Electron Microscopy Characterization Research Articles

A numerical study of the effect of interfacial thermal resistance on thermal conductivity of Cu-B/diamond composites

Cu/diamond composite is a promising thermal management material for heat dissipation of high-power electronic devices. Heat transfer models for a Cu-B/diamond composite with varying boron contents added in the Cu matrix were constructed using the finite element (FE) method, based on the results from transmission electron microscopy (TEM) characterization. The heat transfer behavior of the Cu/diamond composites was then investigated. The predicted effective thermal conductivities were compared to experimental values, using both analytical model calculation and FE simulation. The FE simulation effectively illustrates the dependence of thermal conductivity on interface structure evolution of the composite. The heat transfer behavior of the Cu-B/diamond composites varies as the boron content increases. In the Cu-0.3wt%B/diamond composite, most of the heat flow is concentrated and transferred along the diamond particles. In the Cu-1.0wt%B/diamond composite, the heat flux distribution and flow direction are similar to those in the Cu-0.3wt%B/diamond composite, but the heat flux is substantially lower. The heat transfer behavior is closely related to the interactions between the two phases in the composite and is intensively influenced by the evolution of interfacial carbide morphology. The FE simulation provides a more accurate prediction of effective thermal conductivity compared to the analytical model calculation, as it considers the reasonable interactions between the two phases relating to the actual interfacial structure. The findings provide a fundamental basis for optimizing the interfacial structure of Cu/diamond composites and further improving their thermal conductivity.

Study on Microstructure and Corrosion Fatigue Resistance of 14Cr12Ni3Mo2VN Materials Based on the Composite Technology of High-Frequency Induction Quenching and Laser Shock Peening

This study investigated the microstructure, microhardness, and residual compressive stress of 14Cr12Ni3Mo2VN martensitic stainless steel treated with high-frequency induction quenching (HFIQ) and laser shock peening (LSP). Using rotating bending corrosion fatigue testing, the corrosion fatigue performance was analyzed. Results show that a microstructural gradient formed after HFIQ and LSP: the surface layer consisted of nanocrystals, the subsurface layer of short lath martensite, and the core of thick lath martensite. A hardness gradient was introduced, with surface hardness reaching 524 Hv0.1, 163 Hv0.1 higher than the core hardness. A residual compressive stress field was introduced near the surface, with a maximum residual compressive stress of approximately −575 MPa at a depth of 0.1 mm. Corrosion fatigue results indicate that cycle loading times of samples treated with HFIQ and LSP were 2.88, 2.04, and 1.45 times higher than untreated, HFIQ-only, and LSP-only samples, respectively. Transmission electron microscopy (TEM) characterization showed that HFIQ reduced the lath martensite size, while the ultra-high strain rate induced by LSP likely caused dynamic recrystallization, forming numerous sub-boundaries and refining grains, which increased surface hardness. The plastic strain induced by LSP introduced residual compressive stress, counteracting tensile stress and hindering the initiation and propagation of corrosion fatigue cracks.

Mitigating coherent loss in superconducting circuits using molecular self-assembled monolayers

In planar superconducting circuits, decoherence due to materials imperfections, especially two-level-system (TLS) defects at different interfaces, is a primary hurdle for advancing quantum computing and sensing applications. Traditional methods for mitigating TLS loss, such as etching oxide layers at metal and substrate interfaces, have proven to be inadequate due to the persistent challenge of oxide regrowth. In this work, we introduce a novel approach that employs molecular self-assembled monolayers (SAMs) to chemically bind at different interfaces of superconducting circuits. This technique is specifically tested here on coplanar waveguide (CPW) resonators, in which this method not only impedes oxide regrowth after surface etching but can also tailors the dielectric properties at different resonators interfaces. The deployment of SAMs results in a consistent improvement in the measured quality factors across multiple resonators, surpassing those with only oxide-etched resonators. The efficiency of our approach i3s supported by microwave measurements of multiple devices conducted at millikelvin temperatures and correlated with detailed X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) characterizations of SAM-passivated resonators. The compatibility of SAMs materials with the established fabrication techniques offers a promising route to improve the performance of superconducting quantum devices.

Improvement of uranium adsorption in Kocuria rosea by phosphate: A combined physiological and proteomic analysis

In this study, a combined physiological and proteomic analysis was performed to investigate the effect of phosphate addition on uranium adsorption response of Kocuria rosea. When 0.4–5 g/L KH2PO4 was added to the culture medium, there was no significant change in biomass compared with the control (without KH2PO4 addition). Subsequently, the cells were collected and interacted with uranium solution (300 mg/L, 20 mL), and the adsorption rate of uranium was significantly increased from 22.14 % to 65.32 % with 3.0 g/L KH2PO4 addition. Meanwhile, the cells could release more phosphorus-containing substances and form thin film like uranium precipitates on the cell surface by fourier transform infrared spectroscopy and scanning electron microscopy characterization analyses. Furthermore, a proteomic approach was employed to reveal the regulation mechanism of phosphate on uranium interaction in the K. rosea cells. The bioinformatics analysis revealed that the differentially abundant proteins in K. rosea were mainly involved in cell motility, ribosomes, structural molecule activity, flagellar assembly, and energy metabolism under uranium stress. Interestingly, up-regulated proteins were significantly enriched for organic acid biosynthetic process in the cells with KH2PO4 addition. In addition, KH2PO4 led to upregulation of proteins including phosphohydrolase, asparagine synthase, and the phosphotransferase system (PTS) transporter subunit EIIC, which related to phosphate metabolism for regulation of uranium mineralization.

Vesicular Carriers for Improved Oral Anticoagulation Competence of Rivaroxaban: In Vitro and In Vivo Investigation

Rivaroxaban is an anticoagulant for avoidance and therapy of thromboembolic disorders. Unfortunately, oral bioavailability of rivaroxaban is compromised with dose increments. Accordingly, the aim was to test nano-vesicular lipid systems for improved oral anticoagulation activity of rivaroxaban. Rivaroxaban loaded niosomes, bilosomes and spanlastic formulations were prepared. The prepared systems were assessed in terms of particle size, zeta potential, transition electron microscopic features (TEM), entrapment efficiency, in-vitro drug release, and in-vivo anticoagulation performance in rats. The prepared vesicular systems exposed spherical negatively charged vesicles with mean particle size values between 136.6 nm to 387.9 nm depending on the composition. Rivaroxaban was efficiently entrapped in the vesicular systems with entrapment efficiency values ranging from 92.4% to 94.0%. Rivaroxaban underwent sustained release from the fabricated vesicular systems. The in vivo performance of the tested preparation revealed significant enhancement of the anticoagulation parameters. This was manifested from the prolonged clotting time, and prothrombin time. Moreover, the cut tails of the examined rats receiving the formulated nano-systems exposed a lengthy tail bleeding time compared to those receiving the un-processed rivaroxaban aqueous dispersion. In Conclusion, niosomes, bilosomes and spanlastic nano-dispersions have a potential to overwhelm the oral anticoagulation efficiency of rivaroxaban with spanlastic ranked as best.Graphical

Scanning Electron Microscopy and Magnetic Characterization of Iron Oxides in Suspended Sediments

<p class="Abstract"><span lang="EN-US">River sediment is the product of a sedimentation process in the river environment that originates from the weathering of bedrock or erosion processes, organic materials, particles, or anthropogenic substances. Previous research shows the magnetic mineral content in the sediments of the Citarum River and its tributaries. Suspended sediment was collected from the Citarum River and its tributaries in West Java, Indonesia, for mineralogical and granulometric analysis. The aim of this research is to distinguish between magnetic mineral sources, a scanning electron microscope equipped with energy dispersive X-ray spectroscopy (SEM-EDX), and rock magnetism. The hysteresis parameter verifies that the XRD measurement results show that the main magnetic minerals in suspended sediments are ferrimagnetic minerals such as magnetite (Fe<sub>3</sub>O<sub>4</sub>). According to the results of the SEM-EDX investigations, the magnetic granules in the Citarum River and its tributaries derive from two distinct sources: pedogenic and anthropogenic. The Citarum River and its tributaries’ magnetic granules are generally octahedral or angular in shape, with broken corners, indicating a pedogenic origin</span></p>

Practical Remediation of Hg-Contaminated Groundwater by MoS2: Batch and Column Tests.

Trace mercury contamination in groundwater poses a serious threat to ecological systems and human health. The kinetics and isotherms of MoS2 (MS) for Hg removal were studied in batch tests under an unfavorable high salinity and low mercury environment. Flower-like MS with nanosheets can effectively remove Hg in the groundwater matrix, with a shorter equilibrium time (3 h), superior removal efficiency (94.26%), excellent distribution coefficient (5.69 × 106 mL g-1), and higher maximum adsorption capacity (926.10 ± 165.25 mg g-1). Furthermore, the Adams-Bohart model (R2 = 0.9052-0.9416) can accurately describe the dynamic interception process of the initial stage (≤40 PVs), and the Yan model (R2 = 0.9765-0.9941) depicts the whole process (140 PVs) of MS in a fixed column well. A higher dosage of m, but lower C0 and νp facilitate the interception efficiency in column tests. Based on the characterizations of X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), which were used to simultaneously consider the species of Hg and the groundwater matrix, surface complexation, electrostatic attraction, ion exchange, and precipitation is a plausible interfacial adsorption mechanism of MS for mercury. The excellent performance demonstrates that MS with nanosheets is a promising candidate for the PRB remediation of trace Hg in saline groundwater.

N, S-Codoped Carbon Quantum Dots with High Inhibition Efficiency: Implications for Corrosion Mitigation of Carbon Steel in Acidic Environments.

The environmental friendliness, economic feasibility, and high efficiency of carbon quantum dots (CQDs) render them as highly promising candidates for corrosion inhibitors. The present study proposed the fabrication of nitrogen- and sulfur-codoped CQDs via an one-step hydrothermal method using l-cysteine and 4-aminosalicylic acid as precursors. The structure, particle size, and surface ligands of the prepared CQDs were determined through spectroscopy and transmission electron microscopy characterization. Subsequently, the inhibition performance of the CQDs on carbon steel in a 0.5 M sulfuric acid solution was evaluated through weight loss measurement, electrochemical methods, and surface analysis. The CQDs exhibited remarkable inhibition efficiencies of 97.9% at 293 K and 98.9% at 313 K, with a concentration of 150 ppm. In addition, the obtained CQDs demonstrated a combined physisorption and chemisorption adsorption behavior, which complied with the Langmuir adsorption isotherm. These findings provide insight into the inhibition mechanism and highlight the potential of codoped CQDs for corrosion mitigation applications in acidic environments.

High temperature environmental scanning electron microscopy characterization of transient phase formation during conversion of simulated nuclear waste feed to glass

In-situ High-Temperature Environmental Scanning Electron Microscopy (HT-ESEM) is used to characterize the transient phases formed during the melting of complex glass batch mixtures representing simulated nuclear waste feeds. The first phenomenon that occurs is the formation of oxyanionic salt melt, followed by the reaction of oxyanionic salts with refractory grains containing Si, Al, or Mg through surface reactions to form a molten alkali-alumino-boro-silicate phase. The onset temperatures of gas bubble formation and primary foaming are directly determined from the HT-ESEM measurements. The formation of sulfate lakes as well as the formation of high-temperature transient phases floating at the sample surface are also directly observed and identified. Convection currents are observed and their consequences on glass homogenization are discussed.

Exposure behavior and drilling efficiency of basalt fiber composite impregnated diamond bits in hard granite

Impregnated diamond bits (IDBs) are widely used for drilling in hard formations. To improve the drilling efficiency and exposure behavior of IDBs in granite, three types of Cu-based basalt fiber (BF) composite IDBs were designed and prepared by using the medium-frequency induction hot-pressing and sintering method, in which 0 wt% BF and 25 vol% diamond were used in 0BF25D IDB, 1 wt% BF and 25 vol% diamond were used in 1BF25D IDB, 1 wt% BF and 20 vol% diamond were used in 1BF20D IDB. The drilling efficiency of each IDB was tested under different drilling pressures (WOB), and the exposure behavior of IDBs was investigated by scanning electron microscopy and ultra field microstructural characterization. Results show that drilling granite with grade 9 drillability, low drilling pressure can drill successfully with the addition of BF. The average rate of penetration (ROP) of 1BF20D IBD under 6 kN WOB was 4.78 m/h, which was improved by 60 %∼80 %, energy consumption decreased by 66 % for each meter, torque (TOB) decreased, and rotational speed (RPM) was more stable during the drilling process. The addition of BF and reasonable diamond concentration enhanced the holding power of the diamond which promoted the exposure of the diamond. The average exposed height of the diamond in 1BF20D IDB reached 121.2 μm with 22 %–29 % of the whole diamond.

Rapid Synthesis of Uniformly Small Nickel Nanoparticles for the Surface Functionalization of Epitaxial Graphene

AbstractNickel nanoparticles (Ni NPs) combined with carbon nanomaterials are of significant interest due to their wide range of applications, including catalysis, hydrogen storage, and sensor technologies. However, it is challenging to develop an efficient process to produce small and stable Ni NPs ideal for functionalizing graphene or substrates with complex geometries. For this purpose, a rapid, simple, and cost‐effective method is presented for synthesizing uniformly small Ni NPs. The process involves cooling aqueous solutions of Ni(OAc)2 and cetyltrimethylammonium bromide (CTAB) to ≈1 °C, followed by the rapid addition of NaBH4. Crucial parameters, such as temperature and stirring rate, are precisely controlled to ensure uniform particle growth, with the reaction completing in just a few minutes. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) characterizations reveal spherical NPs with an average diameter of ≈11 nm and a narrow size distribution. Additionally, epitaxial graphene (EG) samples are functionalized with the synthesized NPs and their arrangement on the surface and their stability upon thermal annealing are investigated. X‐ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM) measurements demonstrate the degradation of CTAB, along with the recovery of Ni(0) under mild conditions (below 350 °C), with the NPs maintaining structural stability up to approximately 550 °C.

Mechanical properties and corrosion behavior of SiC reinforced high entropy alloy (Ni-Co-Fe-Ti) matrix composites produced by microwave and conventional sintering techniques

Abstract The aim of this work is to synthesize SiC reinforced Ni-Co-Fe-Ti composite using powder metallurgy (PM) method. Two sintering methods, conventional sintering (CS) using a tubular furnace and microwave sintering (MWS), are employed to synthesize three different weight percentages of SiC (3 wt.%, 6 wt.%, and 9 wt.%) within a Ni-Co-Fe-Ti matrix. The densification behavior of synthesized Ni-Co-Fe-Ti-SiC composites are studied using sinterability function. The highest sinterability of 0.89 was achieved for Ni-Co-Fe-Ti-0 wt.wt.% SiC alloy. The densification rate was found to be higher in MW sintered composites compared to those sintered conventionally. 3.5 wt.% NaCl solution was considered for corrosion examination and it was determined that Ni-Co-Fe-Ti- 9 wt.% SiC MW sintered composite exhibit highest corrosion resistance. Ni-Co-Fe-Ti-9 wt.%SiC MW sintered composite exhibits higher compressive strength of 1050 MPa than conventional sintered Ni-Co-Fe-Ti-9 wt.%SiC (625MPa). Ni-Co-Fe-Ti-6wt.% SiC MW sintered composite possess highest hardness of 58 HRC among other prepared composites. Interestingly, decreasing trend in hardness was observed for further inclusion of SiC with Ni-Co-Ti-Fe matrix. Scanning electron microscopy (SEM) and microstructural characterization technique shows the formation of pores in the conventional sintered composites. But, there is no formation of pores in the MW sintered composite of all the composition. Tribological studies were conducted using pin on disc method. Worn surface morphology was analyzed and it shows that severe pullout was observed in the worn surface of conventional sintered Ni-Co-Fe-Ti- 6wt.%SiC.The best optimum set of parameters (Sliding Speed 1146 rpm, SiC inclusion 6 wt.%, Applied Load 20 N) were found out using Taguchi method.

Low-Temperature Sintering of Colloidal Gold Nanoparticles by Salt Addition

AbstractGold nanoparticles synthetized by pulsed laser ablation in liquid with a mean diameter of 4 nm were joined together by adding potassium bromide solution at various concentrations. By increasing the salt concentration, there is a significant increase of the particle size up to a mean diameter of 18 nm. We have studied the nanoparticle merging by using atomic force and electron microscopy characterizations, also demonstrating that it is possible to deposit sintered nanoparticles on silanized substrates in a fast, simple, cost-effective, energy-saving method with relevance in industrial manufacturing.

A piezoresistive dielectric elastomer switch consisting of inkjet-printed carbon black

The piezoresistive effect is a key physical property utilized in soft and stretchable electronics, functioning as intrinsic electromechanical sensors. However, most conventional piezoresistive sensors can only passively measure and quantify external stimuli. To address these limitations, this work integrates an inkjet-printed piezoresistive pattern and a dielectric elastomer actuator (DEA) into a single monolithic dielectric elastomer film, creating a dielectric elastomer switch (DES). This DES can realize dramatic resistance changes along with DEA actuation, leveraging DEA-driven piezoresistivity for active and effective circuit control and signal processing. Theoretically, the DES operates by exhibiting resistance change through the periodic compression induced by DEA actuation. Experimentally, the piezoresistive pattern and the DEA electrodes were fabricated on an acrylic dielectric elastomer (VHB) using inkjet-printed piezoresistive carbon black (CB) and manually brushed conductive grease, respectively. The optimized DES demonstrated approximately 3.77 (±0.11) orders of magnitude in resistance change at a DEA frequency of 0.1 Hz. Compared to previously reported methods (smearing and stamping), inkjet-printed CB patterns showed significant improvements. These included negligible Joule heating impact, precise digital fabrication control, larger resistance change (up to 3.77 orders of magnitude), faster response speeds to DEA actuation (∼0.25 s for 3 orders of magnitude in resistance change), and greater durability (operating at 0.5 Hz for 112 min). Scanning electron microscopy (SEM) characterization revealed that these improvements were attributed to a more uniform distribution of conductive “CB islands” and appropriate non-conductive gap size among them. For demonstrating the applications of DES, it was employed for LED control, DEA-based soft gripper control, and as a multiplexer for signal processing.

Underlying mechanisms for the effect of Nb micro-alloying on the elemental distribution and precipitation behavior in the X70 weld metal

Niobium (Nb) is a widely recognized micro-alloying element due to its low cost and substantial impact on steel properties. While the effect of Nb in processed steels has been well investigated, studies on its elemental distribution and precipitation behavior in weld metal remain scarce. This study focuses on the weld metal of specially designed Nb-rich X70 pipeline steel by scanning transmission electron microscopy (STEM) and energy-dispersive X-ray spectroscopy (EDS) characterization, complemented with thermodynamic and kinetics modeling analysis. In the majority of the weld, Nb was essentially uniformly distributed. This suggests that Nb primarily exists in the solid solution form in the weld metal, which is also supported by precipitation kinetics modeling results. This is primarily due to the short thermal history associated with the welding process, which leads to insufficient time for the uniform precipitation of Nb. Two instances of Nb precipitates were observed at the weld centerline and reinforcement region. The low partition coefficient of Nb results in an elevated local concentration along the weld centerline. However, precipitation kinetics calculations suggest that this enhancement alone is not adequate to induce precipitate formation. The occurrence of MnS and the prior formation of Ti precipitates may provide heterogeneous nucleation sites for Nb, facilitating the nucleation of Nb precipitates in the weld centerline and reinforcement region.

A unique kind of distribution band of martensitic laths formed along {332}〈113〉 twin boundary in the Ti[sbnd]42Nb alloy subjected to instable deformation

Multi-scale electron microscopy characterization of the {332}<113 > β twins produced in the necking region near fracture surface of the deformed β-type Ti42Nb (wt%) alloy have been carried out. A unique kind of band-shaped zone with plenty of laths of two α″ martensitic subvariants distributed in about 90° crossing directions has been found to be formed in the {332}<113 > β deformation twin along the twin boundary. This finding clearly reveals that intense local stress concentration and its complex accommodation process associated with the β-to-α″ and α″-to-β structural transitions can occur specially in the twinned region of stress-induced α″ martensite phase along its boundary for the β Ti alloy subjected to instable deformation. It is also clearly indicated that the local stress accommodation due to the α”-to-β structural transition can be unsymmetrical with respect to the twin boundary.

Light and scanning electron microscope characterization of mandibular symphysis tissue as a functional adaptation in the mandible development of human fetuses.

When developing, the mandible presents great plasticity and contains condensed mesenchymal cells that develops into Meckel's cartilage, of which the anterior part forms the mandibular symphysis. Mandible human development studies focus on investigating whether the beginning of mandibular fusion in fetal period is related to symphysis ossification and the tensions imposed on it, considering that tongue movements, mouth opening, and closing can be seen in fetuses. This research analyses tissue modifications during human mandibular symphysis growth using light and scanning electron microscopy to relate them to its functional structure. The study sample consisted of 12 human fetuses distributed into two groups: Group I (GI) of 10-14 weeks old and Group II (GII) of 20-24 weeks old. Fragments of mandibular symphysis were removed en bloc together with the surrounding tissues to preserve the relation with adjacent structures. Decalcified specimens were prepared in semi-serial coronal sections 5-μm-thick and stained with hematoxylin and eosin, Masson՚s trichrome, Verhoeff, and Sirius red for histological analysis with light microscopy. Collagen fibers Type I or III and elastic fibers were quantified by volume fraction (Vv). Coronal sections of the GI and GII symphyseal region were submitted to scanning electron microscopy. Comparison between groups used independent t-test. Our study presents the different endochondral ossification stages in the anterior part of Meckel's cartilage in GI. Both groups showed abundantly vascularized mesenchymal tissue with intense cellular activity forming the mandibular symphysis, such as a source of new osteoblasts adjacent to the newly deposited bone matrix. Scanning electron microscopy analysis revealed an invasion of the bony trabecula in the transverse direction from the hemimandible, rectilinear in GI and sinuous in GII due to interdigitating bone process, promoting its ossification. In collagen Vv analysis was verified a prevalence of type I in GII and type III in GI, indicating a proportional relation between maturation and tissue arrangement. Functionally, the collagen and elastic fibers in the mandibular symphysis were arranged in a pantographic network, and the fibrillar interconnectivity clearly contributes to resilience capacity and efficiency of the force transfer. This study inferred the functional significance of the knowledge about the tissue composition of mandibular symphysis, and the importance of this tissue for surrounding structures. The mesenchymal tissue of mandibular symphysis participates in bone growth process, revealing an adaptation mechanism of mandibular symphysis in the fetal period investigated.

Alkyne-rich patchy polymer colloids prepared by surfactant-free emulsion polymerization

While free radical polymerization methods are employed frequently to prepare sub-micron polymer particles, we hypothesized that surfactant-free emulsion polymerization (SFEP)11Surfactant-free emulsion polymerization methodology may prove beneficial for obtaining functional polymer particles by solution polymerization methods that preclude the need for conventional surfactants. To test the effectiveness of SFEP for the preparation of functional colloids, solution polymerization of several monomers, including propargyl acrylate (PA),22Propargyl acrylate. styrene (Sty)33Styrene. and tert-butyl acrylate (t-BA),44Tert-butyl acrylate. was performed over a range of monomer ratios and reaction scales. Electron microscopy and infrared spectroscopy were employed to evaluate the outcome of SFEP for particle size, shape, surface anisotropy, and chemical composition. Combining this characterization with optimized SFEP synthesis, we found that spherical polymer particles—homopolymers of PA as well as copolymers—were obtained in the 60–300 nm diameter size range. Successful inclusion of PA enabled the use of the particles in copper-catalyzed azide-alkyne cycloaddition reactions (CuAAc).55Copper-catalyzed azide-alkyne cycloaddition Moreover, electron microscopy characterization with backscattering revealed chemical and shape anisotropies on copolymer particles indicative of monomer phase-separation during particle formation. Overall, the SFEP methodology represents a straightforward, one-pot, bottom-up approach to yield a library of functional polymer particles, while avoiding undesirable aspects associated with conventional surfactants.

Cu2O/Cu-MOF/Fe-MIL-88B with peroxidase activity for intelligent detection of p-aminophenol and barbituric acid and virtual reality display for detection mechanism

The bimetallic organic framework nanoenzyme Cu2O/Cu-MOF/Fe-MIL-88B is synthesized by the solvothermal method. The characterizations of transition electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry prove that the amounts of oxygen vacancies are existed on the surface of Cu2O/Cu-MOF/Fe-MIL-88B and stronger electron transfer is the key factor for free radical •OH and O2·- production, thus exhibiting excellent peroxidase activity of Cu2O/Cu-MOF/Fe-MIL-88B. On the basis of the excellent peroxidase activity, versatile colourimetric and intelligent detection platforms for p-aminophenol and barbituric acid are successfully constructed on site and timely. The linear ranges of p-aminophenol and barbituric acid are 25–75 μM and 5–45 μM, and the lowest limits of detection (LOD) are 0.51 μM and 0.46 μM, severally. Moreover, the mechanisms for detecting p-aminophenol and barbituric acid were displayed by virtual reality technology. Therefore, the colourimetric and intelligent sensor of p-aminophenol and barbituric acid based on the peroxidase of Cu2O/Cu-MOF/Fe-MIL-88B have a hopeful prospect in the field of biomedicine.

Microstructure and wear resistance of laser cladding AlCoCrFeNiSiB high-entropy alloy with high boron content

In this study, a wear-resistant coating of high boron content Al1.5CoCr2Fe1.5NiSi0.5B2 high-entropy alloy (HEA) was prepared on X65 pipeline steel by laser cladding. The coating underwent microhardness testing, wear performance testing, and analyses including scanning electron microscope (SEM), transmission electron microscope (TEM), and X-ray diffraction (XRD). The results revealed a dual-phase structure of body-centered cube (BCC) and face-entered cube (FCC) in the coating, with the presence of Fe1.1Cr0.9B0.9 phase distributed within the BCC. Utilizing high-resolution transmission electron microscopy (HRTEM) characterization, irregular atomic arrangement regions within the BCC structure were observed. Through the calculation of the α2 and ε parameters of the coating, the degree of lattice distortion in the BCC and FCC phases was quantitatively described. The results suggested that the addition of a substantial amount of boron could strengthen the lattice distortion effect, leading to improved hardness and wear resistance of the coating. The average microhardness of the coating was 912 HV, about 5 times higher than X65 substrate, improved by more than 10 % compared with other AlCoCrFeNi-based high-entropy alloys and B-containing high-entropy alloys. The wear rate was 4.78 × 10−6 mm/N·m, wear performance is nearly 10 times higher than other AlCoCrFeNi HEA without boron, 2 times higher than HEA with born. The wear mechanism of the coating was identified as abrasive and oxidative wear.