Corrosion Rate Of Steel Research Articles

STUDIES ON ESTABLISHING THE CONDITIONS FOR CHEMICAL CORROSION AND THE INFLUENCE OF TEMPERATURE ON THE CORROSION RATE FOR A LOW-ALLOY STEEL

The paper presents studies conducted to establish the conditions for chemical (dry) corrosion and the influence of temperature on the corrosion rate for a low-alloy steel. Two samples of 16MnCr5 steel of different sizes are used, which are placed in an oven at different temperatures, namely 500°C (P2) and 800°C (P1). The mass variation, oxide film thickness, and corrosion rate for each sample are calculated, with these values presented in Table 2. It is observed that the oxide layer increases in thickness with longer maintenance times and higher temperatures. Additionally, the oxidation process depends on the composition of the steel and the environment in which heating occurs. The type of corrosion observed in the experiment is uniform, with the metal being uniformly destroyed over the entire surface and the corrosion products adhering well.

Innovations in nanomaterials: A paradigm shift in surface engineering for corrosion mitigation

The weight loss technique was utilized to examine the corrosion rates of mild steel in various aqueous solutions and operating conditions, both with and without an epoxy coating. It became out that the presence of salt and temperature increased the rate of corrosion while the pH level decreased. Significant reductions in corrosion rates occur in acidic conditions when coatings are present. In a saline solution, it did not work particularly well. Using X-ray diffraction, the diagnosis was acquired after a sol–gel method was used to create a MgO nanoparticle. The highest coating efficacy in an acidic solution was 96.9%, whereas the lowest coating efficacy in a saline solution devoid of nanoparticles was 29.8%. The performance of epoxy coatings in salty environments was improved by applying nanoscale magnesium oxide (MgO) up to a maximum value of 94%. Surface morphology was examined using the SEM test as well. A number of mathematical models were proposed to be employed in order to relate the corrosion rate to the operational state; a high correlation coefficient for the data advised that the polynomial interaction effect model be used.

A MIXTURE OF ACACIA BARK EXTRACT (Acacia mangium Willd) AND POTASSIUM IODIDE AS A CORROSION INHIBITOR IN SULFURIC ACID SOLUTION

Corrosion is a decrease in the quality of a metal material caused by a reaction with the environment. Corrosion cannot be eliminated, but corrosion can be slowed down in several ways by adding corrosion inhibitors and synergistic effects. Acacia bark extract (Acacia mangium Willd) with the addition of 0.02 M KI has the potential as a corrosion inhibitor for steel because it contains secondary metabolites, so it can provide a synergistic effect and increase the value of inhibition efficiency on steel. This research aimed to analyze the effect of a mixture of acacia bark extracts (Acacia mangium Willd) with the addition of KI on inhibition efficiency corrosion of mild steel in sulfuric acid media. The method used in this study is the method of weight loss, adsorption isotherms, and thermodynamic parameters, which were carried out by varying the concentration of acacia bark extract and the immersion temperature of the steel. To strengthen the research results, characterization was carried out using FTIR and SEM. The results showed that the corrosion rate of mild steel immersed in 0.75 M H2SO4 corrosive medium with the addition of 0.02 M KI increased with increasing immersion temperature. These results are reinforced by the results of FTIR and SEM analysis which show that there is an interaction between mild steel and acacia bark extract (Acacia mangium Willd) and KI 0.02 M. Based on the thermodynamic parameters, the resulting values of ∆Hads, ∆Gads, and ∆Sads show that the adsorption process of acacia bark extract (Acacia mangium Willd) in corrosive medium H2SO4 0.75 M with the addition of 0.02 M KI took place spontaneously, showing the type of physical adsorption, adsorbed stable, the adsorption process was exothermic and the degree of irregularity in the adsorption process. The inhibition efficiency of acacia bark extract (Acacia mangium Willd) with the addition of 0.02 M KI was highest at 60 °C with an extract concentration of 2.5 g/L of 81%. The higher the immersion temperature, the greater the resulting synergistic effect

Synergistic inhibitive effect of a hybrid zinc oxide-benzalkonium chloride composite on the corrosion of carbon steel in a sulfuric acidic solution

Abstract Zinc oxide and quaternary ammonium-type surfactants have been separately recognized for their anti-corrosive efficiencies. Their composite, not investigated so far, could provide a synergetic anti-corrosion effect. In this respect, the aim of this study is to synthesize a composite material consisting of zinc oxide and benzalkonium chloride (ZnO-BAC) in varying mass ratios (3:1, 1:1, and 1:3). The inhibitory properties of the ZnO-BAC composite against carbon steel corrosion in a 0.5 M sulfuric acid solution were assessed under ambient conditions. First, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy were used to examine the chemical structure of the prepared composite. Then, the corrosion inhibitive performance of the devised inhibitors was screened using electrochemical, hydrogen collection, and weight loss measurements. Further, the surface morphology was examined using a scanning electron microscope, both before and after immersion in the corrosion medium. The electrochemical measurements indicate that the prepared inhibitor exhibits a predominant cathodic inhibition behavior and the maximum inhibition efficiency, approximately 91.9%, was achieved for one-to-one mass ratio. Similar results were obtained from weight loss and hydrogen evolution measurements, which showed that the ZnO-BAC composite reduced the corrosion rate of carbon steel by 69.9% and 64.9%, respectively. Finally, molecular dynamics and an adsorption equilibrium model were used to elucidate the mechanism of corrosion inhibition by the ZnO-BAC composite, which exhibits a high adsorption energy on the iron surface.

Damage-Tolerant Wood Layers for Corrosion Protection of Metal Structures.

Mechanically strong and damage-tolerant corrosion protection layers are of great technological importance. However, corrosion protection layers with high modulus (>1.5 GPa) and tensile strength (>100 MPa) are rare. Here, we report that a 130 μm thick densified wood veneer with a Young's modulus of 34.49 GPa and tensile strength of 693 MPa exhibits both low diffusivity for metal ions and the ability of self-recovery from mechanical damage. Densified wood veneer is employed as an intermediate layer to render a mechanically strong corrosion protection structure, referred to as "wood corrosion protection structure", or WCPS. The corrosion rate of low-carbon steel protected by WCPS is reduced by 2 orders of magnitude than state-of-the-art corrosion protection layers during a salt spray test. The introduction of engineered wood veneer as a thin and mechanically strong material points to new directions of sustainable corrosion protection design.

Monitoring Atmospheric Corrosion of Carbon Steel Under Controlled Electrolyte Droplet Distributions

Field exposure testing and accelerated corrosion testing are two common approaches applied in the industry to assess the atmospheric corrosion rate of a specific material, both relying on visual inspection and weight change of the specimen. Field exposure testing occurs under natural atmospheric conditions but requires exposure times spanning decades, whereas accelerated corrosion testing shortens the exposure time to weeks; however, the connection between the natural environment and accelerated corrosion chamber conditions remains unresolved. Efforts have been made to correlate accelerated corrosion results with those obtained in field exposure based on weight loss, both qualitatively and quantitatively, primarily empirically and limited to small datasets.This work examines the link between modified field exposure testing and the environment from the electrolyte perspective, under controlled laboratory conditions. In-situ monitoring and analysis of corrosion rate, electrolyte condition, and environment are demonstrated to be feasible, and the effect of NaCl concentration and droplet distribution on the atmospheric corrosion rate of carbon steel has been addressed.This work proposes a setup wherein multiple droplet-based conditions are created, and corrosion kinetics are actively monitored using the electrical resistance method. The sample surface is simultaneously monitored with an optical microscope, through which both droplet distribution evolution and corrosion product formation can be visualized.

Corrosion Behavior of Fe-P Binary Alloys in Low-pH Solution

Phosphorus is well known as an element which is difficult to be completely removed from steels and affects workability, welding property, and corrosion resistance. In atmospheric corrosion of steels, phosphorus improves the corrosion resistance by the formation of compact and high-density rust. In contrast, phosphorus increases the corrosion rate of steels in hydrochloric acid, but the precise reason is still unclear.In this research, the effect of phosphorus on corrosion behavior of Fe-P binary alloys was investigated by electrochemical measurements and immersion test in a low-pH solution, and corrosion morphology was examined by scanning electron microscopy.

Unification and calibration of steel corrosion models based on long-term natural corrosion

The corrosion of steel bars in concrete has a significant influence on the durability deterioration of reinforced concrete structures. The purpose of this study is to investigate the prediction models of steel corrosion rate and the main influencing factors in the case of natural corrosion. The experimental results are obtained from the long-term natural corrosion induced by accelerated chloride erosion. Then, based on electrochemical corrosion kinetics, Ohm’s law, and potential field theory, numerical models for uniform and local corrosion are established respectively, and compared with the experimental results. The main parameters and influencing factors are deeply analyzed through the numerical models. The main conclusions are as follows: (1) The cell model based on Ohm’s law can be well adapted to uniform corrosion, especially when the resistivity of concrete is the controlling factor. (2) Among the parameters of electrode polarization, the cathode Tafel slope has the greatest influence on the numerical results, followed by the anode equilibrium potential.

The Performance of Papaya Leaf Extract on The Corrosion Rate of Carbon Steel in 0.5 M HCl Solution

The performance of papaya leaf extract as a corrosion inhibitor for carbon steel metal in 0,5 M HCl solution was investigated using immersion methods. The measurements were conducted in different concentrations of papaya leaf extract and immersion time. It also investigated the effect of temperature on the corrosion rate of carbon steel without and with the use of papaya leaf extract. It would enhance the corrosion inhibitor regarding these materials since the study is still rarely elaborated. The experiments were conducted using ASTM G-31-72 standard practice for laboratory immersion corrosion testing. The carbon steel corrosion rate and inhibition efficiency were examined. Results show that the concentration of papaya leaf extracts influences the corrosion rate of carbon steel. Higher papaya leaf extract concentration reduces the carbon steel corrosion rate. The increasing immersion time increases the corrosion rate. Moreover, increasing temperatures increase the corrosion rate. The inhibition efficiency increases with the increase of papaya leaf extract concentration. The highest inhibition efficiency is 73.10% which reached a concentration of 5% and immersion times of 5 days.

PEMETAAN KOROSIFITAS ATMOSFER MENGGUNAKAN LOGAM BAJA KARBON RENDAH DAN KARBON TINGGI PADA WILAYAH KOTA SURABAYA

Corrosion of metals is inevitable. One of the factors that affect corrosion is environmental conditions that contain pollutants like SO2, NO2, and Cl- which are found in many industrial and seaside areas. Surabaya is an area that has 2 types of conditions. In addition, Surabaya is the capital of the province where infrastructure development is running rapidly. Thus, this study maps the level of atmospheric corrosion in five areas in Surabaya by collecting corrosion rate data for 4 months with weight loss method using AISI 1020 Steel and SK5 Steel as test metals. XRD and SEM-EDX tests were conducted to compare the corrosion results. The average corrosion rate of low carbon steel was 0,6561 mpy and high carbon steel was 1,2523 mpy. The results concluded that the high level of atmospheric corrosivity of low carbon steel is in Sukomanunggal, Bulak, Rungkut, Pakal, Krembangan, and Bubutan sub-districts. The medium level is in Tegalsari, Gubeng, Tenggilis Mejoyo, Karang Pilang, Jambangan, Sawahan, and Dukuh Pakis sub-districts. The low level is in Lakarsantri, Mulyorejo, Simokerto, Sambikerep, Genteng, and Wonokromo sub-districts. Meanwhile, high atmospheric corrosivity levels for high carbon steel are in Krembangan, Karang Pilang, Bulak, Tenggilis Mejoyo, Pakal, and Jambangan sub-districts. The medium level is in Rungkut, Sawahan, Bubutan, Wonokromo, Tegalsari, Sukomanunggal, and Lakarsantri sub-districts. The level is in Dukuh Pakis, Genteng, Gubeng, Simokerto, Sambikerep, and Mulyorejo sub-districts. This mapping is based on the level of corrosion in each sub-district which is influenced by the presence of industry and its geographical location.

Corrosion evolution and mechanical property deterioration of Q355NH weathering steel in long-term neutral salt spray environment

To investigate the morphology and mechanical behavior of Q355NH steel after long-term corrosion, neutral salt spray accelerated test were conducted for up to 180 days, with Q355 steel as the control group. By macro and micro observations, the evolution of rust layers and cracking mechanisms was elucidated. The corrosion thickness loss was divided into depth of uniform corrosion and pitting depth, and their relationships with corrosion time were established, respectively. Corrosion kinetic equations were also established, revealing no significant differences between two types of steel when the corrosion period was less than 65 days. However, as the corrosion period exceeded the critical time, Q355NH steel gradually exhibited better corrosion resistance. Additionally, corrosion rate for Q355NH and Q355 steel in various environments were compared, the average thickness loss rate of Q355 steel was revealed higher in intermittent neutral salt spray than continuous neutral salt spray. However, Q355NH steel exhibited the opposite trend due to the formation of the protective rust layer. Degradation equations were developed for the relationships between strengths, strains and mass loss rate in both Q355NH and Q355 steel, and constitutive models were also established for these corroded steels. Furthermore, based on the pitting evolution model, a numerical analysis method for evaluating the mechanical properties of corroded weathering steel was proposed and validated. Through parametric analysis, strength degradation formulas for double-sided non-uniform corrosion were established. It is demonstrated that the pit aspect ratio did not affect the strength. However, the strength significantly decreased when the initial thickness was small. For engineering applications involving uncoated weathering steel, a minimum thickness of 6 mm is recommended, preferably greater than 10 mm.

Novel synthesized triazole derivatives as effective corrosion inhibitors for carbon steel in 1M HCl solution: experimental and computational studies

This article outlines the synthesis of two derivatives of 4-amino-5-hydrazineyl-4H-1,2,4-triazole-3-thiol for the prevention of carbon steel corrosion in 1M HCl solution. These derivatives are (Z)-3-(1-(2-(4-amino-5-mercapto-4H-1,2,4-triazol-3-yl)hydrazono)ethyl)-2H-chromen-2-one (TZ1) and 5-(2-(9H-fluoren-9-ylidene)hydrazineyl)-4-amino-4H-1,2,4-triazole-3-thiol (TZ2). Weight loss, electrochemical experiments, surface examinations, and theoretical computation are used to evaluate the effectiveness of the two compounds to be used as corrosion inhibitors. Weight loss and electrochemical studies demonstrate that these derivatives reduce the corrosion rate of carbon steel. To examine the morphology and constitution of the carbon steel surface submerged in HCl solution as well as after adding inhibitors, surface examination tests are performed. Analysis of the test solution via UV–visible spectroscopy is employed to check the possibility of complex formation between inhibitor molecules and Fe2+ ions released during the corrosion process. In order to explore their biological activity, the antibacterial activity was investigated against (E. coli and Bacillus subtilis). Finally, theoretical confirmation of the experimental findings is provided by quantum chemical (DFT) and Monte Carlo (MC) simulation studies. More adsorption sites are present in the derivatives of 4-amino-5-hydrazineyl-4H-1,2,4-triazole-3-thiol, which offer a novel perspective for developing new classes of corrosion inhibitors with substantial protective efficacy, especially at high temperatures.

Corrosion behavior and mechanism of carbon steel in industrial circulating cooling water system operated by electrochemical descaling technology

Electrochemical descaling technology (EDT) can significantly increase the concentration ratio of industrial circulating cooling water systems (CCWSs), thereby reducing water, capital, and energy consumption. However, our understanding of the impact of EDT on carbon steel corrosion in CCWSs is limited, which increases the risk of long-term operation. In this study, the influence of the EDT on the corrosion characteristics of carbon steel was comprehensively investigated in field CCWSs (E-CCWSs) and compared with a system using traditional chemical processes (C-CCWSs). The corrosion characteristics, corrosion products, and corrosion mechanism of carbon steel have been studied using various testing methods, including the weight loss method, electrochemical testing, Confocal Laser Scanning Microscopy (CLSM), Advanced Mineral Identification and Characterization System (AMICS), etc. The research showed that the corrosion behavior of carbon steel in a circulating water system was similar and could be divided into three stages: the initial stage (corrosion rate increased), middle stage (corrosion rate slowed down gradually), and later stage (corrosion rate was stable). Owing to the lack of the corrosion inhibitor film, the corrosion rate of carbon steel in the electrochemical circulating water system was faster in the initial stage. However, the rapidly thickened corrosion product layer had a protective effect on the carbon steel. The corrosion of carbon steel entered the middle and late stages faster, and the corrosion rate decreased rapidly and tended to stabilize. In the long term, the corrosion rate of carbon steel in the electrochemical system was slightly lower than that in the chemical system. E-CCWS encounter serious pitting problems. At 120 days, the pitting depth in electrochemical systems was 108.22 μm, almost twice as deep as that in chemicals (54.79 μm). This research has important reference value for corrosion prevention and risk assessment of EDT for practical applications.

Assessing underdeposit corrosion inhibitor performance for carbon steel in CO2/Sulfide environment

Under deposit corrosion (UDC) that occurs due to the deposition of solid particles, like iron sulfide or organic solids, and CO2 corrosion, cause disasters for pipelines and fluid-handling apparatus. This research investigated the impact of mineral deposits, like iron disulfide, iron sulfide, and sand, on the inhibition performance of the commercial UDC inhibitor in sulfated CO2-saturated brine solution at 60 °C and 1000 rpm flow rates for different immersion times. The deposit characteristics, type, and coverage technique on the steel (full/partial) were explored. The surface morphology, elemental analysis, and particle size of deposits in the absence and presence of the inhibitor were analyzed. The inhibitive effect at different inhibitor concentrations and the corrosion rates of steel in the absence and presence of the deposits were calculated from the fitting process of the electrochemical impedance spectroscopy (EIS) results. The utilized UDC inhibitor has the highest efficiency (about 95 %) at a concentration of 400 ppm. The FeS, FeS2 and SiO2 deposits in the presence of the inhibitor offered a 77.5 %, 94.5 % and 94.6 % inhibition efficiency after 6h of immersion time, resulting in about 77.5 %, 25.6 % and 60.1 % increase in their efficiencies before the addition of the inhibitor. Therefore, the inhibitor can effectively inhibit the UDC triggered by FeS and SiO2 deposits in an aqueous environment containing sulfated CO2. However, it is unavailable in the steel underneath the FeS2 deposit to inhibit corrosion. EDX and XPS analyses confirm the success of the inhibitor movement through deposits and its adsorption on steels.

Corrosion performance of carbon/stainless steel in amine‐based solvents under different conditions for CO2 chemical absorption process

AbstractThe overall corrosion behavior of S304 stainless steel and A3 carbon steel in 30 wt.% MEA (monoethanolamine) and AMP/MEA (2‐amino‐2‐methyl‐1‐propanol / monoethanolamine) blended amine solutions at 40–100°C was investigated. The characterization analysis of the corroded material surfaces was performed, and the changes in the properties of both solvents after long‐term immersion corrosion were measured, including the accumulation of heat stable salts (HSS) and viscosity changes. The results of the long‐term immersion corrosion experiments showed that the corrosion rate of S304 stainless steel was significantly lower than that of A3 carbon steel in both amine solutions. However, the corrosion rate of both materials exhibited a similar trend, initially decreasing and then stabilizing over time. Due to the higher concentration of carbonate ions in the AMP/MEA system, it exhibited better overall corrosion resistance and degradation resistance compared to the MEA system. The main component of the corrosion product on carbon steel was identified as Fe2(OH)2CO3. The electrochemical test results showed that the corrosion current of S304 stainless steel was much smaller than that of A3 carbon steel, and its charge transfer resistance was much higher, indicating that it was less prone to electron loss in the organic amine solutions. Additionally, the AMP/MEA system exhibited superior corrosion resistance. © 2023 Society of Chemical Industry and John Wiley & Sons, Ltd.

Electrochemical investigation on localised corrosion under silica sand deposit layers of carbon steel within a bespoke test cell

The corrosion behaviour of deep pit-like features on carbon steel under silica sand deposits has been evaluated using a bespoke localised corrosion cell. Local pH and electrochemical measurements were performed, including impedance spectroscopy and galvanic coupling. The corrosion rate of X65 carbon steel at four different recession depths up to 9 mm was evaluated in the presence and absence of a ∼8 mm-thick silica dioxide deposit layer, in a carbon dioxide-saturated environment. The deposit reduced corrosion rates to approximately 1 mm·yr−1 and iron carbonate formed on the steel surface under the deposit due to an increase in local pH.

New multifunctional corrosion inhibitor of steel in formation water with oil containing hydrogen sulfide and carbon dioxide

Gravimetric methods were initially employed to examine the influence of inhibitor IB-1 on the corrosion rate of steel in formation water with oil, which contained hydrogen sulfide, carbon dioxide, and a combination of both. In order to assess the effectiveness of inhibitor IB-1, laboratory tests were conducted using samples of steel of grade St3. Corrosion experiments were conducted within sealed containers with a volume of 0.5 liters, using samples sized 30201 mm. The effectiveness of the IB-1 inhibitor in formation water with oil, containing hydrogen sulfide, carbon dioxide, and a simultaneous presence of hydrogen sulfide and carbon dioxide, exhibited a variation within the ranges of 88.3% to 98.0%, 72.4% to 92.7%, and 60.22% to 94.83%, respectively. The laboratory investigations allowed for the determination of the optimal concentration of inhibitor IB-1 to inhibit the growth of sulfate-reducing bacteria and protect steel of grade St3 from corrosion induced by hydrogen sulfide, carbon dioxide, and the concurrent presence of hydrogen sulfide and carbon dioxide.

Control of Corrosion Rate of Metal Alloys: SS 304 And SS 201 Using Phosphate Inhibitor in Nacl 3.5%

Corrosion is metal damage caused by electrochemical reactions with its environment. This environment can be water, air, gas, acid solution, salt solution, and others. Metals are highly active in producing an oxide layer on the metal surface under the influence of an aerobic environment. Metal corrosion is a process where the action of the surrounding media damages metal materials by the introduction of corrosion ions. This study aims to determine the best conditions for phosphate in controlling the rate of corrosion and Knowing the inhibition of phosphate on controlling the rate of corrosion. The materials used were stainless steel 201, stainless steel 304, and phosphate as an inhibitor. Meanwhile the solution NaCl 3.5% as a corrosive media environment and distilled water. Based on this research, the best phosphate concentration in reducing the corrosion rate of stainless steel 201 and 304 is 100 ppm with a reduction in the corrosion rate of stainless steel 201 of 0.022312 mpy with an inhibition percentage of 89.68%, and a reduction in the corrosion rate of stainless steel 304 by 0.045694 mpy with the percentage of inhibition is 94.027%. The corrosion rate of 304 stainless steel is lower than that of 201 stainless steel caused by differences in the Cr element composition of each metal. Stainless steel 304 contains 18.24% Cr while stainless steel 201 contains 13.00% Cr. The lower the Cr content in stainless steel, the stainless steel will be more susceptible to corrosion.

Corrosion behavior and mechanism of N80 steel caused by sulfate reducing bacteria in CO2-saturated shale gas field produced water at 60 ℃

The corrosion of steel caused by sulfate reducing bacteria (SRB) in shale gas environment is one of the big factors leading to the severe failure of pipeline steel. However, the related studies of SRB corrosion especially at a high temperature are still poor. This paper aims to investigate the effects of SRB on the corrosion behavior of N80 steel in CO2-saturated simulated shale gas produced water at 60 °C by weight loss, 3D microscope,electrochemical impedance spectroscopy (EIS) and polarization curves and so on. Results showed that the corrosion rate of N80 steel in the presence of SRB was greater than that of the abiotic control specimen. SRB cells and the inhibitive organics could have a competitive adsorption on the steel surface. The adsorption of inhibitive organics on steel in the abiotic condition caused a slight corrosion of the control specimen. While the adsorption of SRB cells as well as the subsequent formation of biofilm have accelerated the localized corrosion of specimen. Therefore, steel corrosion is accelerated in the presence of SRB at a high temperature.

Relationship of electrical resistivity and corrosion rate in alkali-activated mortars with varying alkalinity and nitrite inhibitor

The quantitative relationship between electrical resistivity and corrosion rate of steel (noted as R-C relationships) is empirical but informative in indicating corrosion risk of reinforced concrete in complex environments. However, it remains unclear how the R-C relationship line is affected by the chemistry and microstructure of cementitious binders. In this work, the corrosion behaviors of steel embedded in alkali-activated slag (AAS) mortars with varying alkali dosages were investigated to uncover the role of hydroxide ion concentration (pH) of pore solution in R-C relationship lines. Additionally, the effectiveness of sodium nitrite as a corrosion inhibitor in AAS was evaluated under high pH and chloride-rich conditions, as well as its effect on the R-C relationships. The results show that the intercept of R-C relationship lines increases with the decrease of alkali dosage in activators, which is mainly attributed to the pH drop in cementitious materials. Moreover, the slope of R-C relationship lines is a parameter related to pore structure and has a linear correlation with the average pore diameter measured by mercury intrusion porosimetry. Additionally, the efficacy of sodium nitrite as a corrosion inhibitor in AAS is insignificant, likely due to its detrimental effect on pore structure and enhanced water absorption.