Environmental boundary and formation mechanism of different types of H2S corrosion products on pipeline steel

2017 ◽  
Vol 24 (4) ◽  
pp. 401-409 ◽  
Author(s):  
Lei Zhang ◽  
Hui-xin Li ◽  
Feng-xian Shi ◽  
Jian-wei Yang ◽  
Li-hua Hu ◽  
...  
Keyword(s):  
Formation Mechanism ◽  
Pipeline Steel ◽  
Corrosion Products ◽  
H2s Corrosion ◽  
Different Types

The Effect of Jet Flow Impingement on the Corrosion Products Formed on a Pipeline Steel in Naturally Aerated Sour Brine

2018 ◽  
Vol 28 (1) ◽  
pp. 431-447 ◽  
Author(s):  
M. A. Domínguez-Aguilar ◽  
M. Díaz-Cruz ◽  
A. Cervantes-Tobón ◽  
B. Castro-Domínguez
Keyword(s):  
Pipeline Steel ◽  
Jet Flow ◽  
Corrosion Products

Effect of Temperature and H2S Concentration on Corrosion of X52 Pipeline Steel in Acidic Solutions

2013 ◽  
Vol 743-744 ◽  
pp. 589-596 ◽  
Author(s):  
Meng Liu ◽  
Jian Qiu Wang ◽  
Wei Ke
Keyword(s):  
Corrosion Rate ◽  
Pipeline Steel ◽  
Corrosion Products ◽  
Effect Of Temperature ◽  
Corrosion Mechanism ◽  
General Corrosion ◽  
Ferrous Sulfide ◽  
Immersion Corrosion ◽  
Different Temperatures ◽  
Diffraction Patterns

The corrosion behavior of X52 pipeline steel in H2S solutions was investigated through immersion corrosion test which was carried out in a high temperature and high pressure autoclave at different temperatures and H2S concentrations. General corrosion rates were calculated based on the weight loss of samples. The morphology and the chemical composition of the corrosion products were obtained by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). The crystal structure of corrosion products was analyzed by X-Ray diffraction patterns (XRD). The corrosion products consisted mainly of the sulfide compounds (mackinawite, cubic ferrous sulfide, troilite and pyrrhotite). The corrosion products included two layers: the inner iron-rich layer and the outer sulfur-rich layer. Under H2S concentrations of 27g/L, the corrosion rate increased with the increase of temperature up to 90°C and then decreased at 120°C, finaly increased again. The corrosion rate first increased with H2S concentrations then decreased at 120°C. The structure and stability of the corrosion products due to different corrosion mechanism had a major impact on the corrosion rate. The corrosion resistance of the corrosion products increased as follows: mackinawite < cubic ferrous sulfide < troilite < pyrrhotite.

Early Corrosion Behavior of Pipeline Steel Containing 1% Cr in Sea Water Environment

2015 ◽  
Vol 1120-1121 ◽  
pp. 773-778
Author(s):  
Zhen Guang Liu ◽  
Xiu Hua Gao ◽  
Lin Xiu Du ◽  
Jian Ping Li ◽  
Ping Ju Hao
Keyword(s):  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Sea Water ◽  
Pipeline Steel ◽  
Water Environment ◽  
Corrosion Products ◽  
Immersion Experiment ◽  
Three Stages ◽  
Stage 1 ◽  
Microscopic Surface

The corrosion behavior of pipeline steel containing 1%Cr is studied by using immersion experiment. The corrosion rust is characteried with macroscopic/microscopic surface morphology, corrosion kinetics and corrosion phases. The results demonstrate that the main corrosion products are lepidocrocite and goethite, Cr-rich compound consists of the inner layer. The corrosion process could be divided into three stages. At stage 1, the corrosion rate decreases fast, and the distributed corrosion products are formed. At stage 2, the granular corrosion products appear on coupons surface gradually, and a plain corrosion rate is obtained. At stage 3, a compact and dense corrosion layer attaches to coupons surface, and corrosion rate decreases mildly.

Electroreduction-based Tb extraction from Tb4O7 on different substrates: understanding Al–Tb alloy formation mechanism in LiCl–KCl melt

RSC Advances ◽  
2015 ◽  
Vol 5 (85) ◽  
pp. 69134-69142 ◽  
Author(s):  
Li-Xia Luo ◽  
Ya-Lan Liu ◽  
Ning Liu ◽  
Kui Liu ◽  
Li-Yong Yuan ◽  
...  
Keyword(s):  
Formation Mechanism ◽  
Formation Mechanisms ◽  
Alloy Formation ◽  
Molten Chlorides ◽  
Different Types

This work presents the electroreduction of Tb(iii) ions, and formation mechanisms of Al–Tb alloys in molten chlorides by applying different types of cathodes: Mo, Al and Al-coated Mo.

scholarly journals Early Stage of Corrosion Formation on Pipeline Steel X70 Under Oxyfuel Atmosphere at Low Temperature

Processes ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 421
Author(s):  
Andreas Kratzig ◽  
Le Quynh Hoa ◽  
Dirk Bettge ◽  
Martina Menneken ◽  
Ralph Bäßler
Keyword(s):  
Raman Spectroscopy ◽  
Pipeline Steel ◽  
Early Stage ◽  
Ambient Pressure ◽  
Corrosion Layer ◽  
Corrosion Products ◽  
X Ray ◽  
Pit Formation ◽  
Additional Water

The early stage of corrosion formation on X70 pipeline steel under oxyfuel atmosphere was investigated by applying a simulated gas mixture (CO2 containing 6700 ppmv O2, 100 ppmv NO2, 70 ppmv SO2 and 50 ppmv H2O) for 15 h at 278 K and ambient pressure. Short-term tests (6 h) revealed that the corrosion starts as local spots related to grinding marks progressing by time and moisture until a closed layer was formed. Acid droplets (pH 1.5), generated in the gas atmosphere, containing a mixture of H2SO4 and HNO3, were identified as corrosion starters. After 15 h of exposure, corrosion products were mainly X-ray amorphous and only partially crystalline. In-situ energy-dispersive X-ray diffraction (EDXRD) results showed that the crystalline fractions consist primarily of water-bearing iron sulfates. Applying Raman spectroscopy, water-bearing iron nitrates were detected as subordinated phases. Supplementary long-term tests exhibited a significant increase in the crystalline fraction and formation of additional water-bearing iron sulfates. All phases of the corrosion layer were intergrown in a nanocrystalline network. In addition, numerous globular structures have been detected above the corrosion layer, which were identified as hydrated iron sulphate and hematite. As a type of corrosion, shallow pit formation was identified, and the corrosion rate was about 0.1 mma−1. In addition to in-situ EDXRD, SEM/EDS, TEM, Raman spectroscopy and interferometry were used to chemically and microstructurally analyze the corrosion products.

Polymorphous FeS corrosion products of pipeline steel under highly sour conditions

2016 ◽  
Vol 102 ◽  
pp. 103-113 ◽  
Author(s):  
Fengxian Shi ◽  
Lei Zhang ◽  
Jianwei Yang ◽  
Minxu Lu ◽  
Jinhui Ding ◽  
...  
Keyword(s):  
Pipeline Steel ◽  
Corrosion Products

scholarly journals Corrosion Processes on Weathering Steel Bridges Influenced by Deposition of De-Icing Salts

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1089 ◽  
Author(s):  
Vít Křivý ◽  
Monika Kubzová ◽  
Petr Konečný ◽  
Kateřina Kreislová
Keyword(s):  
Road Traffic ◽  
Protective Layer ◽  
Corrosion Products ◽  
Weathering Steel ◽  
The Road ◽  
Protective Layers ◽  
Different Types ◽  
Time Of Wetness ◽  
Chloride Deposition

The safety and durability of bridges designed from weathering steels are conditioned by the development of a sufficiently protective layer of corrosion products. Air pollution, microclimate around the bridge, time of wetness, structural solution of the bridge, and the position and orientation of the surface within the bridge structure all influence the development of protective layers on the surface of the weathering steel. In this article, attention is focused mainly on the microclimatic effects resulting from the road traffic under the bridge. The influence of chloride deposition on the development of corrosion products is evaluated using experimental in situ testing. Two neighboring bridges made of weathering steel and crossing different types of obstacles were selected for this experiment. Relations and dependences between the measured parameters (deposition rate of chlorides, corrosion rates, thickness of corrosion products and the amount of chlorides in corrosion products) are evaluated and discussed.

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