scholarly journals Research of Microorganism Corrosion Properties of 2024-T31 Aluminum-Magnesium Alloy in Oil-Water System

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Yan-yu Cui ◽  
Jia Li ◽  
Qing-miao Ding
Keyword(s):  
Magnesium Alloy ◽  
Water System ◽  
Localized Corrosion ◽  
Corrosion Mechanism ◽  
Corrosion Properties ◽  
Initial Stage ◽  
Impedance Technique ◽  
Oil Water ◽  
Biological Films ◽  
Aluminum Magnesium Alloy

The surface analysis techniques and chemical technical means (polarization curves and AC impedance technique) were applied to research the corrosion characteristics of microorganisms SRB of 2024-T31 aluminum-magnesium alloy in the oil-water system, and the corrosion mechanism was finally analyzed. The results showed that SRB accelerate the corrosion process and cause uneven pitting on the surface of the metal matrix. Passive and biological films control the corrosion of the metal substrate in bacterial oil-water system. In the initial stage of immersion, a loose and uneven biofilm formed on the surface of substrate which accelerated its corrosion. In the midterm, the effect of biofilm gradually weakened while the protective effect of the passive film grew more insistently; the rate of corrosion slowed down. In the later period, localized corrosion cell of large cathode/small anode formed on the surface of the substrate which accelerates the corrosion.

A New Corrosion Mechanism for X100 Pipeline Steel Under Oil-Covered Chloride Droplets

CORROSION ◽  
10.5006/2804 ◽  
2018 ◽  
Vol 74 (9) ◽  
pp. 947-957 ◽  
Author(s):  
Hongxing Liang ◽  
Jing Liu ◽  
Rebecca Filardo Schaller ◽  
Edouard Asselin
Keyword(s):  
Pipeline Steel ◽  
Localized Corrosion ◽  
Corrosion Mechanism ◽  
General Corrosion ◽  
Paraffin Oil ◽  
Initial Stage ◽  
X100 Pipeline Steel ◽  
Corrosion Pits ◽  
Stage 1 ◽  
Two Stages

A 1.7 mM NaCl droplet on X100 pipeline steel covered by paraffin oil is used to simulate the corrosive environment encountered in heavy oil or bitumen pipelines. The development of corrosion under the droplet was monitored and explored in two stages. In the initial stage (1 h), the distribution of corrosion pits was heterogeneous with one area under the droplet presenting a higher pit density. As the corrosion proceeded (24 h), the localized corrosion in the area under the droplet with the higher pit density switched to general corrosion, while the other region of the droplet continued to pit. The mechanisms driving this new distinctive corrosion form developed beneath an underoil droplet are explained.

scholarly journals Effect of CO2 Partial Pressure on the Corrosion Behavior of J55 Carbon Steel in 30% Crude Oil/Brine Mixture

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1765 ◽  
Author(s):  
Haitao Bai ◽  
Yongqing Wang ◽  
Yun Ma ◽  
Qingbo Zhang ◽  
Ningsheng Zhang
Keyword(s):  
Carbon Steel ◽  
Corrosion Rate ◽  
Crude Oil ◽  
Partial Pressure ◽  
Initial Period ◽  
Localized Corrosion ◽  
Corrosion Mechanism ◽  
Corrosion Properties ◽  
Co2 Partial Pressure ◽  
Corrosion Scale

The influence of CO2 partial pressure on the corrosion properties, including corrosion rate, morphology, chemical composition, and corrosion depth, of J55 carbon steel in 30% crude oil/brine at 65 °C was investigated. A corrosion mechanism was then proposed based on the understanding of the formation of localized corrosion. Results showed that localized corrosion occurred in 30% crude oil/brine with CO2. The corrosion rate sharply increased as the CO2 partial pressure (P co 2 ) was increased from 0 to 1.5 MPa, decreased from P co 2 = 1.5 MPa to P co 2 = 5.0 MPa, increased again at P co 2 = 5.0 MPa, and then reached a constant value after P co 2 = 9.0 MPa. The system pH initially decreased, rapidly increased, and then stabilized as CO2 partial pressure was increased. In the initial period, the surface of J55 carbon steel in the CO2/30% crude oil/brine mixtures showed intense corrosion. In conclusion, CO2 partial pressure affects the protection performance of FeCO3 by changing the formation of corrosion scale and further affecting the corrosion rate.

scholarly journals Corrosion Properties of Mn-Based Alloys Obtained by Aluminothermic Reduction of Deep-Sea Nodules

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5211
Author(s):  
Šárka Msallamová ◽  
Pavel Novák ◽  
Pauline Miossec ◽  
Jaromír Kopeček ◽  
Alisa Tsepeleva ◽  
...  
Keyword(s):  
Deep Sea ◽  
Potable Water ◽  
Aluminum Content ◽  
Protective Layer ◽  
Aluminothermic Reduction ◽  
Localized Corrosion ◽  
Corrosion Mechanism ◽  
Uniform Corrosion ◽  
Manganese Nodules ◽  
Corrosion Properties

Deep-sea manganese nodules are polymetallic oxidic ores that can be found on a seabed. Aluminothermic reduction is one of the possibilities of manganese nodules processing. This process obtains the polymetallic alloy with a high content of Mn and a varying content of Al, depending on the ratio between aluminum and nodules. The corrosion behaviors of three experimental Mn-based alloys produced by aluminothermic reduction with a content of Mn > 50 wt % were studied. The electrochemical testing in potable water and model seawater was used to explain the corrosion mechanism of Mn-based alloys. The results showed that the corrosion rate of experimental Mn-based alloy decreases with the increase in aluminum content in both potable water and model seawater. It was observed that the uniform corrosion of experimental Mn-based alloys is changed with an increase in aluminum content in alloy to localized corrosion, which was caused by microcells in an environment of model seawater. In contrast, the formation of a semi-protective layer of corrosion products was observed on the surface of Mn-based alloys with a higher content of aluminum in potable water. Moreover, the pitting corrosion of tested Mn-based alloys was observed neither in potable water nor in model seawater.

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.

scholarly journals CORROSION CHARACTERIZATIONS OF CARBON STEEL IN CAI TAU RIVER WATER SYSTEM - VIET NAM

2018 ◽  
Vol 55 (5B) ◽  
pp. 66
Author(s):  
T. K. N. Hoi
Keyword(s):  
Carbon Steel ◽  
River Water ◽  
Surface Analysis ◽  
Pitting Corrosion ◽  
Electrochemical Techniques ◽  
Water System ◽  
Steel Corrosion ◽  
Corrosion Mechanism ◽  
Corrosion Properties ◽  
Passive Behavior

        Corrosion problem happens in Cai Tau river water system; however, the mechanism is still questionable, resulting in unsolved ways. Therefore, this study focuses on the corrosion characterizations of carbon steel in Cai Tau river water system to analyze the corrosion mechanism using advanced electrochemical techniques and surface analysis. Electrochemical results indicated that Cl‾ and SO42- ions shows a significant effect on corrosion of carbon steel, resulting in pitting corrosion. Whereas, carbon steel showed passive behavior when it immersed in solution containing CO32- ion. Furthermore, pH strongly affects the corrosion properties of carbon steel. It indicated that corrosion of carbon steel increased with a decrease of pH. Surface analysis was done to identify the surface area of the pitting corrosion of carbon steel. Corrosion rates, pitting and corrosion products were clearly observed and analyzed by optical microscopy and X-ray diffraction. 

Multifactor mathematical model of criticality of welding process of products from aluminum- magnesium alloys

2020 ◽  
pp. 12-18
Author(s):  
F.A. Urazbahtin ◽  
A.YU. Urazbahtina
Keyword(s):  
Mathematical Model ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Welding Process ◽  
Welding Equipment ◽  
Equipment Operation ◽  
Aluminum Magnesium Alloys ◽  
Aluminum Magnesium Alloy ◽  
Welding Materials

A multifactor mathematical model of the welding process of products from aluminum-magnesium alloys, consisting of 71 indicators that assess the quality of the weld, the welding process, costs, equipment operation and quality of the welded material. The model can be used to control and optimize the welding process of products from aluminum-magnesium alloys. Keywords welding, products, aluminum-magnesium alloy, indicators, process parameters, welding equipment, welding materials, electrode sharpening, lining [email protected]

Ultrasonic Welding of Aluminum-Magnesium Alloy

2003 ◽  
Vol 426-432 ◽  
pp. 315-320 ◽  
Author(s):  
Makoto Hiraishi ◽  
Takehiko Watanabe
Keyword(s):  
Magnesium Alloy ◽  
Ultrasonic Welding ◽  
Aluminum Magnesium Alloy
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