Papers by Keyword: Corrosion Resistance

Abstract: β Ti-18Mo-xCr alloy has been widely used as an orthopedic implant material because this alloy has the advantage of high strength a lower modulus of elasticity than commercial alloys Ti-6Al-4V, good corrosion resistance. and formability. This research aims to find alloys with high corrosion resistance and low modulus of elasticity and identify the presence of phase β after heat treatment. Ti-18Mo-7Cr is obtained from the melting process using an arc melting furnace followed by heat treatment (solution and aging treatment). To determine the modulus of elasticity using a sonelastic tool and hardness test using Microhardness Vickers. The EIS method was used to determine the corrosion resistance using a 0.9% NaCl solution as a simulated body fluid. The modulus of elasticity owned by the solution treatment alloy tends to be lower than that of the aging alloy. The lowest elastic modulus value and the highest hardness value are found in the Ti-18Mo-7Cr ST850 alloy, which is 91 GPa and 471.42 HV. For corrosion resistance, the aging treatment alloy shows a lower corrosion rate than the solution treatment alloy and is much lower than that of the Ti-6Al-4V alloy. On the other hand, the solution treatment can stabilize the β phase and reduce the corrosion rate due to heating below transus temperature, but aging with a longer holding time can also reduce corrosion resistance more than the corrosion resistance of the solution treatment. The alloy Ti-18Mo-7Cr AT500 has the lowest corrosion rate among the samples in this study, which is 0,0004225 mmpy.

Abstract: The automobile industry's increasing need for lightweight, high-performance materials has brought attention to Al-Si-Cu die-cast alloys, which face significant challenges, including porosity-induced defects, galvanic corrosion, and environmental degradation. Traditional chromate-based coatings, while effective, are being phased out due to toxicity and regulatory restrictions under REACH and RoHS. This review evaluates cutting-edge bio-inspired and self-healing coatings as sustainable alternatives to enhance the durability and corrosion resistance of Aluminum alloys. Key innovations include micro/nanocontainer-based inhibitor release systems, LDHs (layered double hydroxides) for on-demand corrosion suppression, and superhydrophobic composites mimicking lotus-leaf topographies. We critically evaluate the performance of these coatings using electrochemical (EIS, SVET) and non-electrochemical (SEM, XRD) techniques, emphasizing their efficacy in mitigating micro-galvanic corrosion caused by the heterogeneous microstructure of aluminum. Challenges such as scalability, mechanical durability, and cost-effectiveness are discussed, alongside emerging trends like graphene-enhanced barriers and bio-based polymers (e.g., phosphorylated chitosan). By bridging material science with bio-inspired design, this review provides a roadmap for developing eco-friendly, high-performance coatings tailored to automotive applications, ensuring compliance with environmental regulations while extending component lifespan under harsh operating conditions.

Abstract: Functionally graded materials represent a promising strategy for locally optimizing component properties while reducing both economic and environmental costs. To date, no study has addressed the development of a compositional gradient between 316L stainless steel and Invar 36 using the Wire Arc Additive Manufacturing (WAAM) process, despite the strong potential of this material combination. Indeed, such a gradient would combine the very low coefficient of thermal expansion (CTE) of Invar 36 with the low cost and excellent chemical resistance of 316L stainless steel. A particularly relevant application for this type of gradient is the storage of hydrogen or liquefied natural gas, where tanks are subjected to severe thermal stresses due to cryogenic operating temperatures. In addition, these structures must withstand aggressive environments and hydrogen exposure, which can induce material embrittlement, while maintaining sufficient mechanical properties to ensure structural integrity during service. Designing an optimal gradient therefore requires a detailed understanding of how mechanical, thermal, and chemical properties evolve with chemical composition. This study provides a preliminary assessment of these evolutions. The results show that the addition of 15–25 wt.% Invar 36 to 316L leads to a reduction in microhardness and ultimate tensile strength (UTS), associated with the disappearance of ferritic and σ phases, while significantly enhancing ductility. At higher Invar 36 contents, microhardness increases and ductility decreases due to carbide formation. From a thermal standpoint, the CTE does not follow a linear trend: it remains high up to approximately 75 wt.% Invar 36 Nb, then decreases sharply as the ferromagnetic behavior characteristic of Invar becomes dominant. Corrosion resistance remains satisfactory for Invar 36 contents below 15 wt.%, whereas higher contents lead to reduced chemical performance due to chromium dilution. Overall, these findings establish clear criteria for selecting optimal compositions in the design of a 316L–Invar 36 compositional gradient. They provide an essential foundation for the development, via WAAM, of robust and high-performance functionally graded materials suitable for applications requiring high dimensional stability, good chemical resistance, and controlled costs.

Abstract: Al₂O₃-SiC-C (ASC) lining bricks for pouring ladle used in pre-treating molten (desulfurization) iron and molten iron ladles, which offer advantages such as high oxidation resistance, strong resistance to slag corrosion, good thermal shock resistance, and excellent resistance to mechanical wear and abrasion, have been investigated. It is expected that the combination of these new techniques will improve the energy and economic efficiency of the steel industry while also contributing to the decarbonization of both the refractory and steel industries. Additionally, the developed technology is expected to be applicable to other energy-intensive industries, such as cement, glass, pulp and paper, and non-ferrous metal processing. Investigating used samples is crucial for reducing wear on both ALKO60A and ALKO66ASC linings. The microstructures of laboratory prepared samples were analyzed using OLM, XRD, and SEM/EDS techniques. It is expected the formation of phases with low melting points, along with spinel solid solutions in the matrix and calcium di-aluminate near the alumina aggregates.

Abstract: During the study of laser cladding processes for manufacturing of structural elements from high-alloy corrosion-resistant steel on a thin-walled base, the issue of reduction of the powder material corrosion durability, applied by such technologies, during their use in corrosive environments, was considered. The aim of this study is to determine the effect of laser radiation intensity, used to form a deposited layer on a thin-walled base made from AISI 316L high-alloy corrosion-resistant steel, on its corrosion resistance. Samples, utilizing a laser cladding method, developed for creation of structural elements on pre-made thin-walled parts, were tested for pitting and intergranular corrosion (IGC) resistance using standard methods. IGC resistance was assessed by optical metallography. According to the results of corrosion tests, it was determined that samples of the layers of high-alloy corrosion-resistant steel AISI 316L, applied utilizing laser cladding technology on a thin-walled base, made from high-alloy corrosion-resistant steel, can be considered resistant to pitting and intergranular corrosion, while maintaining the range of values of power density at 30...50.0 kW/cm². These results align with the results of various studies by other authors who have been testing similar cases in other industries. The results of this study were used for further development of laser surfacing technologies for thin-walled parts used in various extreme conditions and further deepening of knowledge about modern laser cladding processes and expansion of the scope of this technology.

Abstract: This study aims to optimize the corrosion resistance and mechanical properties of angle steel used in transmission towers. It systematically explores the influence of C, Mn, Nb, V, Ti strengthening elements and Cr, Ni corrosion resistant elements on the comprehensive performance of 420 MPa weathering steel. Seven sets of experimental steels were prepared using vacuum melting combined with controlled rolling process. The mechanism of alloy elements on microstructure evolution, mechanical properties, and corrosion behavior was studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), and electrochemical testing. The results showed that the experimental steels exhibited a dual phase structure of ferrite and pearlite, and the strength was significantly improved by the precipitation strengthening of V element through carbonitride (yield strength reached 420-441.5 MPa). The synergistic regulation of C-Mn can effectively optimize the carbon equivalent to balance weldability. In the cyclic infiltration test simulating acid rain environment, the alloy ratio of Cr≥0.45% and Ni≥0.15% can reduce the relative corrosion rate to below 50% of conventional Q420 angle steel. Microscopic analysis reveals that the content of α-FeOOH in the dense rust layer formed on the surface of weathering steel is over 95%, significantly higher than the 49.4% of conventional steel. This stable rust layer effectively improves the corrosion resistance by suppressing the anodic dissolution process. This study provides theoretical basis and process parameters for the composition design of weathering angle steel for transmission towers.

Abstract: This study evaluates and compares the corrosion resistance of zinc coatings deposited on mild steel using three different techniques: electroplating, TREFISSOUD Company hot-dip galvanization, and conventional hot-dip galvanization. Coated and uncoated samples were characterized by electrochemical polarization, microscopic analyses (optical microscopy and SEM), and X-ray diffraction (XRD). Electrochemical results demonstrated a significant decrease in corrosion current density (Icorr) for all zinc-coated specimens compared to bare steel, confirming the protective effect of the coatings. Among the coatings, hot-dip galvanization exhibited superior performance, with the TREFISSOUD Company method achieving the lowest corrosion current and the highest polarization resistance, indicating enhanced corrosion protection. Electroplated zinc, although thinner, provided adequate resistance in moderately aggressive environments. XRD analysis revealed zinc oxide (ZnO) and iron oxide (Fe₂O₃) as the main corrosion products. Their intensity was more pronounced in galvanized coatings than in electroplated zinc. Microscopic observations confirmed uniform and adherent coatings, with hot-dip galvanization producing thicker layers and stronger adhesion than electroplating. Overall, the findings demonstrate that hot-dip galvanization, particularly the TREFISSOUD Company method, provides the best long-term protection for mild steel exposed to harsh conditions. Electroplated zinc, while less durable, remains suitable for applications where a thinner, uniform coating is required. These results highlight the importance of selecting the coating method according to specific service conditions in industrial applications such as construction, pipelines, and marine environments. This study provides a new comparative analysis between conventional and TREFISSOUD company hot-dip galvanization methods, which has not been reported previously in the literature. The results highlight the distinctive performance of the TREFISSOUD Company process in improving coating uniformity, adhesion, and corrosion resistance. This novelty contributes to a better understanding of industrial zinc coating optimization for mild steel.

Abstract: Manganese is a key transition metal essential to metallurgy, particularly for strengthening steel. Alloys of manganese including iron-manganese (Fe-Mn), manganese-aluminum (Mn-Al), manganese-titanium (Mn-Ti), and other multi-element systems are increasingly critical in biomedical, aerospace, energy, and marine industries. This review consolidates current knowledge, highlights research gaps, and charts future directions by examining Mn’s chemical and metallurgical properties, major alloy systems, mechanical and corrosion performance, and modern processing methods. In-depth case studies in automotive (TWIP steels), biomedical (biodegradable stents), and aerospace (high-entropy alloys) applications are presented to illustrate real-world performance. A comparative analysis of advanced manufacturing techniques, including Laser Powder Bed Fusion (L-PBF) and Directed Energy Deposition (DED), reveals the profound impact of processing on microstructure and properties. Drawing on over seventy recent studies, this work assesses how microstructure, phase transformations, and alloying behavior influence performance across structural, biodegradable, and functional applications. Despite notable progress, challenges persist in predicting corrosion, ensuring long-term biocompatibility, overcoming low-temperature brittleness, and mitigating the environmental impacts of manganese processing. A critical evaluation of the manganese lifecycle, from mining impacts to recycling challenges, underscores the need for sustainable practices. To address these challenges, we recommend advanced manufacturing for precise microstructural control, surface treatments to improve corrosion resistance, and computational modeling to predict performance. Future research should prioritize corrosion-resistant, biocompatible alloys, refine additive manufacturing for complex designs, gather long-term biocompatibility data, and improve recycling methods. Collaborative efforts integrating simulations, experimental validation, and sustainable practices will ultimately shape manganese’s role in future innovations.

Abstract: Nano silica was synthesized using the Stober process with ammonia, ethanol, and tetraethyl orthosilicate (TEOS) solution. Equiatomic titanium-nickel pre-alloyed particles were reinforced with silica nanoparticles of constant volume percent with sizes varying as proceeding 50, 100, 250, and 500 nm. The weighed compositions were mixed in a planetary ball mill, followed by compaction via uniaxial compression of 50 MPa. The resultant green pellets were sintered in an argon atmosphere at 1223K for a period of 4 hrs. Following that, by using EDM, the composite pellets were sectioned, soldered, and cold-mounted. Microstructure was analyzed by optical microscopy, mechanical properties by micro-Vickers hardness testing, and electrochemical analysis by Tafel curves, whereas the effect of particle size at constant volume on the densification was determined via Archimedes' Principle. The reinforcement showed increasing hardness up to 120HV and an increase in phase distribution, in addition to the effect complemented by the transformation of silica, whereas the electrochemical evaluation was affected by both reinforcement and phase distribution. Electrochemical corrosion resistance was measured at 6.88mpy in pure TiNi and 10.93mpy in TiNi nano-silica composite.

Abstract: Food-grade piping and water transportation systems extensively use dissimilar welding between stainless steel and carbon steel, where cost-effectiveness and corrosion resistance are essential consideration. However, the fusion zone of dissimilar welds often observed microstructural inhomogeneities and hardness changes, thus compromising mechanical qualities and corrosion resistance. This study was seperated in two phases to investigate and optimize dissimilar welding between carbon steel and stainless steel in both plate and pipe applications. Phase 1 studied welding A36 carbon steel plate and A304 stainless steel using gas tungsten arc welding (GTAW) with ER308L filler metal, the effect of post-weld heat treatment (PWHT) holding time on the mechanical and microstructural propertie. PWHT was performed at 650 °C for 20 and 60 minutes. The 20-minute condition yielded an optimal combination of mechanical strength and microstructural refinement, while the 60-minute condition led to grain coarsening and reduced strength. Phase 2 extended the findings to pipe welding applications, adopting the 20-minute PWHT condition. Welding was performed on dissimilar joints between A106-B carbon steel pipe and A312 TP304L stainless steel pipe (2-inch OD) using ER308L and ER309L filler metals under 99.99% argon shielding. Tensile and hardness testing indicated that welds with ER309L offered superior mechanical performance. Microstructural analysis revealed delta-ferrite and stabilized austenite in the fusion zone, with enhanced Cr and Ni concentrations contributing to improved corrosion resistance, as confirmed by electrochemical testing.