong adhesion with the substrate have been fabricated on Ti6Al4V alloy using novel plasma immersion ion implantation and deposition (PIII&D) based on high power pulsed magnetron sputtering (HPPMS). A macro-particle free chromium plasma is generated by HPPMS while the samples are subjected to high voltage pulses to conduct PIII&D. The CrN coatings have a dense columnar structure and low surface roughness. The grains in the films have the face-center cubic (fcc) structure with the (200) preferred orientation. An excellent adhesion is achieved with a critical load up to 74.7N. An implantation voltage of 18kV yields a hardness of 18GPa and better wear resistance and a low friction coefficient of 0.48 are achieved. [Copyright &y& Elsevier]

A novel plasma immersion ion implantation technique based on high power pulsed magnetron sputtering (HPPMS) discharge that can produce a high density metal plasma is described. The metal plasma is clean and does not suffer from contamination from macroparticles, and the process can be readily scaled up for industrial production. The hardware, working principle, and operation modes are described. A matching circuit is developed to modulate the high-voltage and HPPMS pulses to enable operation under different modes such as simultaneous implantation and deposition, pure implantation, and selective implantation. To demonstrate the efficacy of the system and technique, CrN films with a smooth and dense surface without macroparticles were produced. An excellent adhesion with a critical load of 59.9 N is achieved for the pure implantation mode. [ABSTRACT FROM AUTHOR]

Equal‐period modulated metal/ceramic multilayers have shown promise in enhancing the toughness of ceramic thin films. However, this toughness enhancement typically comes at the sacrifice of hardness, limiting their potential applications. To tackle this issue, this study designed and fabricated two gradient‐structured multilayer variations using Ta/TaB2: one with a higher ceramic layer fraction near the surface (M2) and the other with a converse structure (M3). A conventional equal modulation period Ta/TaB2 multilayer film (M1) served as a reference. M2 exhibited superior performance, with a 30% hardness increase and significant toughness enhancement compared to M1. Conversely, M3 experienced failure due to excessive thermal stress from its unique gradient structure. Finite element simulations revealed that M2's structure could alleviate in‐plane stress and enhance loading uniformity, thus enhancing the film's toughness. These findings suggest that a well‐designed gradient structure holds promise for concurrently improving the hardness and toughness of metal/ceramic multilayer films. [ABSTRACT FROM AUTHOR]

Continuous high-power magnetron sputtering (C-HPMS) is one of the desirable techniques to fabricate coatings with high hardness and a smooth surface to meet the demand by micro-millings for processing/cutting of printed circuit boards (PCBs). However, catastrophic failure can occur on the coatings because of the high residual stress in contact with hard glass fibers in PCBs at a high cutting speed. In this work, CrAlN/CrAl multilayer coatings consisting of thin CrAl interlayers are fabricated and characterized. The thin CrAl layers reduce the residual stress significantly from −6.7 GPa to −1.5 GPa, while the hardness of 35 GPa is preserved. Furthermore, the adhesion strength and wear resistance are improved appreciably by addition of the interlayers. The PCB cutting tests reveal that the CrAl layers mitigate sudden failure of the coatings and improve the cutting stability and service life by near two times. [ABSTRACT FROM AUTHOR]

• Chemosensory genes were identified from antennae of five Bactrocera species. • Chemosensory genes were found to be under less purifying selection. • Differential expression of chemosensory genes was shown among ME- and RK-responders. • Divergence in chemosensory genes are likely responsible for ME- and RK-perception. Insect olfactory systems have evolved to recognize phytochemicals and respond to olfactory-triggered cues that vary depending on needs. Several Bactrocera species are attracted explicitly to particular phytochemicals, including methyl eugenol (ME) and cue lure/raspberry ketone (CL/RK). The attraction of Bactrocerans to ME/RK is primarily driven by olfaction. Therefore, the divergent behavioral phenotypes are due to the differences in genes expressed in antennae. High quality transcriptomes were generated with mRNA from dissected antennae, to analyze the differences in olfaction-related genes of three ME-responders B. dorsalis , B. papayae and B. correcta and two RK-responders B. cucurbitae and B. tau. Many distinct quantitative and qualitative differences were identified in their respective chemosensory repertoires. Tissue- and sex-specific expression analyses identified antennae-predominant and sex-biased chemosensory genes. Sequence comparison revealed variations among family members of odorant-binding proteins and odorant-receptors between ME-responders and RK-responders. Differences in composition, expression levels, and sequence of proteins encoded by olfactory-related genes were identified between ME-responders and RK-responders. Some of the differences might contribute to the divergence in response to plant-derived odorants. Taken together, our results provide insights into the evolution of an olfactory system at molecular level in Bactrocera ME- and CL/RK-responding species. [ABSTRACT FROM AUTHOR]

Background: The males of many Bactrocera species (Diptera: Tephritidae) respond strongly to plant-derived chemicals (male lures) and can be divided into cue lure/raspberry ketone (CL/RK) responders, methyl eugenol (ME) responders and non-responders. Representing a non-responders, Bactrocera minax display unique olfactory sensory characteristics compared with other Bactrocera species. The chemical senses of insects mediate behaviors that are associated with survival and reproduction. Here, we report the generation of transcriptomes from antennae and the rectal glands of both male and female adults of B. minax using Illumina sequencing technology, and annotated gene families potentially responsible for chemosensory. Results: We developed four transcriptomes from different tissues of B. minax and identified a set of candidate genes potentially responsible for chemosensory by analyzing the transcriptomic data. The candidates included 40 unigenes coding for odorant receptors (ORs), 30 for ionotropic receptors (IRs), 17 for gustatory receptors (GRs), three for sensory neuron membrane proteins (SNMPs), 33 for odorant-binding proteins (OBPs), four for chemosensory proteins (CSPs). Sex- and tissue-specific expression profiles for candidate chemosensory genes were analyzed via transcriptomic data analyses, and expression profiles of all ORs and antennal IRs were investigated by real-time quantitative PCR (RT-qPCR). Phylogenetic analyses were also conducted on gene families and paralogs from other insect species together. Conclusions: A large number of chemosensory genes were identified from transcriptomic data. Identification of these candidate genes and their expression profiles in various tissues provide useful information for future studies towards revealing their function in B. minax. [ABSTRACT FROM AUTHOR]

Zeolite internal curing has been proven to be effective in reducing shrinkage of cement-based materials, but the sulfate erosion resistance of materials internally cured by zeolite is unclear. In this study, the interaction between zeolite and sulfate, and its effects on cement hydration were experimentally investigated. Firstly, the effects of sulfate on pore structure characteristics and pozzolanic activity of zeolite were studied, then sulfate ion adsorption and sodium ion exchange property of zeolite were tested. Finally, cement paste specimens with zeolite and sulfate were prepared, cement hydration degree, zeolite pozzolanic reaction degree, hydration product characteristics, and compressive strength of the specimens were studied. The test results show that, 1) Sodium sulfate can increase the pore content and pozzolanic activity of zeolite; 2) Zeolite particles can adsorb sulfate ions, sodium ions can exchange calcium ions in zeolite, alkaline environment inhibits the ion exchange process but promotes the ion adsorption process; 3) Sulfate-zeolite addition increases the hydration degree of cement, the pozzolanic reaction degree of zeolite, and the compressive strength of cement paste; 4) Sulfate erosion increases the porosity of Ordinary Portland cement (OPC) materials and reduces the porosity of Sulphoaluminate cement (SAC) materials, zeolite has an inhibitory effect on the influence of sulfate on pore structure. [ABSTRACT FROM AUTHOR]

Target poisoning is prevalent in reactive magnetron sputtering and causes deleterious effects, especially in deposition using metal targets. Both the deposition rate and the stoichiometry ratio of the coatings will be compromised because of the quicker coverage of the poisoning materials on the target relative to removal by sputtering. Continuous high-power magnetron sputtering (C-HPMS) possesses merits such as more rapid sputtering than high-power impulse magnetron sputtering and better target poisoning resistance. In this work, the discharge and plasma characteristics of C-HPMS for an Al metal target in reactive O2/Ar atmospheres are investigated by modeling and alumina deposition. At a constant oxygen partial pressure, larger discharge power increases target etching significantly compared to surface combination with O2, leading to reduced surface poisoning. Besides, a higher temperature is produced near the target to produce more intense rarefaction effects and decrease the risk of target poisoning. In Al discharge, the stable deposition window in the O2/Ar ratio under 120 W/cm2 is 5 times of that under 20 W/cm2. Moreover, a large deposition rate of 112 nm/min is achieved at the poisoning-saturated point and a target/substrate distance can be increased to larger than 40 cm, thus providing more flexibility in the design of deposition parameters and hardware requirement. Our results show that high discharge intensity improves plasma density and ionization rates of reactive particles boding well for the deposition of under-stoichiometric and higher-quality amorphous Al2O3 films. The reactive C-HPMS technique has large potential in the commercial production of functional coatings and thin films. [ABSTRACT FROM AUTHOR]

The corrosion resistance of aluminum and its alloys requires improvement in some applications. In this work, a 20 μm thick compact alumina coating doping Fe and P is obtained on the substrate of LY12 Al alloy by combining micro-arc oxidation (MAO) and phosphating to improve the corrosion resistance. The reaction mechanism is investigated and proposed. The coating shows a relatively small surface roughness (Ra = 0.5 μm) and a high Vickers hardness (1200 HV). The corrosion resistance is evaluated by the salt spraying test and Tafel polarization and a lifetime of up to 1800 h and a passivation potential of above 10 V are observed. [ABSTRACT FROM AUTHOR]

Crystal defects can enhance the properties of materials without changing the composition but introduction of high-density defects in coatings is challenging. Herein, plasma immersion ion implantation and deposition (PIII&D) is employed to produce high-density crystal defects in CrN coatings to improve the mechanical properties. PIII&D is demonstrated to introduce high-density point defects and stacking faults into the CrN coatings, especially at a bias exceeding 10 kV. The dislocation density significantly increased from 5.2 × 1014/m2 to 1.3 × 1017/m2. In addition, the covered area of defects increased from 30% to 75% with the ion implantation. As a result, the hardness increases significantly from 24.2 GPa to 35.6 GPa, while the fracture toughness is not compromised. [ABSTRACT FROM AUTHOR]

• Much more hetero-interfaces are produced by ion bombardment in CrN coating deposition. • The density of coherent grain boundaries(CGBs) increases 26 times by optimizing the sub-layer thickness. • Highest hardness of 33.4 GPa and toughness of 14.98 MPa m1/2 are achieved by grain boundary architecture. Coherent grain boundaries (CGBs) has been revealed to improve the hardness and toughness simultaneously, but the density are not enough to increase their mechanical properties. Herein, hetero-interfaces are formed by introducing ion bombardment during magnetron sputtering to increase the amount of CGBs in the CrN coatings. By optimizing the sub-layer thickness, the quantity and width of CGBs from the (111) to (200) orientations increase significantly and consequently, the hardness and toughness of the CrN coating increase to 33.4 GPa and 14.98 MPa m1/2, respectively. At last, the effect of the different CGBs to the coating strengthen is discussed. [ABSTRACT FROM AUTHOR]

• A novel 3D flower-like FNZP pigment was fabricated by directly introducing NH 4 + cation into FZP crystal. • The FNZP pigment showed remarkable dispersibility and interfacial compatibility in water-borne epoxy resin. • The superior corrosion resistance of FNZP-embedded coating exhibited were attributed to the synergistic effects of physical shielding and inhibition capability. Herein, the three-dimensional (3D) flower-like pigments of micro-nano scaled zinc phosphate (FZP) and ammonium zinc phosphate (FNZP) were successfully synthesized by hydrothermal synthesis method for improving the corrosion resistance of waterborne epoxy (WEP) coating. The micro-structures, chemical compositions and corrosion resistance of the as-obtained specimens were characterized by SEM, XRD, FT-IR, XPS and EIS, respectively. The results indicated that the 3D flower-like FZP and FNZP pigments were comprised of self-assembled nano-micro sheets with an average thickness of 20 nm ∼ 100 nm. Moreover, the remarkable enhancements of compactness and anticorrosion performance, especially for the FNZP-incorporated coating, were principally contributed to the well dispersibility and favourable solubility, which lengthened the permeation pathway and promoted the formation of passivation film. [ABSTRACT FROM AUTHOR]

Aluminum alloys are widely used in many industrial applications. However, they are susceptible to corrosion especially in aggressive media such as high salinity which can expedite the corrosion reactions. In this work, zinc phosphate modified plasma electrolytic oxidation (PEO) coatings are fabricated and demonstrated to have excellent corrosion resistance for a much longer duration (>11,000 h) than conventional PEO coatings (<1,000 h). Insoluble zinc phosphate is distributed in the pores of the coating serving as a barrier against the high-salinity medium. A self-healing mechanism is discovered as zinc phosphate migrates from the surface to pores continuously wetting the corrosion droplets on the super-hydrophilic coating until all the zinc phosphate is consumed. • The insoluble zinc phosphate is used to modify PEO coatings on Al alloy to improve the corrosion resistance. • The obtained alumina coatings show an unprecedented corrosion resistant duration (>11,000 h) in high salinity environment. • A self-healing mechanism is discovered as zinc phosphate migrates from the surface to the pores continuously. [ABSTRACT FROM AUTHOR]

In physical vapor deposition (PVD), the energy and incident angle of ions can be adjusted easily by applying an electromagnetic field so that coatings with different structures and properties can be produced. In this work, several high-ionization coating techniques are employed to deposit TiAlN coatings to compare the effectiveness of each technique and resulting coating properties. The continuous high-power magnetron sputtering (C-HPMS) technique shows advantages in the deposition rate and coating performance. In addition, a deposition rate of 400 nm/min is achieved by C-HPMS, whereas those of high power impulse magnetron sputtering (HiPIMS) and arc ion plating (AIP) are 85 nm/min and 225 nm/min, respectively. The coating also shows a particle-free and dense morphology with a smaller surface roughness of 22.4 nm. Owing to efficient ionization, the TiAlN coating deposited by C-HPMS has a high hardness of 33.2 GPa which is comparable to those prepared by AIP and HiPIMS but with small residual stress. The results provide valuable information on how to choose the proper techniques and parameters to produce coatings with the desirable adhesion strength, tribological properties, as well as corrosion resistance. [ABSTRACT FROM AUTHOR]

To obtain both high ionization and high deposition rate, a modified global model for a continuous high-power DC magnetron sputtering (C-HPMS) is established by considering the continuous generation of the hot electrons and the high temperature caused by continuous high-power discharge. The results show that the plasma density is on the order of 1019 m−3 for power densities of only 183 W cm−2 (Al) and 117 W cm−2 (Cu). The ionization rate exceeds 90% of high-power impulse magnetron sputtering (HiPIMS) (peak power density of 564 W cm−2) for a DC power density of 180 W cm−2, and the total diffusion fluxes of the two targets are 26 (Al) and 30 (Cu) times that of conventional HiPIMS, leading to very high deposition rates. The work provides a theoretical basis for the realization of C-HPMS and gives an enlightenment to the development of deposition equipment for continuous high-power discharges. [ABSTRACT FROM AUTHOR]

[Display omitted] • The metabolic changes in D. citri induced by two host plants were analyzed. • Six aquaporin genes in D. citri were identified. • The expression of osmotic regulation genes in D. citri altered by different plants. The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Liviidae), is a worldwide citrus pest. It transmits the pathogen Candidatus Liberibacter spp. of Huanglongbing (HLB), causing severe economic losses to the citrus industry. Several genera of plants in the Rutaceae family are the hosts of D. citri. However, the impact of these hosts on the metabolism and osmotic regulation gene expression of the pest remains unexplored. In this study, the contents of total sugars, sucrose, fructose, and glucose in young shoots, old leaves, and young leaves of 'Shatangju' mandarin and Murraya exotica were analyzed. Metabolomic analysis found that sucrose and trehalose were more abundant in the gut samples of D. citri adults fed on M. exotica when compared to what's in 'Shatangju' mandarin. A total of six aquaporin genes were identified in D. citri through the genome and transcriptome data. Subsequently, the expression patterns of these genes were investigated with respect to their developmental stage and tissue specificity. Additionally, the expression levels of osmotic regulation and trehalose metabolism genes in adults fed on different plants were evaluated. Our results provide useful information on the transfer of sugar between plants and D. citri. Our results preliminary revealed the sugar metabolism regulation mechanism in D. citri adults. [ABSTRACT FROM AUTHOR]

To increase deposition rate during pulsed magnetron sputtering (PMS), a novel dual-pulse pulsed magnetron sputtering (DP-PMS) was proposed. The discharge mode of DP-PMS firstly produced a pulsed high ignition voltage with short duration followed by a subsequent pulsed low work voltage with long duration. CrN coatings were deposited by DP-PMS and PMS. The effect of ignition pulse width of DP-PMS on the discharge of Cr target in argon and the deposition rate of CrN coatings was explored. The target current of DP-PMS was featured by an initial peak, which was different from the triangular waveform in PMS. The DP-PMS with a longer ignition pulse produced a higher substrate current and a larger number of Cr0 at unit target power. There existed a proper width of initial ignition pulse (e.g. 15 us) producing the maximum deposition rate at unit target power, which was nearly four times higher than that of PMS. • A novel DP-PMS has been proposed to improve the deposition processes. • A proper ignition pulse width is needed to achieve the synergistic effect in DP-PMS. • The deposition rate at unit target power effectively increased in DP-PMS mode. [ABSTRACT FROM AUTHOR]

Abstract Developing acid-resistant magnesium alloys is challenging because of the high chemical reactivity of magnesium in acidic media. In this work, a bio-inspired strategy by taking advantage of the super-hydrophobic effects on lotus leaves is described. The self-layered coating consisting of an inner compact layer and outer Mg-Al layered double hydroxide (LDH) microsheet-based layer prepared hydrothermally exhibits enhanced corrosion resistance in saline solutions but cannot resist corrosion in sulfuric acid. After depositing a fluorocarbon polymer film on the microsheets using a polytetrafluoroethylene (PTFE) target by magnetron sputtering, a super-hydrophobic surface is created on the magnesium alloy. Compared to the surface modified hydrothermally, the super-hydrophobic surface provides better corrosion protection in H 2 SO 4 due to trapped air pockets in the microsheet array. The dual process offers a promising means to mitigate corrosion of magnesium alloys in acidic media. Graphical abstract Unlabelled Image Highlights • A hydrothermal process produces a barrier with an inner compact layer and outer microsheet layer. • Magnetron sputtering with PTFE target is used to produce a polymer coating on the microsheets. • A super-hydrophobic surface in the Cassie state with a water contact angle of 170° is obtained. • The obtained surface exhibits dropwise water condensation and icing retardation behaviors. • The dual process yields better protection in H 2 SO 4 solutions than the hydrothermal method alone. [ABSTRACT FROM AUTHOR]

Abstract An anode layer ion source (ALIS) is used in magnetron sputtering to deposit TiN films. The effects of the ion source discharge current (I s) on the microstructure, mechanical, and electrochemical properties, and adhesion characteristics of the deposited films are studied. By coupling with magnetron sputtering discharge (I t) and varying the ALIS discharge current, the ion energy (E i) and ion flux density (J i) can be increased to 180 eV and 3.5 × 1016 ions·cm−2·s−1, respectively. The preferred orientation of the films changes from (200) to mixed (111) & (200) and finally to (111) with increasing I s. The microstructure changes from a columnar to dense one and the residual stress in all the films is compressive. The stress increases initially and then decreases slightly with the (111) orientation and the hardness and fracture toughness depend on the residual stress with the hardness increasing from 14.5 GPa to 27.0 GPa and fracture toughness increasing to 70%. As shown by the Rockwell C adhesion test, the films deposited by varying the ion source discharge current show improved adhesion. Electrochemical studies reveal reduced corrosion current density and increased impedance by an order of magnitude. The results reveal for the first time significant changes in the mechanical and electrochemical properties of films deposited by magnetron sputtering with ALIS assistance. This hybrid technique has the advantages that the film structure and mechanical and electrochemical properties can be readily adjusted. Highlights • Deposition of TiN thin films by hybrid anode layer ion source (ALIS) during magnetron sputtering • Effects of ALIS discharge current on structural, mechanical and electrochemical properties • Structural modification to dense granular from columnar morphology whereas increase in residual stresses • 86% increase in hardness and 70% in fracture toughness and improvement in adhesion strength • An order of magnitude increment in the corrosion resistance ability [ABSTRACT FROM AUTHOR]

Abstract Titanium nitride films deposited by conventional magnetron sputtering are prone to contamination, especially residual gas species, and the composition and properties can be affected. In this work, an anode layer ion source (ALIS) is used in magnetron sputtering to deposit TiN films and the effects of the average energy E i and ion flux density J i on the chemical composition of the deposited films are determined. By coupling and varying the magnetron discharge current I t , the ALIS can be used to control E i to as low as 80 eV and J i as high as 3.5 × 1016 ions cm−2 s−1. To discern the roles of E i and J i , the films are deposited under three different conditions of magnetron discharge I t. A reduction of 95% in the oxygen concentration and an increase of 30% in the nitrogen concentration are observed by increasing J i. X-ray photoelectron spectroscopy reveals decreased peak broadening, shifts to higher binding energies, and increase initial slope of the Ti 2p peak with larger J i. The N 1s peak shows decreased broadening while the O 1s peak indicates less oxide-related compounds. Raman scattering reveals reduced intensity ratios of the Ti to N vibration phonon peaks (I Ti /I N) indicating enhanced nitrogen-related optical phonon peaks and that the film resistivity decreases as the oxygen concentration decreases. Our experiments disclose compositional changes especially reduced oxygen incorporation with ALIS assistance during magnetron sputtering. The hybrid technique which can be scaled up readily to meet industrial demand enables control of the film composition without resorting to other parameters like high temperature, biasing, and ultrahigh vacuum that may adversely affect other film properties and add manufacturing costs. Highlights • Deposition of TiN thin films by hybrid anode layer ion source (ALIS) during magnetron sputtering. • Characteristics of ALIS in high flux and low voltage mode • Dependence of changes in composition of film on energy E i and flux density J i of ions • 95% reduction in Oxygen concentration due to ion bombardment • Reduction in the resistivity of films due to ion bombardment [ABSTRACT FROM AUTHOR]

Better orthopedic implants improve the life quality of patients and elderly people. Compared to Ti and Mg alloys commonly found in bone implants, Al alloys have merits such as high specific strength, excellent casting capability, and low cost, but unfortunately, the poor wear resistance, corrosion resistance, and insufficient biocompatibility have hampered wider application to bone replacements. In this study, well structure designed and excellent adhered Al 2 O 3 coating is fabricated by micro-arc oxidation (MAO) on Al alloys to improve the wear resistance and corrosion resistance and inhibit release of potentially harmful Al ions from the Al alloy substrate. Ca, Fe, and Zn are respectively doped into the Al 2 O 3 coating to enhance the biological properties. In particular, the Al 2 O 3 coating doped with Zn delivers outstanding osteogenic performance and the antibacterial rates against E. coli and S. aureus are 99.5 ± 0.56% and 98.77 ± 0.52%, respectively. The improved mechanical and biological properties reveals that the Al 2 O 3 coated Al alloys prepared by MAO coatings have large potential in orthopedic applications. [ABSTRACT FROM AUTHOR]

Abstract Magnesium and magnesium alloys are widely used in the electronics, automobile and aerospace industry but the poor corrosion resistance has hindered some applications. In this work, a transparent fluorocarbon polymeric thin film is deposited on magnesium by magnetron sputtering and the corrosion resistance is evaluated. Potentiodynamic polarization and electrochemical impedance spectroscopy in combination with immersion experiments in 3.5 wt% NaCl reveal markedly improved corrosion resistance. The corrosion mechanism is discussed from the perspective of random defects in the fluorocarbon film. Highlights • A transparent fluorocarbon polymeric thin film is deposited on magnesium by magnetron sputtering. • The corrosion resistance of pure magnesium in NaCl solution is markedly improved by the polymeric film. • The corrosion mechanism is discussed from the perspective of random defects in the fluorocarbon film. [ABSTRACT FROM AUTHOR]

Abstract Hydrogenated diamond like carbon (a-C:H) coatings typically have low friction but high residual stress. The hardness which depends on the sp3 proportion increases not only the coating lifetime, but also the residual stress which can lead to easy film delamination especially for thick coatings. In this work, several thick a-C:H coatings (>10 μm) with different stress and hardness are prepared using stress engineering to mitigate stress accumulation while the hardness is retained. A low compressive residual stress of 0.42–0.84 GPa is achieved from the 8 μm thick a-C:H coating in addition to a high critical load of 63–74 N and hardness of over 26 GPa. The other desirable tribological and anticorrosion properties include a small friction coefficient of 0.13, low wear rate of 1.01 × 10−15 m3/N·m, high corrosion potential of - 479.6 mV, as well as small corrosion current density of 1.77 μA/cm2. Highlights • A universal meaning stress engineering method is proposed. • Low residual stress and high hardness of a-C:H coatings are achieved. • High adhesion up to 74 N are obtained in the a-C:H coatings. • The coatings also show excellent tribological and anti-corrosion properties. [ABSTRACT FROM AUTHOR]

Owing to the increasing use of magnesium alloys in the automotive, aerospace, electronics, and biomedical industry, more Mg-based wastes are being produced. Herein, a new process to electrochemically degrade Mg alloy wastes suitable for sewage treatment is described. Mg alloys are immersed in a sodium chloride solution and a small voltage is applied to accelerate degradation. The solid degradation products are composed of mainly nanostructured magnesium hydroxide and can be used to remove methyl orange from the simulated sewage effectively via adsorption/aggregation. This study provides insights into how to turn Mg wastes into useful forms to lessen the environmental impact. [ABSTRACT FROM AUTHOR]

Corrosion protection of magnesium alloys is a challenge in industrial applications because of the high chemical reactivity of Mg. In this work, a coating is prepared by plasma electrolytic oxidation (PEO) on the AZ31B Mg alloy and then modified by insoluble zinc phosphate to improve the corrosion resistance. To avoid the influence of the weak acidic Zn-containing electrolyte on the formation of the passivation layer on the magnesium alloy, a two-step process is designed to first produce a passivation layer before introduction of zinc phosphate. Zinc phosphate is mainly distributed on the surface and the sidewalls of the holes in the porous coating and blocks the interactions between the corrosive solution and Mg substrate. The corrosion potential of the optimal coating (Zn-15) increase while the passive current density at the terminal potential decreases, suggesting the significantly improved corrosion resistance compared to the pristine AZ31B. The life time demonstrated by neutral salt spraying is 4200 h that is about 3 times longer than that observed from the Mg alloy with the undoped coating. [Display omitted] • Zinc phosphate is successfully introduced into the PEO coatings on Mg alloy. • Two-step strategy avoids the conflict between surface passivation and zinc phosphate. • Zn-modified coating shows excellent corrosion resistance and extra-long lifetime. [ABSTRACT FROM AUTHOR]

Titanium alloys are important aerospace metals but suffer the poor mechanical property in high-loading area. Plasma electrolytic oxidation can improve their hardness and reduce friction but the precursor competition of functional phases in PEO electrolyte is inevitable. This work provides a new strategy to avoid ions competition and precipitation by choosing anionic salt (K 2 ZrF 6) and cationic salt (Ce(Ac) 3) as the precursors of the hard phase (ZrO 2) and lubrication phase (monoclinic CePO 4), respectively. As a result, the ions competition is avoided to achieve simultaneous high-content doping of functional phases. The optimized coating shows a maximum hardness of 626 HV, small friction coefficient of 0.12 and a lower wear rate of only 3.1 × 10−5 ± 0.15 mm3 N−1 m−1, indicating excellent long-term self-lubrication property and wear resistance. [Display omitted] • Anion and cation competition in PEO electrolyte are avoid. • Both high contents of ZrO 2 and CePO 4 are obtained in PEO coatings. • Long-time self-lubrication in high-loading condition are obtained. [ABSTRACT FROM AUTHOR]

• A novel T-shape structured inorganic superhydrophobic alumina surface is reported. • T-shape micro/nano structured is tunable by optimizing the gradient electric field of plasma electrolytic oxidation process. • The large-area superhydrophobic surface is easily scalable prepared. • As-fabricated inorganic superhydrophobic surface shows excellent durability, heat and anti-corrosion stability. T-shape structure can make inorganic materials superhydrophobic, but conventional preparation methods based on etching is usually costly and unscalable. In this work, a facile and scalable technique utilizing plasma electrolytic oxidation (PEO) is employed to prepare superhydrophobic inorganic alumina coatings. By optimizing the gradient electric field, the etching behavior of OH– is tunable so that a T-shape micro/nano structured alumina coating can be prepared in one step. Without any organic modification, the coating shows a water contact angle (CA) of 150°±3° and water rolling angle (RA) of 8°±2°. The prepared inorganic ceramic coating remains superhydrophobicity under a harsh environment including 360 days of sunlight, and they have excellent corrosion resistance and can bear long-time flame burning. The preparation technique is simple and economical thereby boding well for great potentials in applications of solar cells, electronic devices, etc. [ABSTRACT FROM AUTHOR]

Although aluminum alloys are widely used in the aerospace industry, their relatively poor wear and corrosion resistance have hampered some applications and reduce the lifetime of the components. In this work, by using a zinc-containing phosphate electrolyte, the corrosion resistance, surface hardness, and wear resistance of the coatings produced by plasma electrolytic oxidation (PEO) are simultaneously improved. The micro-arc discharge is optimized by changing the phosphate concentration instead of introducing hard phase cations to improve the crystallinity of the zinc-doped alumina coating. Our results reveal that by using a concentration of (NaPO 3) 6 of 50 g/L, the hard phase of crystralline alumina and corrosive-resistant phase of Zn 3 (PO 4) 2 are produced in concert. In the salt spraying test, the lifetime of the PEO coating is over 5000 h and the electrochemical corrosion current density is reduced by about 2 orders of magnitude confirming the improved corrosion resistance and durability. Moreover, the surface hardness increases from 400 HV for the coating prepared using the conventional phosphate electrolyte to 711.8 HV and the wear rate also drops from 8.5 × 10−4 mm3·(N·m)−1 to 2.0 × 10−5 mm3·(N·m)−1. This strategy can guarantee the aluminum alloy PEO coating with simultaneous excellent wear and corrosion resistance to cope with the complex service environment. • A new multivariate electrolyte without agglomeration or precipitation is designed. • The coatings with high-crystallinity alumina shows excellent wear resistance. • Enough zinc phosphate of coating keeps the excellent corrosion resistance. [ABSTRACT FROM AUTHOR]

• A strain of entomopathogenic fungus Clonostachys rosea was characterized. • C. rosea induced mortality in Diaphorina citri adults. • A total of 259 DEGs were identified in D. citri adults after inoculation with C. rosea. • Unigenes encoding proteins involved in immunity, apoptosis and cuticle were changed significantly. Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Liviidae), is a serious pest of citrus. The insect also transmits Candidatus Liberibacter asiaticus, the pathogen of a devastating citrus disease called Huanglongbing. Clonostachys rosea is a versatile fungus that possesses nematicidal and insecticidal activities. The effect of C. rosea against D. citri remains unclear. Here we examined the pathogenicity of C. rosea against D. citri adults. A mortality rate of 46.67% was observed in adults treated with 1 × 108 conidia/mL spore suspension. Comparative transcriptomic analyses identified 259 differentially-expressed genes (DEGs) between controls and samples treated with fungi. Among the DEGs, 183 were up-regulated and 76 down-regulated. Genes with altered expression included those involved in immunity, apoptosis and cuticle formation. Our preliminary observation indicated that C. rosea is virulent against ACP adults and has the potential as a biological control agent for ACP management in the field. [ABSTRACT FROM AUTHOR]