Superior Corrosion Resistance Research Articles

Superior corrosion-resistant Zr-Ti-Ag thin film metallic glasses as potential biomaterials

Low-cost and non-cytotoxic ternary Zr-Ti-Ag thin film metallic glasses (TFMGs) were synthesized by DC magnetron sputtering. Results revealed that Ag addition enhanced the crystallization resistance and thermal stability of TFMGs. An appropriate Ag addition favored the mechanical property and corrosion resistance of TFMGs, while the excessive Ag addition had the opposite effect. Moreover, Ag did not directly form the passive film but altered the passive film stability and anti-corrosion capacity of TFMGs by inducing the disordered atomic arrangement, forming a dense microstructure, and tuning the corrosion-resistant Zr and Ti components. With low Young’s modulus of 116.2 GPa and passive current density of 0.45 × 10−7 A/cm2, the TFMG with an Ag target sputtering power of 11 W exhibited superior corrosion resistance, suggesting its application potential as biomaterials.

Effect of NOX and SOX Contaminants on Corrosion Behaviors of 304L and 316L Stainless Steels in Monoethanolamine Aqueous Amine Solutions

This work is devoted to evaluating the corrosion behaviors of SS 304L and SS 316L in monoethanolamine solutions (MEA) containing SOX and NOX pollutants, examining both lean and CO2-loaded conditions at 25 °C and 40 °C. Electrochemical techniques (potentiodynamic and cyclic polarization) were used along with Scanning Electron Microscopy, Confocal Microscopy and weight loss measurements. The results reveal that the introduction of SOX and NOX pollutants increased the corrosion rate, whereas CO2 loading primarily reduced the corrosion resistance in the lean MEA solution, while its impact on solutions with SOX and NOX was less pronounced. This suggests that SOX and NOX play primary roles in the metal’s dissolution. Also, SS 316L demonstrated superior corrosion resistance compared to 304L in nearly all of the cases examined. Elevated temperatures were also found to intensify the corrosion rate, indicating a correlation between the corrosion rate and temperature. A microscopic observation and EDX analysis revealed that corrosion products are characterized by high concentrations of iron (Fe) and oxygen (O) as well as carbon (C). There is also an indication of the possible formation of amine complexes, suggesting a potential for amine degradation. No pitting corrosion was observed in SS 304L and SS 316L across any tested solution. Finally, the immersion results expose a tendency for passivity in all amine solutions and at both temperatures after several days of exposure. Moreover, they confirm the very low corrosion rate calculated from potentiodynamic curves due to minimal weight loss after 24 days of immersion.

Terbium-reinforced alumina coating produced by plasma electrolytic oxidation and a new strategy for in-situ corrosion monitoring

The multifunctional optimization of traditional coating materials represents a pivotal strategy for expanding their applicability. Herein, we introduce terbium as an electrolyte additive during the plasma electrolytic oxidation process for alumina coating fabrication, aimed at refining both the porous structure and overall performance of the coating. Notably, the core reaction concludes in just 10 min. The resultant terbium-enhanced alumina coating exhibits a more homogeneous and denser surface structure, showcasing superior corrosion resistance compared to conventional coatings. Additionally, the incorporation of terbium endows the coating with anticipated photoluminescent properties. This advantageous combination of corrosion resistance and photoluminescence makes the coating ideal for protecting metallic materials from corrosion and shows great potential for monitoring corrosion in extreme conditions on-site.

Enhanced structural stability and durability in lithium-rich manganese-based oxide via surface double-coupling engineering

Lithium-rich manganese-based oxides (LRMOs) exhibit high theoretical energy densities, making them a prominent class of cathode materials for lithium-ion batteries. However, the performance of these layered cathodes often declines because of capacity fading during cycling. This decline is primarily attributed to anisotropic lattice strain and oxygen release from cathode surfaces. Given notable structural transformations, complex redox reactions, and detrimental interface side reactions in LRMOs, the development of a single modification approach that addresses bulk and surface issues is challenging. Therefore, this study introduces a surface double-coupling engineering strategy that mitigates bulk strain and reduces surface side reactions. The internal spinel-like phase coating layer, featuring three-dimensional (3D) lithium-ion diffusion channels, effectively blocks oxygen release from the cathode surface and mitigates lattice strain. In addition, the external Li3PO4 coating layer, noted for its superior corrosion resistance, enhances the interfacial lithium transport and inhibits the dissolution of surface transition metals. Notably, the spinel phase, as excellent interlayer, securely anchors Li3PO4 to the bulk lattice and suppresses oxygen release from lattices. Consequently, these modifications considerably boost structural stability and durability, achieving an impressive capacity retention of 83.4% and a minimal voltage decay of 1.49 mV per cycle after 150 cycles at 1 C. These findings provide crucial mechanistic insights into the role of surface modifications and guide the development of high-capacity cathodes with enhanced cyclability.

Enhanced tribological behavior and corrosion resistance in AlSiC-based coatings through varied carbon content

A series of AlSiC-based nanocomposite coatings with varying carbon concentrations were fabricated by filtered cathodic vacuum arc (FCVA) technology. These coatings featured an amorphous matrix with embedded Al4Si3C6 nanocrystals. With the increase in carbon content, the proportion of amorphous structure within the structure grew, which was accompanied by a rise in sp3 hybridized carbon bonds. This compositional change led to a significant enhancement in hardness and toughness. Notably, the AlSiC coating deposited at a flow rate of 50 sccm displayed exceptional mechanical properties, including a high hardness of approximately 23.2 GPa, toughness indices of H/E = 0.096 and H3/E2 = 0.216 GPa, a low friction coefficient around 0.18, a wear rate as low as ∼1.09 × 10−5 mm3 N−1 m−1, and a corrosion current density of approximately 1.08 × 10−9 A/cm2. The coating's superior tribological characteristics and corrosion resistance can be attributed to two main factors. The enhanced hardness and toughness indices (H/E and H3/E2) contributed to its improved deformability, which is essential for wear resistance. Secondly, the presence of a graphite layer formed during friction provided self-lubrication, further reducing wear. Additionally, the chemical inertness of both the amorphous SiC and the amorphous carbon phases within the nanocomposite structure significantly bolstered the coating's resistance to corrosion. The AlSiC nanocomposite coatings deposited by FCVA exhibit outstanding mechanical properties, tribological performance, and corrosion resistance, making them highly suitable for applications in environments where wear and corrosion are significant concerns.

Influence of heating temperature and time on mechanical-degradation, microstructures and corrosion performances of Teflon/granite coated aluminum alloys used for non-stick cookware

This study explores the functional characteristics (erosion, corrosion, mechanical damage, and microstructural features) of non-stick cookware made from aluminum alloys. Typically coated with polytetrafluoroethylene (PTFE-Teflon) or ceramic for non-stick properties, we conducted a systematic investigation using corrosion, abrasion, and mechanical tests on six types of cookware from different manufacturers (Manuf-1-6). The cookware was heated at various temperatures [Room temperature (RT), 100, 175, 250, & 350 °C] and times (45 & 120 min). Tests included Taber wear, Adhesive Pull-off, hot & RT corrosion, and surface roughness measurements. Characterization involved optical microscopy, scanning electron microscope (SEM) with electron backscattered diffraction (EBSD), and x-ray diffraction (XRD). Ceramic-coated cookware from Manuf-4 demonstrated superior mechanical strength, wear, and corrosion resistance due to refined microstructures. Manuf-1's PTFE-coated cookware also performed well. Optimal results were observed when heating below 250 °C for up to 45 min. Prolonged heating and temperatures beyond 250 °C adversely affected internal structures of all cookware. Thus, it is advisable to use Al-based non-stick cookware below 250 °C for a maximum of 45 min.

Nacre-mimetic alternating architecture of Ag[sbnd]SnO2 contact: Highly-efficient synergistic enhancement of in-situ self-repairing erosion resistance and naturally evolving impact resistance

Synergistically enhancing the erosion and impact resistance of contacts poses a significant challenge for cutting-edge electrical equipment. Fortunately, mollusk shells in nature have evolved effective strategies to construct microstructures with superior erosion and impact resistance. Inspired by the structure of nacre, AgSnO2 contact material with hierarchical architectures has been designed and fabricated. The mechanistic link between microstructural evolution and dynamic erosion is studied through experiments combined with Computational Fluid Dynamics (CFD) and Finite Element Method (FEM) simulations. Results show that the reconstructed SnO2 skeleton endowed with a highly continuous and anisotropic ‘flowering'-like structure forms a continuous interpenetrating network with Ag, optimizing the conductive pathways on the molten pool surface. Additionally, the Ag-rich regions in the deeper layers on both sides of the molten pool offers a stable ‘nutrient-supply’ for the continuous ‘flowering’ reconstruction of the skeleton, exhibiting excellent in-situ self-repairing erosion resistance. Benefiting from this synergistic strategy, this skeleton is reconstructed based on its natural structure, which further disperses the stress and deformation concentration while inhibiting interfacial debonding, thereby reducing the formation of cracks and significantly enhancing the impact resistance. This work is expected to breakthrough erosion and impact resistance in extreme condition electrical contact materials through biomimetic microstructure design.

Chromium gradient stainless steels with simultaneous high strength, ductility, and corrosion-resistant: In-depth study of continuous hardening mechanisms

Cr-rich stainless steel sheets exhibit superior corrosion resistance but low ductility, which presents a trade-off between fabrication complexity and performance of the materials in multiple industrial applications, such as marine equipment and microreactors. By transitioning the Cr-rich (30 wt.% Cr) stainless steel component to SS 316 L with a smooth composition gradient in the thickness direction, the intrinsic homogeneous elongation of the Cr-rich layer was increased by 260 % while maintaining the naturally high corrosion resistance (100 %) and retaining most of the strength (more than 80 %). By employing in-situ tensile testing and electron backscatter diffraction analysis, it was revealed that the Cr-rich layer in the gradient structure underwent a profound deformation mechanism, including significant heterogeneous deformation-induced hardening and grain reorientation induced by multiplication and accumulation of geometrically necessary dislocations, in such a way to enable a substantial plastic strain and thereby retarding the occurrence of fracture. The proportion of the Cr-rich layer makes a significant impact on the magnitude of the strain gradient in the gradient specimens, therefore affecting the increment of density of geometrically necessary dislocations. The critical proportion value of the Cr-rich layer is found to be around 22 %. Before and after the critical value the gradient specimens showed different sensitivities to the proportion. This discovery underlines the significance of intrinsic plasticity in low-ductility metals and the role of compositional gradient materials in enhancing strength and ductility.

Anti-Corrosion SiOx-Doped DLC Coating for Raster Steel Linear Scales

In this study, we investigated the efficacy of SiOx-doped diamond-like carbon (DLC) films for enhancing the corrosion resistance of raster steel linear scales. The research work highlights the significant role of DLC film materials in enhancing corrosion resistance, making them a promising solution for various industrial applications. The Raman spectroscopy analysis of SiOx-doped DLC films, synthesized via a direct ion beam technique with HMDSO vapor, revealed prominent D and G bands characteristic of amorphous carbon materials, with a high degree of disorder indicated by an ID/IG ratio of 1.85. X-ray diffraction patterns confirmed the amorphous nature of the SiOx-doped DLC films and the minimal impact of the DLC deposition process on the underlying crystalline structure of steel. UV–Vis-NIR reflectance spectra of SiOx-doped DLC on stainless steel demonstrated improvements in the blue wavelength region compared to stainless steel with ripples alone, which is beneficial for applications utilizing blue light. Corrosion tests, including immersion in a 5% salt solution and salt spray testing, showed that SiOx-doped DLC-coated stainless steel exhibited superior corrosion resistance compared to uncoated steel, with no significant signs of corrosion observed after extended exposure. These findings underscore the potential of SiOx-doped DLC coatings to provide long-term corrosion protection and maintain the structural integrity and surface quality of steel components in harsh environments.

Investigation of the evolution and corrosion resistance mechanism of anodized film on Ta surface

The tantalum oxide film was fabricated using an anodization process in a 0.5M H2SO4 electrolyte. The evolution and corrosion resistance mechanism of anodized film on the Ta surface has been investigated by experiments and theoretical calculations. The results indicate that the sample with an anodic oxidation voltage of 20V and an anodic oxidation time of 60 min (Ta20-60) exhibits the thickest oxidation film, measuring 360.00 nm and comprising an outer porous layer and an inner dense layer. Ta20-60 demonstrates the highest Ecorr value of 0.009 V and the lowest Icorr value of 0.879 μA cm−2, with a minimal density of point defects at 1.24 × 1019 cm−3, which imparts superior corrosion resistance. The calculation result shows that the growth rate of Ta anodic oxidation film is controlled by the diffusion and migration of vacancy defects. The O atom passes through one bridge site from the tetrahedral gap to another tetrahedral gap (Path 1) on the complete (110) surface has a low diffusion barrier of 0.470 eV and the shortest diffusion path of 2.04 Å, which is the most favorable path for the diffusion of O atoms. This paper offers a fresh perspective on the corrosion resistance of tantalum while furnishing guidance for improving Ta oxide film performance.

EVALUATING ACETONE AND METHANOL FOR ELECTROPHORETIC DEPOSITION OF SS 316L COATED WITH HYDROXYAPATITE/MULTIWALLED CARBON NANOTUBES DENTAL IMPLANTS: A FOCUS ON CORROSION RESISTANCE

Dental implants offer a reliable solution for replacing damaged tooth roots. This research investigates the comparative performance of acetone and methanol as suspension media in the fabrication of stainless steel type 316L-based dental implants using the Electrophoretic Deposition (EPD) method, a technique known for its simplicity and cost-effectiveness. Voltage variations of 20V, 30V, and 40V were applied to both acetone and methanol suspensions for a duration of 20 minutes. The morphology of the Hydroxyapatite/Multiwalled Carbon Nanotube (HA/MWCNT) coatings was meticulously characterized using Scanning Electron Microscopy (SEM). Corrosion resistance was evaluated through Potentiodynamic Polarization (PDP) and Electrochemical Impedance Spectroscopy (EIS) techniques. Remarkably, at 30V, a homogeneous and crack-free coating was achieved, demonstrating superior corrosion resistance. This was further corroborated by the resistance values of 23.891 Ω and 114.990 Ω for the acetone and methanol samples, respectively. Additionally, the corrosion rates of 0.075 (mmpy) and 0.0004 (mmpy) for the acetone and methanol samples further emphasized the superiority of methanol as a suspension medium. These findings unequivocally establish methanol as the optimal choice for achieving superior deposition quality and corrosion resistance in the context of the EPD method for stainless steel type 316L-based dental implants.

Nature-Inspired Incorporation of Precipitants into High-Strength Bulk Aluminum Alloys Enables Life-Long Extraordinary Corrosion Resistance in Diverse Aqueous Environments.

The safe service and wide applications of lightweight high-strength aluminum alloys are seriously challenged by diverse environmental corrosion, since high strength and corrosion resistance are mutually exclusive for metals while surface protection cannot provide life-long corrosion resistance. Here, inspired by fish secreting slime from glands to resist external changes, a strategy of incorporating precipitants as the slime into bulk metals using the inner cavity of opened carbon nanotubes (CNTs) as the glands is developed to enable high-strength aluminum alloys with life-long superior corrosion resistance. The resulting material has ultrahigh tensile strength (≈700MPa) and extraordinary corrosion resistance in acidic, neutral and alkaline media. Notably, it has the highest resistance to intergranular corrosion, exfoliation corrosion and stress-corrosion cracking, compared with all previously reported aluminum alloys, and its corrosion rate is even much lower than that of corrosion-resistant pure aluminum, which results from the pronounced surface enrichment of precipitants released (secreted) from exposed CNTs forming a protective surface film. Such high corrosion resistance is life-long and self-healing due to the on-demand minimal self-supply of the precipitants dispersed throughout the bulk material. This strategy can be readily expanded to other aluminum alloys, and could pave the way for developing corrosion-resistant high-strength metallic materials.

Impact of cooling rates on the microstructure and cracking susceptibility of hot-dip galvanized Zn-12 wt% Al-5 wt% Mg coatings

Zinc-Aluminum-Magnesium (ZnAlMg) alloy coatings, applied through the hot-dip galvanizing process, are renowned for their superior corrosion resistance. This study investigated how different cooling rates affect the microstructure and cracking tendency of Zn-12Al-5Mg (in wt%) coatings. It was found that faster cooling rates lead to a more refined microstructure with primary MgZn2 grains but also increase the likelihood of cracking. This is primarily attributed to the finer distribution of primary MgZn2 grains and ternary eutectic (Zn/MgZn2/Al) regions, which allows micro-cracks originating from hard and brittle MgZn2 grains to easily propagate through the surrounding eutectic regions and develop into macro-cracks. Notably, we observed an epitaxial relationship between the primary and binary eutectic MgZn2 phases, shedding light on their crystallographic orientation and morphology. Additionally, our investigation revealed that cracking susceptibility depends on the crystallographic orientation of MgZn2 grains relative to the tensile axis. Fiber-like MgZn2 grains tend to crack along their basal planes, while hexagonal grains crack along other crystallographic planes. This insight into cracking behavior is crucial for designing ZnAlMg coatings with enhanced corrosion resistance and mechanical integrity. Overall, while faster cooling rates refine the microstructure, they can also increase the susceptibility to cracking in ZnAlMg coatings with Mg contents exceeding 3 wt%, emphasizing the need for a balanced approach in optimizing coating properties for different applications.

Tribocorrosion properties of NdCl3-modified resin-based polymeric coatings in contaminated lubricating oils

To improve the tribological performance and corrosion resistance of engine bearings exposed to contaminated lubricating oil, polymer coatings containing NdCl3 at concentrations of 3.45 wt%, 5.17 wt%, and 6.89 wt% were developed, respectively. These coatings were applied to the surfaces of copper and aluminum alloys using a liquid spraying technique, aiming to assess their corrosion and wear resistance. Electrochemical experiments showed that the coating with a 3.45 wt% NdCl3 concentration exhibited superior corrosion resistance, as evidenced by the highest self-corrosion potential and polarization resistance. Furthermore, friction tests on the corroded samples revealed that the 3.45 wt% NdCl3 coating also demonstrated the lowest coefficients of friction and wear rates. This is due to the addition of an appropriate amount of NdCl3, which densifies the internal structure of the coating and improves the mechanical properties of the coating, thereby significantly improving its corrosion and wear resistance.

Innovative nanocomposite coating for aluminum alloy: superior corrosion resistance, flame retardancy, and mechanical strength for aerospace applications

Innovative nanocomposite coating for aluminum alloy: superior corrosion resistance, flame retardancy, and mechanical strength for aerospace applications

Water vapor corrosion behavior of SiC/Si/mixed Yb2Si2O7-Yb2SiO5 environmental barrier coating for C/C composites

Tri-layer environmental barrier coatings (EBCs) were developed to provide complete encapsulation for carbon/carbon (C/C) composites, consisting of SiC inner layer, Si bond layer, and mixed Yb2Si2O7-Yb2SiO5 topcoats with varying mass ratios. The protective properties of the EBCs were assessed by exposing the coated samples to a corrosive gas mixture of 50 % O2 and 50 % H2O at 1500 °C, the mass change, phase composition, and microstructure evolution were investigated. The results showed that a small amount of Yb2SiO5 doping could improve water vapor corrosion resistance, but the excessive content of Yb2SiO5 led to a mismatch of the coefficient of thermal expansion (CTE) with inner coating, resulting in coating cracking. The mixed topcoat with 60 wt% Yb2Si2O7 and 40 wt% Yb2SiO5 showed superior water vapor corrosion resistance. After corrosion for 20 h at 1500 °C, no penetrating cracks of large size appeared, the thickness of thermal growth oxide (TGO, 4.6 ± 0.4 μm) was relatively lower, and the C/C substrate was effectively protected from damage.

Recovery of valuable metals from SmCo magnets through sulfation, selective oxidation, and water leaching

ABSTRACT Samarium-cobalt (SmCo) magnets, comprised of rare earth elements (REE), and cobalt (Co) are widely employed in diverse sectors such as aerospace, medical, defense, automotive, and more due to their unique properties such as outstanding high-temperature resistance, superior corrosion resistance, a higher Curie temperature, and high energy density. REE and Co are on the critical metals list for many years, along with increased production costs and challenges. With the increasing amount of waste SmCo, the recycling of these magnets has gained importance. This study investigates the recycling of SmCo magnet scraps through sulfation, selective oxidation, and water leaching. The effect of experimental parameters, such as powder/acid concentration, selective oxidation temperature, selective oxidation time, solid/liquid ratio and leaching time for water leaching are studied in detail. The optimal parameters are determined: 800°C selective oxidation temperature, 1-h selective oxidation time, 1/3 g/ml magnet: acid ratio, 2-h water leaching time and 1/20 water leaching s/l ratio. Under the optimum conditions the extraction efficiency of Sm reached approximately 65%, The solubility of Fe, Co, and Cu metals in the solution is negligible.

Corrosion and erosion behaviour of TiC-TiB2 reinforced epoxy coatings

ABSTRACT This research investigates the impact of incorporating titanium carbide (TiC) and titanium diboride (TiB2) particles into epoxy coatings to enhance corrosion and erosion resistance. The targeted particles were synthesised by subjecting boron and titanium carbide powders to mechanical alloying for a duration of 20 hours. X-ray diffraction (XRD) analysis confirmed the successful formation of titanium diboride and titanium carbide particles. Subsequently, ceramic particles were integrated into the epoxy at concentrations of 0, 5, 10, and 15 wt.%, and the resultant coatings were applied to steel samples through an immersion method. Electrochemical impedance spectroscopy tests on the samples demonstrated a positive influence of TiC + TiB2 particles on enhancing the corrosion resistance of the coatings, with the 15 wt.% concentration exhibiting superior corrosion resistance compared to other formulations. Employing the Box–Behnken method, 13 samples were designed and subjected to erosion testing. The findings revealed that the coating containing 15 wt.% TiC + TiB2 particles exhibited the lowest erosion rate. Moreover, an increase in the speed and angle during the erosion test correlated with a rise in the erosion rate.

Regulating the structure and performance of amorphous carbon-based films by introducing different interlayers for applications in PEMFC bipolar plates

In this work, the effects of inserting an interlayer on the anti-corrosion performance of amorphous carbon (a-C) films in a simulated Proton Exchange Membrane Fuel Cell (PEMFC) environment have been systematically studied. Four a-C films with different interlayers, namely CCr, C-Cr-N, CrN and Cr, were prepared on 316L stainless steel substrates using unbalanced magnetron sputtering. The surface/fractural morphologies, carbon bonding structure and the anti-corrosion performance of the 4 films were observed/characterized in detail. The nanostructure and composition evolution from the film surface down to the film-substrate interface before and after electrochemical tests were also analysed via high resolution transmission electron microscopy (HRTEM). Results indicate that a-C films with CCr and C-Cr-N interlayers display superior corrosion resistance compared to undoped samples and those lacking an interlayer, with the lowest self-corrosion current density (i.e. 2.1 × 10−7 A/cm2, C-Cr-N interlayer) being nearly two orders of magnitude lower than that of the substrate (i.e. 1.1 × 10−5 A/cm2). The doped C-Cr-N interlayer plays a vital role in the corrosion resistance of the samples by accelerating oxidation of surface defect locations, inhibiting the continuous penetration of electrolyte, and improving corrosion resistance. Additionally, a-C films with a C-Cr-N interlayer exhibited an outstanding interface contact resistance (ICR) value (~3.5 mΩ/cm2) than that with a CrN interlayer (~30 mΩ/cm2) or the 316L substrate (~100 mΩ/cm2) at a typical contact pressure of 1.5 MPa. All 4 films demonstrate obviously improved hydrophobicity (contact angles against distilled water under room temperature up to 94.2°) compared to the substrate (75.8° under identical condition). In a word, this study proves that the strategy of inserting an appropriately designed interlayer (with the ternary C-Cr-N being most promising) to a-C films could alter and enhance the anti-corrosion, ICR and hydrophobic properties of 316L, proposing valuable solutions for high-performance bipolar plates (BPs) in the PEMFC industry.

Insight into the hot corrosion behavior of GH4251 high-temperature superalloy fabricated by selective laser melting

In this study, the GH4251 high-temperature superalloy was fabricated using selective laser melting (SLM) and hot isostatic pressing (HIP) post-treatment. The hot corrosion behavior of the SLMed and SLM-HIPed GH4251 was systematically investigated and compared with the as-forged one in a mixed salt of 75 % Na2SO4 and 25 % NaCl at 900 °C. The results indicated that three GH4251 superalloys rank in order of superiority for high-temperature corrosion resistance as follows: SLMed > SLM-HIPed > as-forged. The hot corrosion resistance of the alloy is closely related to its microstructures. A high density and a high proportion of small-angle grain boundaries effectively prevent substrate corrosion from molten salts. High dislocation densities and fine grains can increase the elemental diffusion channels and promote the formation of dense protective oxide films, thereby enhancing the hot corrosion resistance. The SLMed superalloy has high densities, high dislocation densities, a high proportion of small-angle grain boundaries, and an appropriate grain size. This is the reason why the SLMed alloy exhibits the most superior hot corrosion resistance. In addition, the hot corrosion mechanisms of the GH4251 superalloy were also discussed in depth.