Extensive Corrosion Research Articles

Effect of Mechanical Damage during Well Completion Activities on High Chrome Steel Tubulars in High H2S and CO2 Environments

High concentrations of H2S and CO2 make oil producing wells highly corrosive to normal steels alloys, such as carbon steel. The usual solution to this is high chrome steels alloys, such as ferritic stainless steel, i.e. 13Cr. These steels have a good service record in such environments, especially at operating temperatures below 150°C. However the passive film which provides protection can be easily damaged by mechanical activities such as wirelining. The lack of repassivation in these environments means that once damaged by mechanical action these tubulars suffer extensive localized corrosion. A comparison is made of the different workover methods which can exacerbate this problem, particularly wirelining. Where possible we recommend the use of coiled tubing.

Microbial Corrosion in Linepipe Steel Under the Influence of a Sulfate-Reducing Consortium Isolated from an Oil Field

This work investigates microbiologically influenced corrosion of API 5L X52 linepipe steel by a sulfate-reducing bacteria (SRB) consortium. The SRB consortium used in this study was cultivated from a sour oil well in Louisiana, USA. 16S rRNA gene sequence analysis indicated that the mixed bacterial consortium contained three phylotypes: members of Proteobacteria (Desulfomicrobium sp.), Firmicutes (Clostridium sp.), and Bacteroidetes (Anaerophaga sp.). The biofilm and the pits that developed with time were characterized using field emission scanning electron microscopy (FE-SEM). In addition, electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) and open circuit potential (OCP) were used to analyze the corrosion behavior. Through circuit modeling, EIS results were used to interpret the physicoelectric interactions between the electrode, biofilm and solution interfaces. The results confirmed that extensive localized corrosion activity of SRB is due to a formed biofilm in conjunction with a porous iron sulfide layer on the metal surface. X-ray diffraction (XRD) revealed semiconductive corrosion products predominantly composed of a mixture of siderite (FeCO3), iron sulfide (Fe x S y ), and iron (III) oxide-hydroxide (FeOOH) constituents in the corrosion products for the system exposed to the SRB consortium.

Microstructure and Growth Mechanism of Glucose-Carburized Nickel Substrates

In this research, efforts were made to study the modification of microstructure of pure Ni matrices. Modification was attempted using glucose as carburizing medium under a control of heat treatment conditions. Nickel plates were carburized under vacuum conditions at 380°C and 650°C for 3 hours. In order to determine the parameters of the carburizing, thermal properties of glucose along with the thermochemical behavior were examined by Thermogravimetric Analysis (TGA) and Differential Thermal Analysis (DTA). The characterization of the microstructure of the carburized specimens was investigated by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS). For analyzing the effect of temperature treatment on corrosion resistance, electrochemical corrosion tests were conducted. It was observed that the polarization curves for carburized samples at 380°C were shifted to lower corrosion current densities. Consequently, lower corrosion rates were achieved for these samples preventing the formation of extensive corrosion over their surfaces comparing with carburized Nickel substrates at 650°C.

Graphene as a Long-Term Metal Oxidation Barrier: Worse Than Nothing

Anticorrosion and antioxidation surface treatments such as paint or anodization are a foundational component in nearly all industries. Graphene, a single-atom-thick sheet of carbon with impressive impermeability to gases, seems to hold promise as an effective anticorrosion barrier, and recent work supports this hope. We perform a complete study of the short- and long-term performance of graphene coatings for Cu and Si substrates. Our work reveals that although graphene indeed offers effective short-term oxidation protection, over long time scales it promotes more extensive wet corrosion than that seen for an initially bare, unprotected Cu surface. This surprising result has important implications for future scientific studies and industrial applications. In addition to informing any future work on graphene as a protective coating, the results presented here have implications for graphene's performance in a wide range of applications.

Prevention and cost of atmospheric corrosion in Mauritius

PurposeThe purpose of this paper is to obtain a better insight into the impact of atmospheric corrosion in Mauritius by investigating the corrosion prevention strategies used in the country and determining the related costs.Design/methodology/approachCompanies and organizations, in various industrial sectors, affected by atmospheric corrosion were selected. They were inspected and surveys were performed in order to fulfill the aim of the study.FindingsIt has been observed that extensive atmospheric corrosion problems have been encountered in the capital city, leading to the use of a range of corrosion prevention methods. However, carbon steel, which corrodes easily, is very commonly used in the country. This leads to the wide use of alkyd‐based barrier coatings. The cost of atmospheric corrosion has been found to be equal to 0.38 per cent of the GDP.Social implicationsThis study is expected to raise concern on the problem of atmospheric corrosion in Mauritius and the related waste in materials.Originality/valueThis study is expected to help in adopting corrosion prevention policies and strategies in Mauritius.

Influence of sulfate reducing bacterial biofilm on corrosion behavior of low-alloy, high-strength steel (API-5L X80)

The utilization of high strength carbon steels in oil and gas transportation systems has recently increased. This work investigates microbiologically influenced corrosion (MIC) of API 5L X80 linepipe steel by sulfate reducing bacteria (SRB). The biofilm and pit morphology that developed with time were characterized with field emission scanning electron microscopy (FESEM). In addition, electrochemical impedance spectroscopy (EIS), polarization resistance (Rp) and open circuit potential (OCP) were used to analyze the corrosion behavior. Through circuit modeling, EIS results were used to interpret the physicoelectric interactions between the electrode, biofilm and solution interfaces. The results confirmed that the extensive localized corrosion activity of SRB is due to a formed biofilm and a porous iron sulfide layer on the metal surface. Energy Dispersive Spectroscopy (EDS) revealed the presence of different sulfide and oxide constituents in the corrosion products for the system exposed to SRB.

Problems of informational support of chemical and radiation ecological monitoring of long-term technological storage of reactor blocks of utilized submarines afloat in the northwestern region

Complexity of the problems related to utilization of nuclear submarines (NSM) is determined not only by their huge scale but also by the necessity of systemic consideration of diverse factors, including political, economic, ecological, social, technological, and informational. Afloat storage of reactor compartment units is a complex chemical, technological and ecological problem, for sea water induces their extensive corrosion which creates a risk of leakage of radioactive heavy metal isotopes, fission products, and transuranium elements to the environment. While searching for and testing of technological solutions for utilization of NSM, the most important problems are chemical and radiation ecological monitoring of water areas and its informational support. The article contains systemic analysis of problems related to long-term technological storage of reactor compartment units afloat, and an optimal procedure for ecological radionuclide monitoring is proposed. The proposed procedure requires minimal equipment and radiation control range but ensures a sufficient confidence level.

General and crevice corrosion study of the in-wall shielding materials for ITER vacuum vessel

Vacuum vessel In-Wall Shield (IWS) will be inserted between the inner and outer shells of the ITER vacuum vessel. The behaviour of IWS in the vacuum vessel especially concerning the susceptibility to crevice of shielding block assemblies could cause rapid and extensive corrosion attacks. Even galvanic corrosion may be due to different metals in same electrolyte. IWS blocks are not accessible until life of the machine after closing of vacuum vessel. Hence, it is necessary to study the susceptibility of IWS materials to general corrosion and crevice corrosion under operations of ITER vacuum vessel. Corrosion properties of IWS materials were studied by using (i) Immersion technique and (ii) Electro-chemical Polarization techniques. All the sample materials were subjected to a series of examinations before and after immersion test, like Loss/Gain weight measurement, SEM analysis, and Optical stereo microscopy, measurement of surface profile and hardness of materials. After immersion test, SS 304B4 and SS 304B7 showed slight weight gain which indicate oxide layer formation on the surface of coupons. The SS 430 material showed negligible weight loss which indicates mild general corrosion effect. On visual observation with SEM and Metallography, all material showed pitting corrosion attack. All sample materials were subjected to series of measurements like Open Circuit potential, Cyclic polarization, Pitting potential, protection potential, Critical anodic current and SEM examination. All materials show pitting loop in OC2 operating condition. However, its absence in OC1 operating condition clearly indicates the activity of chloride ion to penetrate oxide layer on the sample surface, at higher temperature. The critical pitting temperature of all samples remains between 100° and 200°C.

Structural performance of RC beams under simultaneous loading and reinforcement corrosion

The paper aims to investigate the influence of simultaneous loading and reinforcement corrosion on the structural performance of concrete beams. Five reinforced concrete beams were first loaded to 60% of their strengths, and then subjected to the sustained load and reinforcement corrosion simultaneously, until they collapsed either due to corrosion development or further loading. The experimental results indicate that, under the same loads, the time-dependant deflections of corroded beams increased more rapidly than those of non-corroded beam, and reached their limiting deflections prematurely. A local corrosion of a shorter length of tensile bars decreased beam strength and ductility more greatly than an extensive corrosion of a longer length of bars. Simultaneous loading and corrosion impairs beam strength and ductility more significantly than separate one. Either a further corrosion or an occasional over-loading or both are likely to cause concrete structures under service loads to collapse suddenly without significant deflection.

The stability of illuminated p-GaInP2 semiconductor photoelectrode

Thin p-GaInP2 films were tested 24 h in pH1 NH4NO3 solution at AM 1.5 G, and compared to that tested in 3 M H2SO4. Optical, SEM and EDX investigations confirmed that the surface of the tested sample in pH1 NH4NO3 was kept almost as that of an as-received one, while the sample tested in 3 M H2SO4 experienced extensive corrosion via selective dissolution of Ga. ICP analysis confirmed the very low dissolution of p-GaInP2 in pH1 NH4NO3 solution, compared to that in 3 M H2SO4. The GaInP2 sample tested in pH1 NH4NO3 solution had an XPS depth profile almost identical to that of an as-grown sample, we speculate that absorbed NH3 on the semiconductor surface could be responsible for the observed corrosion inhibition. Thus, the p-GaInP2 should last much longer when working in pH1 NH4NO3 solution, due to this inhibiting effect. This result shows promise toward meeting US DOE's 2013 goal of 8% STH efficiency for 1000 h duration.

Molten carbonate corrosion of a 13-Cr ferritic stainless steel protected by a perovskite conversion treatment: Relationship with the coating microstructure and formation mechanism

A feasibility study has been conducted to determine if a recently developed molten salt perovskite conversion coating process can be applied to protect an intrinsically low corrosion-resistant 13-Cr ferritic stainless steel in Molten Carbonate Fuel Cell (MCFC) demanding environments. The molten salt bath composition has been adapted to evaluate the influence of two different reaction mechanisms, namely dissolution-precipitation and precursor-template synthesis, on microstructure and MCFC corrosion resistance of the LaFeO3-based perovskite coatings. It has been found that the necessary strong basic/oxidizing chemistry conditions for the dissolution-precipitation mechanism to occur cause extensive substrate corrosion that contribute to coating porosity and poor MCFC corrosion protection. On the other hand, excellent corrosion protection of the 13-Cr steel is afforded by a perovskite conversion coating that had been produced via an iron oxide precursor-template route under milder basic conditions. The results show that a decreased salt bath basicity fully suppresses substrate corrosion, while promoting at the same a fine coating microstructure and virtual absence of coating through-porosity, thus markedly improving the barrier properties of coated 13-Cr steel against MCFC corrosion attack.

The effects of storms and diving activities on the corrosion rate across the SS Yongala (1911) site in the Great Barrier Reef

The initial assessment of the condition of the wreck of the SS Yongala (1911) took place in 2005 and was followed with additional in-situ measurements on three field trips in 2007. Analysis of the corrosion potential, pH and plate perforation data confirmed that the superstructure, deck and hull plates are highly corroded and that the most extensive corrosion is on the port side gunwale. The high corrosion rates found at the forward end hull/forecastle deck level and at the stern near the rudder are consistent with the exposed locations which lie proud of the seabed and are subject to significant water movement across the site. Comparison of the original structure and its present condition with site records from previous visits suggest that the wreck is following the Riley waterline theory with the port side frames eventually collapsing and the bow and or stern section breaking off from the vessel. This collapse could happen at or near hold 3 and or around holds 1 and 2. Currently the bow is corroding at a higher rate than the stern end. Changes in the souring of the site and past practices of tying up to the wreck have been significant factors in accelerating the corrosion of this historically significant iron shipwreck.

Corrosion mechanism of aluminum alloy by ethylene glycol‐based solution

AbstractCorrosion and failure mechanisms on an aluminum (Al) alloy by ethylene glycol base solution have been studied. Extensive crevice corrosion damage and localized scale deposition are clearly observed between the failed Al alloy surface and the rubber hose, in which the leakage of ethylene glycol‐based solution occurred under an actual operating. In addition, many micro‐cracks are found at the rubber hose which is clamped with the Al alloy. The scales on the Al surface appear to be due to the occurrence of Al corrosion, followed by the precipitation of additives of ethylene glycol‐based solution in the crevice between Al alloy and rubber hose. The mechanisms that can account for the crevice corrosion and solution leakage on the Al alloy surface are discussed.

Environmental surface degradation of galvanised and mild steels in cattle and poultry wastes and urea solution

An investigation of the corrosive properties of cattle and poultry dung/urine slurries and urea solution and by extension, the corrosion resistance of galvanised and mild steels in these respective test media was performed by the weight loss method. The results showed corrosive surface degradation of galvanised steel and extensive corrosion of the mild steel test specimens by the corrosive constituents of the various test media. The corrosive constituents in the slurries are believed to be urea, uric acid, ammonia and ammonium salts, naturally excreted chloride (common salt), carbon-dioxide and sulphate reducing and sulphur oxidizing bacteria. The galvanised steel is found to be more corrosion resistant than the mild steel. The cattle dung/urine slurry was found to be the most aggressive of the test media and the poultry dung/urine slurry, the least corrosive medium.

Repair of two riveted steel plate girder railway bridges

This paper describes repairs to two 1906-built riveted steel plate girder bridges owned and maintained by the Gloucestershire Warwickshire Steam Railway (GWSR). Stanton Bridge carries the de-trunked former A46 main road over the railway on a 57·38° skew, and had extensive corrosion to the main and secondary girders. Gretton Bridge, which carries the railway over a minor road, needed repairs to the bottom flange and a web stiffener as a result of impact from an over-height road vehicle. GWSR is a volunteer-run organisation operating passenger trains hauled by restored steam locomotives.

Corrosion patterns of seep‐carbonates from the eastern Mediterranean Sea

Terra Nova, 23, 206–212, 2011AbstractPorous seep‐carbonates are exposed at mud volcanoes in the eastern Mediterranean Sea. The 13C‐depleted aragonitic carbonates formed as a consequence of the anaerobic oxidation of methane in a shallow sub‐surface environment. Besides the macroscopically visible cavernous fabric, extensive carbonate corrosion was revealed by detailed analysis. After erosion of the background sediments, the carbonates became exposed to oxygenated bottom waters that are periodically influenced by the release of methane and upward diffusion of hydrogen sulphide. We suggest that carbonate corrosion resulted from acidity locally produced by aerobic oxidation of methane and hydrogen sulphide in the otherwise, with respect to aragonite, oversaturated bottom waters. Although it remains to be tested whether the mechanisms of carbonate dissolution suggested herein are valid, this study reveals that a better estimate of the significance of corrosion is required to assess the amount of methane‐derived carbon that is permanently fixed in seep‐carbonates.

The Corrosion Resistance Properties and Precipitate of Common Artificial Reef Materials

The corrosion properties of several common artificial reef materials were studied using electrochemical methods and by measuring corrosion rates in estuary water and seawater. Experimental results show that the 6063 aluminum alloy can be a reef construction material only in low velocity estuary water. Copper in seawater has high corrosion potential and can be passivated, but the high velocity water will destroy the passivation film and decrease the corrosion resistance of copper. Copper is a suitable reef material in low flow seawater and estuary water. With low open potential, high anode current and extensive corrosion, Q235 steel is only suggested as artificial reef material if applying sacrificial anode protection. Pine block and granite are natural materials whose degradation products won’t harm the environment, but the pine block has short service life while granite has a minimal corrosion rate. PVC has small corrosion rate but leaches toxic substances after degradation, so it is not suitable for wide-ranging use.

Humber Bridge main cable dehumidification and acoustic monitoring – The world's largest retrofitted systems

When opened in 1981, the Humber Bridge became the world's longest span at 1410 m, a record it held for 17 years. Internal cable inspections of the two older major UK suspension bridges from 2004 to 2006 revealed unexpected levels of corrosion and broken wires. Following this discovery the Humber Bridge Board commissioned the development of a pro-active maintenance strategy which led to an internal inspection of the cables in 2009. Although only a few broken wires were found, there was extensive corrosion present which confirmed the need to minimize future deterioration and monitor the cable condition. A cable dehumidification system has been designed and installed on the bridge to prolong the life of the cables, and this sets new standards in terms of speed, quality and safety of the installation of the largest retrofitted system in the world. An acoustic monitoring system has also been installed which is the largest acoustic monitoring system currently fitted on a suspension bridge.

Corrosion of 15th and early 16th century stained glass from the monastery of Batalha studied with external ion beam

This paper reports the study of corrosion in two stained glass panels from the south aisle of Sta. Maria da Vitória monastery, at Batalha (Portugal), one depicting the Last Supper (dated from 1508), and the other one showing a saint (c. 1450). These panels exhibit extensive corrosion with darkening phenomena that are an impediment to their correct visualization, a source of major concern both to conservators and curators. By using external micro-beam Particle Induced X-ray Emission (PIXE) and Particle Induced Gamma Emission (PIGE) spectrometry, the elemental compositions of large fragments were obtained, enabling the selection of representative corroded areas, from which elemental distribution maps were produced by scanning. Calcium and potassium rich structures were found – at the surface and inside cavities in the glass – that were identified as oxalates and carbonates, by Raman microscopy and micro-FTIR. The dark spots present in the glass surfaces were found to be Zn and Pb rich. These findings indicate that the corrosion observed was due not only to reactions with atmospheric water and CO 2 but also with the oxalic acid secreted by micro-organisms. Furthermore, it did not result from reactions with atmospheric SO 2 or acid rain. The information obtained is relevant for a better understanding of the corrosion processes and products formed on the surface of these panels and therefore for the proper planning of much needed adequate conservation–restoration actions and appropriate display conditions.

A Note on the Corrosion Morphology of some Middle Elamite Copper Alloy Artefacts from Haft Tappeh, South-West Iran

The paper reviews the corrosion morphology of some copper-based alloy objects frthe Middle Elamite site of Haft Tappeh, south-west Iran, about 1400 BC. These artefacts have undergone extensive bronze disease corrosion and their interior is completely converted to a greyish-white, tin-rich phase, with corresponding loss of copper.