Cladding Surface Research Articles

Microstructural characteristics of multilayers and interfaces of Cr-coated Zircaloy-4 cladding based on elemental diffusion under high-temperature steam oxidation

A dense and well-adhered Cr coating was prepared on the surface of Zircaloy-4 cladding by arc ion plating. Oxidation tests on Cr-coated Zircaloy-4 claddings were conducted in steam at 700-1300 °C. The surface morphology and cross-sectional microstructure were investigated using SEM, EBSD, FIB and TEM techniques. The results showed that no significant cracking or spalling was observed after oxidation. The oxidized cross-sections showed characteristics of multilayers and interfaces. From the outer to the inner layer, these are, in order, a Cr oxide film and Sn precipitates on its grain boundaries, an amorphous structural layer, a residual Cr coating and (Zr,Cr)xOy oxides on its grain boundaries, a C15-type Zr(Cr,Fe)2 intermediate layer, and a (Cr,O)-rich substrate Zr. The multilayers and interfaces alter the oxygen diffusion path and reduce the oxygen diffusion rate, thus slowing down the oxidation process of the substrate. In addition, the location and cause of amorphous structures and Kirkendall cavities and their effect on microstructure and adhesion properties were discussed.

The effect of process parameters on the residual stress in friction surface cladding

The effect of process parameters on the residual stress in friction surface cladding

Comparative studies on microstructural characteristics and wear behavior of high-speed and low-speed laser cladding graphene/CoCrFeMo0.5NiTi0.5 high-entropy alloy composite layers

To prevent the failure of curved parts due to wear under actual working conditions, a graphene/CoCrFeMo0.5NiTi0.5 high-entropy alloy composite coating was prepared on the surface of a curved part using both high-speed and low-speed laser cladding (LLC). The surface morphology, physical phases, elemental distribution, microstructure, microhardness, and wear behavior of this coating applied via high-speed and LLC were comparatively studied. The results showed that the maximum height difference on the surface of the high-speed laser cladding (HLC) layer was only 44.7 % of that of the LLC layer, and the surface powder was more completely melted. The average microhardness of the HLC layer was about 1.49 times higher than that of the LLC layer and showed a maximum hardness of 666.38 HV0.5, which was about 2.95 times higher than that of the substrate. The internal microstructure of the HLC layer was finer and the diffusion of Fe atoms from the substrate into the coating was significantly reduced. In all three wear environments, abrasive wear occurred in both the low-speed and HLC layers. The total wear rate of the LLC layer was 230.588 μm3 N−1 mm−1, which was about 3.06 times higher than that of the HLC layer (75.395 μm3 N−1 mm−1). The wear surfaces of both cladding layers were oxidized, and the wear rate increased with the oxygen content on the wear surfaces under the same wear conditions. Meanwhile, the oxygen content of the wear surfaces of both cladding layers in sodium chloride solution was significantly higher than that during dry wear.

Investigation on microstructure and high-temperature wear properties of high-speed laser cladding Inconel 625 alloy

Inconel 625 alloy cladding layer was prepared by high-speed laser cladding (HLC) on Q245R steel substrate to improve the service performance of the structural components in the power industry in this work. A comprehensive study on the HLC Inconel 625 coating with different scanning speeds was conducted utilizing Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Laser Scanning Confocal Microscope (LSCM), X-Ray Diffraction (XRD), a microhardness tester, and an SRV-4 high-temperature friction and wear testing machine. The results show that the cladding layer's thickness and surface roughness decrease with the scanning speed increase. The cladding layers with different scanning speeds contain different microstructures. The phases mainly consist of γ-Ni and NbC. The microhardness of HLC coatings is generally higher than that of substrate, but decreased as the scanning speed increased. After the friction wear test at 500 °C, the cladding layer at the scanning speed of 2 m/min showed the best high-temperature wear resistance. The grain boundary area increases due to the formation of small-sized equiaxed dendrites, which resists dislocation slip and crack propagation, thereby enhancing high-temperature wear resistance. For the cladding layers at the higher scanning speed, the abrasive wear and the fatigue wear occur due to the precipitation of solid soluble elements such as Nb and Mo and the columnar crystal structures prone to deformation.

Surface Modification of 42CrMo Steels: A Review from Wear and Corrosion Resistance

This work reviews surface modification techniques for improving the wear and corrosion resistance of 42CrMo steel. The advantages and disadvantages of various methods, including thermal spraying, deposition, hardfacing, laser cladding, nitriding, and laser surface treatment, are discussed. The review elaborates on the materials commonly employed in laser cladding technology, including iron-based, cobalt-based, nickel-based, and high-entropy alloys and reinforced composite coatings. Furthermore, the mechanisms and methods of improving the wear and corrosion resistance of 42CrMo steel are summarized. Finally, this review presents research shortcomings and future opportunities of surface modification techniques. This review also provides a theoretical guide for the application of 42CrMo steel.

Investigation of surface hardness, thermostability, tribo-corrosion, and microstructural morphological properties of microwave-synthesized high entropy alloy FeCoNiMnCu coating claddings on steel

Deposition of high entropy alloy FeCoNiMnCu on SS-304 was carried out by microwave energy for application in “solid oxide fuel-cell (SOFC) interconnects”. The ball-milling has been performed by taking “Fe, Co, Ni, Mn, and Cu” in equal 20 wt. % of before deposited on SS-304 substrate. The deposited steel with 20% Fe 20% Co 20% Ni 20% Mn 20% Cu high entropy alloy (HEA) was exposed to thermal-exposure in the air for up to 10 weeks at 800 °C. The uniform cladding distribution of 20% Fe 20% Co 20% Ni 20% Mn 20% Cu HEA particles can be apparently observed on SS-304 substrate by utilizing Scanning Electron Microscope (SEM), and Optical microscopy analysis. Homogeneity in the interfacial layer was evident by employing Scanning Electron Microscope (SEM) characterization. Results have indicated that after the thermal exposure of deposited steel with 20% Fe 20% Co 20% Ni 20% Mn 20% Cu in the air for up to ten weeks at 800 °C, a “protective Cr2O3 layer”, and “high-entropy spinel coating” of (Fe, Co, Ni, Mn, Cu)3O4 have been formed. During microwave cladding, the emergence of harder-phases has contributed to the raised hardness. The wear behavior after coating of 20% Fe 20% Co 20% Ni 20% Mn 20% Cu HEA on SS-304 substrate has significantly enhanced due to the strengthened wear resistance and hardness of the coatings. Findings have exhibited that the formation of (Fe, Co, Ni, Mn, Cu)3O4 phase is a potential coating material for “SOFC interconnects” applications. Moreover, the cladding of SS304 with a composition of 20% Fe, 20% Co, 20% Ni, 20% Mn, and 20% Cu has demonstrated remarkable stability under thermal expansion studies. As the findings have revealed that the composite cladding has efficiently withstand significant variations in volume when subjected to elevated temperatures for a prolonged period of time, thus, exhibiting its superior thermal stability for SOFC-interconnect applications. Furthermore, the SEM images of the cladding surface, surface hardness, and tribocorrosion behavior of the coated material have been observed to identify the 20% Fe 20% Co 20% Ni 20% Mn 20% Cu HEA coating effect on SS-304 steel-substrate.

Enhanced Microstructure and Wear Resistance of Ti-6Al-4V Alloy with Vanadium Carbide Coating via Directed Energy Deposition.

Ti-6Al-4V alloys are known for their suboptimal tribological properties and are often challenged by durability issues under severe wear conditions. This study was conducted to enhance the alloy's wear resistance by forming a hardened surface layer. Utilizing directed energy deposition (DED) additive manufacturing with a diode laser, vanadium carbide particles were successfully integrated onto a Ti-6Al-4V substrate. This approach deviates from traditional surface enhancement techniques like surface hardening and cladding, as it employs DED additive manufacturing under parameters akin to those used in standard Ti-6Al-4V production. The formed vanadium carbide layer achieved a remarkable thickness of over 400 µm and a Vickers hardness surpassing 1500 HV. Pin-on-disk test results further corroborated the enhanced surface wear properties of the Ti-6Al-4V alloy following the additive-manufacturing process. These findings suggest that employing vanadium carbide additive manufacturing, under conditions similar to the conventional DED process with a diode laser, significantly improves the surface wear properties of Ti-6Al-4V in metal 3D-printing applications.

Microwave-Assisted Cladding of Ni-BaTiO3 Mixture onto SS-304 for Enhancing the Wear Resistance and Surface Hardness

The present study focuses on achieving precise deposition of a Ni and 15% BaTiO3 particle mixture onto SS-304 substrates through meticulous preparation steps. Thorough cleaning of the SS-304 substrate eliminated contaminants, ensuring optimal adhesion. Simultaneously, the Ni-BaTiO3 mixture underwent preheating at 1200°C for 20 hours in a muffle furnace to eliminate moisture content, crucial for preventing coating defects. A uniform and crack-free cladding layer enhances the substrate’s resistance to wear, corrosion, and mechanical stresses, thereby extending its service life and improving overall functionality. The surface hardness of SS-304 experienced a substantial improvement of 39.90% following the cladding process with Ni and 15% BaTiO3. A sliding speed of 2 m/s was meticulously selected to replicate typical velocities encountered in practical applications, ensuring a realistic assessment of frictional behavior and wear resistance. Similarly, the sliding distance of 1000 m and an axial load of 5 N were precisely calibrated to simulate the mechanical stresses experienced during sliding contact, facilitating a thorough examination under relevant conditions. These carefully chosen parameters enabled the determination of key tribological properties essential for evaluating the performance of the cladded surface of SS 304 with Ni + 15% BaTiO3. The wear rate, measured at 0.0016 mm3/m, serves as a critical indicator, revealing the volume of material lost per unit distance of sliding. This parameter provides invaluable insights into the surface’s wear resistance and durability, crucial for assessing the longevity and performance of the cladded surface under abrasive conditions. Additionally, the coefficient of friction, determined to be 0.255, offers a quantitative measure of the surface’s frictional behavior during sliding contact.

Unveiling of grain structure, porosity, phase distributions, microstructural morphology, surface hardness, and tribo-corrosion characteristics of nickel, and titanium dioxide-based SS-304 steel microwave composite coatings cladding

The microstructure, homogeneity, and tribo-corrosion behavior of microwave-developed Nickel as well as titanium dioxide SS-304 cladding surfaces are the primary emphasis of this research. The study includes assessing the hardness enhancement from Ni and TiO2 particles in the cladding surface. The investigation additionally evaluates cladding surface wear rates, friction coefficients, and resistance to corrosion under tribological conditions. The microstructure, homogeneity, and tribo-corrosion behavior of SS-304 cladding surface with Ni and TiO2 developed by microwave cladding energy were investigated in this study. The microstructure was being examined to validate the uniformly homogeneous dispersion of Ni and TiO2 particles, and XRD was employed to determine cladding surface phases. The hardness of the cladding surface was evaluated, and a pin-on-disk tribometer has assessed the wear behavior. Tribo-corrosion was tested in 3.5-percent NaCl solution. To enhance cladding's efficiency, microwave hybrid heating (MHH) utilising charcoal as a susceptor has been employed. Findings exhibited that the microstructure analysis showed that the cladding surface had a uniform distribution of Ni and TiO2 particles and a compact and homogeneous microstructure. The hardness of the cladding surface was significantly improved by about 37.68% due to the incorporation of Ni and 10% TiO2 particles. The FeNi3, NiSi2, Ni3C, NiC, Ni2Si, FeNi, and TiO2 phases were seen by XRD on the cladding surface. The behavior of the cladding surface under tribological conditions was also evaluated using a pin-on-disk tribometer. The outcomes have exhibited that the Ni and 10% TiO2 cladding surface exhibited decreased wear rates and friction coefficients compared to the uncoated SS-304 substrate. Moreover, the tribo-corrosion behavior of the cladding surface was evaluated in a 3.5% NaCl solution. The wear rate and coefficient of friction of Ni and 10% TiO2 cladding surfaces were measured to be 0.00412 mm3/m and 0.297, respectively. The results indicated that the Ni and TiO2 cladding surface had enhanced corrosion resistance compared to the uncoated SS-304 substrate.

High entropy alloy cladding on mild steel substrate using microwave energy at 2.45 GHz: An insight from multi-physics simulation study to experimental investigations

Microwave hybrid heating (MHH) has emerged as a novel technology for cladding high-entropy alloy (HEA) powders on metallic substrates. The existence of a multi-material system (Al, Co, Cr, Ni, and Ti powder) in HEA provides difficulties in microwave cladding. These problems are addressed in the current study by employing silicon carbide as a susceptor material for MHH to microwave-clad AlCoCrNiTi HEA on a mild steel substrate. A multi-physics model of the microwave cladding setup was constructed to investigate the cladding properties. The model was verified using experimental data, and simulation was used to examine the electric field, resistive losses, energy distributions, and temperature-time profile. The simulation results indicated that the electric field intensity, resistive losses, and energy distribution were at their maximum near the susceptor and the cladded surface. As a result, the HEA-cladded surface reached a temperature of 1030 °C at the central plane. This is comparable to the experimental temperature of 1041 °C in 41 min, which shows an error of <10 %. From the microstructural investigation, the HEA powder exhibited a flaky microstructure and a uniform distribution of all the constituents, resulting in a solid metallurgical link between the HEA powder and substrate. The surface hardness of mild steel components was enhanced intensely by three times with the inclusion of AlCoCrNiTi HEA cladding.

Numerical and Experimental Investigation of Residual Stress and Bond Strength in Friction Surface Cladding Process

Numerical and Experimental Investigation of Residual Stress and Bond Strength in Friction Surface Cladding Process

Preparation and properties of water-soluble coatings resistant to scratching on the surface of nuclear cladding

As the second barrier of radioactivity in the reactor core, Zr alloy nuclear cladding tubes are easily to be scratched by the fixed grid during assembly process. In order to protect them from possible damage during their insertion through the skeleton, it is proposed to use water-soluble coatings with excellent scratch resistance to protect nuclear cladding tubes, and then wash away the coating to prevent the impeding the normal operation of the assembly. In this study, polyacrylate emulsion, neutralizer and filler were used to synthesize the coating. The chemical composition, thermal stability and hydrophilic performance of the coating were analysed by Fourier Transform Infrared Spectroscopy (FT-IR), thermal gravimetric analysis (TGA) and water contact angle (WCA) respectively. TGA analysis showed that the weight loss rate of the coating was less than 10 % at 200 °C, indicating the good thermal stability of coating at 200 °C. The water contact Angle of the coating was reduced to 32.78°, indicating that the coating had good hydrophilicity. Scanning electron microscopy displayed that the micro-structure of coating was dense, which was one reason of the good scratching resistant. By adjusting the curing conditions, the optimized preparation parameters of the coating were obtained. When the curing temperature was 90 °C and the curing time was 30 min, the coating had more optimized scratch resistance and water solubility.

Influence of Clad Layer Thickness of Aluminium Alloy by Friction Surface Cladding Process

Friction Surface Cladding (FSC) is a process that enables the deposition of clad material on a substrate through a hollow rotating tool to create thin clad layers at sufficiently high temperatures. Heat is produced during the cladding process by friction at the tool-clad layer and the substrate. This study focus on the influence of clad layer thickness of aluminium alloy AA2024 at the control process temperature around 300℃ to 350℃. The material used is AA2024-T4 for the clad layer and AA2024-T351 for the substrate. A thermal model is built using COMSOL Multiphysics 6.0 and Heat Transfer in Solid (ht) with time-dependent study is used to study the heat transformation as well as optimize the rotational speed at different clad layer thicknesses. The major finding in this study indicates that the heat generated is proportional to the clad layer thickness. The highest heat transformation can be seen at the cladding region between the cladding rod and the substrate and the temperature reaches a maximum of 333.95℃.

3D finite element analysis and experimental correlations of laser synthesized AlCrNiTiNb high entropy alloy coating

A 3D Finite Element Analysis (FEA) model of laser cladding process of AlCrNiTiNb high entropy alloy (HEA) coatings on Titanium alloy (Ti6Al4V) substrate has been developed taking into account heat transfer and free surface movement. The use of Ti6Al4V is highly evident in applications such as aerospace, automobile and marine environments due to their outstanding specific strength to weight ratio. Although they have high strength useful for fabrication of engineering components and movable parts in a mechanical system, Ti6Al4V are restricted to non-friction applications as a result of their low hardness. In this work, AlCrNiTiNb HEA hard-coating with equi-atomic ratio was synthesized on Ti6Al4V alloy substrate by laser cladding technique to mitigate the limitations. Prior to experimental method, a 3D computational model was developed to simulate the physical phenomena based on heat transfers involved during laser surface cladding (LSC) of HEA coating on Ti‐6Al‐4V alloy by a laser-assisted direct energy deposition technique. COMSOL Multiphysics 5.3a was used to create a model using heat transfer in solids module incorporating temperature distribution during the layer-wise build-up of 3 layers. The experimental validation showed that the microstructural analysis by scanning electron microscope (SEM) resulted in coating having dendritic and interdendritic structure which resulted in good metallurgical bonding. X-ray diffraction (XRD) analysis displayed that AlCrNiTiNb alloy coating is composed of ordered and disordered solid solution phases (BCC and FCC) with no intermetallic compounds formed. Energy dispersive spectrometer (EDS) confirmed the presence of elements used. The microhardness of AlCrNiTiNb HEA coating reached maximum value around 892 HV which is more than of the substrate. The microhardness increased significantly due to the combination of BCC and FCC solid solution phases.

AN INVESTIGATION ON MICROSTRUCTURES, MECHANICAL AND WEAR BEHAVIOR OF LASER-CLADDED INCONEL 625 AND NIMONIC 90 OVER NIMONIC 90 SUBSTRATE

The wrought nickel–chromium–cobalt Nimonic 90 alloy is widely used in turbine blades, piston rings and forged tools due to their high stress-rupture strength and creep resistance up to 920∘C. The application components showed unavoidable wear behaviors at high loads due to the reduced resistance of the components. Hence, in order to increase the wear resistance of this alloy, Inconel 625 and Nimonic 90 particle depositions have been carried out on Nimonic 90 substrate through the laser-cladding techniques to study the microstructure, mechanical and tribological behaviors of alloys. The phases, microstructure and microhardness of the claddings were investigated by X-ray diffractometry (XRD), Transmission electron microscopy (TEM), Scanning electron microscope (SEM), Energy-dispersive X-ray spectroscopy (EDS) and hardness test, respectively. Results showed that the mean thickness of the interfacial layer of Inconel 625 and Nimonic 90 was 18.51 ± 4 [Formula: see text]m and 90.68 ± 7 [Formula: see text]m, respectively. The microstructure of the cladding surfaces resulted in dendritic and interdendritic structures. An overall analysis found that the gamma-Ni and hard laves phases were presented in Inconel 625 and Nimonic 90 clad surfaces, respectively. Nimonic 90 clad surface had a high hardness and wear resistance compared with Inconel 625 clad surface and substrate due to the present hard laves phase. Besides, the roughness of the Nimonic 90 clad surface was lower compared with the Inconel 625 clad surface and substrate.

Homogeneity, metallurgical, mechanical, wear, and corrosion behavior of Ni and B4C coatings deposited on 304 stainless steels developed by microwave cladding technique

The microwave cladding technique for depositing Ni and 10 % B4C coatings on 304 stainless steel has yielded significant advancements in material properties and performance. The key findings of this study revealed remarkable improvements, including a 43.33% increase in material hardness, indicating enhanced wear resistance and mechanical properties. This improvement was attributed to the uniform distribution of B4C and Ni on the cladding surface, ensuring a consistent interfacial layer developed between SS 304 and the cladding surface without cracks and porosity. Microstructural analysis at 500× magnification unveiled an impressive 2233.35 grains per square inch, showcasing the refined grain structure achieved during the cladding process. Wear testing demonstrated a low wear rate of 0.00308 mm³/m and a favorable coefficient of friction of 0.1981, confirming the material's suitability for applications with demanding frictional conditions. Furthermore, the corrosion behavior of the coated 304 stainless steel was assessed, revealing a minimal corrosion weight loss of only 0.42 mg for the Ni and 10% B4C coated sample. The presence of various carbide phases, such as Cr2C, Cr23C6, Cr7BC4, Fe5C2, and Fe23B6, within the cladding further contributed to the material's enhanced mechanical and wear properties.

Miniature fiber-optic near-surface gap-coupled cladding waveguide Mach-Zehnder interferometric refractive index sensor inscribed by femtosecond laser

A miniature fiber-optic gap-coupled cladding waveguide Mach-Zehnder interferometer (MZI) is proposed and demonstrated for high-sensitive refractive index measurement. Two straight cladding waveguides respectively coupled with the fiber core are inscribed by a femtosecond laser (fs) to form the MZI structure. At their far ends, the two cladding waveguides are very close to the cladding surface, and a short separation was intentionally designed for the coupling of light between them and generating light field with evanescent wave expanded outside the cladding surface, which makes the MZI structure very sensitive to ambient refractive variations. In a refractive index range of 1.34–1.42, a high sensitivity of −59.90238 nm/RIU is achieved simultaneously with good linearity. The sensing structure also shows good characteristic of temperature insensitivity, which may find practical applications in chemical or biological sensing.

Thermal Hydraulics Simulation of a Water Spray System for a Cooling Fluid Catalytic Cracking (FCC) Regenerator

Olefins are crucial building blocks for petrochemical industry, serving as raw materials for the production of various products such as plastics, synthetic fibers, detergents, solvents, and other chemicals. In FCC, heavy petroleum feedstocks are injected into a catalytic cracking unit, where they are mixed with a catalyst. The catalyst aids in breaking down the large hydrocarbon molecules into smaller fragments, including olefins like Propylene and Ethylene. These polymerization reactions occur at high temperatures. They demand that heat removal occurs as quickly as possible in order to control the reactor temperature and to avoid “hot spots” in the Regenerator or localized oxidation reactions (and to avoid creep rupture of the regenerator steel cladding). The cooling of the regenerator cladding surface can be achieved by impinging water droplets (spray), ejected from a spray nozzle. Spray cooling can provide uniform cooling and handle high heat fluxes in both a single phase and two phases. This research provides a thermal hydraulic design of regenerator spray cooling systems. In the framework of this research, Fire Dynamics Simulator (FDS) software was applied in order to simulate the temperature field and the water vapor mass fraction. A COMSOL Multiphysics finite element code was used in order to calculate the temperature field inside the regenerator cladding. The calculated surface temperatures and heat transfer convective coefficient, obtained using FDS software, were validated successfully against COMSOL numerical results and previous results in the literature. The numerical simulations were carried out for two cases. The first case was carried out at a distance of 0.5 m, and the second case was carried out at a distance of 0.2 m. A grid sensitivity study was carried out on the FDS model. Numerical integrations were carried out over time in order to calculate the average temperatures. The difference between these four average temperatures, calculated by applying different grids, is less than 7.4%. The calculated surface temperatures and heat transfer convective coefficient were validated successfully against COMSOL numerical results and previous research. It was shown that the calculated temperatures decrease in the second case. The water spray system managed to cool the steel wall more effectively as the water spray system approaches the steel cladding.

Scaling laws for the additive manufacturing of the AISI 316 L deposited by laser surface cladding and direct metal deposition methods

This study presents a comparative analysis of the shape and microstructure of individual tracks formed from AISI 316 L stainless steel using laser surface cladding (LSC) and direct metal deposition (DMD) methods. The research aims to identify the relationship between laser radiation parameters (laser spot size, radiation power, scanning speed) and geometric characteristics of created tracks. The result shows that the change in the geometric characteristics of single tracks (depth, width, and height) can be related to two dimensionless parameters: normalized enthalpy H and Peclet number Pe. Based on the experimental data summary, the limiting values of the conditions for realizing keyhole melting (H > 2, Pe < 10) and heat conduction (H < 2, Pe > 10) were determined.

A comparative study on weld-bead geometry of austenitic stainless-steel produced by cold metal transfer welding and pulse metal inert gas welding process

In recent years, weld cladding has become an emerging technique for the surface modification of carbon steel, which has various industrial applications such as chemical, marine, mining, agriculture, and power generation. In this research, cold metal transfer (CMT) welding and pulse metal inert gas (MIG) welding are utilized to study the weld-clad bead of 308L stainless steel over low-carbon steel. To examine the mechanical and wear characteristics of CMT weld-clad samples, welding speed (3, 4, 5, and 6 mm/s) was used as the input process parameter, while current (175 A), nozzle to workpiece distance (10 mm), and shielding gas flow rate (15 l/min) were kept constant. Microstructural analysis of weld bead samples was done through optical microscopy and field emission scanning electron microscopy. With an increase in welding speed, the microhardness and wear properties of the clad surface were improved. The CMT-clad surface had significant improvements in mechanical, wear properties, and lower residual stresses due to low dilution and lesser heat input.