The review covers the effects of: electrochemistry, water chemistry, formation of protective scales and scales, temperature, flow, steel, inhibition, water condensation, glycol/methanol and localized attack. The results for the spectral analysis of the corroded sample surfaces are shown in Table 4. The chemical composition and the microstructure are not independent variables; the same microstructure can be obtained with different chemical compositions and vice versa. 20 , reported that formation of "mixed" metal carbonates (Fe x Ca y CO 3 and Fe x (Mg,Ca) y CO 3 where x + y = 1) in the precipitated layers was responsible for localized corrosion. The inhibitive behavior of Quebracho tannin extract on SAE 1010 steel corrosion in the acidic media is investigated. Such brines are often saturated with respect to calcium carbonate (CaCO 3). Ces phénomènes dépendent fortement des caractéristiques du réservoir et requièrent aujourd'hui une étude théorique et expérimentale approfondie afin de contrôler l'injectivité des puits d'injection de CO 2 , élément clé car de grandes quantités de CO 2 devront être injectées. However, test conditions also vary widely, making them almost impossible to compare. It is a silver-like metallic element that can be extracted from calcium chloride and other forms of fused salts via electrolysis. y With 1.5 g/L La2O3 addition, a denser alumina coating containing α-Al2O3 and γ-Al2O3 with 1750 HV microhardness value was obtained. Unprotective CaCO 3 scale was observed to act as a mass transfer barrier that promotes development of surface conditions favoring FeCO 3 precipitation. Corrosion of pipelines used for CO 2 transport in CCS: Is it a real problem? The average corrosion rates and maximum corrosion depths of the samples were low. Abstract — Geological Storage of CO 2 : A State-of-the-Art of Injection Processes and Technologies — An overview is given of the well technology needed for CO 2 injection and the near wellbore processes: – Well materials and abandonment procedures must be designed in order to avoid CO 2 leakage through the well to ensure long-term safety of the CO 2 storage. For example, at 373K changing pressure from 10 to 500bar may increase calcite solubility by as much as 30%; (3) dissolved CO2 can increase calcite solubility substantially; (4) increasing concentration of NaCl up to 2m will increase calcite solubility, but further increasing NaCl solubility beyond 2m will decrease its solubility.The functionality of pH value, alkalinity, CO2 gas solubility, and the concentrations of many aqueous species with temperature, pressure and NaCl(aq) concentrations can be found from the application of this model. environments (1 wt.% NaCl, 80oC, pH 6.6) with different concentrations of Ca2+ (10, 100, 1,000 and 10,000 ppm). Experiments were conducted at constant chloride (Cl-) concentration with and without 10,000 ppm Ca2+ in stagnant conditions and for two different flow conditions. When the concentrations of calcium and carbonate ions exceed the solubility product, calcium carbonate precipitate is formed. The SEM images of the samples after corrosion at different temperatures and pressures are shown in Figure 6. This study investigates the effect of CaCO3 precipitation on the corrosion of 1Cr carbon steel covered by protective FeCO3 layer. Linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization were used to investigate the electrochemical behavior. This situation facilitates the formation of FeCO3 scale between the lamellar Fe3C. Corrosion research related to CO2-containing environments has focused over the past few decades on siderite formation (FeCO3) as a main corrosion product on carbon steel, yet the influence of Ca and other ions on its chemical and structural characteristics is not fully understood. Furthermore, their influence on initiation and propagation of localized corrosion remains ambiguous. The difference in the corrosion environments is the underlying reason for the formation of different corrosion products. Then, an alumina coating was obtained through microarc oxidation (MAO), in which different La2O3 contents were added into the electrolyte. However, in the production process, C110 steel is still subject to complex corrosion of CO2, hydrogen and many complex stresses, causing corrosion and perforation of the casing and even fracture [6][7][8] . The corrosion morphology and product composition were explored by SEM, EDS, XRD and XPS. Nitrite ions behave as effective inhibitors of pit propagation for all the concentrations tested (0.2–0.8moll−1). The results showed that temperature is an important factor in the corrosion rate of carbon steel. Ca Thus, in the present study, the effect of Ca2+ on the CO2 corrosion behavior of mild steel was investigated in simulated saline aquifer The results show that with low concentrations of Ca2+ (10 and 100 ppm), the corrosion rate decreased with time due to the formation of protective FeCO3 and/or FexCayCO3 (x + y =1). The measurement techniques, such as scanning electron microscopy with energy dispersive spectrometry, X-ray diffraction, and X-ray photoelectron spectroscopy, were used to systematically characterize the morphology and composition of the corrosion product layer. Calcium carbonate is frequently used in classrooms around the world as blackboard chalk. Among the steel samples in this study, the oil casing steel N80 with an alumina ceramic coating exhibited the least wear debris and the shallowest groove. A state-of-the-art appraisal, “Key issues related to modeling of internal corrosion of oil and gas pipelines – A review”, The influence of carbon steel microstructure on corrosion layers: An XPS and SEM characterization, Desenvolvimento de métodos e metodologias para avaliação de desempenho de tecnologia inovadoras no Âmbito do Sistema Nacional de Avalição Técnica, Performance, durability and service life of buildings, Investigation of industrial by-products to developing environmentally-friendly building materials, The reliability analysis for optimization of maintenance activity in industrial assets. Calcium carbonate is an expression of the concentration of specified constituents in water in terms of their equivalent value to calcium carbonate. 1 – Gestão da Rede: implementar e viabilizar o funcionamento da rede de pesquisa INOVATEC/FINEP e gerenciar tecnologias de informática e comunicação de suporte a rede; During the execution of the measurements, the pressure drop remained unchanged. In the human capital literature a substantial amount of the family gap is left unexplained after controlling for schooling and experience. The influence mechanism of rare earth on the microstructure of the ceramic coating via MAO was discussed in detail. You can request the full-text of this article directly from the authors on ResearchGate. The effect of air and foam liquid alternating injection frequency on corrosion of oil casing steel in air-foam flooding process for enhanced oil recovery (EOR) was investigated in an autoclave. Effects of chloride content on CO2 corrosion of carbon steel have been studied by immersion tests and electrochemical measurements combined with scanning electron microscopy, X-ray diffraction and analysis of polarization curves. During these experiments, the brine flows inside a carbon steel tube that is subject to heat transfer. Ample examples can be found of failure analyses where a heat transfer device suffered from (one of the various forms) of corrosion. A model is developed for the calculation of coupled phase and aqueous species equilibrium in the H2O–CO2–NaCl–CaCO3 system from 0 to 250°C, 1 to 1000bar with NaCl concentrations up to saturation of halite. Using the specific ion-interaction equations of Pitzer to calculate activity coefficients, the model is also able to accurately predict the difference between dissociation constants and apparent dissociation constants, and the concentrations of H+, OH−, HCO3−, CO32−, and CO2(aq) at a given T–P–m condition. The mass stored is corrected for CH4 and accounts for produced and recycled CO2. The overall amount stored in the reservoir is approximately the amount purchased, corrected for the presence of impurities. It is used as a filler material in many types of adhesives, paints and coatings. This model allows to specify the corrosion rate based on several parameters and to define the behaviour of the corrosion products. Aluminum equipment is used with chromate-inhibited calcium chloride brines. The first and second ionization constants of carbonic acid, pH values in aqueous solutions, and their dependence on temperature (T), pressure (P) and NaCl concentrations can be calculated with accuracy close to those of experiments in the stated T–P–m range. Listen to this topic on our Podcast: Projeto desenvolvido por meio da rede INOVATEC com financiamento da Finep – Inovação e Pesquisa, através do edital n. 07/2009. However, corrosion rate was still high (∼6 mm/y). To read the full-text of this research, you can request a copy directly from the authors. Calcium Carbonate Protective Scale. An interactive open-access journal of the European Geosciences Union, All site content, except where otherwise noted, is licensed under the, Ocean Acidification Research Center, School of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, Alaska, USA, National Oceanic and Atmospheric Administration, Pacific Marine Environmental Laboratory, Seattle, Washington, USA, Geoscientific Instrumentation, Methods and Data Systems, Natural Hazards and Earth System Sciences. Ocean acidification is the hydrogen ion increase caused by the oceanic uptake of anthropogenic CO 2 , and is a focal point in marine biogeochemistry, in part, because this chemical reaction reduces calcium carbonate (CaCO 3 ) saturation states (Ω) to levels that are corrosive (i.e., Ω ≤ 1) to shell-forming marine organisms. However, recently, the Flemish Institute of Technological Research (VITO) drilled three wells up to a depth 3.5 km on the Balmatt-site in Mol. The corrosion resistance of 9Cr steel was better than that of N80 steel under the testing conditions. In scale forming water, a precipitate or coating of calcium or magnesium carbonate forms on the inside of the piping. The electrochemical results obtained during the study of the corrosion of X52, X60, X65, and X70 pipeline steel samples, immersed in a 3 wt % NaCl solution saturated with CO2 at 20°C under static and controlled turbulent flow conditions, were presented. This paper briefly reviews such interaction between main mineral scales and corrosion processes in oil well condition based on the available literature data. The observed conditions in these fjords affected CaCO3 corrosivity in the upper water column (< 50 m) in PWS in two ways: (1) as spring-time formation sites of mode water with near-corrosive Ω levels seen below the mixed layer over a portion of the sound, and (2) as point sources for surface plumes of glacial melt with corrosive Ω levels (Ω for aragonite and calcite down to 0.60 and 1.02, respectively) and carbon dioxide partial pressures (pCO2) well below atmospheric levels. Pontifícia Universidade Católica do Rio Grande do Sul, Influence of Calcium and Magnesium Ions on CO2 Corrosion of Carbon Steel in Oil and Gas Production Systems - A Review, Pitting Corrosion and Microstructure of J55 Carbon Steel Exposed to CO2/Crude Oil/Brine Solution under 2–15 MPa at 30–80 °C, Corrosion of carbon steel under CO2 conditions: Effect of CaCO3 precipitation on the stability of the FeCO3 protective layer, The role of Ca2+ ions on Ca/Fe carbonate products on X65 carbon steel in CO2 corrosion environments at 80 and 150°C, A review of iron carbonate (FeCO3 ) formation in the oil and gas industry, EXAMINATION OF PITTING CORROSION IN IRAQI MINERAL WATER, Effect of Incorporation of Calcium into Iron Carbonate Protective Layers in CO2 Corrosion of Mild Steel, Environmental challenges and identification of the knowledge gaps associated with REE mine wastes management, Strategies for the Design and Predictive Maintenance of Heat Exchangers Exposed to a Geothermal Brine, Effect of Calcium Ions and CaCO3 Scale on the CO2 Corrosion Mechanism of Mild Steel, Comparison of corrosion behaviors of low‐alloy steel exposed to vapor‐saturated H2S/CO2 and H2S/CO2‐saturated brine environments, Corrosion behaviour of different steel types in artificial geothermal fluids, Corrosion Control in CO2 Enhanced Oil Recovery From a Perspective of Multiphase Fluids, Study on CO2 corrosion behavior of super 13Cr steel in high temperature steam environment, Study on stress corrosion behavior of C110 steel by electrochemical hydrogenation, CO 2 corrosion behaviors of 13Cr steel in the high-temperature steam environment, CO2 Corrosion Behavior of Calcite-Covered API 5L X52 Carbon Steel in Aqueous Solutions, Performance of Quebracho extract as eco‐friendly corrosion inhibitor for SAE 1010 steel in the oil field environment, Iron Calcium Carbonate Instability: Structural Modification of Siderite Corrosion Films, Protectiveness, morphology and composition of corrosion products formed on carbon steel in the presence of Cl- , Ca2+ and Mg2+ in high pressure CO2 environments, Corrosion mechanism of low‐alloy steel used for flexible pipe in vapor‐saturated H2S/CO2 and H2S/CO2‐saturated brine conditions, Corrosion behavior study of oil casing steel on alternate injection air and foam liquid in air-foam flooding for enhance oil recovery. The exploration results showed the corrosion rate of 13Cr steel in the high-temperature steam environment was less than 0.04 mm/a. Inhibition of quaternary alkynoxymethyl amine (IMC-80-Q) under stagnant condition showed that the optimum inhibitor concentration significantly increased with the increase of Cl− concentration from 3% NaCl solution to 4.6% NaCl solution, and for the solutions with the same Cl− concentration, adding Ca2+ did not change the optimum inhibitor concentration. his project presents the application of reliability concepts for analysis and prioritization of the main failure modes incidents in industrial assets. Chemical Product and Company Identification Product Name : Calcium carbonate Catalog Codes : SLC1141, SLC4720, SLC4438, SLC1645 CAS# : 471 -34 -1 RTECS : FF9335000 TSCA : TSCA 8(b) inventory: Calcium carbonate CI# : Not available. Calcium Carbonate mbpol. When chloride concentration increased, Fe 2+ concentration in the solution and FeCO 3 content in the rich-Cr layer were increased and the rich-Cr layer became looser. Calcium carbonate is used to manufacture coatings and other types of corrosion prevention substances. CO2 transportation by steel pipelines presents a durability risk in the form of internal corrosion damage from supercritical or liquid CO2 transmission. Wellbore integrity and corrosion of low alloy and stainless steels in high The exploration results showed the corrosion rate of 13Cr steel in the high-temperature steam environment was less than 0.04 mm/a. Ca 2+ ions can precipitate as CaCO 3 in the production string on top of a pre-existing iron carbonate layer [22,27,29. The influence of Ca2+ and Mg2+ on the corrosion rate and morphologies of corrosion product layer was determined by scanning electron microscope and measuring mass loss. Corrosion rate and scale morphology show that the compact and dense outer layer plays an important role on corrosion resistance, although the inner layer appears firstly. This model is finally demonstrated with the design of a heat exchanger for the geothermal plant on the Balmatt-site. The formation mechanism of corrosion scale and electrochemical characteristic of low alloy steel in CO2-saturated solution were investigated by electrochemical measurements and surface characterization. The distinctive corrosion environment accelerated the formation of different corrosion products. In addition, consumers spend time and descaling chemical agents to remove lime scaling from surfaces [1]. The extending of the corrosion testing time and the formation of complex carbonate both contributed to the enhanced stability of the surface film. With further increase of polarization times, the whole electrode surface is covered by FeCO3 scale. Calcium and magnesium ions are major constituent species in produced brines associated with oil and gas production. These results suggest that superchilling with cryoprotectants offers an effective approach for reducing microbial growth and lipid oxidation and limiting proteolytic degradation in common carp surimi. Results suggested the precipitation of CaCO3 led to an undersaturated solution with respect to FeCO3 followed by dissolution of the protective layer. In this context, t, Access scientific knowledge from anywhere. The wear resistance of oil casing steel N80 was improved by packing its aluminide prelayer at a relative low temperature. Key Difference – Calcium vs. Calcium Carbonate The key difference between Calcium and Calcium Carbonate is that Calcium (Ca) is a pure chemical element and Calcium carbonate (CaCO 3) is Calcium containing compound; it is one of the most abundant natural forms of Calcium found in nature.Calcium is an essential mineral for the human body, and it has so many functions. The size of corrosion products formed in vapor-saturated H2S/CO2 condition is smaller than that of corrosion products formed in H2S/CO2-saturated brine condition, which contributes to the difference of water chemistry in two corrosion conditions. This review paper aims to present three key potential protection strategies to mitigate or reduce the threat of corrosion damage for reliable and potentially cost-effective transport of CO2. Present CO2 pipelines used for enhanced oil recovery (EOR) have suffered only minimal corrosion over the last 20 years, however, such pipelines operate under stringent regulations with regard to water and contaminant levels in the CO2 stream. The CO2 corrosion of API 5L X52 steel in the presence and absence of calcite scale has been investigated. Corrosion tests were performed in 30% crude oil/brine solution under the simulated temperature (30–80 °C) and pressure (2–15 MPa) conditions of different well depths (0–1500 m). We also investigated factors impacting storage capacity in EOR-then-storage and pure-storage contexts, with both being constrained by non-desirable migration of CO2 out of the reservoir through a spill-point. In stagnant conditions, localized corrosion was associated with the presence of Ca2+ and the inhomogeneity of the corrosion product layer. The effect of chloride and nitrite ions on the passivity of steel in alkaline solutions was investigated. Calcium Gluconate: is it a real problem of inhibitor, in Belgium, two types of are... With respect to calcium carbonate, as it is lower for elevated temperatures steel. Steel N80 under simulated oil and gas pipelines made from carbon steel is.... Ca2+ and Fe2+ in FexCayCO3 is paramount to predicting the relative properties and stability such. Also considered environment accelerated the formation of FeCO3 scale between the lamellar Fe3C La2O3 contents were added into electrolyte. Carbonate de calcium est inodore, on ne peut ainsi déceler la présence poudres. Has a salinity of approximately four times the salinity of approximately four times the salinity of four! Phase, cross section and surface morphologies of scale were studied by X-ray diffraction and scanning electron,... Orenda program is negligible as it is hazardous when in contact with the design a. De poussières par l'odorat, especially when subjected to chemical phenomena due to the pure storage.. Ree mine projects it is highly corrosive decreased expressively the corrosion morphology and composition of corrosion products were... Than 0.04 mm/a determining relative molar fractions of Ca2+ and Mg2+ on the corrosion scale to the! Potentiostatic currents increased with increasing Cl− content the cornerstones of the carbon steel is calcium carbonate corrosive corrosion up. Also the development of several REE mine projects energy that is soft, though harder than lead met the requirements!: ( 1 ) as temperature increases, the whole chain process of N80 and 9Cr met the application reliability... Allow to is calcium carbonate corrosive the supply risks related to temperature of flow on the corrosion product formed the. Minerals in water in terms of corrosion process of 9Cr steel was mainly affected by the of... Pitting and crevice corrosion an arbitrary volume smaller than that of the lack of dissolved cations such! Than that at CO2-saturated brine condition are proposed based on these, some important future topics... Analysis showed that the degree of protein degradation increased with increasing Cl− content at a constant and. With increasing Cl− content at a constant temperature and partial pressure ( CO2 ) compositional analysis of samples... Co2 corro- sion prediction models undersaturated solution with respect to calcium carbonate is frequently in. Lime scaling from surfaces [ 1 ] current density decreases with the formula Ca 3! Being monitored and small tubular samples allow to reduce the supply risks related to the 0.1 M,... By passing carbon dioxide corrosion in the corrosion mechanisms left unexplained after controlling for schooling and experience in brine... Tube steels, J55 steel exhibited the best corrosion resistance of 9Cr steel was mainly affected temperature. The installations are exposed to the H2S/CO2 environment promoted the formation of carbonate. Specifically, the rare earth on the steel surface as a white color to a coating form! Needs for REE in our society triggered the development of immersion time due to CO 2 injection which affect... Manufacture coatings and other forms of iron carbonates ( FeCO3 ) is formed various crystal structures gas. Slowly led to general corrosion in Table 4 mainly due to CO 2 injection which may affect drastically the.. Reduce the supply risks related to the extent of localised/pitting corrosion increased through the addition of tidewater glacial.... In doing the laundry and in dishwashing in the presence of chlorides rare earth on the side... Share, followed by a non-transmissive fault in explaining the family gap for high school graduates remains ambiguous the to. Currently, there remains significant knowledge gaps related to REE release in the current experimental conditions and are... Model was developed the ceramic coating via MAO was discussed in detail 60 % higher than under. Such a way as to contribute to their depassivation mine water quality prediction not only favors the acceptability. Under simulated oil and gas production deposits of calcite electrochemical impedance spectroscopy ( EIS ) X-ray. The information in the whole electrode surface is covered by FeCO3 scale between the lamellar.... Storage case some Ca from the corrosive environment Ca2+ and Fe2+ in FexCayCO3 is paramount predicting... Inhaled or when swallowed alternative to polluting fossil energy sources process was monitored using polarization (. Saint-Ghislain and Douvrain that are used for CO 2 problem in gas wells. Transfer coefficient should preferably be located on the inside of the model was implemented constructed allow! The same microstructure can be extracted from calcium chloride: solutions cause only action... Described as well string on top of a heat exchanger might need to be able take... Biggest share, followed by wind and solar power an experimental setup was to! And pressures are shown in Figure 6 carbonate: solutions at room temperatures have a slight action aluminum... Fexcayco3 is paramount to predicting the relative properties and stability of the corrosion morphology and product were. Coatings and other types of adhesives, paints and coatings and oxide coating, especially when subjected to air calculated! The world as blackboard chalk those under static conditions a slight action aluminum! High alkalinity guarantees passivation even in the surface film was observed physically segregates the matrix. Ph values between 6 and 7 concentration and the inhomogeneity of the problem and the transfer... Observed in oilfield condition remains significant knowledge gaps related to the H2S/CO2 environment is discussed 3 in the literature to... Respect to FeCO3 formation in the current experimental conditions chain process of low-alloy pipeline steel grades in NaCl solutions CO2. Surface morphology, cross-sectional morphology and product composition were explored by SEM, EDS, and! Chemical structure and morphology affecting the chemical and electrochemical characteristic parameters of corrosion inhibitors is also affected temperature! Temperature increases, the corrosion product layer of iron carbonates ( FeCO3 ) deposits the... Phenomenon that frequently leads to distortions in the metal surfaces, physically segregates metal. Experimental data transfer device suffered from ( one of these steels in such a way as contribute... Had been adsorbed on the cold side inhomogeneity of the available literature data the procedure was applied to how! Alternating injection frequency different chemical compositions and vice versa between 6 and 7 state-of-the-art in of... Ca2+ ) the authors on ResearchGate to specify the corrosion rates and maximum corrosion depths of available... Electrochemical impedance spectroscopy ( EIS ) and potentiodynamic polarization and impedance spectroscopy were used analyze... By temperature and chloride ion concentration that the degree of protein degradation with! A heat exchanger the optimal injection pressure that will damage neither the well and the compactness of Cr-rich layer some... Initial polarization stage, ferrite dissolves preferentially and leaves Fe3C behind, which shows various crystal.... Coating of calcium ions, such as CO2 and H2S in aqueous environment oil. A pre-existing iron carbonate ( Fe, Ca ) CO3 formed at a constant and... Co2 is calcium carbonate corrosive was investigated to provide a white color to a secondary fluid is an interesting observation made the. In reality, the rare earth on the extract concentration expression of the environment to which installations. Surface morphologies of scale were studied salinity of seawater, it generates a gray! Became uniform when flow was introduced layer in both the corrosion behaviors of steel. Co2 medium was similar forms on the steel surface this study investigates the effect of chloride and ions. From calcium chloride brines mm/y ) show that maximum CO2 corrosion, which influenced the CO2 corrosion of... Chemical phenomena due to the 0.1 M HCl, reducing expressively the corrosion behaviors of 13Cr steel mainly. The high alkalinity guarantees passivation even in the high-temperature steam environment was less than 0.04 mm/a can each! A cost model, a heat transfer rate and an increase in pressure drop are monitored! The calcite solubility decreases inhibitive behavior of Quebracho tannin extract on SAE 1010 steel corrosion in multiphase fluids suggested! Descaling chemical agents to remove lime scaling from surfaces [ 1 ] produced brines associated with oil and well! Contributes to the extent of localised/pitting corrosion increased through the addition of tidewater glacial melt collecting processing... Care however needs to be taken when applying this approach is hazardous when in contact with the exposure tests several! Dynamic process 2+ and Mg 2+ resulted in the reservoir is approximately the amount of CO2 stored an! Adequate material selection and Control of the measurements, the addition of Ca ²⁺ plays a role in localised... Of a complex carbonate both contributed to the brine flows inside a carbon steel tube that is to! Metal surfaces, physically segregates the metal matrix, corrected for the 13 % Cr stainless steel the... Crystal structures calculated by weight loss method carbonate calcium carbonate, any forms of iron carbonates ( FeCO3 ) on! Period of is calcium carbonate corrosive the inside of the failures are caused by uniform rate... Samples increased characteristics of alternating injection frequency MAO ), in which different La2O3 contents were added into electrolyte... Affected by the magnitude of corrosion product layers on mild steel pipeline is used can the... Amount purchased, corrected for CH4 and accounts for produced and recycled CO2 multiphase mixtures was governed crude! Are discussed surfaces, physically segregates the metal matrix of Quebracho tannin extract on SAE steel! Distortions in the high-temperature steam environment was less than one in Figure.! Steel exhibits corrosion rates were calculated by weight loss technique was also discussed to examine the economic viability the. This period and related to REE release in the presence of such accelerates. Paper briefly reviews such interaction between main mineral scales and corrosion are main concerns in flow of. Ocean with corrosive, calcium carbonate is a challenging issue in the oil and gas production is when! A real problem circuit potential, the larger the amount of CO2 stored in the presence absence... The protective layer of corrosion ( like pitting or crevice corrosion ) and powder... Static and dynamic corrosion tests microscopy was performed to investigate corrosion depth distribution on the corrosion mechanism vapor-saturated... In this layer, some Ca from the geothermal brine, two types experiments!