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.

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

scholarly journals The evaluation of corrosion rate of steel during chemical cleaning of steam boilers

Vestnik IGEU ◽  
2019 ◽  
pp. 21-29
Author(s):  
А.Yu. Fedorova ◽  
Е.N. Bushuev
Keyword(s):  
Experimental Data ◽  
Carbon Steel ◽  
Hydrochloric Acid ◽  
Corrosion Rate ◽  
Gravimetric Method ◽  
Metal Corrosion ◽  
Technical Solution ◽  
Chemical Cleaning ◽  
Steam Boilers ◽  
Selection Of

Traditional and new washing acid reagents are used for chemical cleaning of internal surfaces of steam-water pipes of boilers. In previous studies, the rate of removal of lumpy and uniform deposits in the evaporative pipes of high-pressure steam boilers depending on the type of cleaning solution and the duration of cleaning was obtained. However, during chemical cleaning, removing deposits is accompanied by corrosion processes of the metal pipes, which leads to their loss. In the scientific and technical literature there are practically no data characterizing this process when using new detergent reagents. The aim of the study is to obtain experimental data on the corrosion rate of steels during the acid stage of chemical cleaning with the use of new cleaning reagents such as Antirzhavin, Deskam and Auge Pro AC 60. The gravimetric method of determination of metal corrosion rate of evaporative pipes is used. The samples of corrosion in cold and heated washing solutions during chemical cleaning from deposits by etching are employed. The laboratory testing has revealed the dependences of corrosion rate of carbon steel of boiler evaporative pipes and corrosion indicating plates in heated and not heated washing solutions of the inhibited hydrochloric acid and acid reagents on cleaning duration. It has been found that the corrosion rates of carbon steel are reduced during the cleaning process and at the end of the acid stage in solutions of inhibited hydrochloric acid and reagent solutions have values exceeding the maximum permissible corrosion rate in a cold inhibited technical solution of hydrochloric acid. However, they are less than those for pure metal and metal with scale. The experimental data obtained can be used in the selection of a chemical reagent for acid cleaning and its optimal duration, as well as in the selection of the method of steel corrosion control during cleaning.

Evaluation of Atmospheric Corrosivity by ACM Technique

2009 ◽  
Vol 610-613 ◽  
pp. 3-8 ◽  
Author(s):  
Xian Long Cao ◽  
Yi De Xiao ◽  
Hong Da Deng ◽  
Peng Jun Cao ◽  
Bi Jia
Keyword(s):  
Corrosion Rate ◽  
Atmospheric Corrosion ◽  
Early Stage ◽  
Gravimetric Method ◽  
Close Relation ◽  
Test Site ◽  
Electrochemical Process ◽  
Metal Corrosion ◽  
Electrochemical Technique ◽  
Climatic Parameters

The atmospheric corrosion has been shown to be an electrochemical process, the atmospheric corrosion behavior of Q235 stell evaluated with ACM (Atmospheric corrosion monitor) electrochemical technique was investigated in the study. The experimental results showed that there existed a close relation between electrochemical data and climatic parameters was confirmed. Taking into consideration accuracy and sensitivity of electrochemical technique, the ISO-standardized time of wetness (TOW) seems to be too conservative. SO2 seems to be more aggressive than chloride on metal corrosion in the early stage of atmospheric corrosion but the complexion reverses in the final stage of atmospheric corrosion. The ratio of corrosion rate from integration of ACM current to corrosion rate from weight loss of test specimens, that is, cell factor is fairly constant at the same test site but varied greatly between test sites. Based on constant cell factors and close relation between electrochemical data and climatic parameters in all test sites, ACM electrochemical technique can evaluate and classify the short-term atmospheric corrosivity as a substitute for gravimetric method, and the verification shows that atmospheric corrosivity classifications according to integration of ACM current and especially to cell factor coincide with the specifications of ISO Standard.

scholarly journals OBTAINING BLACK METAL CORROSION INHIBITORS METHOD OF PHYSICAL AND CHEMICAL ANALYSIS

2020 ◽  
Author(s):  
И.А. УСПЕНСКИЙ ◽  
И.В. ФАДЕЕВ ◽  
Ш.В. САДЕТДИНОВ ◽  
С.Н. КУЛИК ◽  
Е.В. МИТРОХИНА
Keyword(s):  
Chemical Analysis ◽  
Corrosion Rate ◽  
Corrosion Inhibitors ◽  
Gravimetric Method ◽  
Inhibitory Effect ◽  
Metal Corrosion ◽  
Nacl Solution ◽  
Degree Of Protection ◽  
St3 Steel ◽  
Physical And Chemical

Целью данной работы явилось получение нового эффективного, экологически безвредного ингибитора коррозии из недорогого и недефицитного сырья. Исследована система моноборат натрияформамид-вода при 25 °C, для чего воспользовались методом физико-химического анализа. Получено новое двойное соединение (моноборатнатрийформамид – МБНФ) состава 2NaBO2 – HСONH2 – 2H2 O. Полученные в ходе экспериментов сведения подтверждают получение нового амидоборатного комплекса и позволяют предположить, что он обладает существенными ингибиторными свойствами. Для подтверждения или отклонения гипотезы, что полученное боратное соединение обладает ингибиторными свойствами, гравиметрическим методом было изучено влияние его концентрации на скорость коррозии, ингибиторный эффект и степень защиты стали Ст3 в 3 %-м растворе NaCl. Для опытов использовали образцы размерами 100х25х2 мм из стали Ст3. Установлено, что лучшие ингибиторные свойства МБНФ проявляются при его концентрации 5 г/л в коррозионнойсреде, так как все три показателя, которыми характеризуются ингибиторы коррозии, достигают экстремума при концентрации МБНФ 5 г/л в 3 %-м растворе NaCl: скорость коррозии снижается с 30,32 до 15,36 г/м2 ·ч·10–3, ингибиторный эффект и степень защиты повышаются до 1,93 и 92,1 % соответственно. На основании результатов экспериментов полученное соединение МБНФ можно рекомендовать в качестве эффективного ингибитора в составе противокоррозионных композиций для защиты оборудования животноводческих комплексов и сельскохозяйственных машин в период межсезонного хранения, а также в растворах синтетических моющих средств для мойки деталей при ремонте агрегатов машин с целью повышения их противокоррозионных свойств. he aim of the research was to obtain a new effective, environmentally friendly corrosion inhibitor from inexpensive and non-defi cient raw materials. By the method of physical and chemical analysis, the sodium monoborate - formamide - water system was studied at 25°C. For the experiments, sodium monoborate and formative chemically pure grade were used as starting materials. The formation of a new double compound (monoboratesodiumformamide – MBSF) with the composition 2NaBO2 – HСONH2 – 2H2 O was established. Using IR spectroscopy, data have been obtained that allow us to interpret new amidoborate complexes and predict their effective inhibitory properties. To confi rm or reject the hypothesis that the obtained borate compound has inhibitory properties, the infl uence of its concentration on the corrosion rate, inhibitory effect and degree of protection of St3 steel in a 3% NaCl solution was studied by gravimetric method. For the experiments, we used samples with sizes 100х25х2 mm made of St3 steel. It was found that the best inhibitory properties of MBSF are manifested at a concentration of 5 g/l in a corrosive environment, since all three indicatorsthat characterize corrosion inhibitors reach an extremum at a concentration of MBSF of 5 g/l in a 3% NaCl solution: the corrosion rate decreases from 30.32 to 15.36 g/m²·h · 10–3, the inhibitory effect and the degree of protection increase to 1.93 and 92.1%, respectively. Based on the results obtained, the obtained MBSF compound can be recommended as an effective inhibitor in the composition of anticorrosive compositions for protecting equipment of livestock complexes and agricultural machines during off-season storage, as well as in solutions of synthetic detergents for washing parts when repairing machine assemblies in order to increase their anticorrosive properties .

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.

Unique Autoclave Stress Induced Failure Mechanism

2005 ◽  
Author(s):  
John Butchko ◽  
Bruce T. Gillette
Keyword(s):  
Corrosion Rate ◽  
Grain Boundary ◽  
Failure Analysis ◽  
Failure Mechanism ◽  
Metal Corrosion ◽  
Corrosion Mechanism ◽  
Reliability Testing ◽  
Process Change ◽  
Transistor Reliability ◽  
Pass Through

Abstract Autoclave Stress failures were encountered at the 96 hour read during transistor reliability testing. A unique metal corrosion mechanism was found during the failure analysis, which was creating a contamination path to the drain source junction, resulting in high Idss and Igss leakage. The Al(Si) top metal was oxidizing along the grain boundaries at a faster rate than at the surface. There was subsurface blistering of the Al(Si), along with the grain boundary corrosion. This blistering was creating a contamination path from the package to the Si surface. Several variations in the metal stack were evaluated to better understand the cause of the failures and to provide a process solution. The prevention of intergranular metal corrosion and subsurface blistering during autoclave testing required a materials change from Al(Si) to Al(Si)(Cu). This change resulted in a reduced corrosion rate and consequently prevented Si contamination due to blistering. The process change resulted in a successful pass through the autoclave testing.

The Corrosion of Carbon Steel and Stainless Steel in Simulated Geothermal Media

1985 ◽  
Vol 38 (8) ◽  
pp. 1133 ◽  
Author(s):  
BG Pound ◽  
MH Abdurrahman ◽  
MP Glucina ◽  
GA Wright ◽  
RM Sharp
Keyword(s):  
Carbon Steel ◽  
Corrosion Rate ◽  
Stainless Steels ◽  
Polarization Resistance ◽  
Iron Sulfide ◽  
Low Carbon Steel ◽  
Passive Films ◽  
Low Carbon ◽  
Corrosion Rates ◽  
Good Agreement

The corrosion rates of low-carbon steel, and 304, 316 and 410/420 stainless steels in simulated geothermal media containing hydrogen sulfide have been measured by means of the polarization resistance technique. Good agreement was found between weight-loss and polarization resistance measurements of the corrosion rate for all the metals tested. Carbon steel formed a non-adherent film of mackinawite (Fe1 + xS). The lack of protection afforded to the steel by the film resulted in an approximately constant corrosion rate. The stainless steels also exhibited corrosion rates that were independent of time. However, the 410 and 420 alloys formed an adherent film consisting mainly of troilite ( FeS ) which provided only limited passivity. In contrast, the 304 and 316 alloys appeared to be essentially protected by a passive film which did not seem to involve an iron sulfide phase. However, all the stainless steels, particularly the 410 and 420 alloys, showed pitting, which indicated that some breakdown of the passive films occurred.

scholarly journals A Review of the electrochemical corrosion of metals in choline chloride based deep eutectic solvents

2021 ◽  
Author(s):  
Mihael Bučko ◽  
Jelena Bajat
Keyword(s):  
Ionic Liquids ◽  
Corrosion Rate ◽  
Wide Spectrum ◽  
Choline Chloride ◽  
Electrochemical Corrosion ◽  
Deep Eutectic Solvents ◽  
High Viscosity ◽  
Metal Corrosion ◽  
Melting Points ◽  
Separate Class

Deep eutectic solvents (DESs) are a class of mixtures with melting points notably lower than those of their raw constituent components. These liquids have found a tremendously wide spectrum of applications in the last two decades of their research, so their contact and interaction with technical metals and alloys are inevitable. Therefore, the corrosivity of DESs towards metals is an extremely important topic. This review summarizes research efforts collected in the last two decades related to the corrosion rate of various metals in different DESs. Since the DESs are mainly composed of organic raw compounds, and by their physicochemical properties they may be regarded as a separate class of ionic liquids, the literature data about DESs corrosivity has been compared to the data related to the corrosivity of various organic solvents and ionic liquids as well. All the results gained until now show significantly low corrosivity of DESs. This observation is discussed in relation to the chemical composition of DESs. The absence of the oxidizing agents, the inhibitory action of organic ions and molecules, high viscosity and low electrical conductivity have been recognized as the main factors contributing to the low metal corrosion rate in DESs.

scholarly journals LDA method in psychological assessment of text comprehension

2021 ◽  
Author(s):  
С.А. Свердлов
Keyword(s):  
Psychological Assessment ◽  
Text Comprehension ◽  
Advantages And Disadvantages ◽  
Text Understanding ◽  
Modern Psychology ◽  
Wide Range ◽  
Psychology Pedagogy ◽  
The Moment ◽  
Comparison Of The Results ◽  
Different Content

Проблема понимания текстов и способов его оценки является одной из фундаментальных для современной психологии, педагогики, лингвистики. На настоящий момент имеется большое количество попыток выработки метода оценки понимания текстов, который бы отражал объективную картину интериоризации материала текста читателем, и вместе с тем подходил бы для стандартизации и применения на широком диапазоне текстов различного содержания и структуры, по возможности с минимальными затратами ресурсов оценщика и самого читателя. В настоящей статье раскрываются современные подходы к оценке понимания текстов, их преимущества и недостатки, и формулируется новый перспективный метод оценки понимания текстов, использующий в своём основании модель Латентного размещения Дирихле. Данный метод затем проходит исследование валидности через сравнение результатов его применения и наиболее часто используемых современных методов оценки понимания текстов, делается вывод о его применимости в реальных условиях и перспективах использования в спектре прикладных задач. The problem of understanding texts and methods of assessing it is one of the fundamental for modern psychology, pedagogy, linguistics. At the moment, there are a large number of attempts to develop a method for assessing the understanding of texts, which would reflect an objective picture of the internalization of the material of the text by the reader, and at the same time would be suitable for standardization and application on a wide range of texts of different content and structure, if possible with minimal expenditure of resources of the evaluator and the reader himself. This article reveals modern approaches to assessing text understanding, their advantages and disadvantages, and formulates a new promising method for assessing text understanding, based on the Dirichlet Latent Placement model. This method then goes through a validity study through a comparison of the results of its application and the most commonly used modern methods for assessing text understanding, a conclusion is made about its applicability in real conditions and the prospects for use in a range of applied problems.

scholarly journals Corrosion Inhibition Efficiencies of Polymeric Materials on Alloy Steel in Dilute Hydrochloric Acid and Sodium Hydroxide Solutions at Ambient Temperature

2020 ◽  
Vol 7 (2) ◽  
pp. C27-C32
Author(s):  
I.E. Ekengwu ◽  
O.G. Utu ◽  
K.O. Anyanwu
Keyword(s):  
Corrosion Rate ◽  
Ambient Temperature ◽  
Alloy Steel ◽  
Corrosion Inhibition ◽  
High Density Polyethylene ◽  
Inhibition Efficiency ◽  
Polymeric Materials ◽  
High Density ◽  
Alkaline Solutions ◽  
Ph Values

A corrosion control test was conducted on alloy steel, using polymeric coatings (polyurethane, bitumen (medium airing), and high-density polyethylene) in dilute HCl solutions of pH values 4, 7, and 12, respectively for acid, neutral and alkaline solutions at ambient temperature. In the study, Eighty-four coupons of alloy steel were used. The coupons were mechanized, ground, polished, etched with natal, and weighed using a digital weighing balance (Beva 206B). The mass of each coupon was recorded according to the tag number on them. Twenty-one of the coupons were coated with polyurethane, 21 coated with medium curing bitumen (MC), and 21 coated with high-density polyethylene, while 21 were left uncoated. Seven polyurethane-coated samples, bitumen coating, and uncoated coupons were suspended in dilute HCl solutions of pH values 4, 7, and 12. Every week, one sample is taken from each of the solutions, the coatings and the corrosion products were removed, and the coupons were etched with natal. Then the coupons were reweighed, and their masses were recorded in accordance with their tag number. The weight loss per unit area of the coupons, corrosion rate, and percentage corrosion inhibition efficiencies of the coatings was calculated over seven weeks. The results obtained were tabulated and represented graphically. From the results obtained, it is seen that the corrosion inhibition efficiency of polyurethane coatings is higher compared with bitumen and polyethylene. It is also seen from the graphs that the corrosion rate of the coupons is higher in acid, a little bit lower in alkaline, and much lower in neutral solution. It is also observed that the corrosion rates fall with time as the inhibition efficiency also falls with time.

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