Metal Substrate Research Articles

Influence of anionic alkyl chain on the tribological properties of titanium alloy under water lubrication: Experimental analysis and molecular dynamics simulations

In this work, four types of protic ionic liquids were prepared for use as pure water additives to investigate the effect of anionic alkyl chains on the tribological and drilling performance of a titanium alloy. Copper block immersion tests and electrochemical tests were conducted to compare their corrosion resistance. The results indicate that the ionic liquid containing OH and CC in the anionic alkyl chain led to stronger adsorption onto the metal substrate, providing excellent tribological performance and the highest corrosion inhibition rate (η = 98.45 %). According to density functional theory, wear scar surface analysis, and molecular dynamics simulation, the low energy gap of the anion (ΔE = 0.033 Ha) indicated that it exhibited higher reactivity. Thus, it was more susceptible to frictional chemical reactions with the metal substrate under the action of frictional heat during shearing, ultimately forming a friction film with a thickness of 20–97 nm. The ionic liquid demonstrated good wetting properties in a drilling test, enabling its effective penetration into the gaps between the drill bit and the workpiece to achieve lubrication and cooling effects. Thus, the axial force and drilling temperature were significantly reduced. Additionally, biotoxicity tests indicated that the ionic liquid is an environmentally friendly substance.

Achieving precise graphenization of diamond coatings below the interfacial thermal stress threshold

Abstract Diamond coatings possess numerous excellent properties, making them desirable materials for high-performance surface applications. However, without a revolutionary surface modification method, the surface roughness and friction behavior of diamond coatings can impede their ability to meet the demanding requirements of advanced engineering surfaces. This study proposed the thermal stress control at coating interfaces and demonstrated a novel process of precise graphenization on conventional diamond coatings surface through laser induction and mechanical cleavage, without causing damage to the metal substrate. Through experiments and simulations, the influence mechanism of surface graphitization and interfacial thermal stress was elucidated, ultimately enabling rapid conversion of the diamond coating surface to graphene while controlling the coating’s thickness and roughness. Compared to the original diamond coatings, the obtained surfaces exhibited a 63%–72% reduction in friction coefficients, all of which were below 0.1, with a minimum of 0.06, and a 59%–67% decrease in specific wear rates. Moreover, adhesive wear in the friction counterpart was significantly inhibited, resulting in a reduction in wear by 49%–83%. This demonstrated a significant improvement in lubrication and inhibition of mechanochemical wear properties. This study provides an effective and cost-efficient avenue to overcome the application bottleneck of engineered diamond surfaces, with the potential to significantly enhance the performance and expand the application range of diamond-coated components.

IMPACT OF EDGE PREPARATION ON SURFACE FINISHING PROPERTIES

The properties of protective coatings made from organic coatings on metallic substrates strongly depend on the condition of the substrate surface. This refers to the condition of the edges, welds, and the surface in general. Edge treatment is one of the most important operations prior to the actual coating application. The coating's protective properties and its susceptibility to mechanical damage are directly affected by the edge treatment. The article deals with the problem of edge treatment of the base material and the effect of this treatment on the quality of surface finishing. The edges were modified in three ways on the prepared Kosmalt E 300 T samples. Subsequently, some samples were hot-dip galvanized. An organic coating was then applied as the final surface treatment to all samples. The evaluation of the quality of the surface finishing was carried out on the above-mentioned, differently treated edges. The results strongly indicate the importance of the condition of the substrate surface and its influence on the quality of the final surface finish.

Anti-corrosion Properties of Functionalized Organo-silane Coupling Agents for Galvanized Steel

Silane precursor selection is an important criterion for achieving great anticorrosive performance on steel substrates using sol-gel technology. A density functional theory (DFT) study was performed on functional and nonfunctional organosilane precursors. The global reactivity parameters, such as the global hardness (ƞ), dipole moment (μ), and number of electrons transferred (∆N) to the metal substrate, were calculated to identify suitable silane coupling agents. DFT studies revealed that precursors containing functional groups such as epoxy, amine, and mercapto offer better protection against corrosion to galvanized steel by providing stronger interfacial adhesion than precursors without functional moieties. The DFT-calculated adsorption energy (Eads) is more than 40.0kcal/mol for the adsorption of functional organosilanes onto the (ZnO)12 cluster. Evidence of chemical bond formation at the interface for functional organosilanes is found in the electron density overlap in the MOs. Natural charge analyses revealed clear charge transfer from the organosilane moiety to the (ZnO)12 cluster. The theoretical predictions were validated via experiments. Electrochemical studies demonstrated a protective efficiency of 92.5% for Ie with an impedance of 92.9kΩ·cm2. The presence of the respective functional groups and surface morphology were evaluated by FTIR and SEM. The order of corrosion inhibition of organosilanes was found to be MPTMS≈APTES>GPTMS>TEOS.

Molecular insights into substrate translocation in an elevator-type metal transporter

The Zrt/Irt-like protein (ZIP) metal transporters are key players in maintaining the homeostasis of a panel of essential microelements. The prototypical ZIP from Bordetella bronchiseptica (BbZIP) is an elevator transporter, but how the metal substrate moves along the transport pathway and how the transporter changes conformation to allow alternating access remain to be elucidated. Here, we combine structural, biochemical, and computational approaches to investigate the process of metal substrate translocation along with the global structural rearrangement. Our study reveals an upward hinge motion of the transport domain in a high-resolution crystal structure of a cross-linked variant, elucidates the mechanisms of metal release from the transport site into the cytoplasm and activity regulation by a cytoplasmic metal-binding loop, and unravels an unusual elevator mode in enhanced sampling simulations that distinguishes BbZIP from other elevator transporters. This work provides important insights into the metal transport mechanism of the ZIP family.

Effect of charge state on alkaline OER activity in FeN4–Gr catalyst supported on Ni (111) substrate

Abstract The catalysts of transition metal single−atom embedded in N−doped graphene (TMN4−Gr) have attracted significant attention due to the high utilization of transition metal atoms, remarkable selectivity and tunable catalytic activity. In this study, we have employed first−principles study to investigate alkaline OER activity of FeN4−Gr system supported on a Ni (111) substrate (FeN4−Gr/Ni). The results show that the Ni substrate can significantly enhance the OER activity of FeN4−Gr catalyst. The overpotential of FeN4−Gr/Ni catalyst is 0.63 V, much lower than 0.79 V of the FeN4−Gr, which is closely related to the strong interaction from the Ni substrate. By subtracting electrons from the FeN4−Gr/Ni catalyst, a positive charge environment can be created. It is found that, between the FeN4−Gr and the Ni substrate, a significant electron transfer phenomenon is observed, and the amount can be regulated by the charge state. Besides, the charge state can obviously tune the adsorption strength of *OOH intermediate through the interaction of Ni substrate, further optimizing the OER activity thermodynamically favorable. As the charge state increases to +1.55, the overpotential decreases to 0.23 V. By analyzing the integrated crystal orbital Hamilton populations, the chemical bond strength of Fe−O is discussed. Our results reveal that the Ni substrate can significantly enhance the OER activity of the FeN4−Gr catalyst, and the charge state can also tune the overpotential, offering valuable insights for the design of high−efficiency single−atom catalysts utilizing metal substrate.

Strength gradient in impact-induced metallic bonding

Solid-state bonding can form when metallic microparticles impact metallic substrates at supersonic velocities. While the conditions necessary for impact-induced metallic bonding are relatively well understood, the properties emerging at the bonded interfaces remain elusive. Here, we use in situ microparticle impact experiments followed by site-specific micromechanical measurements to study the interfacial strength across bonded interfaces. We reveal a gradient of bond strength starting with a weak bonding near the impact center, followed by a rapid twofold rise to a peak strength significantly higher than the yield strength of the bulk material, and eventually, a plateau covering a large portion of the interface towards the periphery. We show that the form of the native oxide at the bonded interface—whether layers, particles, or debris—dictates the level of bond strength. We formulate a predictive framework for impact-induced bond strength based on the evolution of the contact pressure and surface exposure.

A Different Perspective on the Solid Lubrication Performance of Black Phosphorous: Friend or Foe?

Black phosphorous (BP), a promising 2D material with exceptional electronic and optical properties, has shown remarkable potential in tribology as an additive in liquid lubrication and a composite in solid lubrication. However, its potential as the standalone solid lubricant is still at its early stage. This study evaluates BP's solid lubrication performance as deposited coating (by drop casting) on a variety of metallic substrates (polished AISI 52 100 steel, aluminum, copper, and iron) under different contact pressures using a ball‐on‐disc linear‐reciprocating test machine in dry conditions. The results demonstrate that BP does not systematically reduce friction and wear. Depending on the contact pressure and the characteristic of the substrate material (particularly surface roughness), its friction and wear behavior vary a great deal. The best results observed are a 33% reduction in friction with increased surface roughness on iron and a 23% reduction in wear on aluminum. While no general trend is observed for contact pressure effects, increased substrate roughness proves beneficial, enhancing lubricant retention and exploiting BP's low interlayer shear mechanism. Therefore, this study demonstrates that while promising, BP's solid lubrication performance is not exceptional. It also highlights the importance of optimizing test conditions and materials for enhanced lubrication.

Metal substrate printed circuit boards as low-cost, robust temperature sensor mounts for cryogenic thermometry

Abstract Cryogenic experiments strongly depend on accurate temperature measurements. Many of the sensors used for these purposes are glued to the object to be measured to achieve adequate thermal contact. This calls for a more flexible, long lasting and robust bolt-mounted solution. Therefore, we present a low-cost (<5$), compact, PCB (printed circuit board) based sensor mount for RTDs (resistance temperature detector) and diodes showing reliable results at temperatures from 50 K to 400 K with possible modifications for an extended range down below 20 K. We anticipate that the robustness and low cost of the reported sensor mount design will strongly enhance the accessibility of reliable temperature measurements at a wide range of temperatures in laboratory applications.

Precursor-Driven Confined Synthesis of Highly Pure 5-Armchair Graphene Nanoribbons.

Armchair graphene nanoribbons (AGNRs) known as semiconductors are holding promise for nanoelectronics applications and sparking increased research interest. Currently, synthesis of 5-AGNRs with a quasi-metallic gap has been achieved using perylene and its halogen-containing derivatives as precursors via on-surface synthesis on a metal substrate. However, challenges in controlling the polymerization and orientation between precursor molecules have led to side reactions and the formation of by-products, posing a significant issue in purity. Here a precision synthesis of confined 5-AGNRs using molecular-designed precursors without halogens is proposed to address these challenges. Perylene and its dimer quaterrylene are utilized for filling into single-walled carbon nanotubes (SWCNTs), following a precursor-driven transition into 5-AGNRs by heat-induced polymerization and cyclodehydrogenation. SWCNTs restrict the alignment of confined quaterrylene enabling their polymerization with a head-to-tail arrangement, which results in the formation of pure 5-AGNRs with three times higher yield than that of perylene, as the free rotation capability of perylene molecules inside SWCNTs lead to the formation of 5-AGNRs concomitant with by-products. This work provides a templated route for synthesizing desired GNRs based on molecular-designed precursors and confined polymerization, bringing advantages for their applications in electronics and optoelectronics.

Ultraflat Cu(111) foils by surface acoustic wave-assisted annealing

Ultraflat metal foils are essential for semiconductor nanoelectronics applications and nanomaterial epitaxial growth. Numerous efforts have been devoted to metal surface engineering studies in the past decades. However, various challenges persist, including size limitations, polishing non-uniformities, and undesired contaminants. Thus, further exploration of advanced metal surface treatment techniques is essential. Here, we report a physical strategy that utilizes surface acoustic wave assisted annealing to flatten metal foils by eliminating the surface steps, eventually transforming commercial rough metal foils into ultraflat substrates. Large-area, high-quality, smooth 2D materials, including graphene and hexagonal boron nitride (hBN), were successfully grown on the resulting flat metal substrates. Further investigation into the oxidation of 2D-material-coated metal foils, both rough and flat, revealed that the hBN-coated flat metal foil exhibits enhanced anti-corrosion properties. Molecular dynamics simulations and density functional theory validate our experimental observations.

Design and testing of an (inert) gas cell for in situ polarization modulation infrared reflection absorption spectroscopic (PM-IRRAS) measurements under specific atmospheres.

Infrared reflection absorption spectroscopy (IRRAS) is a powerful surface-sensitive analytical technique to characterize the adsorbed molecules on metal surfaces down to (sub)monolayer coverage. In this paper, a new (inert) gas cell is presented that expands the scope of the commercially available Bruker PMA50 module. The cell is designed as a sample holder to measure thin films of molecules adsorbed on a metal substrate under a specific gaseous atmosphere. The dimensions of the cell are chosen in such a way that it can be transferred into a glovebox via the standard entrance port (Ø150mm), allowing the investigation of air-sensitive molecules under an inert-gas atmosphere. The cell has two hose connections through which the gas atmosphere can be varied as desired. This also allows for studying the reactivity of the adsorbed structures toward the surrounding gas in situ and in a (potentially) time-dependent fashion. Furthermore, the metal substrate can be irradiated via an exposure window to investigate the influence of light on the adsorbed molecules and/or their reactivity. Using the polarization-modulation (PM-) IRRAS technique along with the described gas cell, an air-sensitive molybdenum(0) tricarbonyl complex adsorbed on an Au(111) surface is investigated. This complex reacts with molecular oxygen to the molybdenum(VI) trioxo analog, and this conversion is accelerated by irradiation with light of 365 and 440nm.

UV Light Triggered Fluorescence Coatings for Early-Stage Corrosion Detection in AA2024-T3 Based on V-CeO2 Nanocomplex

Fluorescent corrosion indicators offer a promising avenue for identifying underlying corrosion on metallic substrates by sensing metal ions generated through corrosion reactions. A key component of fluorescence corrosion detection systems involves nanoparticles loaded with inhibitors. However, developing efficient fluorescent coatings has been hindered by challenges such as fluorescence quenching, sluggish response rates, side reactions, and the requirement for expensive instrumentation. To address these challenges, we present a novel approach involving synthesizing vanadium and cerium dioxide (V-CeO2) nanocomplex consisting of VOx NRs with ∼250 nm in length and ∼60 nm width and CeO2 NSs with a diameter of ∼80 nm were synthesized via modified solvothermal route, resulting in enhanced fluorescence efficiency, and reduced bandgap (1.94 eV) with photoabsorption in the UV range (365 nm). Simulated calculations (density of states (DOS) and integrated crystal orbital Hamilton population (ICOHP)) confirm the reduced bandgap, which facilitates the fast excitation of the electron, resulting in a quick response in fluorescence detection. The V-CeO2 nanocomplex with acrylic latex (Ac2403) as well as epoxy coatings, has been employed to fabricate fluorescent coatings on the AA2024-T3 substrate for early-stage corrosion detection. Both acrylic and epoxy coatings without color pigment(V-CeO2/Ac2403 and V-CeO2/epoxy) and with color pigments (V-CeO2/MO/Ac2403 and V-CeO2/SY/epoxy) show the excellent bright blue fluorescence by reacting with metal ions resulting from corrosion, forming a complex with Al3+ ions. Our findings demonstrate that the current fluorescent corrosion-detecting coatings provide a practical alternative to traditional coatings for real-time monitoring and meeting the increasing demands in potential applications.

Towards remarkable corrosion protection by synergizing PANI with plasma-electrolyzed inorganic layer

Notwithstanding the increasing interest in the enhancement of the corrosion properties of active metallic materials, the role of organic corrosion barrier remains insufficiently understood with respect to the formation of structural microdefects in the inorganic layer and the decrease in the corrosion rate. The present work proposed the mechanism by which an organic polymer would improve the barrier properties of the defective TiO2 coating as an inorganic layer and thereby, improve corrosion protection. This protection mechanism enhances the hydrophobicity of the TiO2 surface because of the notable homogeneity of the organic polymer polyaniline (PANI). The adsorption of PANI on the surface of the TiO2 coating was verified using SEM and EDAX. The electrochemical performance was enhanced remarkably because of the integral synergy between TiO2 and PANI in the composite, which could be controlled by adjusting the number of deposition cycles. In addition, the novel protection mechanism of this hybrid layer was based on the counter anions stored within PANI. These were released as active corrosion inhibitors upon the onset of a severe chemical attack on the TiO2 layer or metal substrate. Thus, these composites reduced the diffusion of metal ions and prevented the penetration of corrosive ions, thereby yielding a remarkable corrosion resistance.

Numerical Investigation of G–V Measurements of metal – A Nitride GaAs junction

In this study, a Schottky diode consisting of Au/GaN/GaAs was fabricated using a radiofrequency nitrogen plasma source. The voltage-conductance characteristics (G/ω-V) of this diode structure were investigated at room temperature. To interpret the changes in the electrical properties of the nitrided GaAs-based Schottky structure, we developed a simulation program. This program employs a numerical model to calculate the G-V characteristics, allowing us to validate the experimental measurements conducted on the Schottky diodes. The geometric model used in our simulation considers not only the GaN layer formed between the metal and GaAs substrate but also the density and distribution of trapped states within the band gap. The program utilizes the numerical resolution of the Poisson and continuity equations to calculate the electrostatic potential and the concentrations of both n and p mobile carriers. These parameters are then used to determine the electric charge, current, capacitance, and conductance. The simulation results were subsequently compared to the experimental measurements to ensure their accuracy.

Enhancement of an intumescent fire shield paint from the nanotube rutile mineral for the fire performance of steel structures

Building and construction fire safety is an important issue for the protection of people and property. Research investigates nano-rutile minerals' synergistic role in intumescent fire shield paint (IFSP). A synergistic ingredient was introduced to intumescent fire shield paint to evaluate its impact on char morphology, fire protection test, fire propagation test, and compare it with current market products. A hydrothermal process was used to create a rutile mineral, with various techniques used to describe its structure, size, and composition. Intumescent char was found in a furnace using FESEM and X-ray fluorescence. The results showed that rutile minerals contain a rutile phase and a nanotube structure. The surface of the sample IFSP A's char showed layer and foam structures with homogenous voids during a fire test, indicating a high porosity structure. Large holes and recurring gaps were observed in the char of the IFSP B, C, and D. Sample IFSP A took more time at the structural critical temperature (about 550 o C) than other intumescent fire shield paint samples, making it a barrier layer that effectively shields the metal substrate from heat. The intumescent char residue had the highest C/O ratio of 0.57, indicating the best char yield degree and anti-oxidation abilities. The IFSP A had a phosphorous content of 36.2%, which could combine with phosphorus and TiO2 to form a ceramic barrier. The increased TiO2 in IFSP A suggests that char layers with TiO2 may still contain strong ceramic structures and function as effective thermal protection layers.

UV light-triggered fluorescence corrosion sensing coatings for AA2024-T3 based on 8-hydroxyquinline loaded vanadium oxide nanorods

Fluorescent corrosion indicators potentially locate the underlying corrosion on metallic substrates based on sensing metal ions caused by corrosion reactions. Nanoparticles loaded with indicators are significant components of the fluorescence corrosion detection system. These fluorescent coatings face challenges (including fluorescence quenching, sluggish response rate, and expensive instrumentation). To tackle such issues, we have developed 8-hydroxyquinoline (8-HQ) loaded oxygen-deficient vanadium oxide (VOx) nanorods (∼220 nm in length and ∼50 nm in width) via solvothermal technique yielding enhanced fluorescence efficiency. 8-HQ/VOx/Ac2403 was utilized to develop a fluorescent corrosion sensing coating for AA2024-T3. The system is designed to detect corrosion within the first few days to weeks after exposure to corrosive conditions by making a complex by reacting with metal ions (Al3+), resulting in a reduction and bright blueish fluorescence effect in the exposure of UV light and can be seen with the naked eye. As a result, fluorescent corrosion-sensing coatings provide a practical substitute for typical coatings to satisfy rising industrial demands by providing corrosion sensing before significant structural damage occurs.

Comprehensive evaluation of MWCNT/HAp and Cu-functionalized MWCNT/HAp coatings on Ti6Al4V implants: Enhancing surface characteristics and biocompatibility via plasma electrolytic oxidation

This study investigates the evolving relationships and interactions between two distinct materials used in hard tissue implants: multi-walled carbon nanotubes (MWCNTs) and copper nanoparticles (Cu NPs). The surface modification of the Ti6Al4V implant substrate was achieved using hydroxyapatite (HAp) and its composite materials with MWCNTs and Cu-functionalized MWCNTs electrolytes. The plasma electrolytic oxidation (PEO) method was employed to enhance the physicochemical properties of the coatings. Incorporating MWCNTs into the HAp composite significantly improved these properties, resulting in superior overall corrosion resistance. MWCNTs effectively inhibited the corrosion process of the underlying metal substrate and reduced the formation of corrosion products. Additionally, it helped stabilize the HAp particles in the coating, reducing their dissolution in the corrosive environment. Additionally, the PEO process led to the formation of copper oxides (CuO and Cu2O) from Cu NPs, which were carefully analysed for their impact on coating properties. The antibacterial properties of the coatings were attributed to specific mechanisms of copper oxide products, including CuO and Cu2O, which generate reactive oxygen species (ROS) and induce oxidative stress in bacteria. These mechanisms, involving ion release, surface interactions, and intracellular effects, were discussed in detail to explain the observed antibacterial activity. Additionally, this study provides a detailed comparison of MWCNTs and Cu/MWCNT coatings applied on Ti6Al4V using a HAp-containing electrolyte, highlighting the physicochemical and antibacterial effects and the factors influencing these properties. The findings suggest that these composite coatings offer promising potential for enhancing the performance of dental implants, thereby contributing to better implant longevity and biocompatibility.

Defect-Engineered Coordination Compound Nanoparticles Based on Prussian Blue Analogues for Surface-Enhanced Raman Spectroscopy.

Surface-enhanced Raman spectroscopy (SERS) is a powerful tool for label-free chemical analysis. The emergence of nonmetallic materials as SERS substrates, offering chemical signal enhancements, presents an exciting direction for achieving reproducible and biocompatible SERS, a challenge with traditional metallic substrates. Despite the potential, the realm of nonmetallic SERS substrates, particularly nanoparticles, remains largely untapped. Here, we present defect-engineered coordination compounds (DECCs) based on Prussian blue analogues (PBAs) as a class of nonmetallic nanoparticle-based SERS substrates. We demonstrate the utility and flexibility of the DECC template by incorporating various metal (M) elements into PBAs to synthesize nanoparticles that deliver substantial chemical mechanism (CM)-based enhancements to the Raman signal with a ∼ 108-fold increase. The introduction of the M-PBA-based DECC nanoparticles as a class of SERS substrates represents a pioneering stride, enabling the straightforward and systematic exploration of a library of compounds for SERS-based analysis of a wide range of target molecules, especially biomolecules.

TIG assisted surface modification of Ti-6Al-4V with B4C, SiC particles

This research article assesses the improved hardness and wear behaviour of Ti–6Al–4V (Titanium-6Aluminium-4Vanadium) ex-situ produced composite case on its surface by TIG Arcing. This method is recognized for its potential to modify the surface of various metallic substrates by carefully controlling the melting and solidification of the substrate using a significantly less expensive high density electric arc heat source of the widely used autogenous (without filler) gas tungsten arc welding (GTAW) process.The molten base and the hard particles in the applied coating through reinforcement led to the development of hard surface characteristics in the Ti-6Al-4V surface matrix. The hard particles that have been reinforced by using TIG arcing to develop a hard wear-resistant surface coating are boron carbide (B4C) and silicon carbide (SiC). The presence of hard particles on the surface of Ti64 has been verified by XRD Pattern and EDS examination. The effect of different reinforced particles on the wear behaviour as well as the hardness of the modified surface has been studied by comparing the Ti64 modified surface without reinforcement and the as-built Ti64 surface samples. Vickers micro hardness testing measures the hardness of the modified particulate surface composite and demonstrates a significant increase in hardness, ranging from 1.5 to 2 times that of the base metal and wear tests confirm that the surface-coated samples of B4C and SiC on the base metal, showed a reduction in wear rate of approximately 55% and 45% respectively, compared to the base metal.