Effect Of Corrosion Research Articles

Paraquat poisoning presenting as sinus bradycardia; a rare clinical manifestation

Paraquat poisoning is a common yet fatal consequence in rural India. Usually it presents with local corrosive effects and early multi organ dysfunction involving lungs, liver and kidney. Here we present a case of a 25 years old man who presented with paraquat poisoning and developed asymptomatic bradycardia after admission. He was treated conservatively with isoprenaline drip, N-acetyl cysteine, steroids and other supportive therapy. The bradycardia recovered spontaneously and patient was discharged.

A novel approach for flotation separation of talc and molybdenite: Scrap steel-molybdenite galvanic corrosion treatment and its mechanism

Molybdenum is an important strategic resource. Talc-type molybdenite is abundant in reserves, but it is difficult to separate talc and molybdenite efficiently and cleanly because of their similar strong hydrophobicity. In this paper, the effect of galvanic corrosion between scrap steel and molybdenite on flotation behavior of molybdenite was studied under different conditions (different scrap steel materials, slurry water content, galvanic corrosion time and galvanic corrosion ambient temperature).The method for flotation separation of molybdenite and talc by galvanic corrosion of scrap steel-molybdenite was established for the first time. In addition, XPS, SEM, TOF-SIMS, contact Angle test and electrochemical test were used to study the effect of galvanic corrosion of scrap steel-molybdenite on the surface properties of molybdenite and talc. The results show that strong galvanic corrosion between scrap steel and molybdenite can significantly reduce the hydrophobicity of molybdenite, but there is no galvanic corrosion between scrap steel and talc under the same conditions, and scrap steel has no significant effect on the surface hydrophobicity of talc. Therefore, the galvanic corrosion of scrap steel-molybdenite can effectively expand the floatability difference between talc and molybdenite, and strengthen the flotation separation of molybdenite and talc. The flotation test results of artificial mixed ore show that in the case of mineral mixing, the galvanic corrosion of scrap steel-molybdenite still shows a strong inhibition effect on molybdenite flotation, so that 97.04 % of molybdenite in the mixed ore is inhibited into the tailings (molybdenite products). The research results expand the new high-value utilization way of scrap steel in sulfide ore flotation, and help to promote the sustainable development of iron and steel industry and sulfide ores industry. In addition, the research results also have reference significance for the use of scrap steel galvanic corrosion to inhibit other sulfide ores such as pyrite and arsenopyrite.

Investigation on the dynamic mechanical properties and mesoscopic damage mechanism of alkali-activated seawater and sea sand concrete in marine corrosive environments

The dynamic mechanical behavior of alkali-activated seawater and sea sand concrete (ASSC) in marine corrosive environments were investigated by splitting Hopkinson pressure bar (SHPB) impact experiment. This study investigated how corrosion age, strain rate, and various corrosion environments influence the mechanical characteristics and macroscopic failure behavior of ASSC. Furthermore, a three-dimensional (3D) mesoscopic model was employed to investigate mesoscopic damage mechanism of ASSC. The outcomes indicate that increasing corrosion age intensifies the corrosion effect on concrete, with the dry-wet cycling having a more pronounced erosive impact compared to solution immersion. The dynamic mechanical properties and failure morphology exhibit a pronounced strain-rate effect. Microscopic analysis showed that cracks first developed in the interfacial transition zone (ITZ) before propagating into mortar. As smaller cracks coalesced into larger ones, their progression ultimately led to the fragmentation of the aggregates.

Low corrosive dual desiccant air conditioning: Antimicrobial activity, performance characteristics, and economic valuation with traditional VCRS

Liquid desiccant dehumidification systems (LDDS) serve as an energy-efficient alternative to conventional vapor compression refrigeration (VCR) systems, providing enhanced control over both temperature and humidity levels. However, the broader implementation of LDDS is limited due to the corrosive effects of the liquid desiccants on metal components. In response, this study introduces an economical blend of potassium formate (HCOOK) and magnesium chloride (MgCl2) designed to minimize corrosion while maintaining energy efficiency and performance. Selection of mixture ratio and solution concentration and determination of thermo-physical properties were conducted by initial lab-scale tests. Significant bactericidal effects against E. coli and S. Aureus were observed. The feasibility and effectiveness of the developed solution were experimentally tested by a comparative investigation in a large-scale solar-integrated liquid desiccant dehumidification system against standard HCOOK (63.5 wt%). The cyclic performance of the novel desiccant solution was examined under varying operational conditions for tropical climates. Results demonstrated that the corrosion levels of the new mixture are comparable to those observed with a standard 63.5 wt% HCOOK solution, while the dehumidification efficiency showed significant improvements, with moisture removal and effectiveness enhanced by 8.7–14.3 % and 5.8–15.2 %, respectively. Significant regeneration occurred between 45 °C and 55 °C. Regeneration efficiency improved by a maximum of 12.5 % relative to the standard HCOOK solution. Notably, the deployment of a solar-assisted regeneration system led to energy cost reductions by 22.8 % compared to traditional VCR systems, achieving a return on investment within 1.8 years.

Feasibility of Recovering and Recycling Polymer Composites from End-of-Life Marine Renewable Energy Structures: A Review

Over the last few decades, several marine renewable energy (MRE) technologies, such as wave energy converters (WECs) and current energy converters (CECs), have been developed. As opposed to traditional materials such as metal alloys, the structure of these technologies is made up of polymer and polymer composite materials. Most structures have been made using thermoset polymer composites; however, since thermoset polymer composites are not recyclable and lack sustainability, and with recent innovations in recyclable resins, bio-based resins, and the development of additive manufacturing technologies, thermoplastic polymers are increasingly being used. Nevertheless, the methodologies for identifying end-of-life options and recovering these polymer composites, as well as the recycling and reuse processes for MRE structures, are not well-studied. Specifically, since these MRE structures are subjected to salinity, moisture, varying temperature, biofouling, and corrosion effects depending on their usage, the recyclability after seawater aging and degradation needs to be explored. Hence, this review provides an in-depth review of polymer composites used in marine applications, the hygrothermal aging studies conducted so far to understand the degradation of these materials, and the reuse and recycling methodologies for end-of-life MRE structures, with a particular emphasis on sustainability.

Finite Element Analysis of the Structural Behavior of a Corroded Pipe Culvert

The stress analysis of buried pipe culverts is a complex task, and accurately characterizing the deterioration of mechanical properties caused by corrosion poses significant challenges. In this study, the finite element analysis software PLAXIS 3D was employed to construct a numerical simulation model of a pipe culvert. By varying the stiffness and thickness of either the entire structure or specific sections, different degrees of corrosion were simulated to investigate the influence of various cross-sectional shapes on corrosion effects. Multiple experimental controls were set to analyze both the bearing capacity and deformation characteristics under different conditions. The findings reveal that different levels of corrosion have distinct impacts on the deformation behavior of pipe culverts. Overall corrosion has the most significant effect on the overall deformation, while crown and middle corrosion show a similar effect on stiffness-related deformations. In contrast, invert corrosion has minimal impact on the stiffness-related deformation. Corrosion affects circular and elliptical pipe culverts similarly. However, the circular pipe culvert is evidently influenced by overall corrosion more significantly than the elliptical ones due to the combined effects from overall and local corrosion in their deformations. Through finite element numerical simulation, it can be used as a reference for practical engineering design and construction.

Corrosion attack in existing reinforced concrete structures: in-field investigation and analysis of naturally corroded bars

Corrosion of steel bars is a major issue for the management of existing reinforced concrete structures, since affecting many ageing structures and infrastructures and introducing risk for safety and reliability, as well as high maintenance costs. Intervention strategies should be planned and carried out according to the effective state of deterioration and to the expected evolution of performances over time. The critical parameters needed to evaluate these performances are the intensity and pattern of the corrosion attack, referring to both extension and depth of the attack. However, this information is rarely available and hard to predict when dealing with real structures. This paper presents a field investigation on existing corroded structures characterized by different environmental conditions. Corroded bars were removed from structural elements, the corrosion patterns were studied, and then the bars were tested to determine their mechanical properties. The objective of this study is to increase the knowledge of the effects of corrosion in natural environments and to propose a method to relate easy-measurable environmental conditions with the characteristics of the expected corrosion attack, which need to be further validated.

Effect of hydro-chemical corrosion on mechanical properties of red sandstone under uniaxial and triaxial compression

The degradation of mechanical characteristics of sandstone, a common engineering material in acid environment, is directly related to the project service life forecast. In order to investigate the influence of water–rock interaction on the mechanical properties of red sandstone, a series of uniaxial and triaxial compression tests were conducted on sandstone immersed in solutions of different pH values and immersion times. Moreover, the effects of acid chemical corrosion on the microscopic structure of the sandstone were analyzed using scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) tests. A chemical damage strength model was then formulated within the theoretical framework of chemical reaction kinetics theory. The results indicate that the different hydro-chemical solutions have a significant deterioration effect on the sandstone. In immersion tests, the water–rock reaction of sandstone is essentially completed after 30 days of immersion. With increasing immersion time, the uniaxial compressive strength of sandstone immersed in neutral and weakly acidic saline solutions shows an initial rapid decrease followed by a slow increase, while sandstone immersed in distilled water and strongly acidic solutions shows varying degrees of decrease over time. High confining pressure weakens the corrosion effect of the solutions on the sandstone, particularly, the neutral solution. In the triaxial compression tests, strong acid has a great corrosion effect on sandstone. The average peak strength of sandstone immersed in pH2, pH4, pH7, and distilled water decreased by 30.2%, 28.7%, 25.1%, and 22.8%, respectively. The model considers calcium precipitation not only reflects the change in pH value of the immersion solution with time but also effectively predicts the strength of sandstone immersed in different solutions. The results deepen our understanding of the deterioration mechanism of silicon-based porous rock under different chemical solutions and would be of importance for the long-term stability analysis of rock engineering in complex groundwater environments.

Performance evaluation of innovative self-healing corrosion protection coatings for prestressing strands

This study presents the design and experimental evaluation of advanced corrosion protection coatings for application on prestressing strands which are the core constituents of prestressed concrete structures such as bridges. Variety of self-heal coatings embodying corrective and protective phenomena in response to the degrading effects of corrosion have been designed and tested in simulated aggressive weathering conditions. Standard 7-wire prestressing strands coated with self-heal epoxy, self-heal toughened epoxy and hybrid epoxy coating systems were subjected to salt fog spray up to a duration of 2500 h, and 3M CalCl2, 3M NaOH, saturated Ca(OH)2 solutions and distilled water up to 45 days duration. Furthermore, rust creepage of the coated prestressing strands was measured after extended exposure to aggressive corrosive environment. Bond strength of the self-heal epoxy coated prestressing strands was evaluated through pullout test using high-strength concrete.Significant improvement in corrosion resistance, hydrolytic stability, marked reduction in rust creepage, and improved bond strength, brought about by the innovative self-heal epoxy coatings were recorded in laboratory tests. Furthermore, electrochemical impedance spectroscopy (EIS) data proved excellent corrosion protection qualities of self-healing coatings. The ATR-FTIR spectra of various self-heal epoxy coating systems and optic microscopic images of the coatings further verified these findings.

Study on Cavitation Erosion Mechanism of Ultra-High Molecular Weight Polyethylene (UHMWPE) and Polytetrafluoroethylene (PTFE)

Polymer materials possess low density, high strength, corrosion resistance, and excellent cavitation erosion resistance. As a result, they are widely used in marine, water conservancy, and other engineering equipment as replacements for metal materials. However, polymer friction pairs working in a water environment for an extended period are easily damaged by cavitation erosion. In this work, the cavitation behavior of polytetrafluoroethylene (PTFE) and ultra-high molecular weight polyethylene (UHMWPE) in deionized water and seawater is investigated through experiments and computational fluid dynamics (CFD) simulations. The results indicate that the cavitation erosion resistance of UHMWPE is significantly better than that of PTFE, and the UHMWPE has four cavitation process stages, while the PTFE has only three cavitation stages. 316 L counterparts in the seawater corrosion and cavitation coupling effect of a large number of metal particles off and wash polymer material surface, so that the cavitation erosion of PTFE and UHMWPE is more serious in seawater environment. CFD simulation demonstrates that the cavitation erosion zone under the radiator shows a semicircular distribution. Meanwhile, the formation of ring-shaped cavitation pit is related to the distribution of bubbles on the surface of the radiator. The cavitation rate of PTFE and UHMWPE is slowed down by the “water cushion effect.”

Eco-friendly impact of a novel green Melilotus officinalis extract as a sustainable inhibitor to reduce acid corrosion of copper.

In this study, we deployed green Melilotus officinalis extract (MOE) as a corrosion inhibitor for copper. The anticorrosion properties of MOE for Cu in 1 M HNO3 were investigated by various experimental and numerical techniques, including potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), and a weight loss (WL) method at different temperatures. Additionally, scanning electron microscopy (SEM) coupled with energy-dispersive X-ray analysis (EDX) and atomic force microscopy (AFM) were utilized to examine the surface morphology of Cu with and without the extract. By contrasting the inhibition effectiveness with and without the extract, the inhibition efficiency (% IE) was observed. The WL method revealed that 300 ppm of the extract had an IE of 93.8% for Cu immersed in one molar HNO3 solution. The MOE was classified as a mixed type according to the PDP study since it delayed both cathodic and anodic processes, with a cathodic predominance. At 25-45 °C, MOE's free adsorption energies were 23.1-21.5 kJ mol-1, showing that mixed-type adsorption occurred on the Cu surface. Additionally, the Langmuir adsorption isotherm and the adsorption data from the WL tests of MOE showed a good match. The extract could adsorb spontaneously onto the metal surface, according to the thermodynamic conditions. Analysis of the corrosion product using different techniques revealed that a protective layer had formed on the metal's surface. Hence, MOE had a good corrosive inhibitive effect on Cu in HNO3 solution. It turned out that all the methods used gave consistent results.

Behavior of Fe-based alloys in a liquid lead-bismuth environment under simultaneous proton irradiation and corrosion

The performance and longevity of nuclear reactors are significantly influenced by the behavior of their structural materials, particularly under conditions of corrosion and irradiation. This study investigates the combined effects of corrosion and irradiation on three alloys: Fe-Ni-Cr-Al-Nb, Fe-Cr-Al-Y, and Fe-12Cr-2Si, exposed to a liquid Pb-4wt% Bi mixture at 675 °C for 4 h. 3 MeV proton irradiation was employed to understand the simultaneous effects of irradiation on the corrosion behavior of these alloys. When exposed to liquid lead-bismuth at 675 °C for 4 h, the Fe-Cr-Al-Y and Fe-12Cr-2Si alloys exhibited superior corrosion resistance compared to the Fe-Ni-Cr-Al-Nb alloy. Conversely, the Fe-Ni-Cr-Al-Nb alloy demonstrated significant Pb-Bi penetration, which was further accelerated by proton irradiation, resulting in increased penetration depth. This revealed that irradiation-induced damage can accelerate the corrosion rate of Fe-Ni-Cr-Al-Nb steel in lead-bismuth environments. Microstructural analysis using SEM/EDX, STEM, and diffraction patterns uncovered complex alloy interactions and potential chemical transformations in the irradiated Fe-Ni-Cr-Al-Nb alloy. This included the presence of lamellar or rod-like structures near Pb-Bi penetration sites and the selective retention of nickel by aluminum. In contrast, the Fe-12Cr-2Si alloy exhibited effective corrosion resistance attributed to a uniform distribution of elements and the formation of a protective Si-rich oxide layer. The Fe-Cr-Al-Y alloy developed distinct oxide layers, with chromium oxide predominating and a slight aluminum oxide layer, indicating the critical role of chromium oxide as a protective barrier.

Mechanical properties and energy evolution law of marble under the coupled effects of chemical corrosion and dry-wet cycles.

The main factors affecting the safety of underground structures are groundwater chemical corrosion and water level fluctuations. To investigate the mechanical properties of marble and the energy evolution pattern during the failure process under the coupled effects of chemical corrosion and dry-wet cycling, samples were subjected to 5, 10 and 20 cycles of dry-wet ageing in chemical solutions with pH values of 4, 7 and 10, respectively, followed by mechanical property testing. The energy evolution pattern during the failure process of the specimens was also studied. It was found that there is a strong correlation between number of dry-wet cycles and pH value of chemical solution. Chemical corrosion at the early stage of dry-wet cycling has the greatest effect on the deterioration of the rock. As the number of dry-wet cycles increases, the degree of corrosion in acidic solutions is most evident, with the uniaxial compressive strength and elastic modulus decreasing by 27.88% and 33.52% respectively, followed by alkaline solutions, and the degree of corrosion in neutral solutions is the lowest. In addition, dry-wet cycling and chemical corrosion lead to an increase in the internal pores of the rock samples and a decrease in the energy storage capacity. Nevertheless, the proportion of energy loss increases with the number of dry and wet cycles, with the proportion of energy loss in acidic media increasing from 35.61% to 41.63%, indicating that the plastic deformability of marble increases under the action of chemical corrosion and dry and wet cycles. The research results have certain guiding significance for the design, construction and maintenance reinforcement of underground structures under the conditions of chemical corrosion and dry-wet cycling.

Effective corrosion detection in reinforced concrete via laser-induced breakdown spectroscopy and machine learning

Corrosion is a major challenge impacting industries such as construction, petrochemicals, and metallurgy. This study presents an innovative approach to predicting corrosion rates in reinforced concrete by employing laser-induced breakdown spectroscopy (LIBS) and machine learning. Corroded samples were analyzed using LIBS to identify elemental compositions and their intensities, focusing on Si, Al, Fe, Ti, Na, Ca, and Cl as input features for the models. Three different machine learning models (Support Vector Regression (SVR), Gaussian Process Regression (GPR), and Decision Tree Regression (DTR)) were trained to predict corrosion rates. The input features were tested in three combinations: Combo-1 (Si, Al, Cl), Combo-2 (Si, Al, Fe, Ca, Cl), and Combo-3 (Si, Al, Fe, Ti, Na, Ca, Cl). The models' performance was evaluated using metrics such as Mean Absolute Error (MAE), Nash Sutcliffe Efficiency (NSE), Root Mean Square Error (RMSE), and Correlation Coefficient (CC). The results showed that Combo-3 consistently achieved the highest prediction efficiency for SVR (NSE = 0.9734, CC = 0.9874) and GPR (NSE = 0.9785, CC = 0.9900) during testing, highlighting the importance of comprehensive input descriptors. However, for the DTR model, Combo-1 (NSE = 0.9997, CC = 0.9970) exhibited the highest prediction efficiency, demonstrating its capability to accurately predict with fewer descriptors. This research offers valuable insights for industries and policymakers aiming to mitigate the adverse effects of corrosion, emphasizing the potential of combining LIBS with machine learning for precise corrosion rate prediction.

Corrosion experimental study of U75V steel and Q235 steel under the influence of dynamic stray current in subway

The intrusion of stray current (SC) into urban power grids will trigger DC bias of transformers and metal corrosion, resulting in economic losses and safety hazards. With limited research on dynamic DC corrosion, this paper monitors SC flow path and establishes a finite element model to simulate SC intrusion scenarios. Based on two scenarios model results, select experimental input currents to study the corrosion effects of U75V steel and Q235 steel under the action of dynamic SC and DC stray current. The corrosion behaviors and mechanisms of DC and dynamic SC are revealed using SEM and polarization curve analysis.

Experimental and Numerical Investigation on the Bearing Capacity of Axially Compressive Concrete-Filled Steel Tubular Columns with Local Corrosion

This study aims to examine the effects of local corrosion on the axial compression performance of concrete-filled steel tubular (CFST) members. Nineteen CFST short columns with local corrosion were designed and fabricated to undergo axial compression mechanical property tests, with the radial corrosion depth of the local corrosion area as the key test parameter. The failure mechanism and mechanical property change laws of CFST axial compression short columns with circumferential full corrosion at the ends and middle were studied. Combined with finite element modeling, the influence laws of the three-dimensional geometrical characteristics of the local corrosion zone, i.e., the axial length, the annular width and the radial depth, on the structural bearing performance were thoroughly explored and discussed. The results revealed that the main reason for the reduction in load-carrying capacity of circular CFST axial columns due to local corrosion is attributed to the reduction of the effective cross-sectional area of the steel tube in the corrosion area. When local corrosion occurs at different axial positions, the variation range of the bearing capacity of CFST columns is within 10%. Regarding the impact of the three dimensions of local corrosion on the axial load-carrying capacity of CFST, the radial corrosion depth was identified as the most influential factor, followed by the annular corrosion width, and finally by the axial corrosion length. When the axial corrosion length exceeds 20% of the specimen length, its further influence on the load-carrying capacity is considered limited. Finally, a practical calculation formula for the bearing capacity of locally corroded CFST columns is proposed. The predicted results of this formula fit well with the test results and can quickly estimate the remaining bearing capacity of the structure by measuring the geometric parameters of the local corrosion area, providing a reference for the assessment and maintenance of CFST structures.

Mechanical and dynamic characteristics for the CFRP, GFRP, and hybrid composites exposed to HCl environment

In the current study, the low-velocity impact (LVI) characteristics of carbon fiber-reinforced polymer (CFRP), glass fiber-reinforced polymer (GFRP), and hybrid composites before and after the corrosive environment exposure were investigated. In this regard, CFRP, GFRP, and hybrid composites were subjected to LVI and tensile loadings after being kept in a 10% diluted HCl environment for 1 week and 1 month, and the impacts of the corrosive environment on the composites’ dynamic and mechanical responses were determined by comparing the outcomes of the control and aged specimens. LVI tests for CFRP, GFRP, and hybrid composites were carried out by transferring 25.2 and 11.2 J impact energy to the specimens with two impact velocities of 3 and 2 m/s, respectively, and thus, the effects of impact energy and hybridization were investigated. Moreover, tensile tests were conducted for the control and aged specimens with 2 mm/min crosshead speed, and thus, the effects of fiber material, hybridization, and corrosive environment on the mechanical properties were determined. The study found that CFRP composites had higher stiffness than GFRPs, whereas hybrid composites exhibited dynamic responses between CFRP and GFRP, as expected. On the other hand, it turned out that the composites absorbed most of the impact energy, which was interpreted as being absorbed by the damage of fiber-reinforced composites, which stand out with their brittle characteristics. Furthermore, it was discovered that the damage severity elevated as expected with a longer aging time, which was attributed to the corrosive liquid attacking the fibers, matrix, and fiber/matrix interfaces and reducing strength. It was also observed that, as predicted, the corrosive effects generally resulted in a reduction in tensile responses, including ultimate strain and tensile strength.

Evaluation of surface properties of modified Ti6Al4V alloy with copper nanoparticles organic nanostructure for biomedical applications: dependency on anticorrosive, antibacterial, and biocompatibility

Abstract In this study, a novel multifunctional copper nanoparticle CuNPs in the organic biomatrix was coated to the surface of Ti6Al4V to create multifunctional features. The synthesis of CuNPs was carried out by plant-mediated green synthesis method obtained from Moringa leaf extract, and the prepared CuNPs were coated on the substrate surfaces as single and double layers with drop casting methods. Characterizations of the synthesized CuNPs were performed by UV–Vis, FTIR, XRD, and SEM methods. Characterization of the modified Ti6Al4V alloy surfaces was performed using SEM-EDS and surface roughness analysis. The electrochemical corrosion, antibacterial behavior, and cytotoxic effects of coated and noncoated Ti6Al4V as a function of biocompatibility properties were also tested. The synthesized CuNPs have a homogeneously dispersed spherical shape. Biocorrosion tests have clearly demonstrated that the coating forms a protective film on the substrate surface, and the resistance increased by 49 %. Antibacterial results show that the single and double-coated Ti6Al4V alloy samples with CuNPs organic nanostructure had improved biocompatibility. However, it was determined that the cytotoxic effect increases proportionally with the coating. The obtained results show the importance of surface modification in the appropriate nanostructure to obtain multifunctional nanoplatforms that show promise in biomedical applications.

Comparative analysis of metal oxide nanoparticle accumulation in landfill gas engine combustion chambers: Insights from three sites

Combustion chamber deposits adversely affect the operating performance of gas engines. In this study, the elemental composition of deposit samples collected from the inner surface of combustion chambers in gas engines across three different facilities was examined using various methods. The proportional changes in metal oxides along the internal cross-sectional surfaces of the deposits were examined to depict the deposit formation process from beginning to end. Additionally, the study investigated the identification of metals accumulated in the engine oil, their contribution to deposit formation, and the accumulation mechanisms of metal oxide nanoparticles on the engine’s interior metal surfaces. The main elements identified in the deposits from the Odayeri and Kömürcüoda facilities were Si, S, and Ca, whereas deposits from the Dilovası facility contained Si and Sb. These major elements, identified by SEM-EDS, were confirmed through XRF analysis. XRD analysis further confirmed the presence of Ca and S as CaSO4 crystals in the deposits. Ca originates from additives used to increase the total base number of engine oil and control the corrosive effects of landfill gas. It has been determined that silicon accumulates in engine oil over time. An important finding is that metal oxides in the combustion chamber primarily accumulate through impaction, sticking, and thermophoresis mechanisms.

Study of aluminum corrosion in contact with biogas before and after purification on different carbons

The study of aluminium corrosion in contact with biogas before and after purification on different types of carbon aims to understand the impact of impurities present in biogas, in particular hydrogen sulphide (H₂S), on aluminium degradation. The study highlights the importance of biogas purification in minimising aluminium corrosion. Depending on the level of purification and the types of carbon used for filtering, it is possible to improve the durability of infrastructures in contact with biogas. This has direct implications for the maintenance and operating costs of facilities using biogas as an energy source. Hydrogen sulfide (H₂S) is a colorless, flammable and highly toxic gas characterized by an unpleasant odor. It is often present in industrial and natural environments, particularly in biogas. This gas is involved in the degradation of metals used in anaerobic digestion equipment, in the petrochemical industry, etc. The aim of this work is to study the performance of biochar and activated carbon prepared from corn cobs in removing H2S from biogas, and to evaluate the reduction of the corrosive effect of filtered biogas on metallic aluminum. The impregnation and carbonization method was used to prepare activated carbon from corn cobs, and the gravimetric method to study the corrosion rate of metal in biogas. The results indicate that the activated carbon prepared is microporous, has a good specific surface and a better adsorption capacity. Furthermore, the prepared activated carbon samples also showed good H2S removal efficiency in the biogas. The aluminum-induced protective power values in filtered biogas for biochar and activated carbon are 58 % and 82.22 % respectively. We plan to increase the contact time and experiment with other metals and carbons.