Search

This paper describes the fabrication and characterization of novel preceramic paper-derived functionally graded materials (FGMs) based on Ti 3 (Si,Al)C 2 MAX phase. The FGMs with different architecture were fabricated via spark plasma sintering of stacked preceramic papers at 1250 °C for 5 min. Microstructure, phase composition and elemental distribution were analyzed by scanning electron microscopy, X-ray diffraction and energy-dispersive X-ray spectroscopy, respectively. Oxidation tests were performed in air at 1300 °C for 5 h. FGMs containing Al- and Si-enriched MAX-phase layers were formed. The fabricated materials exhibit high flexural strength (over 600 MPa), which are dependent on microstructure and composition of individual layers as well as the architecture of composites. It was found that texturing of MAX phase grains during SPS results in anisotropic hardness of the composite. The difference in the composition of the individual layers also provides a hardness gradient in the composite. It was shown that the formation of the outer layer from the Al-enriched Ti 3 Al(Si)C 2 MAX phase increases the corrosion resistance of Ti 3 SiC 2 -based composites. The high corrosion resistance of FGMs is due to the growth of a continuous and dense Al 2 O 3 oxide layer. [ABSTRACT FROM AUTHOR]

The corrosion-resistance properties of modified ultra-thin carbon paper (CP) different graphene oxide (GO) content used in proton exchange membrane fuel cells (PEMFC) are studied for the first time. Results show that CP with 1 wt% GO has distinguished corrosion-resistance property (corrosion current: 5.539E − 8A.cm −2 , minimum weight loss and contact angle variation). And mechanism analysis was found that the CP-1GO-P had uniform florine coating on some area of carbon fiber while T-CP-P has little. Moreover, the addition of GO could introduce more C O and C O groups which interact with the florine atom, thus can strengthen the bonding of PTFE and matrix carbon effectively. [ABSTRACT FROM AUTHOR]

Melamine–formaldehyde (MF) resin-impregnated paper-decorated panels are prone to surface cracking, which can be reduced by changing the brittle structure of the MF resin. To increase the curing degree and toughness of the resin, a hexamethylene diisocyanate trimer blocked with methyl ethyl ketoxime (ME-HDI-tri) was used as a temperature-responsive crosslinker. This latent crosslinking agent only worked above 120 °C, which prevented it from participating in cross-linking reactions during the preparation of the impregnated paper. The chemical structures of the modified MF resins (ME-HDI-tri-MF) were characterized by Fourier-transform infrared (FTIR) spectroscopy. The curing behaviors of the MF resins were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical thermal analysis (DMTA). Impregnated paper was prepared with ME-HDI-tri-MF, and its tensile strength and elongation at break were tested. Blockboard was prepared with ME-HDI-tri-MF, and its cracking and corrosion resistance were tested. The absorption peak of the methylene chain was observed in the FTIR spectrum of ME-HDI-tri-MF after curing, which indicated that ME-HDI-tri participated in the curing reaction of the MF resin. With the addition of ME-HDI-tri 5 %, the curing temperature of the MF resin decreased from 142 °C to 130 °C, and the ultimate tensile stress and elongation at break of the modified impregnated paper increased by 97.70 % and 86.25 %, respectively. The cracking and corrosion resistance of the decorated panel prepared with ME-HDI-tri-MF were also improved. After adding 3 % ME-HDI-tri, the surface cracking of the decorated panels was prevented, which extended the service life and broadened the application range of the decorated panels. [Display omitted] • Temperature-responsive crosslinker adjusted the curing behavior of melamine-formaldehyde (MF) resins. • The toughness of MF resin-impregnated paper was improved. • The surface cracking and corrosion resistance of decorated blockboard was enhanced. [ABSTRACT FROM AUTHOR]

We propose an innovative 3-step manufacturing technique for the synthesis of the catalyst layer of proton exchange membrane electrodes directly over a gas diffusion layer consisting of carbon paper (CP). In the first step, a carbon synthesis catalyst was formed in a bicontinuous microemulsion. In the second step, carbon nano-networks (CNNs) were directly grown over CP by thermal chemical vapor deposition of ethene over the metal catalyst embedded in the simultaneously carbonized microemulsion matrix. In the third step, the electrocatalyst, here Pt, was deposited on the CNNs. The influence of surfactant type, Na-AOT or Triton X-100, carbon synthesis catalyst type, Fe, Co or Pt, and loading on the electrolyte accessible surface area (ESA) and carbon corrosion resistance was evaluated in a three-electrode half-cell. CNNs grown from Fe and synthetized in Na-AOT microemulsions resulted as the best combination in terms of ESA and carbon corrosion resistance and were used for subsequent investigations. The CNNs grown on CP (CNNs/CP) were electrochemically oxidized prior to Pt electro-deposition by means of potential cycling. The effect of oxidation of the CNNs on the size and spatial distribution of the electrodeposited Pt catalyst was evaluated. Increasing the number of functionalizing oxidation cycles from 0 to 100 decreased the average catalyst crystallite size from 19 to 9 nm. The CNNs/CP samples showing the highest electrochemically active surface area (ECSA) were compared to a commercial catalyst with respect to ECSA, catalyst utilization, and durability to potential cycling. The ECSA for the CNNs/CP samples turned out to be lower than that of the commercial catalyst due to the larger catalyst size. On the other hand, the CNN/CP samples proved to be more durable and higher Pt utilization was achieved. [ABSTRACT FROM AUTHOR]

In recent years, calcium phosphate-base composites, such as hydroxyapatite (HA) and carbonate apatite (CA) have been considered desirable and biocompatible coating layers in clinical and biomedical applications such as implants because of the high resistance of the composites. This review focuses on the effects of voltage, time and electrolytes on a calcium phosphate-base composite layer in case of pure titanium and other biomedical grade titanium alloys via the plasma electrolytic oxidation (PEO) method. Remarkably, these parameters changed the structure, morphology, pH, thickness and crystallinity of the obtained coating for various engineering and biomedical applications. Hence, the structured layer caused improvement of the biocompatibility, corrosion resistance and assignment of extra benefits for Osseo integration. The fabricated layer with a thickness range of 10 to 20 μm was evaluated for physical, chemical, mechanical and tribological characteristics via XRD, FESEM, EDS, EIS and corrosion analysis respectively, to determine the effects of the applied parameters and various electrolytes on morphology and phase transition. Moreover, it was observed that during PEO, the concentration of calcium, phosphor and titanium shifts upward, which leads to an enhanced bioactivity by altering the thickness. The results confirm that the crystallinity, thickness and contents of composite layer can be changed by applying thermal treatments. The corrosion behavior was investigated via the potentiodynamic polarization test in a body-simulated environment. Here, the optimum corrosion resistance was obtained for the coating process condition at 500 V for 15 min in Ringer solution. This review has been summarized, aiming at the further development of PEO by producing more adequate titanium-base implants along with desired mechanical and biomedical features. [ABSTRACT FROM AUTHOR]

Unitized regenerative proton exchange membrane fuel cell (URPEMFC) as a self-sufficient hydrogen energy system offers a unique proposition for achieving a net zero emissions future. The system combines the operation of water. Due to the design parameters and operating conditions of URPEMFC, the potential cycling from the mode switching, high temperature, humidified environment and the long exposure of metallic components to hydrogen are the primary factors causing degradation to the system. Consequently, the conventional graphite bipolar plate (BP) suffers heavily under such an environment while giving rise to alternative metallic base materials, such as titanium, stainless steel, and aluminum. Various surface treatment and coating methods are currently under investigation to provide the required corrosion resistance while maintaining feasible manufacturing process and cost. This paper presents an overview into the degradation phenomena of URPEMFC that contributes to the corrosion of BP that is affecting the performance and future commercialization of the system. The operating condition of the system is summarized in terms of fuel cells and water electrolyzers respectively, along with the integration of both operations as a system. Next, the paper outlines the degradation phenomena observed on BP and the behavior of various materials under such conditions. The performances of various base and coating materials have been compiled as have characterization methods that are useful in measuring corrosion resistance. This paper aims to provide a better understanding on the overall degradation of BP in URPEMFC and overview of various material choices to identify the optimal corrosion mitigation solution. [Display omitted] • Breakdown of the URPEMFC operating parameters from the respective operation modes. • System design approaches allowing integration of fuel cell and electrolyzer modes. • Identification of the main degradation mechanism on the BP. • Tabulated data of various base materials and coatings performance. • Discussion of current experimental and modeling methods for corrosion resistance characterization. [ABSTRACT FROM AUTHOR]

Ecologically feasible strategies for constructing superhydrophobic surfaces offer versatile applications in waterproofing, self–cleaning, selective absorption, and corrosion protection. Herein, we prepared low–surface–energy branched–chain–enriched micronanorod (F@SiO 2 @MNC) by hydrolyzing silane coupling agent and modifying fluoropolymer using micro–nanocellulose extracted from waste straw (Chinese hemp). These rods were sprayed and adhered to various substrates precoated with a binder, resulting in superhydrophobic surfaces. F@SiO 2 @MNC addition allowed for the formation of stable spherical liquid droplets when in contact with different types of aqueous liquids. Furthermore, these surfaces demonstrated excellent self–cleaning, robustness, abrasion resistance, UV resistance, cycling stability, and other multifunctionalities. They significantly enhanced the mechanical properties of filter paper, effectively separated oil water mixtures, and improved the corrosion resistance of metals. Our proposed strategy represents a novel approach for developing multifunctional coatings assembled from micronanocellulose. • Micro-nanocellulose (MNC) was extracted from Chinese hemp. • Rods (F@SiO 2 @MNC) enriched with low surface energy branched chains were prepared. • Rods were adhered stably to the surface of various substrates with a binder. • Various surfaces coated with superhydrophobic F@SiO 2 @MNC showed multifunctionality. [ABSTRACT FROM AUTHOR]

Titanium and its alloys have been recognized as biocompatible materials since decades although these materials can at times show wear, corrosion and thrombosis leading to various health complications. Surface coating has been found to be one of the effective techniques to overcome this issue in-vitro as well as in-vivo. In this paper, thin film coating of zirconia (ZrO 2) on Ti6Al4V is reported using pulsed laser deposition (PLD) technique at elevated substrate temperatures ranging from room temperature to 800 °C (TiZr800). The morphology, composition, wettability and average surface roughness of the samples were analyzed by scanning electron microscope, Raman spectrometer, water contact angle (WCA) and profilometer, respectively. Adhesion between film and substrate was qualified using Elcometer. The tribological studies were performed in ball-on-disc against ZrO 2 counterpart, the electrochemical potential analysis was done in simulated body fluid to replicate body environment and the hemocompatibility test was evaluated on the basis of human whole blood adsorption and distribution of Red Blood Cells (RBCs) on the samples. The results revealed an increase in WCA and film adhesion with increased substrate temperature. At 800 °C, formation of zirconium carbide, a relatively harder material, was observed due to diffusion of substrate carbon into ZrO 2 film, as confirmed by the Raman analysis. In comparison to pristine, TiZr800 sample showed a reduction in wear rate from 3.5 × 10−3 mm3/Nm to 1.1 × 10−3 mm3/Nm indicating improved resistance of the sample against abrasive wear. Further, drop in I corr from 4.96 × 10−7 A/cm2 to 2.75 × 10−7 A/cm2 resulted in a 44 % increase in corrosion protective efficiency of the sample coated at 800 °C. Additionally, a 4.5 fold increase in RBC counts was observed on TiZr800 sample. Therefore, it is inferred that while ZrO 2 coating can improve overall surface properties of Ti–6Al–4V, additional benefits can be obtained by performing PLD at higher substrate temperatures, more so when the temperature is such as to promote formation of ZrC in the coating. [ABSTRACT FROM AUTHOR]

Exploring the sealing stability of different media to plasma-sprayed refractory Al 2 O 3 –13%TiO 2 ceramic coatings is of guiding significance for rational application. Thus, the protective performance of commonly used organic and inorganic sealing agents under different environmental temperatures in chloride ion-containing solutions was investigated in this paper. Firstly, the corrosion resistance of each sample at different temperatures was characterized by potentiodynamic polarization studies. Then the effect of solution temperature was analyzed by Arrhenius equation. Moreover, the mechanism of solution temperature influence was discussed via electrochemical impedance spectroscopy, aiming to provide guidance on the selection of sealing agent types for different environments. The results indicated that both sealing agents provided corrosion resistance far beyond that of the as-sprayed coating at different temperatures. However, as the temperature increased, despite the stable behavior of the inorganic sealing coating itself, the organic sealing agent exhibited a more stable application effect in corrosion resistance, even at 80 °C, it can still show a corrosion current density in the order of 10−8 A cm−2. [ABSTRACT FROM AUTHOR]

The exceptional biocompatibility of Ti/Ti bonding technology makes it highly significant for the sealing of implantable devices. However, achieving highly reliable Ti/Ti bonding at low temperatures is challenging due to the facile formation of a native oxide film, which hinders the diffusion of interfacial atoms. This paper develops a low-temperature Ti/Ti bonding process based on plasma activation, resulting in a remarkable bonding strength of 17.5 MPa at 300 °C, which can be used for Si–Si homogeneous and Si-glass heterogeneous integration. After optimizing the processes, the surface oxides of Ti can be partially reduced through Ar/H 2 plasma activation to form unsaturated chemical bonds, thereby overcoming the limitation of film thickness in Ti/Ti bonding. The results indicate that plasma activation can realize high strength Ti/Ti bonding in the film thickness range of 10–50 nm. It is worth noting that the Ti/Ti bonding area and strength remain stable after immersion experiments in DI water and normal saline for 7 days, which proves that Ti/Ti bonding has good corrosion resistance. In addition, the microcavity structures were prepared using photolithography and etching techniques. The Ti/Ti bonding technology enables direct bonding of microcavity structures with plate Ti, and an intact bonding interface near the microcavity was obtained. This low-temperature Ti/Ti bonding technology is suitable for the three-dimensional integration of various substrate materials, and its excellent corrosion resistance makes it promising for application in the sealing of BioMEMS. [ABSTRACT FROM AUTHOR]

The tantalum oxide film was fabricated using an anodization process in a 0.5M H 2 SO 4 electrolyte. The evolution and corrosion resistance mechanism of anodized film on the Ta surface has been investigated by experiments and theoretical calculations. The results indicate that the sample with an anodic oxidation voltage of 20V and an anodic oxidation time of 60 min (Ta 20-60) exhibits the thickest oxidation film, measuring 360.00 nm and comprising an outer porous layer and an inner dense layer. Ta 20-60 demonstrates the highest E corr value of 0.009 V and the lowest I corr value of 0.879 μA cm−2, with a minimal density of point defects at 1.24 × 1019 cm−3, which imparts superior corrosion resistance. The calculation result shows that the growth rate of Ta anodic oxidation film is controlled by the diffusion and migration of vacancy defects. The O atom passes through one bridge site from the tetrahedral gap to another tetrahedral gap (Path 1) on the complete (110) surface has a low diffusion barrier of 0.470 eV and the shortest diffusion path of 2.04 Å, which is the most favorable path for the diffusion of O atoms. This paper offers a fresh perspective on the corrosion resistance of tantalum while furnishing guidance for improving Ta oxide film performance. [ABSTRACT FROM AUTHOR]

A liquid-repellent and corrosion resistant surface was fabricated on AZ31B Mg alloy by the usage of CeO 2 and TiO 2 nanoparticles (NPs), plasma electrolyte oxidation (PEO) method, and subsequent surface modification. The whole process included two main steps: a) applying PEO with CeO 2 –TiO 2 NPs on AZ31B and b) decreasing surface energy by using a fluorinating agent. Elements that were present on the surface were investigated by XRD and EDS analyses. Surface morphology and its roughness were scrutinized by FESEM images and AFM tests, respectively. Contact angles (CA) of water and some oils (Ethylene glycerol and Glycerol) on the prepared surface were measured. CAs of water and ethylene glycerol were reported at 175.6° and 151.4°, respectively. Also, the corrosion behavior of the prepared surface was assessed by EIS and potentiodynamic polarization analyses. Results showed that the corrosion rate of the neat AZ31B decreased noticeably from 127.78 to 0.027 mpy for superamphiphobic PEO-NPs AZ31B. The prepared sample showed high mechanical durability, which was scrutinized by water floatation, abrasive with grit SiC paper, adhesive tape peeling, and bending tests. After immersion of the sample in 5 wt% NaCl solution for various hours, results showed that the prepared sample had a noticeable corrosion resistance stability. [Display omitted] • A durable superamphiphobic surface was fabricated on AZ31B. • The prepared surface showed a remarkable water and oil repellency. • A prepared superamphiphobic surface promoted noticeably the corrosion resistance of AZ31B. • A superamphiphobic surface showed brilliant corrosion resistance stability and mechanical durability. [ABSTRACT FROM AUTHOR]

TC4 titanium alloy is utilized in aerospace and a wide range of other applications due to its high strength and corrosion resistance, but its poor thermal conductivity and high ductility introduce challenges in machining. In this paper, firstly, a mathematical model of workpiece surface morphology under tilted ultrasonic elliptical vibration cutting (TUEVC) was established based on the tip trajectory and material removal mechanism, and the variation of workpiece surface morphology was investigated at different tool tilt angles θ , and it was found that the tilt θ in a certain range could significantly reduce the surface residual height compared with that of ordinary ultrasonic elliptical vibration cutting (UEVC). Second, the TUEVC experiment of TC4 titanium alloy was carried out to comparatively analyze the changes in the surface morphology, surface profile, and surface roughness of the workpiece under different tilt θ , the effect of each machining parameter (cutting speed, feed, and ultrasonic amplitude) on surface roughness was explored. The experimental results indicate that as the tilt θ changes from 0° to 90° throughout the process, the workpiece surface morphology flatness decreases and then increases. When the tilt angle θ is 45°, workpiece cutting surface roughness is minimized (Sa = 0.157), compared with the ordinary ultrasonic elliptical vibration cutting roughness is reduced by 47.6 % maximum. Both the surface morphology flatness and the surface roughness of the workpiece are at their smallest, whereas the theoretical profile curve and cutting surface profile curve are at their most consistent. Under the same machining parameters, TUEVC can reduce the surface roughness more effectively compared with UEVC, this technique reduces surface roughness by 16 %, 23 %, and 26 % at maximum for different cutting speeds, feeds, and ultrasonic amplitudes, respectively. • Machining of TC4 titanium alloy by self-designed tilted ultrasonic elliptical vibration cutting device. • A mathematical model of tilted ultrasonic elliptical vibration cutting was established. • The inclined ultrasonic elliptical vibration cutting technology is able to reduce the surface roughness of the workpiece. The surface roughness is as low as 0.157μm. • Compared with UEVC, TUEVC can reduce the surface roughness of titanium alloy cutting by up to 47.6%. [ABSTRACT FROM AUTHOR]

The addition of Cr3+-oxides in a refractory provides unmatched corrosion resistance at high temperatures but generates toxic and water-soluble Cr6+ compounds, particularly in oxygen-rich and alkaline conditions. In this paper, a Cr3+ raw material (chrome-hibonite) was synthesized by the solid oxide reaction route and was used to make different calcium aluminate cement bonded alumina-based refractory castables. The castables (chrome-free and Cr3+ oxides containing) were compared regarding corrosion resistance against municipal waste slag at 1500 °C under air atmosphere. The relative Cr6+ formation within the castables containing Cr3+ oxides (Cr 2 O 3 and Ca(Al,Cr) 12 O 19) upon heat treatment at 500–1500 °C were investigated using X-ray diffraction (XRD), and Cr6+ leaching test, etc. Compared to castables without Cr3+ oxides, the corrosion resistance increases at least 5 times upon Cr3+-oxides addition, irrespective of their forms (Cr 2 O 3 or Ca(Al,Cr) 12 O 19). However, at all the tested temperatures, Ca(Al,Cr) 12 O 19 addition into the castables could suppress the Cr6+ generation significantly (below the standard solid-waste disposal limit of 3 mg/L) compared to Cr 2 O 3 , which was well above the limit. [ABSTRACT FROM AUTHOR]

• The progress made in the application of DED technology to Mg-alloys has been evaluated. • The predominant imperfections, notably inhomogeneous microstructure evolution, and porosity, observed in Mg-alloy components manufactured through DED are discussed. • The preventive measures implemented to counteract the formation of these defects are explored. • The challenges and prospects of DED of Mg-alloys are summarized. Mg-alloys have gained considerable attention in recent years for their outstanding properties such as lightweight, high specific strength, and corrosion resistance, making them attractive for applications in medical, aerospace, automotive, and other transport industries. However, their widespread application is hindered by their low formability at room temperature due to limited slip systems. Cast Mg-alloys have low mechanical properties due to the presence of casting defects such as porosity and anisotropy in addition to the high scrap. While casting methods benefit from established process optimization techniques for these problems, additive manufacturing methods are increasingly replacing casting methods in Mg alloys as they provide more precise control over the microstructure and allow specific grain orientations, potentially enabling easier optimization of anisotropy properties in certain applications. Although metal additive manufacturing (MAM) technology also results in some manufacturing defects such as inhomogeneous microstructural evolution and porosity and additively manufactured Mg alloy parts exhibit lower properties than the wrought parts, they in general exhibit superior properties than the cast counterparts. Thus, MAM is a promising technique to produce Mg alloy parts. Directed energy deposition processes, particularly wire arc directed energy deposition (WA-DED), have emerged as an advantageous additive manufacturing (AM) technique for metallic materials including magnesium alloys, offering advantages such as high deposition rates, improved material efficiency, and reduced production costs compared to subtractive processes. However, the inherent challenges associated with magnesium, such as its high reactivity and susceptibility to oxidation, pose unique hurdles in the application of this technology. This review paper delves into the progress made in the application of DED technology to Mg-alloys, its challenges, and prospects. Furthermore, the predominant imperfections, notably inhomogeneous microstructure evolution and porosity, observed in Mg-alloy components manufactured through DED are discussed. Additionally, the preventive measures implemented to counteract the formation of these defects are explored. [Display omitted] [ABSTRACT FROM AUTHOR]

• Sputtered Mg–Zr coatings with high Zr content display refined columnar growth structures. • Mg–Zr coatings show ''liquidphilic" behaviour, enhancing biocompatibility in bone implants. • Steady Young's modulus and improved hardness with increasing Zr content. • Mg–Zr coatings balance mechanical properties, mitigating stress shielding effects. • Enhanced corrosion resistance of Mg–Zr coatings is obtained in the range of 1 to 3.4 at.% Zr content. Magnesium (Mg) alloys are widely used for temporary bone implants due to their favorable biodegradability, cytocompatibility, hemocompatibility, and close mechanical properties to bone. However, rapid degradation and inadequate strength limit their applicability. To overcome this, the direct current magnetron sputtering technique is employed for surface coating in Mg-based alloys using various zirconium (Zr) content. This approach presents a promising strategy for simultaneously improving corrosion resistance, maintaining biocompatibility, and enhancing strength without compromising osseointegration. By leveraging Mg's inherent biodegradability, it has the potential to minimize the need for secondary surgeries, thereby reducing costs and resources. This paper is a systematic study aimed at understanding the corrosion mechanisms of Mg–Zr coatings, denoted Mg-xZr (x = 0–5 at.%). Zr-doped coatings exhibited columnar growth leading to denser and refined structures with increasing Zr content. XRD analysis confirmed the presence of the Mg (00.2) basal plane, shifting towards higher angles (1.15°) with 5 at.% Zr doping due to lattice parameter changes (i.e., decrease and increase of " c " and " a " lattice parameters, respectively). Mg–Zr coatings exhibited "liquidphilic" behavior, while Young's modulus retained a steady value around 80 GPa across all samples. However, the hardness has significantly improved across all samples' coating, reaching the highest value of (2.2 ± 0.3) GPa for 5 at.% Zr. Electrochemical testing in simulated body fluid (SBF) at 37 °C revealed a significant enhancement in corrosion resistance for Mg–Zr coatings containing 1.0–3.4 at.% Zr. Compared with the 5 at.% Zr coating which exhibited a corrosion rate of 32 mm/year, these coatings displayed lower corrosion rates, ranging from 1 to 12 mm/year. This synergistic enhancement in mechanical properties and corrosion resistance, achieved with 2.0–3.4 at.% Zr, suggests potential ability for reducing stress shielding and controlled degradation performance, and consequently, promising functional biodegradable materials for temporary bone implants. [ABSTRACT FROM AUTHOR]

• The formation process and corrosion properties of PEO coatings formed in phosphate, aluminate, and mix of phosphate and aluminate electrolytes have been systematically investigated. • Coatings prepared from single phosphate electrolytes and phosphate-aluminate low concentration electrolytes have greater potential than aluminate coatings based on microstructure and corrosion performance of layers. • In the case of low concentration solution, the thickness of aluminate-based coating cannot be significantly increased by increasing concentration of electrolyte. In this paper, the formation process, morphology, and electrochemical performance of PEO coatings on AM50 magnesium alloy prepared in low concentration phosphate, aluminate, and phosphate-aluminate electrolytes were systematically studied. The results show that the coatings prepared from the phosphate electrolytes have a higher thickness and better corrosion resistance properties compared to the other electrolytes. The coatings prepared from low concentration phosphate-aluminate mixed electrolytes have slightly thinner thickness, a similar coating structure and an order of magnitude lower value of electrochemical impedance compared with phosphate electrolyte coatings. The Coatings prepared from low concentration aluminate electrolytes have the lowest thickness and the worst corrosion resistance properties which gets close to corrosion behavior of the bare AM50 under the same test conditions. Considering application, coatings prepared from single low concentration phosphate electrolytes and low concentration phosphate-aluminate electrolytes have greater potential than single low concentration aluminate coatings. However, reducing the electrolyte concentrations of coating forming ions too much has negative influence on the coating growth rate. [ABSTRACT FROM AUTHOR]

In this paper, a rare earth-Cr composite boronizing method to prepare boride ceramic coatings for AISI H13 steel was proposed. The effect of rare earth elements and Cr on the microstructure, hardness, wear resistance, high temperature oxidation resistance, and corrosion of boride ceramic layers was researched. The characteristics of the boride layers were investigated by means of X-ray diffraction (XRD), scanning electron microscope (SEM), electron probe microanalysis (EPMA), wear tests, high-temperature oxidation tests, and corrosion immersion tests, etc. The results showed that the boride layer comprised of Fe 2 B, FeB, CrB and Cr 2 B phases. The addition of rare earth CeO 2 and Cr nanopowder promoted the growth of the boride layer, and its surface hardness increased by 3.5 times compared with that of tempered AISI H13 steel. In addition, the addition of CeO 2 and Cr significantly reduced the wear rate of the boride layer, with the surface wear mechanism being abrasive oxidative wear. Furthermore, the oxidation rate of the boride layer was 71 % lower than that of AISI H13 steel, demonstrating excellent high-temperature oxidation resistance; and the boride layer showed good acid corrosion resistance in corrosion immersion tests. [Display omitted] • A boride ceramic coating prepared by solid composite boronizing method was proposed • Rare earth (RE) and Cr significantly improved hardness and adhesion of the boride layer. • The wear rate of H13 steel was reduced by 82% by Re-Cr composite boronizing. • The RE-Cr boride layer effectively improved the oxidation resistance of H13 steel. • The RE-Cr boride layer manifested excellent acid corrosion resistance. [ABSTRACT FROM AUTHOR]

In this paper, the effects of applied electric field on the corrosion resistance of slag-line (ZrO 2 -C material) of SEN under mold flux-molten steel coupling condition (near working condition) was systematically studied. The results show that the applied electric field can regulate the ion movement in the mold flux and affect the graphite activity in slag-line, thereby affecting the corrosion resistance of the slag-line. In the actual production, the corrosion resistance of the slag-line can be improved by inserting the electrode into the mold flux and using the sacrificial anode to protect the cathode. [ABSTRACT FROM AUTHOR]

• UHP Mg-Ge showed good corrosion resistance in a simulated physiological environment. • Mg 2 Ge played key roles in cathodic kinetics inhibition. • Ge accelerated surface film formation and improved the film's passivity. • Creating UHP alloys is a promising strategy to make corrosion-resistant Mg alloys. UHP Mg-Ge alloys was recently found to provide excellent corrosion resistance. This paper provides new insights on the mechanism of improved corrosion resistance of UHP Mg-Ge alloys in Hanks' solution. The studied UHP Mg-0.5Ge and UHP Mg-1Ge alloys showed superior corrosion resistance compared to UHP Mg and WE43, with the Mg-1Ge exhibiting the best corrosion performance. The exceptional corrosion resistance of the UHP alloy is attributed to (i) Mg 2 Ge's ability to suppress cathodic kinetics, (ii) Ge's capability to accelerate the formation of a highly passive layer, and the (iii) low amounts of corrosion-accelerating impurities. [ABSTRACT FROM AUTHOR]

The effect of Sc 2 O 3 content on the corrosion behaviors of x Sc 2 O 3 -3.5Y 2 O 3 co-doped ZrO 2 (ScYSZ, x = 4.5, 5.5 and 6.5 mol.%) in calcium-magnesium-alumino-silicate (CMAS) at 1300 °C was investigated in this paper. It is shown that the ScYSZ ceramic exhibits better resistance to molten CMAS attack when doping with more Sc 2 O 3. The CMAS penetration depth in the ScYSZ ceramic decreases with increasing Sc 2 O 3. It is about 18 µm of CMAS penetrated depth in the 6.5Sc3.5YSZ after corrosion for 4 h at 1300 °C, including an 11 µm and 7 µm for the reaction-reprecipitation and grain-boundary infiltration layers, respectively. High thermochemical stability and weak reactivity of the ScYSZ to the glassy CMAS melt are beneficial to enhance the high temperature corrosion resistance, attributing to the low solubility in molten CMAS and the weak affinity to Ca2+ for small ionic radius Sc3+. The mechanism of enhancing the resistance to CMAS is discussed. [ABSTRACT FROM AUTHOR]

Despite superhydrophobic ceramic coatings have been successfully prepared, there lacks an improvement in their corrosion resistance in long-term saltwater environments due to the porous properties. In this paper, two coatings were prepared again by heat repair treatment and construction of double-layer composite structure, and the surface characteristics of the coatings were determined by scanning electron microscope, infrared spectrometer and contact angle measuring instrument, and the electrochemical performance and corrosion resistance of the coatings were evaluated by electrochemical test and immersion test. The results showed that the original porous ceramic coating had superhydrophobic property, and the water contact angle (CA) and sliding angle (SA) were 150.4°and 8.7 ° , respectively. Through knife scratching, sandpaper abrasion and tape peeling tests, the coating had good bond strength and mechanical durability. Compared with the original coating, the corrosion resistance of heat repair coating and composite coating had better corrosion resistance and a protective effect on the substrate. This protective mechanism can be attributed to the repair effect of heat treatment on the hydrophobicity of the coating, and the composite structure resists the penetration of external liquids. Based on these results, heat repair and double-layer composite structures can improve the defects of long-term insufficient durability of superhydrophobic ceramic coatings, which have potential marine application prospects. [ABSTRACT FROM AUTHOR]

Metal materials such as stainless steel (SS) and titanium alloys have been considered as ideal materials for bipolar plates (BPs) in proton exchange membrane fuel cells (PEMFCs) owing to high electrical conductivity, high thermal conductivity, good mechanical strength and processability. However, metal BPs would be corroded in the acidic working condition of PEMFC. In recent years, conducting polymer coatings (CPCs) have attracted much attention in the corrosion protection of metal BPs for the good corrosion resistance and conductivity. In this paper, we systematically review the recent advances in CPCs for metal BPs based on the two categories of non-intrinsic conducting polymer (NICP) coatings and intrinsic conducting polymer (ICP) coatings. The progress of NICP coatings for metal BPs mainly focuses on the three types of conducting fillers: noble metal materials, carbon materials and transition metal compound materials, while the progress of ICP coatings for metal BPs is discussed based on the three modification strategies: doping modification, nanomaterial modification, and bilayer coatings. Furthermore, the challenges and perspectives of CPCs coatings for metal BPs are also discussed, which would help to provide guidance for the further research of CPCs for metal BPs. In this paper, we systematically review the recent advances in conducting polymer coatings (CPCs) for metal bipolar plates (BPs) based on the two categories of non-intrinsic conducting polymer coatings (NICP) and intrinsic conducting polymer (ICP) coatings. The progress of NICP coatings for metal BPs mainly focuses on the three types of conducting fillers: noble metal materials, carbon materials and transition metal compound materials, while the progress of ICP coatings for metal BPs are discussed based on the three modification strategies: doping modification, nanomaterial modification, and bilayer coatings. [Display omitted] • The advances in conducting polymer coatings for metal bipolar plates are systematically summarized. • Three types of conducting fillers for non-intrinsic conducting polymer coatings are introduced. • Three modification strategies for intrinsic conducting polymer coatings are introduced. • The challenges and perspectives of conducting polymer coatings for metal bipolar plates are discussed. [ABSTRACT FROM AUTHOR]

The purpose of this paper was to develop ceramics materials with high thermal shock resistance and corrosion resistance for preparing gas blowing components. In this paper, MgO-rich MgO–ZrO 2 ceramics were obtained by using MgO powder and ZrO 2 powder as starting materials and CeO 2 as an additive. Changes in the properties in terms of thermal shock resistance, mechanical properties, and slag corrosion-resistance with chemical compositions were examined correlated to microstructure and phase changes. Especially, the effect of doping CeO 2 on phase transition of zirconia in MgO-rich system was discussed. The results showed that doping amount of CeO 2 significantly improved properties of MgO–ZrO 2 ceramics. Especially when doping amount of CeO 2 was 2 wt%, residual strength ratio was enhanced over 100% after thermal shock testing. In samples doped with CeO 2 , ZrO 2 was stable in cubic or tetragonal form due to complete solution of CeO 2 , which was important reason for the improvement of various properties of MgO–ZrO 2 ceramics. [ABSTRACT FROM AUTHOR]

With the increasing demand for environmental protection, the recovery and reuse of fly ash has attracted more and more attention. In this paper, the fly ash based porous ceramic membrane is modified from hydrophilic to superhydrophobic successfully. Average contact angle and roll-off angle of the modified superhydrophobic fly ash based ceramic membrane are 151.3° and 11.3°, respectively. Additionally, a variety of performances of the prepared superhydrophobic fly ash based ceramic membrane are characterized. Dynamic process of droplets with different initial velocities impacting on the surface of superhydrophobic fly ash based ceramic membrane is photographed by high-speed camera. It is proved that dynamic process of droplet impacting on superhydrophobic surface includes spreading, retraction and partial rebound. Spreading, retraction and solid-liquid contact time of droplets are about 2.9 ms, 11.5 ms and 14.4 ms, respectively. The above data is almost unaffected by impact velocity of droplets. In addition, experiments show that the prepared superhydrophobic fly ash based ceramic membrane has good acid and alkali corrosion resistance, and self-cleaning performance. In this paper, superhydrophobic ceramic membrane prepared by fly ash shows excellent performance and it can provide guidance for the reuse of fly ash. [ABSTRACT FROM AUTHOR]

[Display omitted] • The paper provides a comprehensive review of state-of-the-art titanium alloys and composites for orthopedic implants. • Recent advances in surface modification techniques aimed at enhancing implant biocompatibility are highlighted. • Recent advances in manufacturing methods for tailored titanium biomaterials are investigated. • The paper summarizes the transformative impact of machine learning on alloy design, process optimization, quality control, and customization. The increasing demand for orthopedic implants has driven the search for materials that combine strength, biocompatibility, and long lifetime. Compared to stainless steel and Co-Cr-based alloys, titanium (Ti) and its alloys are favored for biomedical implants because of their high strength, corrosion resistance, and biocompatibility. This comprehensive review delivers a wide overview of the field of Ti-based biomaterials for orthopedic implants applications, focusing on their types, mechanical and chemical resistance, surface modifications, innovations in fabrication techniques, Ti matrix composites, and machine learning (ML) advancements. Ti alloys of different crystalline phases, including α, near-α, (α + β), β, and shape memory alloys, offer diverse options for orthopedic applications. Strengthening properties, wear, fatigue, and corrosion resistance are crucial factors influencing the performance and reliability of Ti implants. Moreover, this review discussed the challenges to Ti-based biomaterial durability through surface modifications to enhance their biofunction, wear resistance, corrosion resistance, and antibacterial properties. Recent developments in fabrication techniques for Ti-based biomaterials are also discussed. Eventually, this review investigated how ML revolutionized Ti orthopedic implants by providing insights into the behavior of new alloys, aiding in manufacturing optimization, allowing for real-time quality control, and advancing the development of personalized, biocompatible, and reliable implants. [ABSTRACT FROM AUTHOR]

• This paper proposes a novel, non-destructive and high-throughput testing technique to evaluate the film thickness of corrosion products and the corrosion surface damage. • The difference between the measurement result and the conventional value is only 0.03 μm. • The new measurement method can accurately characterize corrosion heights of approximately 0.2 µm and above. • By using the established technology, we found that there is a certain correlation between the corrosion rate and the product film thickness, but the film thickness is not the only factor determining the corrosion rate. This paper proposes an accurate and high-throughput testing technique to characterize the film thickness of corrosion products and the corrosion surface damage. This method first selected the optimal instrument parameters and sample preparation methods. Secondly, three approaches were implemented to improve test accuracy: eliminating initial errors, optimizing post-processing processes, and excluding the impact of critical data. Finally, this technology is applied to evaluate the corrosion resistance of B10 pipes. The results in the range of 4 mm × 4 mm indicate that when the fluctuation range is −400 μm ∼ 100 μm and the magnification 20 × 1, the optimal combination of acquisition time and image quality could be achieved. After implementing three processing methods to improve accuracy, the difference between the measurement result and the conventional value is reduced to 0.03 μm, and the variance is reduced to 0.002. This method is verified to accurately characterize a corrosion height of approximately 0.2 µm. [ABSTRACT FROM AUTHOR]

In this paper, high current pulsed electron beam (HCPEB) irradiation was employed to improve the surface density and properties of cold spray Al coating. The effects of the energy density on the microstructure, phase composition, stress, microhardness, wear, and corrosion behavior of coatings as-fabricated were investigated. HCPEB remelting treatment has improved the surface defects of cold spray coatings. The microhardness of treated coatings is higher than that of untreated coating, and the highest microhardness of the treated coatings occurs in the subsurface layer of the coatings. The wear track width and depth of the treated coating were lower than those of the untreated sample. The corrosion potential of the treated samples increases from −1.12 v to −0.95 v, and the corrosion current density reduces from 15.64 µA/cm2 to 3.31 µA/cm2. Our results demonstrated the wear and corrosion resistance of the cold spraying Al coating were dramatically improved by HCPEB irradiation. [ABSTRACT FROM AUTHOR]

Hafnium nitride (HfN), as one of the most stable of transition metal nitrides, has shown great application potential in many fields. In this paper, a series of Hf-B-N films doped with different B contents were prepared. The results show that when the doping amount of B is 6.56 at.%, the hardness of Hf-B-N film is 24% higher than that of undoped HfN film, which is 35.27 GPa. And the wear rate of the film is one order of magnitude lower than that of the undoped HfN film. Solid solution strengthening and the stress generated by the coherent interface are responsible for the enhancement of strength. When the content of B continues to increase, the fracture toughness of HfN film is nearly 6 times higher than that of binary HfN film, and the highest fracture toughness is 5.98 MPa m1/2. It is found that the amorphous BN phase and the nanocrystalline HfBN phase coexist, and the synergistic effect of the ductile nanocrystalline phase and the amorphous phase improves the fracture toughness and bonding strength of the films. The films with high boron content have excellent oxidation resistance and corrosion resistance. [ABSTRACT FROM AUTHOR]

Instantaneous reactions of Al, Mn, Zn, Zr and Y with Ni by mixing the prepared Mg-8Al-0.4Mn, Mg-6Zn-2Y-0.5Zr and Mg-0.6Ni melts were investigated in this work to reveal the underlying mechanisms of their effects on the removal of Ni impurity. The results indicate three Ni-containing intermetallics, namely Al 4 NiY, Al 4 Ni(Y,Zr) and Al 31 Ni 2 Mn 6. The former two phases present lath-like and have a relatively larger size (> 20 µm in length) than the latest one which is granular with the diameter of ∼120 nm. This illustrates that Al and Y(/Zr) can efficiently remove Ni by forming Al 4 NiY or Al 4 Ni(Y,Zr) which would precipitate to the bottom of the melt. Furthermore, adding Y into Mg-Al based alloys can simultaneously remove Fe and Ni, which contributes their excellent corrosion resistance. Finally, this paper proposes two methods helped to efficiently remove Ni for both Mg-Al based alloys and Al-free Mg alloys, and both of them are also benefit to improve alloys' strength. [ABSTRACT FROM AUTHOR]

Electromagnetic interference (EMI) shielding materials have become very important materials in modern society due to the increasing electromagnetic pollution. Although metal-based materials exhibited high shielding performance, they had lots of drawbacks, such as high density, less flexibility, low corrosion resistance, costly processing, and high surface reflection. Conductive polymer composites (CPC) gradually have come to the fore in recent years because the shortages of metal-based materials could overcome by CPC. However, the high-performance EMI shielding usually required high content of conductive fillers in CPC, which leaded to new drawbacks, such as mechanical deterioration, cost increase, and processing difficulties. Therefore, the main challenge for EMI shielding CPC was to achieve high EMI shielding effectiveness (SE) at low content of conductive fillers. In this paper, the CPC with multiple interfaces which has demonstrated to improve EMI SE was reviewed. First of all, the theory of EMI shielding in CPC was introduced in detail. Second, the CPC with various multiple structures, including foamed/porous, segregated, multi-component, multilayered/sandwiched, and prefabricated conductive networks, was discussed. Third, the reported mechanism of CPC with multiple interfaces was given in this paper. [Display omitted] [ABSTRACT FROM AUTHOR]

In this paper, inorganic phosphate bonded coatings (IPBCs) via embedding reduced graphene oxide (rGO) modified with heptadecafluoro-1,1,2,2-tetradecyl trimethoxysilane (FAS) were prepared through sol-gel method. Aim of this paper is to research the corrosion resistance of IPBCs with the addition of rGO modified with FAS. Firstly, the Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy (Raman) and surface morphology of GO and rGO modified with and without FAS were characterized. Results indicated that the hydrophobic –CF 2 – and –CF 3 groups were successfully introduced into GO and rGO after modification. And IPBCs with rGO-FAS exhibited higher hydrophobicity and corrosion resistance than IPBCs with the addition of GO or GO-FAS. That is because the hydrophobicity and the introduction of low surface energy material is conducive to overcoming the interaction of rGO itself, thus rGO can be better utilized and played, which resulting the excellent corrosion performance of IPBC@rGO-FAS. [ABSTRACT FROM AUTHOR]

High entropy nitride (HEN) films have attracted much attention due to their versatile properties, such as satisfactory mechanical properties, excellent anti-oxidation performance, outstanding corrosion resistance, and vitally important thermostability, indicating high application potentials. This paper reviews the four core effects and discusses several empirical parameters for phase prediction in HEAs. Then, this review focuses on the recent developments of HEN films, introducing how N contents as well as other factors influences the microstructures and thus leads to changes in relevant properties, such as mechanical, tribological, and chemical stabilities, what follows is the related mechanisms contributing to. Lastly, future trends and outlooks are briefly introduced. This review is aimed to give a comprehensive introduction to recent developments in HEN films, and to make it convenient to explore the research gaps for students and researchers. In this review, the "four core effects" of high entropy materials and related phase prediction criterias are fully introduced. Then, structural characteristics and influencing factors of HEN films, such as deposition parameters, post-treatments, etc. are discussed. What is more, this review encompasses a detailed analysis of the properties of HEN films, including mechanics, friction, corrosion resistance, etc. Finally, the paper offers a brief outlook into the future prospects and development potential of HEN nitride films. [Display omitted] • The "four core effects" of high entropy materials and their related phase prediction criterias are fully introduced. • The structural characteristics and influencing factors of HEN Films, such as post-treatments, etc. are discussed. • This review encompasses a detailed analysis of the properties of HENs, including mechanics, corrosion resistance, etc. • The paper offers a brief outlook into the future prospects and development potential of HEN nitride films. [ABSTRACT FROM AUTHOR]

Corrosion and hydrogen damage cause problems to oil and gas industry equipment. FeS (sulfur-iron) compounds generated by H 2 S causes surface corrosion and covers the surfaces of the equipment where the extent of corrosion and hydrogen damage are influenced by these compounds. Different types of FeS compounds have different crystal structures, and there by influence their corrosion and hydrogen resistance. In this paper, single-structure pyrrhotite and pyrite were synthesized by hydrothermal method, which was controlled by controlling the temperature and Fe, S ratio. Their structures are hexagonal sheet and polyhedron respectively. The interfacial properties and hydrogen barrier properties of FeS were tested and the results show that pyrrhotite possesses anion selectivity. The electrochemistry shows low impedance modulus and high corrosion current density, which indicates low corrosion resistance. Pyrrhotite has the lowest hydrogen permeation current density and has good inhibition of hydrogen permeation ability. For the high impedance modulus and low corrosion current density pyrite possesses cation selective, which shows strong resistance to corrosion. However, its hydrogen permeation current density is high and hydrogen blocking effect is weak. • The hydrothermal method was used to obtain pure FeS. • The structures of pyrrhotite and pyrite are the same with FeS generated in H 2 S environment. • Pyrrhotite possesses anion selectivity and pyrite possesses cation selectivity. • The hydrogen barrier effect of pyrrhotite is better than pyrite. [ABSTRACT FROM AUTHOR]

In this paper, the ultrasound-assisted sealing with aluminum phosphate and silicone resin was used to fill the pores in the subsonic plasma sprayed nanostructured Al 2 O 3 -13TiO 2 coating, with which the corrosion resistance of the coating can be improved. Since ultrasonic environment accelerated the penetration of the sealant, the polarization resistance of the Al 2 O 3 -13TiO 2 coating after sealing with aluminum phosphate and with silicone resin was about 6.3 times and 119.6 times that of the as-sprayed Al 2 O 3 -13TiO 2 coating, respectively. With regard to the aluminum phosphate sealant, the heat-treatment improved the stability of sealant, while the evaporation of water in sealant resulted in the occurrence of micro-cracks in the coating. Meanwhile, the evaporation route of water also created some pits in the aluminum phosphate sealant, which weakened the surface sealing effect to a certain degree. For the silicone resin, the good elasticity and low drying temperature of silicone resin provided the sealant with a dense structure and thus ensured a remarkable sealing effect. In contrast with the aluminum phosphate sealant, the nanostructured Al 2 O 3 -13TiO 2 coatings after ultrasound-assisted sealing with silicone resin possessed higher corrosion resistance in 3.5 wt% NaCl solution. [ABSTRACT FROM AUTHOR]

Thermal barrier coatings (TBCs) are widely used as insulating layers to protect the underlying metallic structure of gas turbine blades. However, the thermal cycling performance of TBCs is affected by their complex working environments, which may shorten their service life. Previous studies have shown that preparing a mesh structure in the bonding layer can relieve thermal stress and improve the bonding strength, thereby prolonging the service life of TBCs. In this paper, a micromesh structure was prepared on the surface of the bonding layer via wet etching. The microstructure and failure mechanism of the micromesh TBCs after CMAS (CaO-MgO-Al 2 O 3 -SiO 2) thermal erosion were investigated. Numerical simulation was combined with thermal shock experiments to study the stress distribution of the micromesh-structured TBCs. The results showed that the circular convex structure can effectively improve the CMAS corrosion resistance and thermal shock resistance of TBCs. [ABSTRACT FROM AUTHOR]

In order to fabricate the stable superhydrophobic coatings with antifouling and anticorrosion functions. In this study, a series of nickel-coated superhydrophobic surfaces were designed on carbon steel (CS) using a one-step electrodeposition route. The structures of the prepared superhydrophobic Ni (SN) coatings were identified by scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR), and the wettability was also tested by contact angle goniometer. The findings displayed that the hierarchical micro-flower structures of the optimal SN coating (0.64 A of circuit density and 9.5 min of deposition time) imparted it excellent superhydrophobic property; the water contact angle (CA) and sliding angle (SA) were 168 ± 1.1° and 4.7 ± 0.6°, respectively. The optimal SN coating was found to have superior mechanical and chemical stabilities, as tested by knife scratching, adhesive tape peeling, sandpaper abrasion, and chemical corrosion resistance. Additionally, the optimal SN coating exhibited outstanding self-cleaning property, anti-corrosion, and superhydrophobic stability. Based on these results, it appears that SN coating prepared by one-step electrodeposition can solve the defect of insufficient long-term durability of electrodepositied superhydrophobic coatings, and has potential industrial application prospects. [ABSTRACT FROM AUTHOR]

Thermal barrier coatings with excellent thermal performance and corrosion resistance are essential for improving the performance of aero-engines. In this paper, (Y 3-x Yb x)(Al 5-x Sc x)O 12 (x = 0, 0.1, 0.2, 0.3) thermal barrier coating materials were synthesized by a combination of sol-gel method and ball milling refinement method. The thermal properties of the (Y 3-x Yb x)(Al 5-x Sc x)O 12 ceramics were significantly improved by increasing Yb and Sc doping content. Among designed ceramics, (Y 2.8 Yb 0.2)(Al 4.8 Sc 0.2)O 12 (YS-YAG) showed the lowest thermal conductivity (1.58 Wm−1K−1, at 800 °C) and the highest thermal expansion coefficient (10.7 × 10−6 K−1, at 1000 °C). In addition, calcium-magnesium- aluminum -silicate (CMAS) corrosion resistance of YS-YAG was further investigated. It was observed that YS-YAG ceramic effectively prevented CMAS corrosion due to its chemical inertness to CMAS as well as its unique and complex structure. Due to the excellent thermal properties and CMAS corrosion resistance, YS-YAG is considered to be prospective material for thermal barrier coatings. [ABSTRACT FROM AUTHOR]

Abstract: Fe-based stainless steels are the promising candidate materials for bipolar plate of proton exchange membrane fuel cell (PEMFC) due to low cost, ease stamping manufacture, good heat and electric conductivity. A surface modification technology of electroplating Cr followed by heat-diffusion in vacuum furnace is applied for AISI 304SS stainless steel in this paper to improve the Interfacial Contact Resistance (ICR) and corrosion resistance. The electrochemical tests such as potentiodynamic and potentiostatic polarization in the simulation PEMFC environments are carried out and the ICR between the carbon paper (diffusion layer) and the sample is evaluated. The results show that ICR is reduced markedly and corrosion resistance is better than the untreated substrate steel. The modified stainless steel with high Cr surface may be better candidate for the bipolar plates of PEMFC. After polarization, the contact resistance increased in some content. A surface nitride formation is under going on to lower the ICR further. [Copyright &y& Elsevier]

The evolutions of the microstructure and properties of 6061 aluminum alloy irradiated by the pulsed electron beam generated by pseudo-spark discharge is the main focus of this paper. The pseudo-spark discharge is a low-pressure, transient discharge which has been recognized as a high efficient electron beam source with the rapid current growth of ~1012 A/s , high power density of ~109 W/cm 2, short-duration pulse of 102~103 ns and self-focusing beam diameter of 0.5~6mm. These characteristics enable the material treated by the pseudo-spark pulsed electron beam to melt and cool rapidly, and form the fine grain structure. In this work, the evolutions of the micromorphology and surface properties of 6061 aluminum alloy and the influences of the beam parameters are investigated and analysed. The corrosion resistance of the surface is investigated by the electrochemical corrosion experiments. The mechanism of the "crater" in the surface microstructure formed by the pseudo-spark pulsed electron beam under varying beam accelerating voltages is also analysed and discussed. The experimental results in this paper demonstrate that the re-melting layer of the material surface appears after the given pseudo-spark pulsed electron beam irradiations, and "large crater" morphology forms under higher voltage. The homogenization of the element distributions on the surface and reduction of the impurity on the re-melting layer after given pulsed electron beam treatments are capable of improving the mechanical properties of the alloy workpiece surface, and the corrosion resistance of the surface is also increased after given pulsed electron beam treatments. [ABSTRACT FROM AUTHOR]

• We propose a human identification method based on dental impression images. First, we extract a geometric feature called the calibrated offset distance to describe the dental arch. The dental arch is a distinctive feature of individual teeth. To address the challenges in describing the dental arch, this paper introduces a novel calibrated offset distance that captures the characteristics of the arc, changes in radian, and distances between arc breakpoints simultaneously. • We propose an adaptive threshold strategy for the tooth print detection model based on the YOLOv8 network. We design a gradient training strategy to achieve a robust detection model. Building upon its high positioning accuracy, we propose an adaptive threshold strategy to further enhance the detection accuracy. • We propose a multi-scale and multi-dimensional tooth print aggregation feature. In order to enhance the ability to recognize individuals with similar teeth structures, we further integrate SIFT features to provide a detailed description based on geometric features. This aggregation feature is composed to improve the performance of human identification. In large-scale natural disasters and special criminal cases, surface features of bodies, such as faces and fingerprints, are easily destroyed. Teeth possess strong high-temperature resistance, corrosion resistance, and high hardness, which can compensate for the shortcomings of the aforementioned situations. This paper proposes an identification method based on the aggregated features of multi-scale dental impression images. Firstly, a method exploiting the adaptive object detection method based on YOLOv8 is proposed to segment toothprints. Next, a novel geometric feature named calibrated offset distance is extracted, combined with the SIFT feature method, to extract multi-scale and multi-dimensional features from the global toothprint, local toothprints, and single-tooth prints. Finally, all features are aggregated to enhance the descriptive ability and robustness. Experimental results indicate that the method proposed in this paper demonstrates good identification performance. [ABSTRACT FROM AUTHOR]

Aimed at getting rid of the complicated preparation procedure, multi-functional superhydrophobic coatings inspired by natural plants have been successfully constructed on different matrix via a facile and effective spraying technology in this paper. The innovation of this paper lies in directly employing the unmodified fillers to establish the superhydrophobic coatings system with high performance. The results have revealed that the water contact angle (WCA) and water sliding angle (WSA) of as-prepared coatings can reach 155.4° and 8°, confirming the superhydrophobicity with low surface adhesion is achieved. And the potential superhydrophobic mechanism can be ascribed to the enrichment of low surface energy components on the homogeneous and rough grain structure of as-prepared coatings. Simultaneously, as-prepared coatings have exhibited the good self-cleaning property, anti-fouling property, and anti-icing property. Surprisingly, the mechanical stability of superhydrophobic coatings can be maintained after 50 cycles during the friction experiments. And the oil-water separation ability for the coated metal meshes was also obtained with high separation efficiency of 95%. Moreover, the anti-corrosion ability was also systematically investigated and its potential anti-corrosion mechanism of superhydrophobic coatings is primarily deduced. Therefore, the multifunctional and robust superhydrophobic coatings with biomimetic structure were established via a simple strategy, which is expected to be applied in field of metal corrosion and protection and multi-functional surface material in the future. [Display omitted] [ABSTRACT FROM AUTHOR]

In this paper, a multi-functional composite coating with low friction coefficient, high wear resistance and excellent tribocorrosion resistance is fabricated on AZ31 Mg alloys by micro-arc oxidation and spray-coating methods. The microstructure, and composition of the coating are characterized by SEM, EDS, XRD, and FT-IR. Potentiodynamic polarization and EIS tests are conducted to evaluate the corrosion resistance of the composite coating. The tribocorrosion property is also studied using pin-on-disk tribometer in 3.5 wt.% NaCl solution. It is found that the composite coating possesses better long-term corrosion resistance than the single MAO coating. The tribocorrosion tests prove that the composite coating exhibits much better wear and tribocorrosion resistance than the single MAO coating and can protect the substrate from corrosion under a sliding condition. [ABSTRACT FROM AUTHOR]