<abstract xml:lang="en">The goal of the study was to assess corrosion of a cable bundle after a forty-year exposure to atmosphere. The assessed bundle consisted of a galvanized steel wire carrying core and aluminium external guide wires. Optical microscopy, electron dispersive microscopy and X-ray diffraction techniques were used for the assessment. Aluminium oxide was identified to be the most prevailing aluminium corrosion product. The average residual thickness of the steel wire zinc coat was 33 μm, even though there were locations where the zinc coat corroded through totally. Service life of aluminium wires is limited predominantly by the pitting corrosion rate, which reached 5 μm/ year.</abstract>

Evaluation of corrosion of long-term exposed aluminium conductor / Hodnocení korozního napadení hliníkových vodičù po dlouhodobé expozici

<abstract><italic>Přehledový článek postihuje vztah mezi korozním chováním</italic><italic>žárově zinkované oceli v betonu a její soudržností. Korozní</italic><italic>chování povlakované oceli vychází z předešlých výzkumných</italic><italic>článků hodnotících její odolnost v modelových pórových roztocích</italic><italic>v rozsahu pH 11-13,5. Podle platných norem je popsána</italic><italic>soudržnost výztužné oceli s betonem, metodika jejího zkoušení</italic><italic>a jsou rovněž uvedeny faktory, které ji ovlivňují, konkrétně</italic><italic>změna pórovitosti cementového tmelu způsobená vyloučeným</italic><italic>vodíkem na fázovém rozhraní a vliv vzniklých zinečnatanů</italic><italic>na zpomalení tvrdnutí betonu. Na základě publikovaných</italic><italic>výsledků je zhodnocena soudržnost žebírkované a hladké zinkované</italic><italic>výztuže ve srovnání s běžnou výztužnou ocelí se stejnou</italic><italic>geometrií povrchu. Závěrem je krátce zhodnoceno současné</italic><italic>nahlížení na použitelnost zinkované výztuže.</italic></abstract>

Vliv koroze zinkované oceli na soudržnost s betonem / The influence of galvanized steel on bond strength with concrete

<abstract>V článku jsou diskutovány nejčastější problémy, které negativně ovlivňují kvalitu povlaků žárového zinku. Jsou to jmenovitě vady na straně povlakovaného materiálu (poškozený povrch, nevhodné složení materiálu, tvářený materiál), nedostatečné omoření materiálu, složení taveniny (hlavně obsah Al, Ni, Pb, Bi a Sn) a technologie povlakování (teplota lázně, obsah tavidla, doba ponoru).</abstract>

Frequent defects on hot-dip galvanized goods – causes and posibilities of prevention

<abstract><title style='display:none'>Abstract</title>The paper summarizes the impact of produced hydrogen and calcium hydroxyzincate (Ca[Zn(OH)3]2·2H2O) on the formation of the porous structure of cement paste in the vicinity of hot-dip galvanized steel. These substances result from cathodic (hydrogen) and anodic (zincates-formed by reaction with hydroxides) corrosion reactions of hot-dip galvanized steel (or pure zinc) in the cement paste.The cement binder pore structure was studied by means of mercury porosimetry and analysis of scanning electron microscopy and confocal microscopy images. The porosity of the cement paste at the galvanized steel / cement interphase increased as a result of galvanized steel corrosion while hydrogen was formed. Such a porous structure was maintained throughout the maturation of cement paste. Kinetics of galvanized steel corrosion related primarily to water transport through the binder. The formation of calcium zincate did not result in transition of galvanized steel from active to passive state corrosion.</abstract>

VŠCHT Praha – Ústav anorganické technologie

VŠCHT Praha – Ústav kovových materiálů a korozního inženýrství

The impact of produced hydrogen gas and calcium zincate on changes of porous structure of cement paste in the vicinity of hot-dip galvanized steel

<abstract>Atmosférická koroze a klasifi kace agresivity atmosfér je dlouhodobým předmětem studia SVUOM. Ve spolupráci s CGS byly v roce 2001 vytvořeny mapy korozních rychlostí a korozních tříd pro uhlíkovou ocel, patinující ocel, zinek, měď, bronz a hliník. Tento článek uvádí aktuální přístup k modelování atmosférické koroze v České republice, který je založen na modifi kovaných funkcích zahrnujících klimatická data, znečištění ovzduší a nově i vliv rozmrazujících solí v okolí dálnic.</abstract>

Nové mapy korozní agresivity Èeské republiky / Up-dated maps of atmospheric corrosivity for Czech Republic

<abstract><title style='display:none'>Abstract</title>High sensitivity of lead to organic compounds leads to degradation of historical lead objects stored in the depositories of museums or archives. High concentration of organic compounds in the atmosphere of depositories is caused by degradation of organic materials (wood, glue, leather, paper). Organic materials are stored together with lead objects or they are used as a packaging material. This study was aimed on the influence of packaging material properties to aggressiveness towards lead with different state of surface by the resistometric method. The results showed that aggressiveness of packaging material is determined by a complex influence of material properties. The presence of corrosion products on the lead surface significantly increases its sensitivity to organic compounds.</abstract>

Effect of the presence of corrosion products on the corrosion rate of lead during the exposition with paper packaging materials

<abstract>
<title style='display:none'>Abstract</title>
Carbon steel has long been used in storing the saline water that results from oil washing in the oil industry. However, a high corrosion rate is reported, resulting in significant economic losses for oil companies. In the Middle East oil field, the temperature touches 50⁰C in Summer, causing increasing in corrosion rate for saline water steel storage tanks and pipes. In the present work, abundantly available wheat straw was used to prepare a cost-effective silicate inhibitor. The high inhibition efficiency of up to 94 % decreased the corrosion rate from severe corrosion for no-inhibitor specimen to close to low corrosion category for optimum inhibitor concentration specimen. The mechanism of the inhibition effect is the formation of a chemically adsorbed layer on the steel surface, which is successfully described by Langmuir isotherm. Additionally, at high concentrations of nano-silica, complex aggregates might form and be physically adsorbed on the surface of steel above the chemically adsorbed nano-silicate monolayer.
</abstract>

Using green corrosion inhibitor to reduce maintenance cost for carbon steel saline water storage systems in the oil industry

<abstract><title style='display:none'>Abstract</title>
Galvanised steel serves as a base material for pipelines in fire protection systems. However, this system is known for its occasional corrosion failures. The Systems with residual water and oxygen access contribute to formation of macrocells due to different aeration, which can lead to severe damage of the pipes. The aim of this work was to investigate the cause of localized corrosion on the galvanised pipes designated for the fire protection system. The results proved that the main cause of the fire protection pipe system was the residual water in the pipe. The influence of differential aeration on the corrosion of zinc and steel was studied by resistometric technique and showed no effect on the failure of material.
</abstract>

Localized corrosion attack on the galvanised steel pipes of the fire protection system

<abstract><title style='display:none'>Abstract</title>
The paper deals with the case studies of stainless steel piping corrosion in caustic soda transfer lines at a hydrocarbon processing plant, in the Asian region. The lines were in service of transferring the caustic soda solution from the storage tank farm to different process units, for subsequent use in reaction vessels. To maintain a minimum temperature of the fluid to avoid its precipitation, the lines were accompanied by a steam heat-tracer, throughout the line route. The material of construction (MOC) of the line was stainless steel type 316. After a period of about 3.5 years, 2” caustic line suffered fluid leakage, which was noticed through significant salt accumulation over insulation at one location. A valve was also noticed to leak through a weld at a 1.5” distribution line. The affected components were removed from service and subjected to detailed inspection and laboratory investigation, using advanced tools of metallurgical analysis and characterization. It was found that leakage in 2” line had occurred due to poor workmanship used during the repair of a manufacturing defect at the affected location and leakage of the valve had taken place due to the use of improper welding practice (in the case of subjected weld). In addition, the significant role of metallurgical defects in the parent metal was also disclosed to result in the observed failures. In addition, the contribution of process excursions can’t be completely ruled out. Finally, remedial measures are given to avoid the recurrence of such failure.
</abstract>

Corrosion failure of stainless-steel in caustic soda lines

<abstract><title style='display:none'>Abstract</title>
Organic corrosion inhibitors have been widely used to prevent and mitigate the damaging effects of corrosion on metal surfaces. However, their underlying mechanisms of action and effectiveness are still not fully understood. In recent years, the use of density functional theory (DFT) has emerged as a powerful tool to investigate the interaction between organic inhibitors and metal surfaces at the molecular level. This review article provides an overview of the principles of DFT, its advantages and limitations, and its application to the study of organic corrosion inhibitors. The factors affecting the performance of organic inhibitors, such as molecular structure, functional groups, and metal surface properties, are discussed in detail. The interaction between organic inhibitors and metal surfaces, including the adsorption and desorption of inhibitors, the role of intermolecular forces, and the effects of pH and temperature, are also explored. Finally, the challenges and future directions in the development of organic inhibitors using DFT are highlighted, including limitations and challenges in using DFT and potential avenues for further research. Overall, this review demonstrates the potential of DFT to provide valuable insights into the mechanism of organic corrosion inhibitors and to guide the development of new and more effective inhibitors for the protection of metal surfaces.
</abstract>

Understanding the mechanism of organic corrosion inhibitors through density functional theory

<abstract>
<title style='display:none'>Abstract</title>
The topic of this work was the investigation of an alternative brassing technique consisting of electroless zinc plating of a copper object in a strongly alkaline solution and subsequent annealing to achieve a characteristic brass appearance. Within the scope of the work was the determination of the mechanism of zinc deposition on the copper surface, the optimisation of the NaOH concentration (30 and 40 wt. %), time of deposition (5-120 min), as well as temperature (150 and 200 °C) and annealing time (15 – 60 min). Electrochemical methods (potentiodynamic curves and open-circuit potential), metallography, X-ray diffraction (XRD), and glow-discharge optical emission spectroscopy (GD-OES) were used to study the brassing mechanism. Electrochemical measurements have shown that zinc powder significantly decreases the surface potential of copper to the value of zinc itself and also acts as a reducing agent. The diffusion of zinc in copper was found to occur during the primary deposition of zinc with the formation of the γ phase (Cu5Zn8). The optimal NaOH concentration is 40 wt.% and the deposition time is 60 min. The optimal conditions of annealing are 200 °C and 60 min. The primary γ phase is transformed during the annealing process into β and α phases.
</abstract>

Electroless brassing of historical artefacts

<abstract>
<title style='display:none'>Abstract</title>
This study successfully conducted a comprehensive analysis of the AZ91D magnesium alloy, encompassing micro-structural, mechanical, and corrosion assessments. The microstructure consisted of primary α-Mg crystals and an aluminum-rich α-Mg/β-Mg17Al12 eutectic phase, with intermetallic phases predominantly precipitating at grain boundaries. The microhardness was quantified at 49.96 ± 1.76 HV. Thermostatic tests unveiled a noTab. increase in corrosion rates with rising temperatures, signaling reduced corrosion resistance at elevated environments. Conversely, thermos-cyclic tests showed relatively lower corrosion rates attributed to the accumulation of protective debris on the specimen surface, which could mitigate corrosion during temperature fluctuations. Electrochemical corrosion behavior revealed susceptibility to pitting corrosion at –1.204 V, limiting its application as a sacrificial anode in marine settings.
</abstract>

Influence of temperature and thermal cycles on the corrosion mechanism of wrought AZ91D magnesium alloy in simulated sea water solution

<abstract xml:lang="en"><title style='display:none'>Abstract</title> The aim of this work is to describe and analyze corrosion problems and their solutions in oil, gas, and refining industry. Corrosion phenomena and factors influencing them are discussed. Corrosion control and monitoring methods are illustrated. Corrosion management plays vital role in the solving of corrosion problems. The results are summarized in new book of the author “Corrosion Problems and Solutions in Oil Refining and Petrochemical Industry” published by Springer in 2016.</abstract>

Corrosion problems and solutions in oil, gas, refining and petrochemical industry

<abstract>
<title style='display:none'>Abstract</title>
Most organic corrosion inhibitors have polar groups through which the molecule can be adsorbed strongly or specifically on the metal surface. In this investigation, terephthalo- hydrazide and isophthalohydrazide were synthesized as corrosion inhibitors, and their corrosion-inhibiting properties on mild steel were evaluated in a corrosive environment by weight loss measurements. The results of corrosion experiments revealed that terephthalohydrazide and isophthalohydrazide as inhibitors controlled or reduced corrosion through adsorption mechanism and showed inhibitive efficiencies of 96.4 % and 97.2 %, respectively, at the optimum concentration of 0.5 mM. The surface morphology of the metal was evaluated by scanning electron microscopy. The terephthalohydrazide or isophthalohydrazide molecules were adsorbed on the mild steel surface, and the process of adsorption follows chemical adsorption. Quantum chemical calculations of the tested corrosion inhibitors were consistent with the experimental observations.
</abstract>

Terephthalohydrazide and isophthalo- hydrazide as new corrosion inhibitors for mild steel in hydrochloric acid: Experimental and theoretical approaches

<abstract><title style='display:none'>Abstract</title>The paper focuses on assessment the resistance of hot-sprayed coatings applied by HVOF technology (WC–Co–Cr created using powder of two different grain sizes) against erosive wear by dry-pot wear test in a pin mill at two sample angles. As these coatings are designated for the environment with varying elevated temperatures and often are in contact with the abrasive, the coatings have been subjected to thermal cyclic loading and their erosive resistance has been determined in as-sprayed condition and after the 5th and 10th thermal cycles. The corrosion resistance of coatings was evaluated by linear polarization (Tafel analysis).</abstract>

Properties of coatings created by HVOF technology using micro-and nano-sized powder

<abstract><title style='display:none'>Abstract</title>A novel pyridine derivative was synthesized, and its corrosion inhibition effects on mild steel in a 1M hydrochloric acid environment were investigated by gravimetric techniques, The results demonstrated that the inhibitive performance increased with the increasing of inhibitor concentration. At 303, the inhibition efficiency of pyridine derivative 4-hydroxy-3-(pyridin-2-ylaminomethyl)toluene accomplished 96.2% at the inhibitor concentration of 0.005 M. The mechanism of inhibition implicated the forming of a protective layer from inhibitor molecules on the surface of mild steel by a Langmuir adsorption isotherm. The presence of nitrogen and oxygen atoms in the structure of 4-hydroxy-3-(pyridin-2-ylaminomethyl)toluene confirmed by CHN-analysis revealed the adsorption of inhibitor molecules on the surface of mild steel surface.</abstract>

Corrosion inhibition of mild steel using novel pyridine derivative in 1 M hydrochloric acid

<abstract><title style='display:none'>Abstract</title>The corrosion inhibition efficiency of the novel pyridine namely, 4-(Benzoimidazole-2-yl)pyridine has been studied for mild steel in a 1 M hydrochloric acid environment by utilizing gravimetrical techniques. The synthesized inhibitor exhibits a significant inhibitive efficiency of 93.8% at 0.005 M. The adsorption isotherm of the investigated inhibitor on mild steel surface obeys the Langmuir isotherm. Surface morphology investigated by utilizing scanning electron microscopy (SEM) demonstrates a smooth metal surface with the addition of 4-(Benzoimidazole-2-yl)pyridine in a hydrochloric acid environment. Quantum chemical calculations using density functional theory (DFT) have been used to investigate the molecular structure and behavior of 4-(Benzoimidazole-2-yl) pyridine as a corrosion inhibitor. Different parameters have been calculated using DFT, such as energies of highest occupied molecular orbital and lowest occupied molecular orbital (EHOMO and ELUMO), energy gap (∆E), and dipole moment (μ). These parameters were important to elucidate the behavior of the investigated molecule as a corrosion inhibitor in acidic solution and also suggest the mechanism of inhibition.</abstract>

Gravimetrical, theoretical, and surface morphological investigations of corrosion inhibition effect of 4-(benzoimidazole-2-yl) pyridine on mild steel in hydrochloric acid

<trans-abstract xml:lang="en"><title style='display:none'>Abstract</title>The paper summarises the aspects of testing and influencing of reinforcement-concrete bond strength. It is focusing on the assessment of the extent of influence of the inevitable corrosion of the zinc coat in fresh concrete. The impact on concrete bond strength induced by evolving hydrogen and expanding zinc corrosion products is verified on plain steel bars. The zinc coat was produced by a conventional hot-dip galvanising technology. Standardised prism tests according to ČSN 73 1328 (“pull-out test”) were applied to test reinforcement-concrete concrete bond strength. The conclusion discusses also other impacts that might affect the cohesion progress, namely the impact of the contents of chromium (VI) compounds in the used concrete and the composition of the deposited coat.</trans-abstract>

VŠCHT Praha, Ústav kovových materiálů a korozního inženýrství

The assessment of the impact of corrosion of galvanised steel on bond strength of plain bars with “NSC” concrete

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Koroze a ochrana materiálu

KOM – Corrosion and Material Protection Journal

The journal is primarily focused on corrosion engineering and surface treatment of metallic materials. We accept also articles concerning degradation of paints, enamels and other...

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The journal is primarily focused on corrosion engineering and surface treatment of metallic materials. We accept also articles concerning...