Effects of environmental factors on corrosion behavior of high-silicon cast iron in Shanxi soil medium

2018 ◽  
Vol 65 (6) ◽  
pp. 538-546
Author(s):  
De Ding ◽  
Yue Zhang ◽  
Xiaobing Yu ◽  
Benling Fang ◽  
Jipu Guo ◽  
...  
Keyword(s):  
Cast Iron ◽  
Corrosion Rate ◽  
Water Content ◽  
Corrosion Behavior ◽  
Chloride Concentration ◽  
Chemical Compositions ◽  
Corrosion Mechanism ◽  
Soil Medium ◽  
Content Type ◽  
High Silicon

Purpose High-silicon cast iron has excellent corrosion resistance in some specific medium. But the effects of pH value, chloride concentration and soil moisture content on corrosion behavior are still unknown. This study aims to provide reference for the application of high-silicon cast iron in different environments. Design/methodology/approach Electrochemical impedance spectroscopy and potentiodynamic polarization curves were used to investigate the corrosion mechanism and rate. The morphology was observed by scanning electron microscopy. The chemical compositions of the corrosion products were detected by energy-dispersive spectroscopy and X-ray diffraction. Findings When the solution is acidic, the corrosion of high-silicon cast iron is more serious. When the chloride concentration is 0.1 per cent, the corrosion rate of high-silicon cast iron is the largest. A passive film is formed on the surface to prevent the corrosion reaction with the increasing of chloride concentration. The corrosion rate is the largest when water content is 15 per cent, and the corrosion is the lightest when water content is 30 per cent. Originality/value This study provides support for the selection of high-silicon cast iron as grounded material.

Influence of anions, pH and coating on the localized corrosion behavior of AZ31 magnesium alloy in physiological environments

2016 ◽  
Vol 63 (4) ◽  
pp. 301-307 ◽  
Author(s):  
Qian Hu ◽  
Jing Liu ◽  
Feng Huang
Keyword(s):  
Magnesium Alloy ◽  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Substrate Surface ◽  
Electrochemical Techniques ◽  
Az31 Magnesium Alloy ◽  
Localized Corrosion ◽  
Corrosion Mechanism ◽  
Content Type ◽  
Average Corrosion Rate

Purpose The purpose of this paper was to clarify the influence of H2PO4-, HCO3-, pH increase and phosphate coating on corrosion rate and localized corrosion tendency of AZ31 magnesium alloy. Design/methodology/approach The corrosion behavior of AZ31 magnesium alloy in physiological environments was investigated by hydrogen evolution collection measurements, electrochemical techniques and by use of a three-dimensional digital microscope. Findings H2PO4- and HCO3- have corrosion inhibition effects on AZ31 magnesium alloy in normal saline solutions. After immersing for 54 h, the surface undulations decrease from 100 to about 60 μm and 45 μm. The average corrosion rate decreased with increasing pH value. The localized corrosion tendency, however, increased significantly. CaHPO4·2H2O [dicalcium phosphate dehydrate (DCPD)] coating could decrease the initial icorr of AZ31 substrate in Hank’s solution. With partial dissolution of the coating, localized corrosion was readily evident on the AZ31 substrate surface, and a large corrosion pit with depth of over 350 μm appeared. The combined effect of the presence of inhibited ions, the increase in pH during corrosion process and the DCPD coating caused the decrease in the average corrosion rate while enhancing the localized corrosion tendency, resulting in the observed localized attack. Originality/value The paper provides an essential insight into the localized corrosion mechanism of AZ31 magnesium alloy in physiological environments.

Corrosion Behavior of X70 Pipeline Steel and Corrosion Rate Prediction Under the Combination of Corrosive Medium and Applied Pressure

2017 ◽  
Author(s):  
Kaikai Li ◽  
Wei Wu ◽  
Guangxu Cheng ◽  
Yun Li ◽  
Haijun Hu ◽  
...  
Keyword(s):  
Natural Gas ◽  
Corrosion Rate ◽  
Tensile Stress ◽  
Partial Pressure ◽  
Corrosion Behavior ◽  
Pipeline Steel ◽  
Applied Pressure ◽  
Chloride Concentration ◽  
X70 Pipeline Steel ◽  
Co2 Partial Pressure

Natural gas transmission pipeline is prone to internal corrosion due to the combination of corrosive impurities in the pipe (such as CO2, H2S and chlorides) and applied pressure of the pipeline, which seriously affects the safe operation of the pipeline. In this work, the corrosion behavior of a typical X70 pipeline steel was investigated by using potentiodynamic polarization and electrochemical impendence spectroscopy (EIS). The polarization and EIS data under different CO2 partial pressures (0–1 atm), H2S concentrations (0–150 ppm), chloride concentrations (0–3.5 wt%) and tensile stress (0–400 MPa) were obtained. The results show that corrosion rate increases with the increase of CO2 partial pressure and chloride concentration, respectively, while first increases and then decreases with the increase H2S concentrations. The corrosion rate is less affected by elastic tensile stress. In addition, a quantitative prediction model for corrosion rate of natural gas pipeline based on adaptive neuro-fuzzy inference system (ANFIS) was established by fitting the experimental data which maps the relationship between the key influencing factors (i.e. CO2 partial pressure, H2S concentration, chloride concentration and tensile stress) and the corrosion rate. The prediction results show that the relative percentage errors of the predicted and experimental values are relatively small. The prediction accuracy of the model satisfies the engineering application requirement.

Effect of electrolysis parameters on corrosion resistance of extra-low carbon high silicon iron-based alloy

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yue Zhang ◽  
Jun Xiao ◽  
Shaoguang Yang ◽  
Aimin Zhao
Keyword(s):  
Corrosion Resistance ◽  
Correlation Analysis ◽  
Corrosion Rate ◽  
Low Carbon ◽  
Silicon Iron ◽  
Content Type ◽  
Grey Correlation ◽  
Grey Correlation Analysis ◽  
Iron Based ◽  
High Silicon

Purpose High silicon iron-based alloys possess excellent corrosion resistance in certain specific media, but the effects of electrolysis parameters on corrosion resistance remain unknown. This study aims to guide the development and application of an extra-low carbon high silicon iron-based alloy (ECHSIA) in electrode plates. Design/methodology/approach The corrosion resistance of ECHSIA and a conventional high-silicon cast iron (CHSCI) was analyzed through experimental characterizations. The morphology was observed by scanning electron microscopy. The influence of electrolysis parameters on the corrosion resistance of ECHSIA was investigated through corrosion experiments. The relationship between the electrolysis parameters and the corrosion resistance of ECHSIA was statistically investigated using the grey correlation analysis method. Findings The corrosion resistance of the ECHSIA is better than that of the CHSCI. The corrosion rate showed an increasing tendency with the increase in the nitric acid concentration (CHNO3), electrolyte temperature and current density. The grey correlation analysis results showed that the CHNO3 was the main factor affecting the corrosion rate of the ECHSIA. Originality/value An ECHSIA with a single ferrite microstructure was prepared. This study provides a guideline for the future development and application of ECHSIAs as electrode plates.

In situ study on the influence of bicarbonate, chloride and outer electrode potential on crevice corrosion occurrence and development of X70 steel

2019 ◽  
Vol 66 (5) ◽  
pp. 651-660 ◽  
Author(s):  
Qian Hu ◽  
Saiwen Lu ◽  
Jing Liu ◽  
Feng Huang
Keyword(s):  
Corrosion Behavior ◽  
Electrode Potential ◽  
Crevice Corrosion ◽  
Chloride Concentration ◽  
Current Density Distribution ◽  
Outer Electrode ◽  
Active Dissolution ◽  
Content Type ◽  
Modeling And Experiments

Purpose The purpose of this paper is to clarify the influence of bicarbonate, chloride and outer electrode potential on crevice corrosion occurrence and development of X70 steel. Design/methodology/approach The crevice corrosion behavior in NaHCO3 and NaCl solutions was investigated through modeling and experiments. The electrode potential and current density distribution were simulated, and the acidification of crevice solution was monitored in situ. Findings The bicarbonate concentration and outer electrode potential remarkably influenced the occurrence of crevice corrosion. The former changes the passivation curves, and the latter alters the initial potential. Moreover, chloride concentration exerted minimal influence. The location of acidification and pitting occurrences depended on the potential difference between the outer electrode and electrode at the active dissolution current peak. Originality/value This study provides a better understanding of the crevice corrosion behavior and mechanism under natural conditions.

Long-term monitoring of zinc corrosion behavior in typical hot and dry atmosphere environment in Turpan, China

2018 ◽  
Vol 65 (5) ◽  
pp. 471-483 ◽  
Author(s):  
Chunhui Kang ◽  
Decheng Kong ◽  
JiZheng Yao ◽  
Chunyun Guo ◽  
Li Wang ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
Exposure Time ◽  
Corrosion Products ◽  
Corrosion Mechanism ◽  
Corrosion Morphology ◽  
Transfer Resistance ◽  
Positive Direction ◽  
Pure Zinc ◽  
Content Type ◽  
X Ray

Purpose This paper aims to investigate the corrosion behavior of zinc in a typical hot and dry atmosphere. It proposes the dynamic corrosion for different exposure periods. Results can provide the basic data and corrosion mechanism of zinc in such environment. Design/methodology/approach In this paper, the authors investigated the corrosion behavior of pure zinc exposed in the typical hot and dry environment in Turpan for one-four years, which has never been studied. Scanning electron microscopy, laser scanning confocal microscopy, electron probe micro-analyzer (EPMA), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) were conducted to measure the corrosion morphology and products of zinc. Finally, combining electrochemical impedance spectroscopy and scanning Kelvin probe techniques, the corrosion mechanism of zinc in Turpan was examined. Findings The thickness loss of the zinc followed an exponential law with respect to exposure time: D = 3.17 t0.61, and both of the rust layer resistance and the charge transfer resistance increased with exposure time. The corrosion products mainly comprised ZnO, Zn(OH)2, Zn5(CO3)2(OH)6, Zn4SO4(OH)6·5H2O and Zn12(SO4)3Cl3(OH)15·5H2O. The Kelvin potentials shifted toward the positive direction from −0.380 to −0.262 V (vs saturated calomel electrode [SCE]) when the exposure time extended from one to four years and the distribution of the corrosion products became more and more uniform. Originality/value The corrosion behavior of pure zinc in the typical hot and dry environment in Turpan has not been studied. The dynamic corrosion for different exposure periods was obtained. The corrosion products were systemically investigated via energy-dispersive X-ray spectroscopy, EPMA, XPS and XRD.

Corrosion and inhibition of N80 steel in 5% HCl solution by SA1-3

2017 ◽  
Vol 64 (6) ◽  
pp. 634-643 ◽  
Author(s):  
Liqiang Zhao ◽  
Yanhua Zhu ◽  
Pingli Liu ◽  
Jian Zhang ◽  
Yigang Liu
Keyword(s):  
Corrosion Inhibitor ◽  
Corrosion Behavior ◽  
Theoretical Basis ◽  
Inhibition Mechanism ◽  
Corrosion Mechanism ◽  
Protective Film ◽  
Content Type ◽  
N80 Steel ◽  
Weight Loss Method ◽  
Hcl Solution

Purpose This paper aims to describe the corrosion behavior and possibility of inhibition by corrosion inhibitor SA1-3 in acidizing solution (5 per cent hydrochloric acid [HCl] solution). The study aims to explain the mechanism of corrosion and inhibition of N80 steel in 5 per cent HCl solution to provide theoretical basis for expanding the range of application of N80 steel in acidification process. Design/methodology/approach This paper opted for a laboratory study using simulation of acidizing solution to do the experiments. The results of experiments including weight-loss method, electrochemical method and surface analysis were used to explain the mechanism of corrosion and inhibition so as to predict the dissolution progress of N80 steel in 5 per cent HCl solution with and without inhibitor SA1-3. Findings This paper provides theoretical insights about how to inhibit the corrosion behavior of N80 steel in 5 per cent HCl solution. It suggests that the corrosion inhibitor which can form a protective film on the steel surface should be used to expand the application of N80 steel in acidizing solution. The inhibitor SA1-3 is a kind of cathodic corrosion-controlling inhibitor which mainly inhibits cathode corrosion; it cannot change the corrosion mechanism of N80 steel. Originality/value This paper provides a theoretical basis for the corrosion behavior and inhibition mechanism of N80 steel in acidizing solution.

Influence of heat treatment on corrosion behavior of laser welded Mg-Gd-Y fusion zones

2020 ◽  
Vol 67 (4) ◽  
pp. 337-343
Author(s):  
Lyuyuan Wang ◽  
Jian Huang ◽  
Yong Peng ◽  
Yang Jia ◽  
Rong Ni
Keyword(s):  
Corrosion Resistance ◽  
Fusion Zone ◽  
Corrosion Behavior ◽  
Corrosion Mechanism ◽  
Content Type ◽  
Treated Condition ◽  
Heat Treated ◽  
Protective Films ◽  
Heat Treated Condition ◽  
Treated State

Purpose This paper aims to evaluate the corrosion resistance of fusion zones in different heat treated condition from laser welded Mg-Gd-Y alloys and analyze their intrinsic corrosion mechanism. Design/methodology/approach The corrosion behavior of fusion zone from laser-welded Mg-Gd-Y alloy joints in the as-welded, ageing and solution + ageing conditions was investigated in the 3.5 wt.% NaCl solution by immersion tests. Findings The corroded surface of as-welded fusion zone consists of dark and bright regions, and the bright regions were composed of high-density needle-like products, whereas some different extended direction of the cracks with lots of long ultrafine needle-shaped corrosion products appeared in the dark regions. The corrosion resistance of the fusion zone is slightly decreased after the ageing treatment. Originality/value The solution + ageing treated fusion zone exhibits the highest corrosion resistance than that of the as-welded and ageing treated state because of the full dissolution of the cathodic coarse eutectic compound, grains growth and relatively compact protective films. The inhomogeneous distribution of the β′ can somewhat improve the corrosion rate of solution + ageing treated fusion zone when compared with base metal.

Corrosion behavior of carbon steel in H2S-CO2-H2O-methyldiethanolamine (MDEA) solution under the presence of chloride ions

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Guiyang Wu ◽  
Xikui Gu ◽  
Wanwei Zhao ◽  
Rui Fan ◽  
Ting Mao
Keyword(s):  
High Temperature ◽  
Carbon Steel ◽  
Low Temperature ◽  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Chloride Ion ◽  
Chloride Ions ◽  
Corrosion Products ◽  
Content Type

Purpose This paper aims to study the effect of chloride ions concentration on the corrosion behavior of carbon steel in methyldiethanolamine (MDEA) aqueous solution in the sight of different process parameters of purification plant. Design/methodology/approach Due to the decrease of filtration efficiency and separation efficiency, the chloride ion in the desulfurization solution is enriched. The corrosion behavior of carbon steel under chloride ion enrichment environment was studied by weight-loss method, electrochemical impedance spectroscopy, cyclic polarization curve, X-ray photoelectron spectroscopy and scanning electron microscopy. Findings The results show that temperature and hydrogen sulfide loads are the main factors of corrosion in CO2-MDEA-H2O-H2S environment. The enrichment of chloride ions reduces the corrosion rate at low temperature but promotes the corrosion rate at high temperature. The chloride concentration should be controlled below 3000 mg/L, and no pitting corrosion was found under the experimental conditions. Originality/value The effect of chloride ion enrichment on MDEA solution corrosion shows that at low temperature, the increase of chloride ion will reduce the acid gas load and increase the density of corrosion products, so as to reduce the corrosion; on the contrary, at high temperature, the density of corrosion products will decrease and the corrosion will be intensified as well. It is believed that the chloride ion should be controlled below 3000 mg/L according to the results of the tests.

Corrosion behavior of steel bar embedded in high-ductility cementitious composites under the coupled action of dry–wet cycles and chloride attack

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Li-Ping Guo ◽  
Li-Juan Chai ◽  
Yan-Hui Xu ◽  
Cong Ding ◽  
Yuan-Zhang Cao
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Steel Corrosion ◽  
High Ductility ◽  
Chloride Permeability ◽  
Content Type ◽  
Steel Bar ◽  
Chloride Attack ◽  
Structure Engineering

Purpose High-ductility cementitious composites (HDCC) have an excellent crack controlled capacity and corrosion resistance capacity, which has a promising application in structure engineering under harsh environment. The purpose of this study is to explore the corrosion mechanism of steel bar in HDCC. Design/methodology/approach Intact and the pre-cracked HDCC specimens under the coupled action of different dry–wet cycles and chloride attack were designed, and intact normal concrete (NC) was also considered for comparison. Corrosion behavior of a steel bar embedded in HDCC was analyzed by an electrochemical method, a chloride permeability test and X-ray computed tomography. Findings Steel corrosion probability is related to the chloride permeability of the HDCC cover, and the chloride permeability resistance of HDCC is better than that of NC. Besides, crack is the key factor affecting the corrosion of steel bars, and the HDCC with narrower cracks have a lower corrosion rate. Slight pitting occurs at the crack tips. In addition, the self-healing products and corrosion products fill up the cracks in HDCC, preventing the external aggressive ions from entering and thereby decreasing the steel corrosion rate. Originality/value HDCC has a superior corrosion resistance than that of NC, effects of variable crack width on corrosion behavior of steel bar in HDCC under the coupled actions of different dry–wet cycles and chloride attack are investigated, which can provide the guide for the design application of HDCC material in structure engineering exposed to marine environment.

Study on the corrosion behaviors of high-silicon chromium iron in acidic and alkaline soil solutions

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Kechen Lv ◽  
Xinyu Yang ◽  
Tangqing Wu ◽  
Song Xu ◽  
Lanlan Liu ◽  
...  
Keyword(s):  
Soil Solution ◽  
Corrosion Behavior ◽  
Material Selection ◽  
Southern China ◽  
Acid Soil ◽  
Alkaline Soil ◽  
Content Type ◽  
Soil Solutions ◽  
High Silicon ◽  
Corrosion Pits

Purpose High-silicon chromium iron (HSCI) has been used in ground grids in southern China, while there was a lack of study on its corrosion behavior in this soil environment. The purpose of this paper is to discover the corrosion of HSCI in acidic and alkaline soil solutions. Design/methodology/approach The original defects on the HSCI surface were observed using optical microscopy, and the corrosion behavior of the HSCI in the acidic and alkaline soil solutions were jointly detected using electrochemical measurements and scanning electron microscopy/energy dispersive spectrometer. Findings The results showed the corrosion rates of the HSCI in the acidic and alkaline soil solutions were limited, and the high contents of Cr and Si in matrix was responsible for its high corrosion resistance. The HSCI showed a similar corrosion tendency in the two solutions, while its corrosion rate in the acid soil solution was higher than that in the alkaline soil solution. The corrosion pits on the specimen surface were originated from the original defects in matrix, and the edges of the corrosion pits were more rounded than the original defects after 720 h immersion in the two solutions. The original defects in the HSCI matrix played a significant role in the corrosion process. Originality/value The paper discovered the corrosion evolution of HSCI in the acidic and alkaline soil solutions. What is more, the acceleration role of the original defects on the corrosion of the HSCI in the acidic and alkaline soil solutions was discovered in the paper. The results are beneficial for the material selection of ground grid equipment in engineering.

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