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.

The brazing effect on the corrosion mechanism of a multilayer material with Cu

2017 ◽  
Vol 64 (6) ◽  
pp. 664-671 ◽  
Author(s):  
Ting Yuan ◽  
Min-da Zhang ◽  
Jia-hui Ni ◽  
Ya-xuan Chen ◽  
Fei Geng
Keyword(s):  
Corrosion Behavior ◽  
Sea Water ◽  
High Sensitivity ◽  
Localized Corrosion ◽  
Corrosion Mechanism ◽  
Uniform Corrosion ◽  
Multilayer Material ◽  
Content Type ◽  
The Core ◽  
Before And After

Purpose The purpose of this paper is to compare corrosion behavior of a modified multilayer material with Cu before and after brazing process. Design/methodology/approach Sea water acidified accelerated tests (SWAATs), potentiodynamic polarization tests and scanning electron microscopy were used to study the corrosion behavior and macro/micro structures. Results indicate that the corrosion mechanisms of the sheets before and after brazing process are completely different. Findings The un-brazed material is uniform corrosion, while the brazed material has a high sensitivity to localized corrosion and loses cathodic protection to the core. It is found that brazing process causes copper transition from the core alloy into eutectic phases in the cladding, leading to higher Ecorr and different potential distribution compared with those of un-brazed materials. Originality/value For the modified multilayer material after brazing, there are two stages of corrosion. First, corrosion attack takes place along eutectic phases in the cladding material, and then core alloy dissolves by forming a galvanic couple with the nobler residual cladding.

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 Resistance Measurement of 316L Stainless Steel Manufactured by Selective Laser Melting

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4509
Author(s):  
Rigoberto Guzmán-Nogales ◽  
Francisco Estupiñán-López ◽  
Citlalli Gaona-Tiburcio ◽  
Omar E. Lopez-Botello ◽  
Juan G. Ramírez-Rodríguez ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Selective Laser Melting ◽  
316L Stainless Steel ◽  
Electrochemical Techniques ◽  
Localized Corrosion ◽  
Corrosion Mechanism ◽  
Uniform Corrosion ◽  
Laser Melting ◽  
New Era

Selective laser melting (SLM) technology is ushering in a new era of advanced industrial production of metal components. It is of great importance to understand the relationship between the surface features and electrochemical properties of manufactured parts. This work studied the influence of surface orientation on the corrosion resistance of 316L stainless-steel (SS) components manufactured with SLM. The corrosion resistance of the samples was measured using linear polarization resistance (LPR) and electromechanical noise (EN) techniques under three different environments, H2O, 3.5 wt.% NaCl, and 20% H2OSO4,, analyzing the horizontal (XY) and vertical (XZ) planes. The microstructure and morphology of the samples were obtained by optical (OM) and scanning electron microscopy (SEM). The obtained microstructure showed the grains growing up from the fusion line to the melt pool center and, via SEM-EDS, the presence of irregular and spherical pores was observed. The highest corrosion rate was identified in the H2SO4 solution in the XZ plane with 2.4 × 10−2 mm/year and the XY plane with 1.31 × 10−3 mm/year. The EN technique along with the skewness factor were used to determine the type of corrosion that the material developed. Localized corrosion was observed in the electrolyte, for the XY and XZ planes (−1.65 and −0.012 skewness factors, respectively), attacking mainly the subgrains of the microstructure and, in some cases, the pores, caused by Cl ions. and solutions presented a uniform corrosion mechanism for the two observed orientations. The morphology identified by SEM was correlated with the results obtained from the electrochemical techniques.

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.

The Calculation of the Thickness for Uniform Corrosion and Localized Corrosion in Steel Corrosion

2011 ◽  
Vol 255-260 ◽  
pp. 514-518
Author(s):  
Zheng Yi Kong ◽  
Shan Hua Xu ◽  
Yu Sheng Chen
Keyword(s):  
Corrosion Rate ◽  
Constant Temperature ◽  
Safety Assessment ◽  
Steel Corrosion ◽  
Localized Corrosion ◽  
Power Relationship ◽  
Uniform Corrosion ◽  
Experiment Data ◽  
Temperature And Humidity ◽  
Corrosion Pits

Because of the complexity of corrosion, the law of uniform corrosion and localized corrosion is still not clear,so it is difficult to assess their impact on the structure safety. In order to differ them and find their own law, we obtain a lot of corrosion specimens by ways of constant temperature and humidity, and then detect the size of corrosion pits by roughness tester. After that, the method for calculating the thickness of uniform corrosion and localized corrosion is proposed. Then the method is used to analyze the experiment data. The result indicates the thickness of uniform corrosion and localized corrosion all increase with the rate of corrosion, and they all show a power relationship with corrosion rate, so it will provide a basis for distinguishing them in safety assessment.

V.—Manganese in the Sea

1876 ◽  
Vol 1 (2) ◽  
pp. 50-53 ◽  
Author(s):  
A. H. Church
Keyword(s):  
Chemical Analysis ◽  
Deep Sea ◽  
The Other ◽  
Manganese Nodules ◽  
Red Clay ◽  
Chemical Examination ◽  
Sea Bottom ◽  
Ample Supply

To the geologist, the mineralogist and the chemist, two of the observations made during the voyage of the Challenger are of especial interest. One of these observations is the occurrence over vast areas of the deep sea bottom of a peculiar red clay, containing silica, peroxide of iron, and alumina. The other discovery to which I refer has been described by Sir Wyville Thomson as the occurrence throughout this red clay of nodules of “nearly pure peroxide of manganese.” To these nodules, as well us to the red clay, an organic origin has been assigned. But the immediate source of so much manganese is hard to find, for this element is by no means an abundant constituent of animal or vegetable organisms. The difficulty is, however, somewhat lessened when the manganese nodules are submitted to a more minute chemical examination. From two correspondents I have received an ample supply of these curious concretions, accompanied by a suggestion that they should be submitted to chemical analysis.

scholarly journals Corrosion study of metallic biomaterials in simulated body fluid

10.30544/384 ◽  
2011 ◽  
Vol 17 (1) ◽  
pp. 13-22 ◽  
Author(s):  
Hamid Reza Asgari Bidhendi ◽  
Majid Pouranvari
Keyword(s):  
Stainless Steel ◽  
Simulated Body Fluid ◽  
Corrosion Behavior ◽  
Body Fluid ◽  
Pure Titanium ◽  
Localized Corrosion ◽  
Commercially Pure Titanium ◽  
Corrosion Properties ◽  
Cyclic Polarization ◽  
Cp Ti

Titanium alloys and stainless steel 316L are still the most widely used biomaterials for implants despite emerging new materials for this application. There is still someambiguity in corrosion behavior of metals in simulated body fluid (SBF). This paper aims at investigating the corrosion behavior of commercially pure titanium (CP-Ti), Ti–6Al–4V and 316LVM stainless steel (316LVM) in SBF (Hank’s solution) at37 ºC using the cyclic polarization test. Corrosion behavior was described in terms of breakdown potential, the potential and rate ofcorrosion, localized corrosion resistance, andbreakdown repassivation. The effects of anodizing on CP-Ti samples and the passivation on the 316LVM were studied in detail. It was shown that CP-Ti exhibited superior corrosion properties compared to Ti–6Al–4V and 316LVM.

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