Steel Corrosion Patterns in Neutral and Alkaline Iron Oxide Slurry

2021 ◽  
pp. 142-155
Author(s):  
V.A. Shelontsev ◽  
I.G. Gorichev ◽  
A.V. Kuzin ◽  
I.V. Gerasimova ◽  
E.A. Eliseeva
Keyword(s):  
Iron Oxide ◽  
Corrosion Rate ◽  
Dissolved Oxygen ◽  
Polarization Resistance ◽  
Gravimetric Method ◽  
Sharp Decrease ◽  
Steel Corrosion ◽  
Chloride Ions ◽  
Diffusion Control ◽  
Ph Range

The study identifies and theoretically substantiates the steel corrosion patterns in aqueous slurry of iron-ore concentrate. The purpose of the study was to examine the effect that the content of dissolved oxygen(PO2), pH, the concentration of chloride ions (CCl-) and the rate of movement of the iron oxide slurry (ω) produce on the corrosion losses of steel 20. Comparative analysis of the corrosion rate values obtained by the gravimetric method and the polarization resistance method showed that the reciprocal of the polarization resistance and the corrosion rate change symbatically with increasing pH, the corrosion rate values are quantitatively well consistent with each other. To identify the corrosion patterns, the method of polarization resistance was used. The dependence of the corrosion rate (ρ) on рН revealed two characteristic areas: in the first one, there is no dependence of the rate on pH (6.5--9.0); in the second one, there is a sharp decrease in corrosion losses when the pH goes from 9.0 to 12.5. For pH = 6.5--9.0, the corrosion rate increases linearly with an increase in the partial pressure of oxygen, and corrosion losses in the slurry are higher than in the background solution. The dependence ρ(√ω) is linear over the entire pH range (6.0--9.0), which indicates the diffusion control of the corrosion process. Findings of research show that in order to protect carbon steel from corrosion in the iron oxide slurry, it is necessary to take into account the pH and О2 concentration. Optimal reduction of corrosion losses can be achieved by alkalizing the slurry and removing dissolved oxygen

Aluminium corrosion studies. II. Corrosion rates in water

1977 ◽  
Vol 30 (4) ◽  
pp. 721 ◽  
Author(s):  
A Berzins ◽  
JV Evans ◽  
RT Lowson
Keyword(s):  
Corrosion Rate ◽  
Dissolved Oxygen ◽  
Chloride Concentration ◽  
Chloride Ions ◽  
Oxide Surface ◽  
Corrosion Rates ◽  
Saturated Water ◽  
Corrosion Studies ◽  
Competitive Action ◽  
Ph Range

The corrosion rate of aluminium in flowing neutral waters at 50�C has been determined as a function of pH, oxygen concentration and chloride concentration. The corrosion rate, At, as total aluminium lost between the 4th and 80th day was observed to be logarithmic according to At = B log t+C with a minimum rate in the pH range 5-6, and with B c. 3 x 10-5g cm2, C c. 20 x 10-5 g cm-2 and t in days for oxygen-saturated water. Saturating the water with nitrogen or adding up to 15 mg Cl- l-1 increased the corrosion rate. It was concluded that this was due to competitive action on the oxide surface, between dissolved oxygen and chloride ions.

Evaluation of the Corrosion Rate for Acidic Bottom Plates of an Aboveground Oil Tank by the AE Method

2008 ◽  
Author(s):  
Naoya Kasai ◽  
So Soon Park ◽  
Kentaro Utatsu ◽  
Kazuyoshi Sekine ◽  
Shigeo Kitsukawa ◽  
...  
Keyword(s):  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Polarization Resistance ◽  
Corrosion Damage ◽  
Strong Acid ◽  
Chloride Ions ◽  
Impedance Method ◽  
Test Pieces ◽  
Oil Storage ◽  
Ae Signals

An AE method is an effective technique that can inspect corrosion damage of tank bottom plates to prevent leakage accidents of oil storage tanks. However, a correlation between AE signals and the corrosion behavior for bottom plates is not fully clarified. In this study, the authors considered that the corrosion regions in bottom plates become a strong acid environment by chloride ions as shown our previous work. The correlation between the AE signals and the corrosion behavior with a potentiostat for test pieces was examined in the environment. The polarization resistance was measured with an AC impedance method using a frequency response analyzer. It was clear that the polarization resistance indicated the corrosion rate for a test pieces in the experiments. While measuring the AE signals, the corrosion rate was monitored with a test piece. As a result, the AE signal showed the good correlation with the corrosion rates of the test pieces.

scholarly journals Effect of Fe, Ni, and Cr on the corrosion behaviour of hyper-eutectic Al-Si automotive alloy under different pH conditions

2018 ◽  
Vol 8 (3) ◽  
pp. 241-253
Author(s):  
Mohammad Salim Kaiser ◽  
Maglub Al Nur
Keyword(s):  
Corrosion Rate ◽  
Oxide Film ◽  
Corrosion Behaviour ◽  
Chloride Ions ◽  
Surface Oxide ◽  
Surface Oxide Film ◽  
Sem Images ◽  
Optical Micrograph ◽  
Ph Conditions ◽  
Ph Range

Effect of Fe, Ni and Cr on the corrosion behaviour of hyper-eutectic Al-Si automotive alloy was studied. The test of corrosion behaviour at different environmental pH 1, 3, 5, 7, 9, 11 and 13 was performed using conventional gravimetric measurements and complemented by resistivity, optical micrograph, scanning electron microscopy (SEM) and X-ray analyser (EDX) investigations. The highest corrosion rate was observed at pH 13 followed by pH 1, while in the pH range of 3.0 to 11, there is a high protection of surface due to formation of stable surface oxide film. The highest corrosion rate at pH 13 is due to presence of sodium hydroxide in the solution in which the surface oxide film is soluble. At pH 1, however, high corrosion rate can be attributed to dissolution of Al due to the surface attack by aggressive chloride ions. Presence of Fe, Ni and Cr in hyper-eutectic Al-Si automotive alloy has significant effect on the corrosion rate at both environmental pH values. Resistivity of alloy surfaces initially decreases at pH 1 and pH 13 due to formation of thin films. The SEM images of corroded samples immersed in pH 1 solution clearly show pores due to uniform degradation of the alloy. In pH 13 solution, however, the corrosion layer looks more packed and impermeable.

scholarly journals Tetrahydro-dibenzo[a,d][7]annulene-5,11-dihydrazone and Magnesium oxide Used to Control the Corrosion of Aluminium in Chloride ions Environment

2020 ◽  
Vol 3 (2) ◽  
Author(s):  
Rajesh Kumar Singh ◽  
Jay Prakash ◽  
Dharmendar Kumar
Keyword(s):  
Corrosion Rate ◽  
Chemical Vapour ◽  
Gravimetric Method ◽  
State Equation ◽  
Chloride Ions ◽  
Coverage Area ◽  
Barrier Formation ◽  
Corrosion Reaction ◽  
Chemical Vapour Deposition Technique ◽  
Aluminium Metal

Chloride ions interact with aluminium in marine atmosphere to form corrosion cell. Due to this corrosion reaction occurs on their surface, aluminium is oxidized into Al3+. The corrosion reaction accelerates deterioration in metal and it produces galvanic, pitting, stress, crevice, intergranular corrosion. Chloride ions decrease internal and external strength of aluminium metal. It is a very important metal so used in different appliances for e.g. road, water, air transports, housing, railways and other fields. Nanocoating and electrospray techniques used to check the corrosion of aluminium metal. For nanocoating and electrospray materials applied tetrahydro-dibenzo[a,d][7]annulene-5,11-dihydrazone and MgO. Both materials formed composite barrier and developed a passive surface for Cl- ions. This barrier reduced the corrosion rate of aluminium. Nozzle spray and chemical vapour deposition technique used for coating process. The corrosion rate of metal was determined by gravimetric method. Corrosion potential and current density were calculated by potentiostat. The composite barrier formation was confirmed by activation energy, heat of adsorption, free energy, enthalpy and entropy. These thermal parameters were obtained by Arrhenius equation, Langmuir isotherm and Transition state equation. The adsorption of tetrahydro-dibenzo[a,d][7]annulene-5,11-dihydrazone and MgO electrospray on aluminium surface was depicted by Langmuir, Frundlich and Temkin isotherm.  The results of surface coverage area and coating efficiency were noticed that both materials were mitigated the corrosion rate of aluminium in chloride ions environment.

Research of atmospheric corrosion activity on oil pumping stations with tank farms

2021 ◽  
pp. 88-92
Author(s):  
Павел Олегович Ревин ◽  
Алексей Витальевич Макаренко ◽  
Андрей Алексеевич Губенков ◽  
Ирина Олеговна Осина
Keyword(s):  
Corrosion Rate ◽  
Atmospheric Corrosion ◽  
Gravimetric Method ◽  
Steel Corrosion ◽  
Steel Structure ◽  
Climatic Conditions ◽  
International Standards ◽  
Corrosion Activity ◽  
Climatic Regions ◽  
Pumping Stations

В настоящее время в отечественных национальных и международных стандартах отсутствуют данные по коррозионной активности атмосферы регионов, в которых расположены нефтеперекачивающие станции с резервуарными парками, эксплуатируемые российским оператором магистральных нефте- и нефтепродуктопроводов. В нормативных документах ПАО «Транснефть», регламентирующих требования к антикоррозионным покрытиям для наружной поверхности резервуаров, определены три категории коррозионной активности атмосферы по ISO 12944-2:2017. Данная классификация учитывает климатические условия регионов, но не учитывает скорость коррозии стали. В этой связи с целью определения скорости коррозии стальных конструкций в различных климатических районах, где расположены объекты организаций системы «Транснефть», была проведена серия испытаний. На 28 НПС в восьми климатических районах были установлены стенды с образцами из стали 09Г2С. Скорость коррозии металла образцов определяли гравиметрическим методом после выдержки в течение шести месяцев, одного года, двух, трех, четырех и пяти лет. Установлено, что скорость коррозии металлических образцов составила от 55 до 236 г/(м∙год), что соответствует категории коррозионной активности атмосферы С2 и С3 по ISO 12944-2:2017 и ГОСТ 34667.2-2020. Наибольшая скорость коррозии - от 177 до 236 г/(м∙год) - наблюдалась в районах расположения НПС в непосредственной близости от моря (до 1,5 км от береговой линии). Currently, there is no data included in the state and international standards on the corrosion activity of the atmosphere in the regions in which oil pumping stations with tank farms are situated, which are operated by Russian main oil and oil products pipeline operators. In the regulatory documents of Transneft PJSC, which specify the requirement for anticorrosion coatings for the outer surfaces of tanks, three categories of atmospheric corrosion activity are defined as per ISO 12944-2:2017. This classification takes into account the climatic conditions of the regions, but not the steel corrosion rate. In this regard, in order to determine the corrosion rate of steel structure in various climatic regions, where Transneft facilities are situated, a series of tests was performed. The test bench with 09G2S steel samples was installed on 28 oil pumping stations in eight climatic regions. The corrosion rate of the metal samples was determined by the gravimetric method after tempering within the period of six months, one year, two, three, four and five years. It has been established that the corrosion rate of the metal samples amounted from 55 to 236 g/(m·per year), which corresponds to the atmospheric corrosion activity category C2 and C3 as per ISO 12944-2:2017 and GOST 34667.2-2020. The highest corrosion rate, from 177 to 236 g/(m·per year) - was observed in the OPS location regions with close proximity to sea (1,5 km to shore line).

Determining the Metal Corrosion Rate by Various Techniques and Comparison of the Results

2021 ◽  
Vol 410 ◽  
pp. 142-148
Author(s):  
Inna V. Artamonova ◽  
Igor G. Gorichev ◽  
Evgeny B. Godunov
Keyword(s):  
Corrosion Rate ◽  
Polarization Resistance ◽  
Gravimetric Method ◽  
Metal Corrosion ◽  
Disk Electrode ◽  
Advantages And Disadvantages ◽  
Ph Values ◽  
Carbonate Ions ◽  
Carbonate Solutions ◽  
Comparison Of The Results

The paper considers methods for calculating the rate of metals corrosion. A comparative analysis of the experimental data on the steel 10 corrosion rate in carbonate solutions with different pH values (6-12.5) and the concentration of carbonate ions on the disk electrode made of steel 10. The calculation of the corrosion rate by the gravimetric method and the method of polarization resistance is carried out. A detailed description of the calculating the corrosion rate stages index from experimental electrochemical data (I-E) obtained on the potentiostat IPC PRO is given. The advantages and disadvantages of the considered methods are indicated.

scholarly journals Empirical models of corrosion rate prediction of steel in reinforced concrete structures

2020 ◽  
Vol 14 (2) ◽  
pp. 98-107
Author(s):  
Nguyen Ngoc Tan ◽  
Dang Vu Hiep
Keyword(s):  
Reinforced Concrete ◽  
Corrosion Rate ◽  
Prediction Models ◽  
Concrete Structures ◽  
Steel Corrosion ◽  
Empirical Models ◽  
Chloride Ions ◽  
Reinforced Concrete Structures ◽  
Damage Prediction ◽  
Rate Prediction

Corrosion rate is one of the most important input parameters in corrosion-induced damage prediction models as well as in calculation of service-life for reinforced concrete structures. In most cases, instantaneous measurements or constant corrosion rate values used in damage prediction models is irrelevant. The new factors appearing such as corrosion-induced cover cracking, concrete quality to change the corrosion rate should be taken into consideration. This study shows several empirical models to predict the corrosion rate and their limits of application. The predicted values of steel corrosion rate using four empirical models are compared with the measured values of a series of 55 experimental samples collected from the literature. The results show that the empirical models overestimated the experimental corrosion rate. Using model proposed by Liu and Weyers provided the best agreement with the experimental data. Keywords: corrosion rate; prediction model; reinforced concrete; chloride ions; reinforcement corrosion.

Embedded Sensors for Corrosion Monitoring of Existing Reinforced Concrete Structures

2008 ◽  
Vol 587-588 ◽  
pp. 677-681 ◽  
Author(s):  
E.V. Pereira ◽  
R.B. Figueira ◽  
Manuela M. Salta ◽  
I.T.E. Fonseca
Keyword(s):  
Reinforced Concrete ◽  
Corrosion Rate ◽  
Polarization Resistance ◽  
Concrete Structures ◽  
Steel Corrosion ◽  
Embedded Sensors ◽  
Corrosion Monitoring ◽  
Reinforced Concrete Structures ◽  
Reinforcement Corrosion ◽  
Galvanic Current

In this work the performance of two surface treatments and the efficiency of a corrosion inhibitor were evaluated, in the control of steel corrosion in concrete induced by chlorides, through measurements of galvanic current and polarization resistance applied to embedded sensors fixed in existing concrete using different methodologies. From the results obtained the use of the different embedded sensors in the measurement of corrosion rate is discussed aiming the development of new systems for permanent evaluation of the on site performance of products for repairing reinforced concrete structures affected by reinforcement corrosion.

Adsorption and corrosion inhibition characteristics of two medicinal molecules

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Hydrochloric Acid ◽  
Corrosion Rate ◽  
Mild Steel ◽  
Corrosion Inhibition ◽  
Half Life ◽  
Thermodynamic Data ◽  
Inhibition Efficiency ◽  
Gravimetric Method ◽  
Corrosive Environment ◽  
Corrosion Inhibition Efficiency

The corrosion inhibition characteristics of two medicinal molecules phenylalanine and rutin on mild steel in 1.0M Hydrochloric acid were evaluated using gravimetric method. Corrosion inhibition efficiency of 83.78 and 90.40 % was obtained respectively after seven days. However, phenylalanine showed weak accumulative higher corrosion inhibition efficiency. The presence of both molecules in the corrosive environment reduced the corrosion rate constant and increased the material half-life. Thermodynamic data calculated suggests a spontaneous adsorption of the molecules on the mild steel’s surface.

scholarly journals Investigation of Corrosion Rate and Rust Expansion Form of Segment Reinforcement for Shield Tunnel by Combined Action of Soil Loading, Chloride Ion and Stray Current

2021 ◽  
Vol 13 (6) ◽  
pp. 3444
Author(s):  
Zheng Li ◽  
Hao Jin ◽  
Shuo Yu
Keyword(s):  
Corrosion Rate ◽  
Steel Corrosion ◽  
Chloride Ion ◽  
Shield Tunnel ◽  
Uniform Corrosion ◽  
Stray Current ◽  
Soil Loading ◽  
Capacity Degradation ◽  
Expansion Form ◽  
Combined Action

Segment reinforcement corrosion can cause bearing-capacity degradation of shield tunnel, which is unsafe for the metro operation. Therefore, a three-dimensional computational model was proposed in this paper to study the corrosion rate and rust expansion form of segment reinforcement by the combined action of soil loading, chloride ion and stray current. The results show that the arch waist segment steel corrosion rate in the middle is larger than the ends. The rust expansion form of segment reinforcement appears be an eccentric circle. The radius size and circular center are related to the non-uniform corrosion coefficient and the maximum corrosion current density.

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