Steel Substrate Research Articles

Underwater Structurally‐Colored Adhesives for Visualized Adhesion Monitoring in Aqueous Media

AbstractAssessment of the local strain/stress changes of adhesives is highly desirable for their service to avoid premature failure. However, monitoring local strain/stress variations in adhesives in practical settings remains challenging, especially in aqueous media. Here, an underwater structurally‐colored adhesive for visualized local strain/stress monitoring in aqueous media is reported. The structurally‐colored adhesive is obtained by shearing composites of poly(butyl acrylate‐co‐acrylic acid) copolymer and carboxylated polystyrene colloidal particles. The resultant structurally‐colored adhesive exhibits underwater adhesive strength (i.e., 238 kPa for stainless steel substrates) to various substrates (e.g., metals and plastics) thanks to hydrophobic segments and carboxyl groups. Notably, they can shift color in response to external force, enabling real‐time visual monitoring of localized strain/stress changes. As a proof of concept, the structurally‐colored adhesive can be used to seal a leaking hole on a bottle or tube, and it can precisely visualize the localized pressure distribution, providing critical information on the adhesion performance and the local pressure. These distinctive properties make the structurally‐colored adhesive suitable for application in wet environments as a real‐time visual pressure tracking device.

Corrosion Behavior of High-Pressure Cold-Sprayed Zn30Al Alloy Coating on Q235 Steel

This study employed a high-pressure cold spray to apply a Zn30Al alloy coating to Q235 steel substrates to provide corrosion protection for steel in marine environments. The corrosion resistance of the coatings was investigated through full immersion tests, and the corrosion mechanisms were further analyzed using electrochemical experiments. The results were compared with those of traditional flame-sprayed Zn30Al alloy coating. The findings indicate that the high-pressure cold-sprayed Zn30Al alloy coating possesses a dense microstructure with a porosity of only 0.32%, providing effective cathodic protection to the substrate during the immersion tests. The cold-sprayed Zn30Al alloy coating maintained good integrity after 720 h immersion in 3.5 wt.% NaCl solution, whereas the flame-sprayed Zn30Al alloy coating exhibited significant pitting corrosion.

A novel route of carburizing through microwave hybrid heating

Abstract Carburizing is a surface treatment process by diffusing carbon into the steel. These days, manufacturing industries demand highly efficient processes that consume low power. Microwave processing is a newly evolving process that consumes low power. This study proposes a novel route for carburizing mild steel (substrate) through experimental and simulation studies using a microwave heating. Charcoal powder was used as a susceptor to convert microwave energy into heat energy and to deposit carbon on the surface of the specimen. The mild steel specimens were exposed to the microwave power input of 900 W and 360 W for exposure time of 1500 s and 1980 s naming it as S2 and S3 respectively. The microstructural analysis of specimens S2 and S3 confirms the formation of pearlite structures at the surface. However, the amount of pearlite structure was significantly higher for the S3. The higher carbon content is confirmed through energy-dispersive x-ray spectroscopy (EDS) analysis of specimen S3. The average hardness of the S3 specimen was determined to be 220.8 HV, which shows an increase of 38.36% compared to the S1 (base metal). x-ray diffraction (XRD) results indicate the additional cementite peaks (Fe3C) and ferrite-confirming phase transformations for carburized samples. The wear analysis of S2 and S3 was conducted through pin-on-disk testing. The peak COF of 0.73 and 0.64 was observed for S2 and S3 respectively. The hard surface of S3 resists the penetration of the counter body to a greater extent due to the fine morphology of pearlite. From the FEM study, the maximum value of 7.96 × 10 3 (V/m) was determined at the center region for the electric field distribution in the microwave cavity, which is the optimum value for efficient heating. The maximum temperature of the mild steel obtained during the carburization process was 900 °C in 1800 s. The microwave carburizing process requires relatively less time than the conventional carburizing process which will save energy consumption.

Nanoarchitectonics of highly flexible iron-oxide nanoporous electrodes on stainless steel substrate for wearable supercapacitors

Nanoarchitectonics of highly flexible iron-oxide nanoporous electrodes on stainless steel substrate for wearable supercapacitors

Improved solid-state lithium-ion battery on stainless steel substrate with graphene nanowalls by microwave plasma-enhanced chemical vapor deposition

Improved solid-state lithium-ion battery on stainless steel substrate with graphene nanowalls by microwave plasma-enhanced chemical vapor deposition

Electrochemical synthesis, physical properties and corrosion behavior of electropolymerized polyaniline films developed on 316L stainless steel

AbstractPolyaniline (PANI) films may be developed on metallic substrates by a variety of electrochemical techniques. In the present work, PANI films were electrodeposited on AISI 316L stainless steel substrates by cyclic voltammetry (CV), chronoamperometry (CA), and chronopotentiometry (CP) with the objective of comparing the efficacy of each method, based on the integrity of the developed films. Cyclic voltammetry and anodic polarization were used to determine optimal electrodeposition parameters for the development PANI films using the CA and CP methods. The structure and morphology of the coatings were characterized by scanning electron microscopy, energy‐dispersive x‐ray spectroscopy, Fourier‐transform infrared spectroscopy, and ultraviolet–visible spectroscopy. Among the evaluated techniques, CV led to the formation PANI films with the best homogeneity as well as the lowest number of defects, such as cracks or pores. Subsequently, the corrosion resistance of AISI 316L steels with and without PANI was compared in a physiological saline solution (0.9% NaCl). Potentiodynamic polarization tests indicated that the PANI‐coated samples exhibited lower corrosion current density values (0.012 vs. 0.018 μA/cm2) and lower passive current density values (0.04 vs. 0.06 μA/cm2) in comparison to the bare AISI 316L steel. Additionally, long‐term monitoring by electrochemical impedance spectroscopy revealed that PANI films consistently exhibited superior polarization resistance up to 32 days of exposure in the 0.9%NaCl solution (233,000 vs. 207,000 Ωcm2).

Nano Material Innovation in Enhancing Corrosion Resistance of Offshore Structures

Offshore structures are constantly exposed to the corrosive marine environment, causing significant material degradation and potentially jeopardizing structural integrity. This research explores recent innovations in nanomaterial technology to improve the corrosion resistance of offshore structures. The main focus is given to the development of nano-composite coatings incorporating metal oxide nanoparticles and carbon nanotubes. An electrophoretic deposition method was used to apply the coatings on steel substrates, followed by characterization using scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). Results showed a significant improvement in corrosion resistance, with the nano-composite coatings exhibiting a reduction in corrosion rate of up to 85% compared to conventional coatings. In addition, these coatings exhibited superior adhesion and abrasion resistance in simulated extreme marine conditions. These findings highlight the great potential of nanomaterials in extending the service life and improving the reliability of offshore structures, with important implications for the oil and gas and offshore renewable energy industries.

Finite element analysis and design of a magnetostrictive material based vibration energy harvester with a magnetic flux path

Abstract This work presents the development of a nonlinear 2D finite element (FE) framework for magnetostrictive material based energy harvesters of beam geometry. The FE model is developed in COMSOL Multiphysics and compared with existing literature for validation. The FE model is subsequently used to study the effect of a closed magnetic flux path, consisting of ferromagnetic components, on the harvester output. Specifically, the voltage output is obtained by performing simulations on unimorph type harvester devices with and without a closed magnetic flux path, both operating at the same natural frequency and volume of the magnetostrictive material Galfenol. The harvester design considered here consists of a magnetostrictive layer (Galfenol) bonded to a steel substrate layer, a tip mass, a pick-up coil and a magnetic flux path consisting of soft iron core and NdFeB permanent magnets. Our results demonstrate a voltage gain of around 70% for the closed flux path design. Furthermore, a proof of concept prototype of the modified flux path design is developed, tested under impulse loading, and the voltage, power output are compared with FE simulation results for validation. The simulation results match well with experimental observations at two operating frequencies for the flux path design.

Study on the Microstructure and Performance of the Multi-Field Composite-Assisted Laser Cladding of Nickel-Based Tungsten Carbide Coatings

Improving the hardness and wear resistance of die cutting tools is an important issue in the study of the service life of die cutting equipment. Using laser cladding technology, nickel-based composite coatings with varying BiFeO3 contents were prepared on a 45 steel substrate, because BiFeO3 can have an effect on the dilution rate and microstructure of the sample; morover BiFeO3 is a new type of multiferroic material with certain magneto-electric coupling effects which can be prepared for the study of added magnetic fields. The microstructure and morphology were characterized to determine the optimal BiFeO3 content. Based on the optimal addition of BiFeO3, a comparative analysis was conducted to investigate the effect of different magnetic field strengths under a composite energy field on the microstructure, hardness, and wear resistance of Ni-based WC cladding layers. The results show that the optimal addition of BiFeO3 was 5 wt%. At this concentration, there were no significant porosity defects in the coating, and the dilution rate was appropriate (4.77%). Additionally, the interface bonding strength was also increased. With optimal BiFeO3 addition, stirring with different magnetic field strengths was applied to the cladding layer, and the results show that the aspect ratio of the cladding layer gradually increased with increasing the alternating magnetic field strength. When the magnetic field strength in the composite energy field was 40 mT, the microstructure was fine and uniform, the hardness of the cladding layer reached the highest level, about 925.2 HV1.0, the wear resistance was also the best, the friction coefficient of the cladding layer was about 0.54, and the width of the wear mark was about 0.53 mm.

A new methodology to calculate interface thermal resistance between intumescent coating and steel substrate

Interface thermal resistance (ITR) plays a very important role in heat transfer and thermomechanical coupling response from intumescent coating to steel substrate in fire. However, the dynamic ITR between intumescent coating and steel substrate during burning is seldom reported. In this paper, a new methodology is presented to calculate dynamic ITR between intumescent coating and steel substrate under high incident heat flux based on the interface conservation equation. The new methodology focuses on measuring the temperature distribution and thermal conductivity of intumescent coating and steel substrate, with fewer variables. In this way, the calculation of ITR can be simplified. Firstly, the temperature variation function curves inside the intumescent coating and the steel substrate were fitted separately based on the temperature measurement data. Secondly, the interface temperatures (Tci,Tsi) were determined separately at the interface position by temperature variation function curves inside the intumescent coating or the steel substrate. Finally, the ITR calculation formula was deduced and the key parameters required for ITR calculation were obtained by cone calorimetry et al. An illustrative example was studied and validate the applicability of the new methodology.

Mitigation effect of a biodegradable surfactant N,N,N-trimethyl-2-(((hexadecyloxy)carbonyl)oxy)ethan-1-aminiumiodide for mild steel corrosion in 5% HCl: Experimental and theoretical insights

A cleavable cationic surfactant having carbonate linkage, N,N,N-trimethyl-2-(((hexadecyloxy)carbonyl)oxy)ethan-1-aminiumiodide referred to as THC was synthesised and characterized employing elemental analysis, FT-IR (Fourier Transform Infrared Spectroscopy), 1H NMR (Nuclear Magnetic Resonance) and 13C NMR. The extent of corrosion inhibition of THC was for the first time studied experimentally and theoretically on mild steel (MS) substrate in 5 % HCl solution at temperatures 303, 313, 323, 333, 343, 353 K. Experimental investigations include gravimetric analysis, potentiodynamic polarization (PDP) and electrochemical impedance analysis (EIS). THC provided maximum inhibition efficiency of 93.2 % at concentration of 1×10−4 M at 303 K which was further raised to 98.1 % at 353 K. PDP studies reveal that given surfactant is mixed type inhibitor. Surface studies such as contact angle measurement, AFM (Atomic Force Microscopy), SEM-EDX (Scanning Electron Microscope-Energy Dispersive X-ray Analysis), and XPS (X-ray Photoelectron Spectroscopy) were employed to justify the adsorption of inhibitor molecules on MS surface. Furthermore, biodegradability test on THC was done to support the environment friendly nature of the surfactant.

Influence of Printing Parameters on the Morphological Characteristics of Plasma Directed Energy-Deposited Stainless Steel

This study investigated the influence of printing parameters and strategies on the morphological characteristics of austenitic stainless steel beads deposited on carbon steel substrates, using plasma directed energy deposition (DED). The experimental setup varied the welding current, wire feed speed, and torch travel speed, and we analyzed three printing strategies: simple-linear, overlapping, and oscillating. Moreover, advanced 3D scanning and computational analysis were used to assess the key morphological features, including bead width and height. The results showed that the computational model developed by using parabolic assumptions accurately predicted the geometric outcomes of the overlapping beads. The oscillating printing strategy was the one that showed improved morphological uniformity and bead substrate wettability, so these features were used for multi-layer component manufacturing. The use of equivalent wavelength–amplitude values resulted in maximum combinations of bead height and width. Moreover, cost-effective carbon steel substrates were feasibly used in microstructural and elemental analyses, with the latter ones confirming the alignment of the bead composition with the wire-fed material. Overall, this study provides practical insights for optimizing plasma DED processes, thus enhancing the efficiency and quality of metal component manufacturing.

Investigation of the effect of current density and ZrO2 bath concentration on electrodeposited Ni-P/ZrO2 composite coatings

In this study, Ni-P/ZrO2 nanocomposite coatings were deposited on St-37 steel substrates using the electroplating method with varying ZrO2 concentrations and current densities. To investigate the effects of electrolyte components and current density on coating properties, analyses were performed regarding microhardness, wear performance, and surface morphology. As a result of the analyses, it is observed that different bath concentrations and current densities significantly affect properties such as morphology, hardness, and wear performance. It is seen that the surface morphologies of the obtained coatings are generally smooth, but it is understood from the optical images that the surfaces of all nanocomposite coatings are rougher. While adding ZrO2 nanoparticles to the main matrix increases microhardness by approximately 40% compared to pure nickel, a similar but higher hardness value was obtained with the increase in current density. When examined in terms of wear performance, an average friction coefficient value of 3.15 times higher than that of pure nickel nanocomposite coatings was obtained.

Transition metal carbo chalcogenides: A novel family of 2D solid lubricants

Two-dimensional (2D) layered materials such as transition metal dichalcogenides (e.g., MoS2, WS2) and MXenes (e.g., Ti3C2Tx), as well as hybrids of these materials are the focus of current research in solid lubrication due to their outstanding performance. Transition metal carbo-chalcogenides (TMCCs), consisting of an MXene core and a TMD-like surface, represent an inherent combination of TMDs and MXenes without the need to construct hybrids out of the individual layers. Due to their layered structure and surface chemistry, favorable tribological properties can be expected from these novel materials. Here, multilayer Ta2S2C and Nb2S2C TMCCs are deposited solely as a powder onto a steel substrate and their tribological properties under linear sliding against different counterbodies, i.e., Al2O3, SiC, 100Cr6, and polytetrafluoroethylene (PTFE) are discussed. Advanced materials characterization techniques are used to detect the presence of TMCCs inside the wear tracks and to reveal their 2D structure within the tribofilm. Finally, density functional theory (DFT) simulations are used to unravel the easy shearability of TMCCs at the nanoscale. The results demonstrate the great potential of this new 2D material family, which also offers many possibilities for defined tuning of the solid-solid interface.

Environmentally friendly MoS2-hBN solid lubricants: A Comprehensive Tribological Evaluation

Abstract MoS2-based solid lubricants have obtained significant attention and are extensively employed in the aerospace industry due to their desirable tribological performance. However, to enhance their performance in humid environments, MoS2 is often doped with Pb-based compounds. Considering the health and environmental concerns associated with Pb, it is necessary to develop eco-friendly alternatives. In this study, hexagonal boron nitride (hBN) has been used as a potential substitute for Pb-based dopants in MoS2-based solid lubricants and coatings with varying hBN contents (9.5, 11.5, 13.5, 15.5, and 17.5 wt.%) were applied to stainless steel substrates using a spray bonding technique. The friction and wear characteristics of the coatings were analyzed by using a ball-on-flat tribometer, employing constant load conditions. Subsequently, ex-situ analysis techniques such as scanning electron microscopy (SEM), raman spectroscopy, and atomic force microscopy (AFM) were used to characterize the coatings. The results showed that the coating with a lower hBN concentration presented improved tribological properties, which was correlated with the development of an effective MoS2-based transfer/tribo-film. This suggests that optimizing hBN content is crucial for enhancing the lubrication performance.

The characteristics of Zn–5Al–2Mg coating on low carbon steel by two-step galvanizing method

The aim of this work is to characterize the complicated microstructure of a multilayer material that has been produced using a two-step batch galvanizing technique, with a particular focus on its extraordinary resistance to corrosion. The corrosion testing was performed using cyclic salt spraying, which involved the use of a salt mist chamber, wet chamber, and dry chamber. The results indicated that the Zn–5Al–2Mg (ZMA) coating system consists of four distinct layers: α, β, θ, and π layers. The top layer consisted of ternary and binary eutectic phases, whereas the central section had a branch-like Fe4Al13 phase. A continuous layer of Fe4Al13 was produced at an interface with the substrate. After undergoing 270 corrosion cycles, the coating demonstrated the capability to generate corrosion products that were dense and compact, including Zn5(OH)6Cl2H2O, Zn5(CO3)2(OH)6, and Mg6Al2(CO3)(OH)16⋅H2O. The corrosion products inhibited the corrosive substance from reaching the steel substrate, hence enhancing the durability of the coating.

Effect of laser power during laser powder bed fusion on microstructure of joining interface between Tungsten and AISI 316L steel

This study investigates the deposition of tungsten (W) onto a 316L steel substrate by laser powder bed fusion (L-PBF), to optimize process parameters and analyze the interface between W and 316L. To obtain high-density W structure (98.89%), the optimal laser power was 350 W, and scan speed was 500 mm/s, but these parameters cause significant dilution of W in the W-316L interface; as a result, Fe7W6 intermetallics form, despite L-PBF being a non-equilibrium solidification process. These intermetallics which are brittle could degrade joint strength. By reducing laser power below 250 W, the dilution of W can be mitigated, and potentially minimize formation of intermetallics and increase joint stability for advanced manufacturing applications.

The Effect of Spray Distance on the Hot Corrosion Behavior of HVOF‐Sprayed NiCrAlY Coatings in a Simulated Gas Turbine Environment

ABSTRACTTo utilize the unique properties of coatings produced using the high‐velocity oxy‐fuel (HVOF) method, this study examined the effect of spray distance on the hot corrosion behavior of NiCrAlY coatings deposited on a steel substrate. The coating samples were obtained at spray distances of 20, 25, and 30 cm. The flow rates of oxygen and propane were maintained constant at 300 and 60 lit/min, respectively. Additionally, the powder feeding rate was 32 g/min. The samples were then subjected to the hot corrosion test in a salt mixture of Na2SO4−60% V2O5 at 900°C in an ambient atmosphere. The surface and the cross section of the samples were observed using a scanning electron microscope (SEM) and the chemical composition of different sections was determined by energy‐dispersive spectroscopy (EDS). The phases were also characterized using X‐ray diffraction analysis (XRD). The best corrosion resistance was found in the sample coating formed at a spraying distance of 20 cm, as the results showed that increasing the spraying distance led to a reduction in the thermal and kinetic energy of the flame, resulting in increased porosity in the coating. This behavior can be attributed to the low oxide content of the coating, the higher aluminum content, and the richer NiAl phase, which serves as a reservoir for aluminum.

Hardness and corrosion resistance of Zn coatings on mild steel obtained by electrodeposition and hot-dip galvanization

The purpose of this work is a comparative study of the characteristics of the layers of Zn on a substrate of mild steel from two different processes (electrodeposition and galvanizing), and to review the progress that has been made in understanding the intermetallics phases’ effect on the corrosion behavior. The obtained Zn-containing film was investigated using diverse instrumental methodologies such as microhardness, X-ray diffraction, and potentiodynamic polarization measurements. This study allows the conclusion that the layers of Zn developed have: a homogeneous structure and good hardness. The corrosion test results showed an improvement in corrosion resistance for electrodeposition coatings compared with galvanizing coatings. XRD results identify that the electrodeposition and the galvanizing coatings have similar phases and the maximum hardness is obtained for the galvanizing process. Intermetallic phases were found to influence the corrosion behavior of mild steel. The results show that the size of Fe–Zn particles gradually decreases with the immersion time.

Effects of Cu Coating Addition on Mechanical Properties of Vacuum Brazed Joints

In this study, a copper brazing filler metal coating is fabricated on a 304 stainless steel (304SS) substrate using an electroplating technique. The effect of using electroplated copper brazing filler metal coatings compared to pure copper foil of the same thickness for vacuum brazing of stainless steel joints is investigated. The microstructure and microhardness of the brazed joints are characterized using X‐ray diffraction (XRD), scanning electron microscopy (SEM), and a Vickers hardness tester. The shear strength of the brazed joints is measured using an INSTRON 5869 universal testing machine. The results indicate that the electroplated Cu coating is dense, predominantly with a single cubic phase, with a few copper particles aggregating on the surface. Under electroplating conditions of 20 mA cm−2 for 1 h, the coating thickness was 56 μm. The shear strength of the brazed joint with this coating reached a maximum of 333.7 MPa, which is higher than that of a brazed joint with a 60 μm thick copper foil, which exhibits a shear strength of 303.2 MPa. The shear strength of the brazed joints shows an initial increase followed by a decrease as current density and electroplating time increase. This study provides significant technical support for brazing complex shapes or precision components. It suggests a method to simplify the brazing process, reduce production costs, and enhance the strength of brazed joints.