Active Corrosion Research Articles

Corrosion mapping of intermetallic in a dissimilar weldment using in-situ alternating current scanning electrochemical microscopy

In the present work, in-situ corrosion activity mapping across explosively welded 304 L SS-Zr-4 dissimilar joint interfaces was performed using intermittent contact alternating current-scanning electrochemical microscopy (IC-AC-SECM). Two weld joint samples, one with a regular interface and another with an irregular interface, were examined for their local surface activities at an open circuit potential in tap water without using a redox mediator. The SEM micrographs showed the formation of intermetallics at localized regions of the irregular interface weld sample but not in the regular interface sample. The 304 L SS regions of the welds were relatively anodic, with current and impedance magnitude values of 270 ± 20 nA and 380 ± 20 kΩ respectively, when compared to the Zr-4 regions with the corresponding values of 160 ± 20 nA and 630 ± 20 kΩ, due to galvanic coupling effect. The IC-AC-SECM technique enabled the in-situ determination of corrosion activity of localized intermetallic region within the weldment. The current and impedance magnitude values of the intermetallic region were ∼ 240 nA and ∼ 450 kΩ, respectively, showing only a slightly lesser anodic activity as compared to the 304 L SS base metal. The results obtained from the IC-AC-SECM mapping showed a good correlation with the EDS elemental mapping of the dissimilar weldment with intermetallic. The findings indicate the effectiveness of the IC-AC-SECM technique for the in-situ localized corrosion mapping of dissimilar weld joints, showcasing its potential for various applications in assessing weld integrity.

The Ways of Forming and the Erosion/Decay/Aging of Bioapatites in the Context of the Reversibility of Apatites

This study primarily focused on the acid erosion of enamel and dentin. A detailed examination of the X-ray diffraction data proves that the products of the acid-caused decay of enamel belong to the family of isomorphic bioapatites, especially calcium-deficient hydroxyapatites. They are on a trajectory towards less and less crystallized substances. The increase in Bragg’s parameter d and the decrease in the energy necessary for the changes were coupled with variability in the pH. This was valid for the corrosive action of acid solutions with a pH greater than 3.5. When the processes of natural tooth aging were studied by X-ray diffraction, a clear similarity to the processes of the erosion of teeth was revealed. Scarce data on osteoporotic bones seemed to confirm the conclusions derived for teeth. The data concerning the bioapatite decays were confronted with the cycles of apatite synthesis/decay. The chemical studies, mainly concerning the Ca/P ratio in relation to the pH range of durability of popular compounds engaged in the synthesis/decay of apatites, suggested that the process of the formation of erosion under the influence of acids was much inverted in relation to the process of the formation of apatites, starting from brushite up to apatite, in an alkaline environment. Our simulations showed the shift between the family of bioapatites versus the family of apatites concerning the pH of the reaction environment. The detailed model stoichiometric equations associated with the particular stages of relevant processes were derived. The synthesis processes were alkalization reactions coupled with dehydration. The erosion processes were acid hydrolysis reactions. Formally, the alkalization of the environment during apatite synthesis is presented by introducing Ca(OH)2 to stoichiometric equations.

Microbiological and chemical corrosion study of Egyptian petroleum samples: microbial community and corrosion activity

Microbiological and chemical corrosion study of Egyptian petroleum samples: microbial community and corrosion activity

Long-term corrosion protection of reinforcing bars via a self-responsive coating incorporating ZrP functional fillers

The conventional coating of reinforcing bars exhibits inadequate anti-corrosion efficacy stemming from a non-specific, blind protection mechanism, poses a threat to the durability of concrete. We devised a novel self-responsive functional filler, L-arginine (LA) intercalated zirconium phosphate (LCZrP), synthesized via an intercalation reaction. This innovative filler was seamlessly integrated into an epoxy (EP) resin matrix, yielding a smart anticorrosive coating that harmoniously combines active and passive corrosion protection strategies. The integration of LCZrP within the coating matrix serves a trifecta of purposes: it extends the corrosion propagation path, effectively disperses nanofiller agglomeration, and enhances interfacial adhesion with the epoxy coating. Critically, the controlled release of corrosion inhibitors from the interlayer further fortifies the coating's resistance to corrosion, imparting a multi-layered protective shield. After enduring a 60-day immersion in a simulated concrete pore solution, the LCZrP/EP coating demonstrated exceptional durability, maintaining a low-frequency impedance modulus value consistently within the range of 4.27×1010 to 5.12×1010 Ω·cm2, marking a remarkable 34-fold enhancement over the performance of the epoxy coating alone. This breakthrough underscores the LCZrP/EP coating's potential as a groundbreaking solution for reinforcing bar protection in concrete, harnessing the complementary strengths of epoxy resin's physical barrier, the impermeability of two-dimensional lamellar structures, and the proactive release of corrosion inhibitors to forge a robust, multi-faceted passivation layer.

Interaction behaviour of alloy 690 upon exposure to P2O5 containing borosilicate glass at simulated vitrification conditions

This study investigates the interaction between alloy 690 and two types of glasses: pristine borosilicate and P2O5-containing borosilicate glass, at typical glass pouring temperatures encountered during the vitrification of high-level radioactive waste in the back-end of Nuclear Fuel Cycle (NFC). Partial crystallization of both glasses was observed at the alloy 690/glass interface, with certain, though not entirely identical, crystalline phases forming at the interface. The density of these crystalline phases is significantly higher than that of the surrounding glass, which raises concerns about these reaction products settling at the bottom of the furnace. Such sedimentation could potentially obstruct the freeze valve, thereby halting the vitrification process. Additionally, intergranular grooves on the alloy surface exposed to P2O5-containing borosilicate glass were found to disappear with prolonged exposure. This phenomenon is attributed to the strong corrosive action of the highly basic and oxidizing P2O5-bearing glass, leading to the peeling away of the entire exposed surface of alloy 690.

Exploring machine learning to study and predict the chloride threshold level for carbon steel reinforcement

Chloride-induced corrosion of steel reinforcing bar (rebar) is the primary cause of deterioration in reinforced concrete structures, posing a significant infrastructure challenge. The chloride threshold level (CTL) of rebar, which represents the critical amount of chloride needed to initiate active corrosion, is crucial in corrosion and service life prediction models. However, substantial uncertainties and a multitude of influencing factors, along with the absence of a universally accepted testing framework, hinder the achievement of a consistent CTL range for service life models and complicate comparisons of published values. This study addresses these challenges by developing multiple machine learning models to predict CTL, considering 21 carefully selected features. A comprehensive database of 423 data points was compiled from an exhaustive literature review. Seven machine learning models—linear regression, decision tree, random forest, K-nearest neighbors, support vector machine, artificial neural network, and an ensemble model—were developed and optimized. The ensemble model achieved superior prediction performance, with a mean absolute error of 0.218 % by weight of binder, root mean square error of 0.321 %, and a coefficient of determination of 0.751 on unseen CTL data. Partial dependence plots generated using the support vector machine model quantified the effect of each feature on CTL. The random forest model identified SiO₂ binder content and exposed rebar area to chlorides as the most influential factors. The study also examined the impact of supplementary cementitious materials (SCMs), finding that only blast furnace slag positively affected CTL.

Development of an automated system for the purification of alkanolamine solutions

The alkanolamine solutions used in natural gas purification processes are inevitably degraded over time. This occurs due to accumulation of reaction products from the reactions with carbon dioxide, hydrogen sulphide, oxygen and other impurities present in the gas streams, as well as from thermal degradation. The degradation of solutions leads to the formation of thermostable compounds that not only reduce absorption efficiency, but also increase corrosive activity. Furthermore, part of the amine turns into a bound state and becomes ballast. The necessity of purification of alkanolamine solutions is becoming more and more urgent since the cost of maintaining efficient operation of gas treatment plants grows, and environmental safety requirements increase. Purification of solutions makes it possible to prolong their service life, reduce the cost of purchasing new reagents and reduce the negative impact on the equipment. In this work the method of anion-exchange technology of purification is used. Unlike vacuum distillation and electrodialysis, the considered technology does not require significant energy costs for generation and maintenance of vacuum, and heating of solutions, it can be easily integrated into the existing production process without any significant changes in the infrastructure. The described problem is relevant for Kazakhstan oil refineries, two of which use methyldiethanolamine, and one of which uses diethanolamine, and the existing practice of maintaining the operability of the systems is based on periodic replacement of part of the solution with pure amine. The development of automated systems for purification of such solutions makes it possible to significantly improve process control, minimise manual labour, and improve the overall economic efficiency of production.

In the LiCl-KCl melt at 500<sup>о</sup>С depending on the content of Li<sub>2</sub>О и LiOH

Molten alkali metal chlorides used in pyrotechnologies are aggressive corrosive agents. The high operating temperature of the process, the heterogeneity of the environment, and the significant corrosion activity of the molten salt necessitate both the search for stable structural materials and the development of methods for protecting the structural elements of high-temperature technological devices. Corrosion loss reduction techniques traditionally used in low temperature environments are not applicable at high temperatures. The article examines the influence of oxygen-containing impurities (lithium oxide and hydroxide) on the corrosion behavior of metallic nickel (grade NP1) – the main component of candidate structural alloys, a thermodynamically and structurally stable material in the melt for the process of electrolytic refining of spent nuclear fuel. A method for preparing the LiCl–KCl salt electrolyte and obtaining lithium oxide by thermal decomposition of anhydrous lithium hydroxide under vacuum is described, and the concentrations of impurities in the electrolyte and the synthesized lithium oxide are determined. An installation for conducting corrosion tests in an inert atmosphere of a glove box is presented. To assess the corrosion resistance of the material, the following were used: gravimetric analysis, X-ray diffraction analysis of the surface and cross-sectional sections, and X-ray diffraction analysis of the surface of the samples. The dependences of the corrosion rate of the material on the concentration of oxygen-containing additives Li2O and LiOH were obtained. Based on a combination of gravimetric, X-ray microspectral and X-ray phase analysis data, it was established that metallic nickel samples demonstrate high corrosion resistance in the studied melts with the introduction of Li2O and LiOH additives.

An Experimental Assessment Using Acoustic Emission Sensors to Effectively Detect Surface Deterioration on Steel Plates

Acoustic emission (AE) testing is used for the continuous evaluation of structural integrity and the monitoring of damage evolution in structural components and materials. During operation, the environmental and loading conditions of metal structures can result in corrosion and surface wear damage. The early detection of surface degradation flaws is crucial, as they can serve as local stress concentration points, leading to crack initiation and failure. In this work, the effectiveness of AE in monitoring corrosion and surface wear flaw formation was experimentally evaluated. AE sensors were installed on steel test plates during the artificial induction of corrosion and surface wear in order to detect and record the generated AE signals. Corrosion-related AE signals typically exhibit low amplitude, count, and energy values. The direct detection of active corrosion can be challenging in noisy environments, but it can be carried out under certain conditions using dedicated AE sensor groups. Surface-wear-related AE signals exhibit high amplitude, energy, and count values, with long duration values that are associated with wear and grinding conditions. It was found that AE sensors can be utilised to detect corrosion and surface degradation events. The effectiveness of the AE method in detecting surface degradation in noisy environments can be improved by implementing a filtering methodology. This will limit the recording of noise-related signals that can mask out actual surface degradation AE events.

Concrete carbonation in tropical urban and urban/marine environments after 20 years of natural exposure

This work is part of the DURACON project, which seeks to characterize the durability of concrete exposed to environmental conditions prevailing in Ibero-America and is based on the exposure of unreinforced and reinforced concrete specimens in marine and urban environments in each participating Ibero-American country. This research presents the results obtained from exposing unreinforced and steel-reinforced concrete specimens to prevailing environmental conditions in twelve natural exposure sites in Mexico during an exposure period of approximately 20 years to determine an empirical model that allows predicting the value of the carbonation rate, k′CO2, as a function of the nth-root of time (NRT) for the concretes evaluated. The concrete specimens, plain and reinforced, exposed to the elements in these cities were manufactured with two types of concrete, one with a w/c ratio = 0.65 and the other with a w/c ratio = 0.45. The tests mainly focused on measuring the concrete carbonation front depth during the ∼ 20 years of exposure and the measurement of environmental parameters at the exposure sites, such as temperature, relative humidity, rainfall, and atmospheric CO2 concentration. The electrochemical parameters of the reinforcing steel (half-cell potential, Ecorr, and current density, icorr) in the reinforced specimens were also obtained after ∼ 20 years of exposure to corroborate which sites showed lower or higher corrosion activity. This model to obtain k′CO2 as a function of the environmental parameters of the Mexican exposure sites and the physical properties of the concretes was compared with the value of kCO2 obtained from the square root of time (SRT) model. It was found that the k′CO2 values were 30 % higher on average than the kCO2 obtained with the empirical SRT equation. However, it should be noted that k′CO2 must be linked to the corresponding nth-root of time, whereas the value of n to obtain kCO2 is constant and equal to ½. An agreement was also obtained between the probability of activation of the reinforcing steel, using the corrosion parameters (Ecorr and icorr), and the probability of eCO2 ≤ 15 mm (lowest concrete cover used in this study).

The effect of oxide scale on the corrosion resistance of SUS301L stainless steel welding joints

The effect of thermal oxidates on the corrosion of SUS301L stainless steel welded joint was investigated using electrochemical corrosion test and TEM microstructure observation. Activation dissolution behavior without passive region was found in the potentiodynamic polarization curves on the welding zone and heat affected zone. The activation corrosion is related to the preferential dissolution of the NiFe layer at the interface between chromium oxide and substrate. However, the passive region in the polarization curve reappears after the unstable NiFe dissolves in the salt-frog test. The passivation behavior due to microstructure evolution beneath the thermal oxide film was discussed during the corrosion process.

Deterioration of fire resistance of ultra-high-performance polypropylene-fibre-reinforced concrete (UHPPFRC) under long-term acid rain corrosion action

The application of ultra-high-performance polypropylene-fibre-reinforced concrete (UHPPFRC) has become widespread due to its superior mechanical properties and non-flammable characteristic. Compared to UHPC, the fire resistance of UHPPFRC, which is crucial in ensuring structural integrity and safety during fire incident, has been improved by the addition of PP fibres. In recent years, the escalation of industrial emission has resulted in a more pronounced pollution of acid rain, a major type of sulphate attack on outdoor concrete structures, leading to the aging of UHPPFRC. Given the long service life of civil engineering structures, the fire performance of aging UHPPFRC should be given significant consideration, yet few studies have taken it into account. This study, for the first time, analyses the deterioration of fire resistance of acid-rain-induced aging UHPPFRCs and compares their probability of failure under fire condition across different corrosion durations, providing guidance for the maintenance of UHPPFRC in acid-rain-prone areas. A novel coupled chemo-thermal-mechanical model is developed, which is employed to investigate the sulphate penetration process and internal stress development within UHPPFRC during the corrosion stage, and to predict temperature and internal stress distribution during the subsequent heating stage. The effects of sulphate concentration, heating rate and fibre dosage on the probability of failure of aging UHPPFRC are then studied. The results obtained from the numerical investigation indicate that the aging effect can significantly compromise the fire resistance of UHPPFRC and augment the probability of failure at elevated temperature. Also, the probability of failure of aging UHPPFRC is more sensitive to changes in sulphate concentration than changes in heating rate.

Gallocyanine-mediated non-covalent functionalization and exfoliation of h-BN for efficient anticorrosion reinforcement of waterborne epoxy coating

Hexagonal boron nitride (h-BN) is commonly used to enhance the anti-corrosion of organic coatings due to its excellent barrier properties, dielectricity and mechanical robustness. However, the bulky h-BN tends to create poor dispersibility and interfacial compatibility problems with the resin matrix, leading to coating cracking and failure. H-BN nanosheets exfoliated by conventional methods only provide passive barrier effect with coatings at the initial stage of corrosion. Herein, we used a mussel-inspired non-covalent functionalization strategy, using the catechol groups and heteroaromatic ring structure of gallocyanine to achieve the functionalization and exfoliation of h-BN through ball milling, and obtained ultra-thin h-BN@G nanosheets. Remarkably, spare gallocyanine can further suppress the erosion, whose inhibition efficiency is 95.48 % at the concentration of 100 mg/L in 1 M HCl within 9 h. Typically, after 105 days of immersion in 3.5 wt% NaCl solution, the low-frequency impedance of h-BN@G/WEP coating is still as high as 1.45 × 109 Ω cm2, which is two orders of magnitude higher than that of the pure coating. The superior long-term anti-corrosion capacity can be ascribed to the triple protection of enhanced shielding property of desirable-exfoliated h-BN, passivation films adsorbed on the metal and coordination bonds formed between gallocyanine and the iron to resist the active corrosion. Our work offers an innovative idea for the functionalization and exfoliation of other lamellar materials, which can be applied to the implementation of long-lasting anti-corrosion coatings.

Combating Cl− and SO42−-induced molten salt corrosion by laser cladding FeCrNiMoAl high-entropy alloy coating

FeCrNiMoAl high entropy alloy coating was successfully prepared by laser cladding method with phases of dominant face-centered cubic (FCC) and minor intermetallics (AlFe and AlNi). After 144 h of corrosion in the molten salt mixture of 40 % NaCl + 40 % KCl + 10 % Na2SO4 + 10 % K2SO4 at 600 °C, FeCrNiMoAl exhibited a much lower corrosion rate than conventional Inconel 625 by a reduction of 34 %. XRD and SEM were used to characterize the corroded samples. To combat Cl-induced active corrosion and S-induced sulfidation, Inconel 625 develops a single Cr2O3 layer while FeCrNiMoAl developed dual layers of outer Cr2O3 and inner Al2O3, which effectively prevents penetration of Cl and S.

COMPOSITES BASED ON OYMASH SALT

In recent years, an urgent task is to find materials of domestic origin and create on their basis affordable and cheap, easy-to-use, reliable composite compositions for the preparation of well killing fluid. Nowadays, the need for process fluids that help preserve and restore reservoir properties always remains. Available and inexpensive natural salt from the Oimash deposit (Mangistau region) can create the required density in the well killing fluid and be its main component. The aim of the work is to develop compositions based on Oimash salt for the preparation of well killing fluids, which include all necessary additives. Methodology: The physicochemical characteristics of the composite compositions for the preparation of well killing fluid (bulk density, mass fraction of insoluble substances in water, mass fraction of moisture, solubility) and using standard methods corrosion activity studied. Results. The physicochemical parameters of Oimash salt showed that the salt is not prone to caking, the proportion of insoluble substances in sea water is 0.45%, and in waste water - 0.54%. The solubility of the developed compositions depending on the types of water was studied. All compositions are soluble in various types of water. The solubility of all compositions in seawater is 96.64-97.56%, and in wastewater from 95.59% to 95.97%. The optimal composition of the salt composition is the composition of sample No. 1 with the percentage content of components TPPF: NTF: PAA = 0.5: 0.5: 0.1:30, with a bulk density of 0.7055 t/m3, a mass fraction of insoluble substances in water - 1.4334%, well soluble in sea and waste water 97.56 and 95.66%. As the results of samples No. 1 showed, the corrosive environment is slightly aggressive in terms of aggressiveness.

Investigation of the Corrosion–Wear Interaction Behavior of 8Cr4Mo4V Bearing Steel at Various Corrosion Intervals

The corrosion–wear coupling damage failure of 8Cr4Mo4V bearing steel under marine atmospheric conditions significantly limits aeroengine bearing applications. The present work aims to investigate the evolution of the corrosion–wear properties of 8Cr4Mo4V bearing steel at varied corrosion intervals and estimate the corrosion–wear interaction (CWI) effect. Neutral salt spray tests combined with tribological experiments were employed to explore the effect of corrosion on wear and the influence of wear on corrosion, and a quantitative characterization method of corrosion–wear interactions was proposed by establishing the component relationships of material losses in the corrosion–wear process. The results indicate that the corrosion rates initially increase and then decrease, ultimately resulting in a pattern characterized by predominant total corrosion and nested localized corrosion. The corroded surfaces tremendously influence the friction coefficient curves at the third stage, and a synergistic acceleration effect exists in the CWI behavior of 8Cr4Mo4V bearing steel under the action of corrosion and wear. A sample corroded for 6 h displayed the significant facilitative effect of corrosion on wear, exhibiting the highest CWI ratio and a greater total mass loss primarily attributed to corrosion. This study offers a significant reference for the quantitative assessment of the tribo-corrosion properties of bearings in a marine atmospheric environment.

Phosphorization of α-Fe2O3 Boosts Active Hydrogen Mediated Electrochemical Nitrate Reduction to Ammonia.

Inexpensive iron-based materials are considered promising electrocatalysts for nitrate (NO3 -) reduction, but their catalytic activity and spontaneous corrosion remain challenges. Here, the α-Fe2O3 active surface is reconstructed by gradient phosphorization to obtain FePx with higher electrochemical activity. FeP2.0 optimizes the adsorption energy of NO3 - and its reduction intermediates, meanwhile promote the generation of active hydrogen (*H) but inhibit its generation of H2. More importantly, Fe and P can serve as binding sites for NO3 - and *H, respectively, which improves the electron utilization of NO3 - deoxygenation and the efficiency of the subsequent hydrogenation for the selective synthesis of NH3. 91.7% NO3 - conversion rate is achieved for the reduction of 100mL 200mg L-1 NO3 --N, 99.3% ammonia (NH3 selectivity (yield of 1.79 mg h-1 cm-2), and 91.4% Faraday efficiency in 3 h. The high-purity solid NH4Cl is finally extracted by gas extraction and vacuum distillation (81.4% recovery). This study provides new insights and strategies for the conversion of NO3 - to NH3 products over iron-based electrocatalysts.

Active Control of Properties of Fresh and Hardening Concrete

Concrete mixtures have an optimized mix design in view of attaining desired properties. However, after mixing, during further processing, it is typically not possible to further adjust the performance of the fresh and hardening concrete. A new and emerging approach is to actively control the concrete properties by means of responsive particles or polymers triggered by an externally applied signal. Active control of properties of concrete refers to the concept of on- demand changes of one or more properties of the concrete after mixing by triggering a response to one or more of the constituents using a specific trigger signal (e.g. thermal, chemical, electrical, magnetic...). The on-demand control of properties can focus on the processing stage (including e.g. pumping, casting, 3D printing), the curing and hardening stage (including e.g. control of capillary pressure, shrinkage, setting, and hardening) and even on the hardened stage during service life (e.g. active corrosion control, active crack healing...). Addressing specific obstacles in cementitious environments, ensuring responsive material stability, controlling signal applicability, cost, logistics, and on-site safety is crucial for successful implementation. A RILEM technical committee has been initiated in 2023, working on the concept of Active Control of Properties of Concrete (RILEM TC 317-ACP). The committee will focus on active control of properties of fresh and hardening concrete. This paper gives a short introduction to scope and activities of TC 317-ACP.

Optimization of Zn-Cr proportions for hybrid multilayer electroplating of AISI 1045 steel – towards super-hydrophobicity and anti-corrosive nature

Localized corrosion in steel heat exchangers is a major concern, occurring mostly during operational shutdowns. Due to the absence of flow and moisture content availability, corrosion reduces operation efficiency. A study aimed to optimize the proportions of Zinc and Chromium (Zn-Cr) for developing a hybrid multi-layer electroplating method to inhibit corrosion in hypo-eutectoid carbon steel commonly used in heat exchangers. The Zn-Cr coating was performed using the amperometric method in an electrochemical workstation, producing coatings of varying thicknesses by varying the potential and time. The surface morphology was characterized using Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) analysis. The average thickness of the Zn-Cr coating was found to be 2.5 µm using the scanning probe microscope analysis. The corrosive action of a standard 3.5% NaCl solution was investigated on both coated and uncoated specimens through open circuit potential measurement and electrochemical impedance spectroscopy. The results indicated that the Zn-Cr coating effectively resisted corrosion. Contact angle measurement of water particles with the Zn-Cr coated specimen revealed a near-super hydrophobic nature with the highest contact angle of 146.8°.

Enhanced steam thermal cycle resistance of Yb2Si2O7 environmental barrier coatings via Al modification

SiC-based ceramic matrix composites are susceptible to performance losses in steam environments, necessitating the use of environmental barrier coatings for their protection. The high Si activity of Yb2Si2O7 material may induce the emergence of Si(OH)4 in steam environments, resulting in the development of a pore structure within Yb2Si2O7. This pore structure weakens the service life of the coating, highlighting the importance of enhancing the steam corrosion resistance of environmental barrier coatings as a key factor in improving their overall longevity. In the present study, we employed Al modification technique to improve the steam corrosion resistance of Yb2Si2O7 coatings. The results indicated that Al-modified Yb2Si2O7 coatings exhibited superior steam thermal cycle corrosion resistance compared to the non-modified Yb2Si2O7 coatings after testing performed at 1523 K for 1000 h (10 h per cycle). This improvement was attributed to the presence of Yb3Al5O12 and Al2O3 composite phases within the Al-modified Yb2Si2O7 coatings, which exhibited low steam activity and effective steam corrosion resistance. Moreover, Al-modified Yb2Si2O7 coatings obtained the dual excellent performance of improving the steam corrosion resistance of Yb2Si2O7 coating and not weakening the thermal cycle ability, providing a guarantee for the longer life of Yb2Si2O7 coating.