Effect of Sulfur and Chlorine on Fireside Corrosion Behavior of Inconel 740 H Superalloy

2018 ◽  
Vol 37 (3) ◽  
pp. 245-251 ◽  
Author(s):  
Lu Jin-tao ◽  
Li Yan ◽  
Yang Zhen ◽  
Huang Jin-yang ◽  
Zhu Ming ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Oxide Film ◽  
Corrosion Behavior ◽  
Flue Gas ◽  
Coal Ash ◽  
Corrosion Process ◽  
Fireside Corrosion

AbstractFireside corrosion behavior of Inconel 740H superalloy was studied at 750 °C in simulated coal ash/flue gas environments by means of XRD, SEM and EDS. The results indicated that the corrosion behavior was strongly related to the SO2 levels and was significantly affected by NaCl additions. In presence of the atmospheres with 0.1 % SO2, the alloy exhibited the highest corrosion resistance due to formation of a stable and dense Cr2O3 film. In presence of the atmosphere with 1.5 % SO2, however, a non-coherent and porous Cr2O3 film was formed. The thickness of film and internal sulfides were substantially increased. The NaCl additions significantly accelerated the corrosion process. A non-protective outer oxide film was formed, composed by multiple layers with serious inner sulfide and spallation. The depths of internal oxidizing and sulfuration zones were significantly increased. The mechanism of ash corrosion formation was also discussed.

Evaluation of the corrosion behavior of AZ31 magnesium alloy with different protein concentrations

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yucong Ma ◽  
Mohd Talha ◽  
Qi Wang ◽  
Zhonghui Li ◽  
Yuanhua Lin
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Surface Film ◽  
Energy Dispersive Spectrometer ◽  
Inhibitory Effect ◽  
Corrosion Process ◽  
High Concentration ◽  
Content Type ◽  
Atomic Force

Purpose The purpose of this paper is to study systematically the corrosion behavior of AZ31 magnesium (Mg) alloy with different concentrations of bovine serum albumin (BSA) (0, 0.5, 1.0, 1.5, 2.0 and 5.0 g/L). Design/methodology/approach Electrochemical impedance spectroscopy and potential dynamic polarization tests were performed to obtain corrosion parameters. Scanning electrochemical microscopy (SECM) was used to analyze the local electrochemical activity of the surface film. Atomic force microscope (AFM), Scanning electron microscope-Energy dispersive spectrometer and Fourier transform infrared spectroscopy were used to determine the surface morphology and chemical composition of the surface film. Findings Experimental results showed the presence of BSA in a certain concentration range (0 to 2.0 g/L) has a greater inhibitory effect on the corrosion of AZ31, however, the presence of high-concentration BSA (5.0 g/L) would sharply reduce the corrosion resistance. Originality/value When the concentration of BSA is less than 2.0 g/L, the corrosion resistance of AZ31 enhances with the concentration. The adsorption BSA layer will come into being a physical barrier to inhibit the corrosion process. However, high-concentration BSA (5.0 g/L) will chelate with dissolved metal ions (such as Mg and Ni) to form soluble complexes, which increases the roughness of the surface and accelerates the corrosion process.

Corrosion behavior of new type Co-based superalloys with different Ni contents

2017 ◽  
Vol 35 (6) ◽  
pp. 455-462 ◽  
Author(s):  
Bo Gao ◽  
Lei Wang ◽  
Yang Liu ◽  
Xiu Song ◽  
Shu-Yu Yang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Hot Corrosion ◽  
Corrosion Layer ◽  
Corrosion Process ◽  
Corrosion Properties ◽  
Oxidation Processes ◽  
Ni Content ◽  
Ni Addition ◽  
New Type

AbstractThe corrosion properties of γ′-strengthened Co-xNi-Al-W-Cr (where x=15, 20, 25, and 30 at.%) superalloys were investigated in the mixture of 75 wt.% Na2SO4+25 wt.% NaCl at 900°C. The results showed that the corrosion behavior is associated with both sulfuration and oxidation processes. It was demonstrated that increasing the addition of Ni effectively promoted the formation of continuous Al2O3 scales, so that the hot corrosion resistance could be improved. When Ni content is more than 20 at.%, a large amount of Ni3S2 precipitates during the corrosion process. Sulfuration can destroy the integrity of the corrosion layer and increase the activity of oxygen. In this way, the internal oxidation of the alloys becomes more serious. Therefore, it is recommended that the optimum Ni addition is about 20 at.% for new type Co-Ni-Al-W-Cr superalloys.

scholarly journals Study on Corrosion Behavior of Ultrafine-Grained Ti-6Al-7Nb Fabricated by Equal Channel Angular Pressing

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 950 ◽  
Author(s):  
Zequn Yu ◽  
Yuecheng Dong ◽  
Xin Li ◽  
Jingzhe Niu ◽  
Igor Alexandrov ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Oxide Film ◽  
Equal Channel Angular Pressing ◽  
Corrosion Behavior ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Electrochemical Measurement ◽  
Coarse Grained ◽  
Angular Pressing ◽  
Ultrafine Grained

The aim of this study was to investigate the corrosion resistance of ultrafine-grained (UFG) Ti-6Al-7Nb fabricated by equal channel angular pressing (ECAP) and coarse-grained (CG) Ti- 6Al- 7Nb. The microstructure of each specimen was investigated by the electron backscattered diffraction (EBSD) method. The corrosion behavior of each specimen was determined by electrochemical measurement in Ringer’s solution. The surface corroded morphologies and oxide film formed on Ti-6Al-7Nb alloy after electrochemical measurement were investigated by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). EBSD investigation shows that the grain size of UFG Ti-6Al-7Nb decreased to ~0.4 µm, accompanied by low angle grain boundaries (LAGBs) accounting for 39%. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) results indicated that UFG Ti-6Al-7Nb alloy possessed a better corrosion resistance. The surface corroded morphologies revealed many small and shallow corrosion pits, which can be attributed to the good compactness of the oxide film and a rapid self- repairing ability of the UFG Ti-6Al-7Nb alloy.

Corrosion behaviour of Mn‐Si‐Fe‐Cu‐Al alloy explosion suppression materials

2013 ◽  
Vol 60 (5) ◽  
pp. 234-238
Author(s):  
Yan Jing ◽  
Chao Zhang ◽  
Jun Ma ◽  
Yongzhong Jia
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Design Methodology ◽  
Room Temperature ◽  
Corrosion Behaviour ◽  
Corrosion Process ◽  
Al Alloy ◽  
Content Type ◽  
Explosion Suppression ◽  
Strengthening Phases

PurposeThe purpose of this paper is to prepare the Mn‐Si‐Fe‐Cu‐Al alloy explosion suppression materials, and determine the corrosion behavior of aluminum alloy explosion suppression materials in HCl and NaOH solutions. The different mechanism of corrosion was discussed.Design/methodology/approachIn this paper, Mn‐Si‐Fe‐Cu‐Al alloy explosion suppression materials were prepared, and the electrochemical behavior of the EAESM was studied. The corrosion parameters were calculated and the mechanism of the corrosion process was discussed. The corrosion behavior was characterized by immersion tests and SEM at room temperature.FindingsMn‐Si‐Fe‐Cu‐Al alloy explosion suppression materials have been prepared. SEM, the polarization curves showed that materials have corrosion resistance. The best content of Al alloy is Mn 0.880%, Si 0.135%, Fe 0.383% and Cu 0.0835%.Originality/valueThe results of this investigation show that adding alloying elements can form new strengthening phases that influence the corrosion resistance of alloys.

scholarly journals Corrosion Behavior of the Ni–Cr–Fe Base Superalloy GH984G in a Synthetic Coal Ash and Flue Gas Environment

2017 ◽  
Vol 30 (9) ◽  
pp. 863-868 ◽  
Author(s):  
Guang-Ming Liu ◽  
Hua-Chun Yang ◽  
Qin Liang ◽  
Xiao-Chuan Yang ◽  
Shan-Ping Ren ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
Flue Gas ◽  
Coal Ash ◽  
Gas Environment ◽  
Base Superalloy

Corrosion Behavior of Al2O3 Ceramics in the Acid and Alkaline Solutions

2012 ◽  
Vol 512-515 ◽  
pp. 509-512 ◽  
Author(s):  
Long Huang ◽  
Shan Shan Luo ◽  
Wen Kui Li
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Sea Water ◽  
Working Life ◽  
Corrosion Process ◽  
Alkaline Solutions ◽  
Acid Solutions ◽  
Wide Range ◽  
Alkaline Conditions ◽  
Corrosion Time

Al2O3 materials were used in a very wide range due to its good mechanical properties and relative low manufacture cost. The corrosion resistance of Al2O3 materials in acid, alkaline and sea water solutions gained more and more attention because many application situations are severe and the working life is shorten due to the corrosion. In this paper, the corrosion behavior of Al2O3 based materials in acid and alkaline solutions was studied and effect of corrosion time on the corrosion behavior of Al2O3 materials was investigated. The microstructure of as prepared Al2O3 materials was characterized by SEM. Possible corrosion process and mechanism was discussed in details. The results reveal that the as prepared Al2O3 materials show better corrosion resistance in alkaline solution than in acid solutions. In both acid and alkaline conditions, the corrosion mainly occurs in the grain boundary. Mass loss increased with increasing corrosion time, while the corrosion rate was decreased.

Data-driven modeling of fireside corrosion rate

2017 ◽  
Vol 64 (4) ◽  
pp. 397-404 ◽  
Author(s):  
Amrita Kumari ◽  
S.K. Das ◽  
P.K. Srivastava
Keyword(s):  
Fly Ash ◽  
Corrosion Rate ◽  
Flue Gas ◽  
Thermal Power ◽  
Coal Ash ◽  
Gas Temperature ◽  
Ann Model ◽  
Fireside Corrosion ◽  
Content Type ◽  
Network Training

Purpose This paper aims to propose an efficient artificial neural network (ANN) model using multi-layer perceptron philosophy to predict the fireside corrosion rate of superheater tubes in coal fire boiler assembly using operational data of an Indian typical thermal power plant. Design/methodology/approach An efficient gradient-based network training algorithm has been used to minimize the network training errors. The input parameters comprise of coal chemistry, namely, coal ash and sulfur contents, flue gas temperature, SOX concentrations in flue gas, fly ash chemistry (Wt.% Na2O and K2O). Findings Effects of coal ash and sulfur contents, Wt.% of Na2O and K2O in fly ash and operating variables such as flue gas temperature and percentage excess air intake for coal combustion on the fireside corrosion behavior of superheater boiler tubes have been computationally investigated and parametric sensitivity analysis has been undertaken. Originality/value Quite good agreement between ANN model predictions and the measured values of fireside corrosion rate has been observed which is corroborated by the regression fit between these values.

scholarly journals Calculation of Oxygen Diffusion Coefficients in Oxide Films Formed on Low-Temperature Annealed Zr Alloys and Their Related Corrosion Behavior

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 850 ◽  
Author(s):  
Lina Zhang ◽  
Liang-Yu Chen ◽  
Cuihua Zhao ◽  
Yujing Liu ◽  
Lai-Chang Zhang
Keyword(s):  
Corrosion Resistance ◽  
Weight Gain ◽  
Oxide Film ◽  
Corrosion Behavior ◽  
Diffusion Coefficients ◽  
Oxygen Diffusion ◽  
Short Circuit ◽  
Oxide Films ◽  
Zirconium Alloys ◽  
Second Phase

The growth of oxide film, which results from the inward oxygen diffusion from a corrosive environment, is a critical consideration for the corrosion resistance of zirconium alloys. This work calculates the oxygen diffusion coefficients in the oxide films formed on zirconium alloys annealed at 400~500 °C and investigates the related corrosion behavior. The annealed samples have a close size for the second-phase particles but a distinctive hardness, indicating the difference in substrate conditions. The weight gain of all samples highly follows parabolic laws. The weight gain of the sample annealed at 400 °C has the fastest increase rate at the very beginning of the corrosion test, but its oxide film has the slowest growth rate as the corrosion proceeds. By contrast, the sample annealed at 500 °C shows the lowest weight gain but the highest corrosion rate constant. Such a corrosion behavior is attributed to the amount of defects existing in the oxide film formed on the annealed samples; fewer defects would provide a lower fraction of short-circuit diffusion in total diffusion, resulting in a lower diffusion coefficient of oxygen in the oxide film, thereby producing better corrosion resistance. This is consistent with the calculated diffusion coefficients of oxygen in the oxide films: 3.252 × 10−11 cm2/s, 3.464 × 10−11 cm2/s and 3.740 × 10−11 cm2/s for the samples annealed at 400 °C, 450 °C, and 500 °C, respectively.

Effect of Rare Elements on Corrosion Behavior of SPCC in CSP

2013 ◽  
Vol 634-638 ◽  
pp. 1698-1703
Author(s):  
Yan Feng Zhou ◽  
Wei Jian Qiu ◽  
Wei Xiao Li ◽  
Jiang Xie
Keyword(s):  
Corrosion Resistance ◽  
Rare Earth ◽  
Grain Refinement ◽  
Corrosion Behavior ◽  
Electrochemical Corrosion ◽  
Corrosion Process ◽  
Rust Layer ◽  
Rare Elements ◽  
Treated Steel ◽  
Current Densities

The corrosion process of rare earth (RE) SPCC steel and SPCC steel in CSP in 3.5% NaCl solutions was investigated by SEM, EDS, XRD and polarization curve measurements. The results show that grain refinement can be obtained, the inclusions will be formed, and the electrochemical corrosion of microscopic region is weakened and therefore the corrosion resistance of SPCC steel could be improved by addition of RE. The rust layer of RE treated steel generated in the solution is more compact, the α-FeOOH content in rust layer is higher, and the content of activated γ-FeOOH and β-FeOOH is smaller, which are helpful to protect the steel. It also shows that current densities of SPCC steel is lower and the corrosive tendency will decrease with the addition of RE, which also makes the corrosion resistance of steel improved.

Corrosion Behavior of Anodic Films Formed on Aluminium 7A04 Alloy in Boric/Sulphuric Mixed Acid and in Chromic Acid

2011 ◽  
Vol 399-401 ◽  
pp. 95-98
Author(s):  
Shan Deng ◽  
Lei Xu ◽  
Qiu Ze Li ◽  
Xing Min Huang ◽  
Shu Lin Liang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Oxide Film ◽  
Corrosion Behavior ◽  
Copper Sulfate ◽  
Chromic Acid ◽  
Anodic Oxide ◽  
Anodic Oxide Film ◽  
Anodic Films ◽  
Mixed Acid ◽  
Better Than

The corrosion behavior of the anodic oxide film on aluminium 7A04 alloy is investigated in current paper, where the different anodic oxide films are prepared. Morphology observation on different anodic films is carried out by using laser confocal microscopy (LCM) and copper sulfate test. Meanwhile, the electrochemical properties are evaluated through using electrochemical impedance spectroscopy (EIS). The LCM observation shows that the anodic oxide film formed in boric/sulphuric mixed acid is uniform with porous appearance, while the anodic oxide film formed in chromic aid is nonporous one but defective. The copper sulfate test results show that the corrosion regions almost developed from micropores in strong corrosive media. The evaluation of EIS in NaCl solution demonstrates that the corrosion resistance of specimen with anodic oxide film is much better than that without film. Furthermore, the corrosion resistance of anodic film formed in boric/sulphuric mixed acid is better than that formed in chromic acid.

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