Metal Surface Research Articles

Corrosion and wear mechanisms of rare earth (Gd, Sc, Y)-doped Zr-based amorphous alloys

Rare-earth elements have been utilized in the design and development of new amorphous alloys to improve the corrosion and wear resistance of Zr-based amorphous alloys. In this study, a rare-earth doped Zr-based amorphous alloy (Zr-BMG(RE)) was prepared by the copper mold casting method, which was investigated by corrosion and wear experiments. The results show that Zr-BMG(RE) has a completely amorphous structure, and the doping of rare earths Gd and Y raises the crystallization transition temperature of the amorphous. The addition of rare earth elements Gd and Sc increases the microhardness of Zr-based amorphous alloys, while rare earth element Y causes a slight decrease in microhardness. Gd and Sc will make Zr-based amorphous materials corrosion current density increases, the material pitting and localized corrosion, acid corrosion resistance is reduced. Y doping improves the self-corrosion potential of Zr-based amorphous alloys, reduces the corrosion current density, the surface passivation film is the densest, and the degree of charge transfer on the metal surface is the most difficult, Zr-BMG(Y) has a better corrosion resistance compared with other alloy materials. Zr-BMG(Gd) has the smallest friction rate (1.72×10-7mm3N-1mm-1), and the wear rates of the rare earth doped Zr-based amorphous alloys are all smaller than that of Zr-BMG, and the main loss mechanism of Zr-based amorphous alloys is the interaction of adhesive wear, abrasive wear, oxidative wear and fatigue wear. The mechanism of corrosion and wear resistance of rare earth to Zr-based amorphous alloys is discussed, which provides a new idea for the design of amorphous alloys.

Efficient sodium ion transport enhanced by anionophilic sites in polymer-supported plastic crystal electrolyte for high performance sodium metal anode

The design of sodium metal batteries (SMBs) is seen as an excellent solution to solve the request of next-generation energy storage technologies with high energy density, high safety, low cost, and environmental friendliness. However, the direct use of sodium metal as an anode produces the dendritic sodium, which harms the normal operation of battery. Inspired by solid-state lithium metal batteries, solid-state electrolyte (SSE) designed for SMBs effectively solves this shortcoming. Herein, a novel SSE with mask-based polymer membrane supporting plastic crystal electrolyte with ZIF-67 (MPPZ) is designed. The experimental results and density functional theory (DFT) calculations indicate that the addition of ZIF-67 in MPPZ electrolyte availably fixes TFSI− and achieves high Na+ transference number. Additionally, a protective layer of NaF is formed in situ on the surface of sodium metal to avoid side reactions between Na and MPPZ electrolyte while further guide the uniform deposition of Na. Accordingly, Na||Na symmetric battery with NaF-coated Na metal anode and MPPZ electrolyte has a stable deposition and stripping of Na for 3000 h. The assembled room temperature solid-state sodium-sulfur battery (RTSSSSB) exhibits a good cycle stability. This study provides an innovative thinking for the construction of high performance dendrite-free SMBs.

Colloidal Bimetallic RuNi Particles and their Behaviour in Catalytic Quinoline Hydrogenation.

Colloidal metal nanoparticles exhibit interesting catalytic properties for the hydrogenation of (hetero)arenes. Catalysts based on precious metals, such as Ru and Rh, promote this reaction efficiently under mild reaction conditions. In contrast, heterogeneous catalysts based on earth-abundant metals can selectively hydrogenate (hetero)arenes but require harsher reaction conditions. Bimetallic catalysts that combine precious and earth-abundant metals are interesting materials to mitigate the drawbacks of each component. To this end, RuNi nanoparticles bearing a phosphine ligand were prepared through the decomposition of [Ru(η4-C8H12)(η6-C8H10)] and [Ni(η4-C8H12)2] by H2 at 85 °C. Wide angle X-ray scattering confirmed a bimetallic segregated structure, with Ni predominantly on the surface. Spectroscopic analyses revealed that the phosphine ligand coordinated to the surface of both metals, suggesting, as well, a partial Ni shell covering the Ru core. The RuNi-based nanomaterials were used as catalysts in the hydrogenation of quinoline to assess the impact of the metallic composition and of the stabilizing agent on their catalytic performance.

Stable-to-unstable transition in quantum friction

We investigate the frictional force arising from quantum fluctuations when two dissipative metallic plates are set in a shear motion. While early studies showed that the electromagnetic fields in the quantum friction setup reach nonequilibrium steady states, yielding a time-independent force, other works have demonstrated the failure to attain steady states, leading to instability and time-varying friction under sufficiently low-loss conditions. Here, we develop a fully quantum-mechanical theory without perturbative approximations, and we unveil the transition from stable to unstable regimes of the quantum friction setup. Due to the relative motion of the plates, their electromagnetic response may be active in some conditions, resulting in optical gain. We prove that the standard fluctuation-dissipation leads to inconsistent results when applied to our system, and, in particular, it predicts a vanishing frictional force. Using a modified fluctuation-dissipation relation tailored for gain media, we calculate the frictional force in terms of the system Green's function, thereby recovering early works on quantum friction. Remarkably, we also find that the frictional force diverges to infinity as the relative velocity of the plates approaches a threshold. This threshold is determined by the damping strength and the distance between the metal surfaces. Beyond this critical velocity, the system exhibits instability, akin to the behavior of a laser cavity, where no steady state exists. In such a scenario, the frictional force escalates exponentially. Our findings pave the way for experimental exploration of the frictional force in proximity to this critical regime. Published by the American Physical Society 2024

Ambient pressure x-ray photoelectron spectroscopy study on the initial atomic layer deposition process of platinum

The initial adsorption of MeCpPtMe3 is investigated using synchrotron-based ambient pressure x-ray photoelectron spectroscopy (XPS). The experiments are done on a native oxide-covered Si substrate. In addition, a reaction with O2 and the created Pt surface was investigated. Inspiration for the reaction studies was found from atomic layer deposition of metallic Pt, process that uses the same compounds as precursors. With time-resolved XPS, we have been able to observe details of the deposition process and especially see chemical changes on the Pt atoms during the initial deposition of the Pt precursor. The change of the binding energy of the Pt 4f core level appears to occur on a different timescale than the growth of the active surface sites. The very long pulse of the Pt precursor resulted in a metallic surface already from the beginning, which suggest chemical vapor deposition-like reactions occurring between the surface and the precursor molecules in this experiment. Additionally, based on the XPS data measured after the Pt precursor pulse, we can make suggestions for the reaction pathway, which point toward a scenario that leaves carbon from the MeCpPtMe3 precursor on the surface. These carbon species are then efficiently removed by the subsequent coreactant pulse, leaving behind a mostly metallic Pt film.

Low‐Solvent‐Coordination Solvation Structure for Lithium‐Metal Batteries via Electric Dipole‐Dipole Interaction

AbstractUnveiling inherent interactions among solvents, Li+ ions, and anions are crucial in dictating solvation‐desolvation kinetics at the electrode/electrolyte interface. Developing an electrolyte with a low ion‐transport barrier and minimal solvent coordination in its interfacial solvation structure is essential for forming an anion‐derived solid‐electrolyte interface, a key component for high‐performance Li‐metal batteries. In this study, we harness electric dipole‐dipole synergistic interactions to formulate an electrolyte with significantly reduced interfacial solvent coordination. Operando characterization and theoretical analysis reveal that 2‐fluoropyridine (FPy) with high dipole preferentially adsorbs onto the Li metal surface. The adsorbed FPy molecule squeezes succinonitrile in the primary solvation sheath through steric hindrance, leading to the formation of an inorganic‐rich interphase. Consequently, the introduction of FPy enhances the reversible capacity of the LiCoO2||Li cell, which maintains a capacity of 143 mAh g−1 after 500 cycles at a 1 C rate. Moreover, the cycle life of LiCoO2 batteries with a limited supply of lithium extends from 120 cycles to over 200 cycles. These findings offer a strategy that can be applied broadly to design interfacial solvation structures for various metal‐ion/metal‐based batteries.

Ajuga orientalis L. Extract as a Green Corrosion Inhibitor of Aluminum in an Acidic Solution: An Experimental and DFT Study

The inhibitory effect of A. orientalis L. extract (AO) on aluminum corrosion in a 1.0 M HCl solution was investigated utilizing weight loss, electrochemical polarization, electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM). The results show that AO is a potent inhibitor in an acidic environment, and that the inhibition potency increases with concentration. Temperature investigations showed that, in an acidic medium, the efficiency decreased, increased, and then decreased as the temperature rose. Adsorption isotherms from Freundlich, Temkin, El Awady, and Redlich–Peterson (R-P) approximated the inhibitor’s adsorption properties. For the inhibitory behavior, a physical and chemical adsorption mechanism is proposed. The adsorption process’s thermodynamic parameters (Ea, ΔH*, and ΔS*) were determined and explained. The inhibitor, AO, was identified as a mixed-type (anodic and cathodic) inhibitor based on polarization studies. According to the SEM findings, the inhibitor partially covers the metal surface, providing it with a respectable level of protection. The weight loss, electrochemical polarization, EIS, scanning electron microscopy (SEM), and quantum chemical calculations show a strong agreement, indicating that the AO extract is a highly effective inhibitor of aluminum in an acidic solution.

Synthesis of novel N-substituted tetrabromophthalic as corrosion inhibitor and its inhibition of microbial influenced corrosion in cooling water system

This study investigates the efficacy of newly synthesized inhibitor with a dual function of corrosion inhibition and biocide for control of microbial influenced corrosion (MIC) in carbon steel API 5LX in the cooling tower water (CTW) environment. Four types of N-substituted tetrabromophthalic inhibitor (N-TBI) were synthesized, and the structural characterization was performed via proton nuclear magnetic resonance spectroscopy, thermogravimetric analysis and high-resolution mass spectrometry. These studies revealed the distinctive optical, thermal, and dielectric properties of the synthesized inhibitors. The corrosion inhibition efficiency has been evaluated by the weight loss (WL) analysis and electrochemical measurements (ECM) and biofilm assay. Biofilm assays and WL showed that inhibitor II exhibited the highest inhibition efficiency 74% and 79% respectively than others. Further ECM showed that the higher charge transfer resistance and the lower corrosion current, suggesting a protective film formed on the metal surface which was due to the adsorption of the N-TBI. Fourier transform infrared spectroscopy confirmed the adsorption of the N-TBI as C–O stretching and C–H bending with the Fe complex. X-ray diffractometer revealed that the presence of inhibitors in the corrosion product (Fe3O4, Fe2O3, FeH2O2, FeS) were highly reduced than the control system. Overall, this study highlighted the potential application of N-TBI with dual function of corrosion inhibition and biocide to control the MIC for carbon steel API 5LX used in the CTW environment.

Guilty or innocent? Could the exotic lizard Hemidactylus mabouia (Squamata, Gekkonidae) be responsible for the displacement of the native species Notomabuya frenata (Squamata, Mabuyidae) in anthropic environments?

Hemidactylus mabouia is a gecko species that has successfully colonized southern North, Central, and South America. In Paraguay, there is a commonly held belief that this species has displaced the native skink Notomabuya frenata in urban areas. In this study, we compared several ecological features of N. frenata and H. mabouia to better understand the degree of their niche overlap. A comparative analysis was conducted based on a literature survey and the examination of museum specimens from Asunción (Paraguay). Furthermore, differences in microhabitat use between H. mabouia and N. frenata were investigated through a review of observational records available on iNaturalist. Our findings indicate that the two species share only a few biological traits, such as an insectivore diet, an ability to adapt to living close to human dwellings, and the use of mimesis as a primary defensive strategy. Both lizards are generalist feeders, although there are notable differences in their frequency of prey consumption. Regarding habitat use, the majority of N. frenata specimens were documented on grass or other natural substrates, as well as on trees and shrubs. In the case of H. mabouia, the majority of records originate from smooth and brick walls, including metal and glass surfaces. Consequently, there is no evidence to suggest that dietary overlap could induce competition between these species. Therefore, it can be posited that the displacement of the native lizard N. frenata is a consequence of human activities that have altered its preferred microhabitat while expanding potential habitat for H. mabouia.

A Poly(2,7‐anthrylene) with peri‐Fused Porphyrin Edges

Anthracene has served as an important building block of conjugated polymers with the connecting positions playing a crucial role for the electronic structures. Herein, anthracene units have been coupled through their 2,7‐carbons to develop an unprecedented, conjugated polymer, namely, poly(2,7‐anthrylene) featuring additional peri‐fused porphyrin edges. The synthesis starts from a 2,7‐dibromo‐9‐nickel(II) porphyrinyl‐anthracene as the pivotal precursor. Polymerization is achieved by an AA‐type Yamamoto coupling, followed by a polymer‐analogous oxidative cyclodehydrogenation to obtain a peri‐fusion between porphyrin and anthracene moieties. Although further cyclodehydrogenation between the repeating units cannot be achieved in solution, the thermal treatment of the precursor polymer derived from 2,7‐dibromo‐9‐porphyrinyl‐anthracene on a metal surface realizes the full cyclodehydrogenation. The difference between solution and on‐surface reactivity can be rationalized by the larger dihedral angle between repeat units in solution, which is reduced under the pronounced interaction with the metal surface. The peri‐fusion in the title polymer gives rise to a narrow electronic band gap optical absorptions extending far into the near‐infrared region. Oligomeric models are synthesized as well to support the analyses of the electronic and photophysical properties.

A Poly(2,7-anthrylene) with peri-Fused Porphyrin Edges.

Anthracene has served as an important building block of conjugated polymers with the connecting positions playing a crucial role for the electronic structures. Herein, anthracene units have been coupled through their 2,7-carbons to develop an unprecedented, conjugated polymer, namely, poly(2,7-anthrylene) featuring additional peri-fused porphyrin edges. The synthesis starts from a 2,7-dibromo-9-nickel(II) porphyrinyl-anthracene as the pivotal precursor. Polymerization is achieved by an AA-type Yamamoto coupling, followed by a polymer-analogous oxidative cyclodehydrogenation to obtain a peri-fusion between porphyrin and anthracene moieties. Although further cyclodehydrogenation between the repeating units cannot be achieved in solution, the thermal treatment of the precursor polymer derived from 2,7-dibromo-9-porphyrinyl-anthracene on a metal surface realizes the full cyclodehydrogenation. The difference between solution and on-surface reactivity can be rationalized by the larger dihedral angle between repeat units in solution, which is reduced under the pronounced interaction with the metal surface. The peri-fusion in the title polymer gives rise to a narrow electronic band gap optical absorptions extending far into the near-infrared region. Oligomeric models are synthesized as well to support the analyses of the electronic and photophysical properties.

Boosting Propane Dehydrogenation to Propylene via Electron Hole-Hydrogen Coupling on Cobalt Metal Surface.

Nonoxidative dehydrogenation of propane is useful for the high selectivity to propylene but is suffering from the heavy coke deposition on the catalyst surface. Herein, we present a proof-of-concept application of a hole-hydrogen (H) couple on a metallic cobalt surface to decrease the deactivation rate. The coupled H atoms on the Co surface, partially resulting from propane dehydrogenation, enabled the desorption of propylene to avoid deep hydrogenolysis and coke deposition and realize selective and durable propylene production, while conventional Co metal-based catalysts do not generate propylene. The optimized hole-H coupled Co catalyst provided a low deactivation rate (0.0036 h-1) and a high turnover frequency (55.6 h-1) for propylene production with a high propane flux (48 vol.% C3H8 in gas feeds) at 550 °C.

Halogen-Bonding Nanoarchitectonics in Supramolecular Plasticizers for Breaking the Trade-Off between Ion Transport and Mechanical Strength of Polymer Electrolytes for High-Voltage Li-Metal Batteries.

The low ionic conductivity of poly(ethylene oxide) (PEO)-based polymer electrolytes at room temperature impedes their practical applications. The addition of a plasticizer into polymer electrolytes could significantly promote ion transport while inevitably decreasing their mechanical strength. Herein, we report a supramolecular plasticizer (SMP) to break the trade-off effect between ionic conductivity and mechanical properties in PEO-based polymer electrolytes. Accordingly, the SMP is constructed by tetraethylene glycol dimethyl ether (G4) and SbF3 through halogen bonds. The SMP-plasticized PEO electrolyte (PEO/SMP) presents a simultaneously enhanced ionic conductivity of 2.4 × 10-4 S cm-1 (25 °C) and a high mechanical strength of 8.1 MPa, compared to those of pristine PEO-based electrolytes. Benefiting from the halogen bonds between G4 and SbF3, the Li-O coordination in PEO/SMP is evidently weakened, and thus rapid Li+ transport is achieved. Furthermore, the PEO/SMP electrolyte possesses a wide electrochemical stability window of 4.5 V and, importantly, derives an inorganic-rich SEI with a low interfacial resistance on a lithium metal surface. By using PEO/SMP, the lithium-metal battery with the LiNi0.5Co0.2Mn0.3O2 cathode exhibits a good rate and long-term cycling performance with a capacity retention of 75.3% (500 cycles). This work offers a rational guideline for the design of polymer electrolytes suitable for high-performance lithium-metal batteries.

MCM-41 from rice husk silica as a support for Ni catalyst in the emission-free production of H2 by CH4 cracking.

Selecting a sustainable source of silica from biomass waste was the research challenge that was put forth in this investigation. Herein, the MCM-41 support has been synthesized using a renewable rice husk and explored as a support for Ni-Cu catalyst in the production of zero-emission H2 through CH4 pyrolysis. The role of Cu promoter was investigated by doping different amounts of Cu loading to 30wt%Ni/R-MCM-41catalyst, which improved the catalytic performance in terms of CH4 conversion and stability. An optimum Cu loading of 3wt% addition to 30wt%Ni/R-MCM-41 catalyst demonstrated the best catalytic performance compared to all the catalysts in terms of hydrogen yield (15,218mol H2/mol Ni) and carbon formation rate. The Ni-Cu alloy formation was confirmed by X-ray diffraction, H2-temperature programmed reduction, and pulse chemisorption studies, as demonstrated by decreased H2 uptake (from 41 to 33μmol/gcat) and enhanced N2O (from 89.2 to 138.3μmol/g) uptakes, which results in a significant improvement in the availability of the surface metal species (both Cu and Ni), which in turn contributed to increase the CH4 cracking performance and stabilization of Ni species. Additionally, doping Cu results in better carbon nanotube production, as shown by the lowest ID/IG ratio from the Raman spectroscopic analysis.

Dendrite-Free Lithium Batteries Enabled by an Artificial High-Dielectric Biopolymer Interface Layer.

Lithium (Li) metal batteries face challenges, such as dendrite growth and electrolyte interface instability. Artificial interface layers alleviate these issues. Here, cellulose nanocrystal (CNC) nanomembranes, with excellent mechanical properties and high specific surface areas, combine with polyvinylidene-hexafluoropropylene (PVDF-HFP) porous membranes to form an artificial solid electrolyte interphase (SEI) layer. The porous structure of PVDF-HFP equalizes the electric field near metallic lithium surfaces. The high mechanical modulus of CNC (6.2 GPa) effectively inhibits dendrite growth, ensures the uniform flow of lithium ions to the lithium metal electrode, and inhibits the growth of lithium dendrites during cycling. The synergy of high polarity β-phase poly(vinylidene fluoride) (PVDF) and CNC provides over 1000 h of stability for Li//Li batteries. Moreover, Li//LiFePO4 (LFP) full cells with this artificial protective layer perform well at 5 C, showcasing the potential of this film in lithium metal batteries.

An Assessment of the Presence of Clostridium tetani in the Soil and on Other Surfaces

Introduction: Standard emergency medicine practice includes tetanus vaccine administration as part of wound care management for patients who are not fully immunized. Since there have been no available studies in the United States reaffirming the prevalence of Clostridium tetani (C tetani) since 1926, we sought to identify its prevalence in a major urban county in the US. Methods: We sampled soil, rusted metal, concrete, and dog feces to determine the prevalence of C tetani in a single metropolitan county in the United States. Soil samples and swabs were collected from four locations: the soil of a public park and an elementary school; dog feces from a single public dog park; and rusted surfaces (metal and concrete) in common student areas of a university campus. The presence of C tetani in each sample was determined using a quantitative polymerase chain reaction. Results: In total, 200 samples were collected, of which 37 (18.5%) tested positive for C tetani DNA. Among the 140 samples taken from the soil, just one (0.7%) tested positive for C tetani DNA. Of the 40 samples of rusted metal and concrete surfaces, 30 (75%) tested positive for C tetani, and six (30%) of the 20 samples from dog feces tested positive for C tetani. Conclusion: We found that C tetani is frequently present on rusted metal and concrete surfaces but rarely in soil samples. Minor wounds contaminated with soil may be considered low risk for tetanus. However, future studies should assess the burden of C tetani in other similar urban, suburban, and rural environments to help determine the threat of C tetani more exactly.

Fatigue Failure of Alloy Grade P22 Hot Reheat Auxiliary Steam Pipe

A leak was discovered in the hot reheat auxiliary pipe. The pipe was found to have a bulging condition and a crack at the base metal area. A circumferential crack was discovered near a repair weld spot on the external surface. The failure was investigated using material characterization techniques, including in-situ replication, glow discharge spectroscopy (GDS), microhardness analysis, optical microscopy, and energy dispersive X-ray spectroscopy (EDX). Based on microstructure analysis, numerous cracks were observed to have initiated at the internal surfaces of the pipe. Most of the cracks were found on the parent metal. The cluster of cracks concentrates on the plane of 0⁰ - 180⁰. Microstructure analysis shows that the cracks are multiple, parallel, mainly transgranular, oxide-filled with branching crack tips. It is thought that the cracking is associated with fatigue and, most likely, high cyclic stress is the key contributory factor. The steam oxide cracked gradually as a result of the cyclic stress. As more metal surface was exposed, new oxide formed, causing cracks to propagate into the metal as this process was repeated due to cyclic loading.

Control of Orientation and Periodicity of Laser‐Induced Surface Structures on Metals

AbstractLaser‐induced periodic surface structures (LIPSS) can be created on various materials, and they hold an exceptional potential for surface nanopatterning, enabling new industrial applications in medicine, biology, optics and other fields. However, LIPSS formation is typically restricted to a specific orientation and periodicity. In this work, a novel approach is demonstrated for full control of the LIPSS periodicity and orientation on metallic surfaces using a 1064 nm nanosecond laser. Analytical expressions and experimental verification are presented to show that by simultaneously manipulating three parameters of the laser beam, such as the polarization, angle of incidence, and direction of the laser scan along the surface, LIPSS can be formed with the desired geometrical configuration. This enhanced control opens vast possibilities for laser processing technologies as a flexible and highly competitive solution for advanced applications relying on surface modifications in the fields of anisotropic surface wettability, thermal and electrical conductivity, structured colors, diffraction gratings, and many others.

Engineering Chemical and Catalytic Activity of Metal Surface Sites by Controlling Strain and Ligand Effects in Nonmodel Nanoparticle Catalysts

Engineering Chemical and Catalytic Activity of Metal Surface Sites by Controlling Strain and Ligand Effects in Nonmodel Nanoparticle Catalysts

Fractal surface states in three-dimensional topological quasicrystals

We study topological states of matter in quasicrystals, which do not rely on crystalline order. In the absence of a band-structure description and spin-orbit coupling, we show that a three-dimensional quasicrystal can nevertheless form a topological insulator. It relies on a combination of noncrystallographic rotational symmetry of quasicrystals and electronic orbital space symmetry, which is the quasicrystalline counterpart of the topological crystalline insulator. The resulting topological state obeys a nontrivial twisted bulk-boundary correspondence and lacks a good metallic surface. The topological surface states, localized on the top and bottom planes respecting the quasicrystalline symmetry, exhibit a different kind of multifractality with probability density concentrated mostly on high-symmetry patches. They form a near-degenerate manifold of immobile states whose number scales proportionally to the macroscopic sample size. This can present an opportunity for a platform for topological surface physics distinct from the crystalline counterpart. Published by the American Physical Society 2024