Cladding Technique Research Articles

Wear and corrosion resistant iron-based amorphous coating in diluted biodiesel environment

Biodiesel is an eco-friendly source of energy that is synthesized from plant or animal-based oils and fats. However, the commercial use of biodiesel is limited due to its drawbacks such as auto-oxidation and moisture absorption, leading to accelerated corrosion of the metallic parts and degradation of wear resistance. In this work, a novel amorphous metal coating was proposed to promote the wear and corrosion resistance under multigrade diesel engine oil (15W-40) diluted with 7% palm oil-based biodiesel (B30). The coating was performed using laser cladding technique at different scanning speeds (40 and 60 mm/s) and constant laser power 280 W. Microstructure investigation and X-ray diffraction confirmed amorphous structure and crystalline phase (FeCr). It was found that the wear rate was reduced for the coated specimens by about 90% compared to the uncoated samples. The corrosion rates decreased by 54.74% and 69.96% for scanning speeds 40 and 60 mm/s, respectively. Thanks to the reduced microstructural defects such as grain boundaries in the amorphous structure of the coating. These findings showed that amorphous metal coating provides promising solutions to increase the reliability of using biodiesel without the need for corrosion inhibitors which reduce the combustion efficiency.

Ultrasonic shot peening (USSP) post-treatment of Ni laser cladding on mild steel

The ultrasonic shot peening (USSP) technique serves as a reliable post-treatment method for various industrial components to prevent functional failures. This study aims to develop hybrid Ni claddings approximately 300 µm thick on mild steel using laser cladding (LC) and USSP techniques. Morphological studies reveal that the claddings exhibit enhanced closure of cracks, increased hardness, and improved scratch resistance after peening. XRD analysis confirms the presence of compressive residual stress, as well as grain refinement and texturing effects after the peening. Furthermore, the research endeavors to improve their mechanical and electrochemical properties by employing USSP's varied process parameters in a hybrid approach. After undergoing USSP treatment, the average surface roughness was increased by up to 6 µm due to the formation of dimples, while it was 8 µm in the as-cladded and only 1.5 µm after polishing. Furthermore, compared to the as-cladded and polished claddings, the hybrid claddings exhibit a hydrophobic character linked to improved corrosion resistance and better in-depth roughness profiles.

Experimental Investigation on Tribological Performance of TiB2-CoTi Composite Coating Fabricated on AISI 304 Stainless Steel by Argon Arc Cladding Technique

Experimental Investigation on Tribological Performance of TiB2-CoTi Composite Coating Fabricated on AISI 304 Stainless Steel by Argon Arc Cladding Technique

Study on the microstructure and wear resistance of Fe-Co-Sm alloy coatings with different Sm contents assisted by alternating magnetic field during laser cladding

This study employs a 20 mT alternating magnetic field-assisted laser cladding technique to fabricate high wear-resistant Fe-Co alloy coatings with varying Sm content on a 42CrMo substrate. The research investigates the changes in lattice constants and magnetostrictive effects in paramagnetic materials under the influence of an alternating magnetic field. Different Sm content coatings were characterized in terms of their micro-structure and phase composition. Measurements were taken for the hardness and elastic modulus of the coating surface, and friction and wear tests were conducted. It was found that a minor addition of Sm enhances the magnetic properties of Fe-Co-based materials, leading to a stronger magnetostrictive effect. Furthermore, the grain structure of the cladding layer is significantly refined, the eutectic regions between dendrites are reduced, and the hardness and wear resistance of the coating are markedly improved. With a composition of 1.2 wt% Sm, the coating showed the greatest microhardness and elastic modulus, and its wear resistance increased by 45.6 % compared to the original coating. With increasing Sm content, the wear resistance of the coating initially increases and then decreases. The combined application of the alternating magnetic field and the addition of rare earth element Sm significantly enhances the overall performance of the Fe-Co alloy coating.

Microstructure and tribological property of laser cladding Stellite 6 alloy by laser remelting and ultrasonic surface rolling

Stellite 6 alloy was deposited onto the surface of 27SiMn steel using the laser cladding (LC) technique, which was then followed by laser remelting (LR) and ultrasonic surface rolling (USR).The surface roughness, microstructure, microhardness, surface residual stress, and wear resistance of LC, LR, and LR-USR samples were studied using electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray stress analyzer, Vickers hardness tester, and material surface performance tester. The results showed that compared with LC, LR-USR significantly refined the surface dendrites of the cladding layer, with the average dendrite size decreasing from 16.37 μm to 6.92 μm. After USR, the samples converted from tensile residual stress (TRS) to compressive residual stress (CRS), and the high-density dislocations and strain generated in the grains near the surface of the cladding layer. The wear depth volume of the LR-USR samples was the smallest, showing typical abrasive wear.

Extending interfacial toughness and thermal cycling lifetime of thermal barrier coatings via interfacial 3D pattern

AbstractWeak interface bonding is a critical factor that compromises the long‐term durability of the thermal barrier coatings. To mitigate this, we introduce an innovative interface‐strengthening approach by integrating four types of 3D patterns at the top coat/bond coat interface using the laser cladding technique. Tensile tests demonstrate a significant enhancement in interfacial bonding strength, increasing by over 139.2% from 21.6 ± 1.7 MPa for conventional thermal barrier coatings without patterns to 51.67 MPa for the patterned coatings. Moreover, the thermal cycling lifetime has been extended by 41%, from 1026 ± 25 cycles for the conventional coating to 1936 ± 164 cycles for the patterned coating. This enhancement in interfacial toughness and thermal cycling lifetime is primarily because of the blocking and deflection effects of 3D patterns on interfacial crack propagation. Besides, the geometric parameters of the patterns play a crucial role in determining the failure behavior of the thermal barrier coatings. This strategy presents a practical solution for the development of durable thermal barrier coatings and provides the valuable insights for the optimization of other heterogeneous interfaces.

Experimental analysis on tribological behavior of Co/TiC/CaF2/Y2O3 composite coating developed by plasma transferred arc (PTA) cladding technique on AZ91D Mg alloy substrate

Abstract In this study, Co/TiC/CaF2/Y2O3 composite coating was fabricated on AZ91D Mg alloy by plasma transferred arc cladding (PTA) technique. The composite coating was fabricated with parameters as PTA current of 40 A and scan speed of 150 mm/min. The coating powders consisted of Co (60 wt%) and Y2O3 (1 wt%), with varying amounts of TiC (ranging from 34 wt% to 19 wt%) and CaF2 (ranging from 5 wt% to 20 wt%). An investigation on the effect of TiC and CaF2 content on the mechanical and wear performance of Co/TiC/CaF2/Y2O3 composite coatings has been conducted. Characterization of the coatings such as microstructure, elemental analysis, and phase analysis were investigated by scanning electron microscopy (SEM) with energy dispersive x-ray spectroscopy (EDX), and x-ray diffraction (XRD) respectively. Results showed that the phase constituents in the coatings were TiC, CoO, CoTi, Co2Y3, YTiO3, CoYC, TiO2, and CaF2. The maximum average microhardness of the clad layer was about 1162HV0.05, while the average microhardness of AZ91D Mg alloy substrate was about 68HV0.05. Based on this study, it has been found that the coating has 17 times more hardness than the AZ91D Mg substrate. Also, it can be concluded that the coating has nearly 37 times higher wear resistance than the AZ91D Mg alloy substrate.

The influence of WC content on the microstructure and properties of laser cladding CoCrFeMnNiSi1.6 high-entropy alloy coatings

In order to deeply investigate the influence mechanism of different contents of ceramic reinforced phase WC on the microstructure, microhardness, wear resistance and corrosion resistance of high-entropy alloy composite coatings. CoCrFeMnNiSi1.6-(WC)x high-entropy alloy composite coatings were prepared on the surface of AISI 1045 steel by laser cladding technique. The results showed that the coating without added WC particles consisted of FCC phase, silicide phase and BCC phase structure. The carbide phase started to appear in the coating after the addition of WC particles. The microhardness of the coatings increased gradually with the increase of WC content, and the average hardness of the composite coatings reached the highest when 40 wt% of WC particles were added, which was 782.2 HV0.5, an increase of 52 % compared with the WC0 coatings without added WC particles. With the addition of WC particles, the wear resistance of the high-entropy alloy composite coatings gradually increases and then decreases.WC3 has the lowest coefficient of friction, which is 9.23 % lower compared with the WC0 composite coating without added WC. With the addition of WC particles, the corrosion resistance of the coatings first gradually increased and then decreased. When 30 wt% of WC particles were added, the passivation film on the surface of the coating was the most stable and dense with the best corrosion resistance. The results of this paper provide a theoretical basis for the preparation of high-entropy alloy composite coatings doped with ceramic reinforced phase WC.

Effect of Heat Input on Tin Bronze-Induced Intergranular Cracks During Arc Cladding Process

This work aimed to figure out the effect of heat input on the characteristics, formation, and elimination of liquid tin bronze-induced intergranular cracks in steel sheets with a thickness of 2 mm. Tin bronze cladding layers were prepared using an arc cladding technique on the steel. A statistical method was adopted to analyze the severity of intergranular cracks. Microstructures and intergranular cracks were characterized by SEM and TEM. The tensile experiments were carried out using an electronic universal testing machine. For the bare steel sheets, the intergranular cracks originated from the cladding layer and propagated into the interior of the steel along the grain boundaries. The intergranular cracks could evolve into macrocracks and lead to the failure of steel. With the increase in heat input, the maximum temperature, maximum stress, and contact time between steel and liquid tin bronze increased. The severity of intergranular cracks was also increased, and the longest crack reached 520 μm. The mechanical properties of the steel sheets decreased with the increase in heat input. For nickel-plated steel sheets, intergranular cracks were eliminated under low heat input, and a transition layer with a nickel content of 12.32 wt.% was generated. The intergranular cracks generated under high heat input and nickel content in the transition layer were only 1.34 wt.%. The strength of the nickel-plated steel also decreased drastically, and the ductility was almost zero.

Improving microstructure and frictional wear behavior of plasma cladding FeCoCrNiMo high-entropy alloy layers by annealing treatment

The application of high-strength, wear-resistant materials for the restoration of large-scale coal development equipment is pivotal in ensuring efficient production and energy conservation within the industry. In this study, FeCoCrNiMo high-entropy alloy (HEA) cladding layers were fabricated on Q235 steel using plasma cladding techniques and subsequently subjected to annealing at 700°C, 800°C, 900°C, and 1000°C, respectively. The microstructural evolution, hardness, and wear resistance of the annealed cladding layers were thoroughly investigated. The results indicated that the microstructure of FeCoCrNiMo HEAs predominantly consisted of alternating eutectic formations of FCC, σ, and μ phases. The content of σ phase initially increased and then decreased with the increase of the annealing temperature. As the σ phase increased, both the microhardness and wear resistance were enhanced. Compared to HEA layers annealed at other temperatures, the HEA layer annealed at 900°C exhibited the highest hardness (700 HV). The wear mechanisms of the cladding layers were predominantly characterized by oxidative wear and adhesive wear. Notably, a stable oxide film was observed on the surface of the cladding layer treated at 900°C, with a wear rate as low as 1.27×10−7 mm3N−1mm−1. This study provided a technological basis and theoretical support for the repair of coal equipment.

Effect of ultrasonic field on the friction and oxidation characteristics of FeCrAl coatings

FeCrAl coatings were applied to the surface of F/M steel using ultrasonic vibration-assisted laser cladding (UVALC) technique. The introduction of an ultrasonic field refined the microstructure of the FeCrAl coating, enhancing its microhardness and the integrity of the oxide film at elevated temperatures. The increased hardness led to a shift in the wear mechanism from oxidation wear to abrasive wear. In high-temperature conditions, a finer microstructure of the coating resulted in a denser oxide layer, improving the tribological properties and oxidation resistance of the coating. Furthermore, high-temperature oxidation analysis revealed that the predominant oxides formed were Fe2O3 and Cr2O3.

Investigation of corrosion resistance offered by the Fe-based clad layer under salt spray and electrochemical workstations

The present work aims to evaluate the electrochemical characteristics of the Fe–based alloy coating formed on the 27SiMn steel substrate under neutral salt spray and 3.5 wt% NaCl environments. By adopting the high-speed laser cladding technique, the Fe-based clad layer was fabricated to perform microstructural and electrochemical characterizations. The microstructure and phase of the coating were analyzed using a scanning electron microscope (SEM), electron backscatter diffraction (EBSD) and X-ray diffraction (XRD), and its corrosion performance was also discussed using the salt spray corrosion chamber and the electrochemical workstation. The results show that the microstructure of the coating surface contains equiaxed crystals and long dendritic crystals which arise due to the higher solidification rate after the cladding process. The Fe–based coating was rich in FeCr phase throughout its microstructure without the formation of the intermetallic compounds. Compared to the substrate, the corroded surface of the coating tends to be compact containing a few corrosion pits after different corrosion times, which is attributed to the formation of Cr oxide on it. The electrochemical tests on the potentiodynamic polarization curve (PPC) and electrochemical impedance spectrum (EIS) indicate that the corrosion resistance of the coating is superior to the substrate, presenting a higher corrosion potential (−0.298 V), lower passive current density (1.36 × 10−6 A•cm2), and higher charge transfer resistance (8.23 × 106 Ω·cm2). Additionally, the corrosion mechanism of coating in salt spray and electrochemical tests is the local pitting corrosion due to the autocatalytic effect on the localized region, which facilitates Cl− ions penetrating the coating and leads to the dissolution of Fe and Cr oxides.

The effects of Nb on the microstructure and performance of laser-cladded Fe50-xMn30Co10Cr10Nbx high entropy alloy coatings

A laser cladding technique was employed to produce a Fe50-XMn30Co10Cr10NbX (X = 2.5, 5, 7.5, 10at%) high entropy alloy coating. This study delved into the influence of Nb concentration on the coating’s phase constitution, microstructural features, hardness, and wear resistance. The high entropy alloy coating exhibited a multifaceted structural composition, encompassing FCC (Face-Centered Cubic), HCP (Hexagonal Close-Packed), and BCC (Body-Centered Cubic) structures, along with the presence of Laves phase. Notably, the incorporation of Nb led to an augmentation in the Laves phase and modifications within the microstructure. The hardness of the cladding layer is higher than that of the substrate. With the increase of Nb content, the hardness of the cladding layer increases first and then decreases; the average hardness of the Fe42.5Mn30Co10Cr10Nb7.5 cladding layer is the highest, the maximum hardness is 429.8Hv, and the average hardness is 382.3Hv. The friction coefficient and weight loss of the cladding layer decreases first and then increases with the increase of Nb content. The friction coefficient and weight loss of the Fe42.5Mn30Co10Cr10Nb7.5 cladding layer are the smallest, which are 0.0132 g and 0.5974, showing the best wear resistance. The wear types of high entropy alloy cladding layer are both adhesive wear and abrasive wear. The addition of Nb into high entropy alloy will form the Laves phase, which can improve the mechanical properties of high entropy alloy.

Microstructure and Tribological Properties of WC/Ni-MoS2 Titanium-Based Composite Coating on TC4

To improve the mechanical properties of a TC4 surface, TC4 + Ni-MoS2 + xWC (x = 5%, 10% and 15% wt.%) composite coatings were prepared by the coaxial feeding laser cladding technique, and the effect of the WC content on the microstructure and tribological properties of the coatings were investigated using multiple characterization methods. The results indicated that increasing the WC content negatively impacted the forming quality of the coating, but did not change the coating phase which predominantly comprised Ti2Ni, Ti2S, TiC, matrix β-Ti and residual WC. With the addition of WC, TiC exhibited an increase in both quantity and particle size, accompanied by a transition in growth morphology from spherical to petal-like. MoS2 completely dissolved in all coatings and the S element provided by it effectively synthesized a strip-like phase Ti2S which presented a morphology similar to the lubricating phase TiS in the Ti-based melt pool system. The microhardness and wear-resistance of all the coatings were higher than that of TC4 and gradually improved with the addition of WC, which indicated that raising the WC content was conducive to enhancing the mechanical properties of the coatings. The friction coefficient of TC4 was lower than that of the three WC content coatings, indicating that Ti2S was not the lubricating phase. The wear mechanism of all coatings was abrasive wear.

Adapting high-speed indentation mapping for investigating microstructure-property correlations in chromium carbide-nickel alloy coatings: Challenges and solutions

This study investigates the microstructural and mechanical characteristics of chromium carbide‑nickel rich alloy coatings produced through laser cladding, detonation spraying, and plasma spraying techniques. While all three processing techniques used the same feedstock powder, each method yields coatings with unique microstructures encompassing varying compositions and length scales. Employing Field Emission Scanning Electron Microscopy (FE-SEM) in combination with Energy Dispersive Spectroscopy (EDS) and nanoindentation mapping, local microstructure and mechanical properties were assessed at the micrometre length scale. Laser-clad coatings exhibit a typical metal matrix composite microstructure with high carbide content, distinct (MoNb)C2 phases, and Fe in the metallic matrix, while the thermal sprayed coatings showed carbides of varying sizes and metallic matrix with varying degrees of chromium dissolved in it. The instrumented indentation technique helped precisely record the microstructural features in all the coatings. Chromium carbide consistently emerges as the hardest phase across all coatings, with variations in metallic matrix hardness. Higher matrix hardness in thermal sprayed coatings correlates with increased Cr content, attributed to extended solid solubility of Cr and the presence of Mo and Nb. Energy dispersive spectroscopy and transmission electron microscopy provided clearer insight into the microstructure. This study highlights a direct one-to-one correlation between microstructure and mechanical properties mapped using instrumented indentation techniques in chromium carbide‑nickel rich coatings across different deposition methods.

Fabrication and tribological behavior of laser cladding Cu/Ti3SiC2 reinforced CoCrW matrix composite coatings on Inconel718 surface

To satisfy the need for high wear resistance of Inconel718 alloy under harsh working conditions, laser cladding technique was adopted to fabricate the Cu/Ti3SiC2-CoCrW metal matrix composite coatings on that surface. The phase composition, microstructure, microhardness, surface energy, and tribological properties of the composite coatings were systematically analyzed by characterization methods such as XRD/ SEM/ EDS/ XPS and performance test methods such as high-temperature friction and wear test, and the wear mechanism at different temperatures was deeply discussed. The research results indicate that the microhardness of coatings is increased by 2.2–2.9 times compared to the substrate, which is mainly owing to the solid solution strengthening effect and the diffusely distributed hard reinforcing phases such as Cr7C3, WCx, and TiC. Regarding the wear resistance, the wear rate of coatings is significantly reduced by 1–2 orders of magnitude over the substrate. Among them, the Co-based coating adding 10 wt% Cu - 10 wt% Ti3SiC2 exhibited the lowest wear rates at room and high temperatures, which were 0.22 and 3.23 × 10−5 mm3/ N·m, respectively, with 98.22 % and 88.19 % reductions in comparison with the substrate. The low surface energy (27.94 mN/m) was one of the main reasons for the good tribological properties. When the friction environment changes from room temperature to 600 °C, the primary wear mechanism of coatings changes from abrasive and adhesive wear to oxidative wear.

Optimization of defects and high temperature corrosion resistance of laser cladding FeCrAl coatings: Influence of process parameters

To enhance the surface quality and high-temperature corrosion resistance of FeCrAl coatings further, a laser cladding technique was employed to deposit Fe-13Cr-7Al coatings on the surface of 12Cr1MoV heat-resistant steel. The study investigated the influence of laser power, scanning speed, and powder feed rate on the quality and high-temperature corrosion resistance of the Fe-13Cr-7Al coatings. Utilizing 25 orthogonal experiments, coatings were prepared and evaluated through high-temperature corrosion tests to explore the corrosion resistance and mechanisms microstructural analysis of the coatings, including their elemental distribution and corrosion mechanisms, was conducted using optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The optimal parameter combinations for laser cladding coatings were discussed. The results indicated that the coating quality was optimal within specific ranges of parameters (laser power 1875–2250 W, scanning speed 33–44 mm/s, powder feed rate 12–18 g/min); deviations outside these ranges led to issues such as incomplete coverage or coating detachment from the substrate. The structure of the laser cladded Fe-13Cr-7Al coatings consisted of columnar grains and α-Fe phase. In high-temperature corrosion testing, the coatings exhibited superior corrosion resistance compared to the substrate, with nearly twice the corrosion resistance variation observed under different process parameters. This study provides a scientific basis for optimizing laser cladding process parameters of Fe-13Cr-7Al coatings, demonstrating that precise control of process parameters significantly enhances the high-temperature corrosion resistance of coatings, thereby opening new possibilities for improving material performance in high-temperature applications.

Construction of hard BCC phases FeCrVMnTix wear-resistant high-entropy alloy coatings enhanced by solid solution of Ti elements

To address the complex working conditions encountered by 1Cr13 ferritic/martensitic steel during operation, it is imperative to develop high-entropy alloys (HEAs) protective coatings with enhanced friction resistance. In this work, guided by the valence electron concentration criterion, we constructed a single-phase body-centered cubic (BCC) structure with high hardness. This was achieved through the introduction of titanium (Ti), which has a significantly different atomic radius compared to other elements. FeCrVMnTix (x = 0, 0.5, 1.0, 1.5, and 2.0) coatings were fabricated on 1Cr13 steel surfaces using laser cladding techniques, and the microstructure, mechanical properties, and wear-resistance properties of Ti-doped HEA coatings were investigated. The results reveal that the FeCrVMnTix coatings are comprised of a BCC solid solution. Increasing Ti content refined the dendritic structure of the coatings, enhancing the Vickers hardness from 4.35 GPa to 8.27 GPa and the Young's modulus from 232.6 GPa to 273.2 GPa. Additionally, the wear rate decreased from 3.07 × 10−5 mm3·N−1·m−1 to 4.94 × 10−6 mm3·N−1·m−1. Notably, the FeCrVMnTi2.0 coating demonstrated excellent wear resistance that can be attributed to the solid solution strengthening effect of Ti. These findings underscore the pivotal role of Ti in enhancing the wear resistance of the coatings.

Properties of Laser-Clad Stainless Steel–Ni/WC Double-Layer Coatings

In order to improve the wear and corrosion resistance and enhance the tribological and mechanical properties of gray cast iron, the laser surface cladding technique was employed to fabricate double-layer coatings with different Ni/WC ratios on the surface of gray cast iron. The effects of laser processing parameters and the type of Ni-based alloy on the microstructure and properties of the gray cast iron matrix and laser-clad layer were investigated. A 316L stainless steel transition layer was introduced between the gray cast iron substrate and the Ni/WC coating to prevent the cladding layer from cracking. The tribological and mechanical properties of the laser-clad coatings were characterized with various tests at the macro- and micro-scales; the residual stresses on the coating surfaces were measured, and electrochemical tests were also carried out. The microstructures of the clad layers were analyzed by scanning electron microscope (SEM) and X-ray diffraction (XRD). The results show that the laser-clad layers exhibit excellent vibration and noise reduction performance, which is partially due to the reduction and stabilization of the coefficients of friction (COFs) and the high levels of compressive residual stress on the surface of the laser-clad layers. The wear and corrosion resistance of the laser-clad layers are significantly improved, and the maximum wear loss of the laser-clad coating was about only 5% of that of the unclad gray cast iron substrate. This research has significance for the laser surface modification of cast iron, steel, and other metals, which is an increasingly important topic, especially in the automotive friction brake industry.

Effect of alternating magnetic field on microstructure and mechanical properties of Ni60/La2O3 laser cladding layer

A Ni60 cladding layer containing 1.6 wt% La2O3 was prepared on 35CrMoV steel using an alternating magnetic field-assisted laser cladding technique. The microstructure, phase composition, microhardness, and tribological properties of the composite coatings were characterized. Based on experimental results, the main components of the 1.6 % Ni60 + La2O3 cladding layer are γ-(Fe,Ni), Cr23C6, FeNiSi, Ni3B, Ni4B3 and Cr2B. The EBSD analysis reveals that the increase in intensity of the alternating magnetic field leads to a significant refinement in the average grain size of the cladding layer, thereby greatly enhancing microstructural uniformity. The average grain sizes of the layers with 0–15 mT magnetic field intensity are 28.515 μm, 26.076 μm, 23.878 μm and 18.337 μm, respectively. The TEM bright field images reveal that the enhancement of magnetic field intensity facilitates the precipitation of γ′ within the cladding layer. Friction and wear experiments demonstrated that a Ni60 composite coating containing 1.6 % La2O3 exhibited superior friction and wear performance at a magnetic field intensity of 15 mT due to its highest average hardness (608.97 HV1), lowest friction coefficient (0.394), and excellent wear morphology.