WorldWideScience

Sample records for corrosion rate probes

  1. Detective probe prevents corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2001-07-01

    A black liquor recovery boiler is the main investment in a pulp mill, accounting for: about a third of the total cost of FIM 3-4 billion. Environmental aspects required that all the harmful chemicals involved in the process have to be kept within a pulp mill, rather than be released outside, and closed water circulation systems have to be introduced. These have led to the enrichment of some process and non-process chemicals causing corrosion problems and process disturbances in the boiler. The recovery boiler receives the liquor after the digestion stage, i.e. when woodchips are cooked to make cellulose, and burns it. During digestion, the wood produces out lignin, mixed with the liquor (consisting of sodium sulphide and hydroxide). The black liquor is burnt at the bottom of the boiler after the organic parts have been fired off. The rest goes into the recovery system and the chemicals are recycled producing energy, saving repurchasing chemicals and protecting the environment from toxic emissions.

  2. Corrosion Rate Monitoring in District Heating Systems

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Nielsen, Lars Vendelbo; Andersen, A.

    2005-01-01

    Quality control in district heating systems to keep uniform corrosion rates low and localized corrosion minimal is based on water quality control. Side-stream units equipped with carbon steel probes for online monitoring were mounted in district heating plants to investigate which techniques would...... be applicable, and if on-line monitoring could improve the quality control. Water quality monitoring was applied as well as corrosion rate monitoring with linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), electrical resistance (ER) technique, mass loss and a crevice corrosion...... cell for localized corrosion risk estimation. Important variations in corrosion rate due to changes in make-up water quality were detected with the continuous monitoring provided by ER and crevice cell, while LPR gave unreliable corrosion rates. The acquisition time of two-three days for EIS...

  3. Corrosion Rate Monitoring in District Heating Systems

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Nielsen, Lars Vendelbo; Andersen, A.

    2005-01-01

    Quality control in district heating systems to keep uniform corrosion rates low and localized corrosion minimal is based on water quality control. Side-stream units equipped with carbon steel probes for online monitoring were mounted in district heating plants to investigate which techniques would...... be applicable, and if on-line monitoring could improve the quality control. Water quality monitoring was applied as well as corrosion rate monitoring with linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), electrical resistance (ER) technique, mass loss and a crevice corrosion...... cell for localized corrosion risk estimation. Important variations in corrosion rate due to changes in make-up water quality were detected with the continuous monitoring provided by ER and crevice cell, while LPR gave unreliable corrosion rates. The acquisition time of two-three days for EIS...

  4. Development and Testing of a Linear Polarization Resistance Corrosion Rate Probe for Ductile Iron Pipe (Web Report 4361)

    Science.gov (United States)

    The North American water and wastewater community has hundreds of millions of feet of ductile iron pipe in service. Only a portion of the inventory has any form of external corrosion control. Ductile iron pipe, in certain environments, is subject to external corrosion.Linear Pola...

  5. Monitoring corrosion rates and localised corrosion in low conductivity water

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    2006-01-01

    Monitoring of low corrosion rates and localised corrosion in a media with low conductivity is a challenge. In municipal district heating, quality control may be improved by implementing on-line corrosion monitoring if a suitable technique can be identified to measure both uniform and localised...... corrosion. Electrochemical techniques (LPR, EIS, crevice corrosion current) as well as direct measurement techniques (high-sensitive electrical resistance, weight loss) have been applied in operating plants. Changes in the corrosion processes are best monitored in non-aggressive, low conductivity media...... with sensitive electrical resistance technique and crevice corrosion current measurements....

  6. The Corrosion Inhibition Characteristics of Sodium Nitrite Using an On-line Corrosion Rate Measurement System

    Energy Technology Data Exchange (ETDEWEB)

    Park, Mal-Yong; Kang, Dae-Jin [Korea Polytechnic University, Shiheung (Korea, Republic of); Moon, Jeon-Soo [Future Technology Research Laboratory, KEPCO Research Institute, Daejeon (Korea, Republic of)

    2015-04-15

    An on-line corrosion rate measurement system was developed using a personal computer, a data acquisition board and program, and a 2-electrode corrosion probe. Reliability of the developed system was confirmed with through comparison test. With this system, the effect of sodium nitrite (NaNO{sub 2}) as a corrosion inhibitor were studied on iron and aluminum brass that were immersed in sodium chloride (NaCl) solution. Corrosion rate was measured based on the linear polarization resistance method. The corrosion rates of aluminum brass and iron in 1% NaCl solutions were measured to be 0.290 mm per year (mmpy) and 0.2134 mmpy, respectively. With the addition of 200 ppm of NO{sub 2}{sup -}, the corrosion rates decreased to 0.0470 mmpy and 0.0254 mmpy. The addition of NO{sub 2}{sup -} caused a decrease in corrosion rates of both aluminum brass and iron, yet the NO{sub 2}{sup -} acted as a more effective corrosion inhibitor for iron. than aluminum brass.

  7. Screening of soil corrosivity by field testing: Results and design of an electrochemical soil corrosion probe

    DEFF Research Database (Denmark)

    Nielsen, Lars vendelbo; Bruun, Niels Kåre

    1996-01-01

    The corrosivity of different types of soil have been assessed by exposing carbon-steel plates at 50 different locations in Denmark for an extended period of time. The investigations included weight loss measurements and analysis of the chemical compositions of the corrosion products formed...... on the plates during exposure. An electrochemical soil corrosion probe has been designed and manufactured allowing for simultaneous measurements of several qauntities to predict corrosion. The probe consists of individual sections capable of measuring redox-potential, corrosion potential, soil resistivity...

  8. Corrosion of Carbon Steel under Epoxy-varnish Coating Studied by Scanning Kelvin Probe

    Institute of Scientific and Technical Information of China (English)

    XIAO Kui; DONG Chaofang; ZHANG Xin; WU Junsheng; XU Longjiao; LI Xiaogang

    2012-01-01

    The corrosion behavior of partly coated carbon steel was investigated by salt spray test and scanning Kelvin probe (SKP) in order to understand the long-term corrosion behavior of coated carbon steel in marine atmosphere environment.The localized corrosion was accurately characterized by SKP in both coated and uncoated regions.The SKP results showed that Volta potential varied with the test time,and the more the corrosion products,the more positive the potential.The borderline between coated and uncoated regions of partly coated steel shifted towards the coated side with the increasing of test time.The coating disbonding rate could be determined according to the shift of potential borderline measured by SKP.The corrosion mechanism of partly coated steel in NaC1 salt spray was discussed according to the potential maps and corrosion morphologies.

  9. Aqueous Corrosion Rates for Waste Package Materials

    Energy Technology Data Exchange (ETDEWEB)

    S. Arthur

    2004-10-08

    The purpose of this analysis, as directed by ''Technical Work Plan for: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 171583]), is to compile applicable corrosion data from the literature (journal articles, engineering documents, materials handbooks, or standards, and national laboratory reports), evaluate the quality of these data, and use these to perform statistical analyses and distributions for aqueous corrosion rates of waste package materials. The purpose of this report is not to describe the performance of engineered barriers for the TSPA-LA. Instead, the analysis provides simple statistics on aqueous corrosion rates of steels and alloys. These rates are limited by various aqueous parameters such as temperature (up to 100 C), water type (i.e., fresh versus saline), and pH. Corrosion data of materials at pH extremes (below 4 and above 9) are not included in this analysis, as materials commonly display different corrosion behaviors under these conditions. The exception is highly corrosion-resistant materials (Inconel Alloys) for which rate data from corrosion tests at a pH of approximately 3 were included. The waste package materials investigated are those from the long and short 5-DHLW waste packages, 2-MCO/2-DHLW waste package, and the 21-PWR commercial waste package. This analysis also contains rate data for some of the materials present inside the fuel canisters for the following fuel types: U-Mo (Fermi U-10%Mo), MOX (FFTF), Thorium Carbide and Th/U Carbide (Fort Saint Vrain [FSVR]), Th/U Oxide (Shippingport LWBR), U-metal (N Reactor), Intact U-Oxide (Shippingport PWR, Commercial), aluminum-based, and U-Zr-H (TRIGA). Analysis of corrosion rates for Alloy 22, spent nuclear fuel, defense high level waste (DHLW) glass, and Titanium Grade 7 can be found in other analysis or model reports.

  10. Strain rate effects in stress corrosion cracking

    Energy Technology Data Exchange (ETDEWEB)

    Parkins, R.N. (Newcastle upon Tyne Univ. (UK). Dept. of Metallurgy and Engineering Materials)

    1990-03-01

    Slow strain rate testing (SSRT) was initially developed as a rapid, ad hoc laboratory method for assessing the propensity for metals an environments to promote stress corrosion cracking. It is now clear, however, that there are good theoretical reasons why strain rate, as opposed to stress per se, will often be the controlling parameter in determining whether or not cracks are nucleated and, if so, are propagated. The synergistic effects of the time dependence of corrosion-related reactions and microplastic strain provide the basis for mechanistic understanding of stress corrosion cracking in high-pressure pipelines and other structures. However, while this may be readily comprehended in the context of laboratory slow strain tests, its extension to service situations may be less apparent. Laboratory work involving realistic stressing conditions, including low-frequency cyclic loading, shows that strain or creep rates give good correlation with thresholds for cracking and with crack growth kinetics.

  11. Corrosion-Inhibitor Efficiency Control: Comparison by Means of Different Portable Corrosion Rate Meters

    OpenAIRE

    Martinez Sierra, Isabel; Andrade Perdrix, Maria del Carmen; Rebolledo Ramos, Nuria; Luo, L; De Schutter, G

    2010-01-01

    Corrosion-inhibiting substances have been applied to suppress corrosion mainly on bare steel, but when corrosion is progressing, suppression can be achieved if anodic and cathodic reactions are avoided, which is not an easy objective, particularly if the bare metal is surrounded by concrete. In the present article, several corrosion inhibitors are studied to identify their inhibition efficiency in concrete. The percentage of reduction of the corrosion rate without and with inhibitor is named ...

  12. High temperature corrosion in straw-fired power plants: Influence of steam/metal temperature on corrosion rates for TP347H

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Biede, O; Larsen, OH

    2002-01-01

    The corrosion in straw-fired boilers has been investigated at various straw-fired power plants in Denmark. Water/air-cooled probes, a test superheater and test sections removed from the actual superheater have been utilised to characterise corrosion and corrosion rates. This paper describes...... the corrosion rates measured for the TP347H type steel. The corrosion morphology at high temperature consists of grain boundary attack and selective attack of chromium. The corrosion rate increases with calculated metal temperature (based on steam temperature), however there is great variation within...... these results. In individual superheaters, there are significant temperature variations i.e. higher temperature in middle banks compared to the outer banks, higher temperature in leading tubes, which have a high impact on corrosion. In a single loop the assumption that heat uptake (and heat flux) is linear...

  13. High temperature corrosion in straw-fired power plants: Influence of steam/metal temperature on corrosion rates for TP347H

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Biede, O; Larsen, OH

    2002-01-01

    The corrosion in straw-fired boilers has been investigated at various straw-fired power plants in Denmark. Water/air-cooled probes, a test superheater and test sections removed from the actual superheater have been utilised to characterise corrosion and corrosion rates. This paper describes...... the corrosion rates measured for the TP347H type steel. The corrosion morphology at high temperature consists of grain boundary attack and selective attack of chromium. The corrosion rate increases with calculated metal temperature (based on steam temperature), however there is great variation within...... these results. In individual superheaters, there are significant temperature variations i.e. higher temperature in middle banks compared to the outer banks, higher temperature in leading tubes, which have a high impact on corrosion. In a single loop the assumption that heat uptake (and heat flux) is linear...

  14. Corrosion rate of steel in concrete - Evaluation of confinement techniques for on-site corrosion rate

    DEFF Research Database (Denmark)

    Nygaard, Peter Vagn; Geiker, Mette Rica; Elsener, Bernhard

    2009-01-01

    Earlier on-site investigations and laboratory studies have shown that varying corrosion rates are obtained when different commercially available instruments are used. The different confinement techniques, rather than the different electrochemical techniques used in the instruments, are considered...... to be the main reason for the discrepancies. This paper presents a method for the quantitative assessment of confinement techniques based on monitoring the operation of the corrosion rate instrument and the current distribution between the electrode assembly on the concrete surface and a segmented reinforcement...... bar embedded in the concrete. The applicability of the method was demonstrated on two commercially available corrosion rate instruments based on different confinement techniques. The method provided an explanation of the differences in performance of the two instruments. Correlated measurements...

  15. Corrosion rate of steel in concrete - Evaluation of confinement techniques for on-site corrosion rate

    DEFF Research Database (Denmark)

    Nygaard, Peter Vagn; Geiker, Mette Rica; Elsener, Bernhard

    2009-01-01

    Earlier on-site investigations and laboratory studies have shown that varying corrosion rates are obtained when different commercially available instruments are used. The different confinement techniques, rather than the different electrochemical techniques used in the instruments, are considered...... to be the main reason for the discrepancies. This paper presents a method for the quantitative assessment of confinement techniques based on monitoring the operation of the corrosion rate instrument and the current distribution between the electrode assembly on the concrete surface and a segmented reinforcement...... bar embedded in the concrete. The applicability of the method was demonstrated on two commercially available corrosion rate instruments based on different confinement techniques. The method provided an explanation of the differences in performance of the two instruments. Correlated measurements...

  16. Effects of alternating magnetic field on the corrosion rate and corrosion products of copper

    Institute of Scientific and Technical Information of China (English)

    GUO Bin; ZHANG Peng; JIN Yongping; CHENG Shukang

    2008-01-01

    The effects of alternating magnetic field on the corrosion morphologies, corrosion rate, and corrosion products of copper in 3.5% NaCl solution, sea water, and magnetized sea water were investigated using electrochemical test, scanning electron microscopy/energy dispersive analysis system of X-ray (SEM/EDAX), and X-ray diffraction (XRD). The results show that the corrosion rate of copper in magnetized sea water is minimal. Moreover, the surface of the specimen in magnetized sea water is uniform and compact as compared with those in 3.5% NaCl solution and sea water. The corrosion products of copper in magnetized sea water are mainly Cu2O and CuCl2. However, the corrosion products in sea water are CuCl, Cu2Cl(OH)3, and FeCl3·6H2O. The electrochemical corrosion mechanisms of copper in the three media were also discussed.

  17. Effect of Flow Velocity on Corrosion Rate and Corrosion Protection Current of Marine Material

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seong Jong [Kunsan National University, Kunsan (Korea, Republic of); Han, Min Su; Jang, Seok Ki; Kim, Seong Jong [Mokpo National Maritime University, Mokpo (Korea, Republic of)

    2015-10-15

    In spite of highly advanced paint coating techniques, corrosion damage of marine metal and alloys increase more and more due to inherent micro-cracks and porosities in coatings formed during the coating process. Furthermore, flowing seawater conditions promote the breakdown of the protective oxide of the materials introducing more oxygen into marine environments, leading to the acceleration of corrosion. Various corrosion protection methods are available to prevent steel from marine corrosion. Cathodic protection is one of the useful corrosion protection methods by which the potential of the corroded metal is intentionally lowered to an immune state having the advantage of providing additional protection barriers to steel exposed to aqueous corrosion or soil corrosion, in addition to the coating. In the present investigation, the effect of flow velocity was examined for the determination of the optimum corrosion protection current density in cathodic protection as well as the corrosion rate of the steel. It is demonstrated from the result that the material corrosion under dynamic flowing conditions seems more prone to corrosion than under static conditions.

  18. Development of Copper Corrosion Products and Relation between Surface Appearance and Corrosion Rate

    Energy Technology Data Exchange (ETDEWEB)

    Lan, Tran Thi Ngoc; Binh, Nguyen Thi Thanh [Vietnam National University, Ho Chi Minh (Viet Nam); Tru, Nguyen Nhi [Vietnam Institute for Tropical Technology and Environmental Protection, Ho Chi Minh (Viet Nam); Yoshino, Tsujino [Osaka Prefecture, Osaka (Japan); Yasuki, Maeda [Osaka Prefecture University, Osaka (Japan)

    2008-04-15

    Copper was exposed unsheltered and sheltered in four humid tropical sites, representing urban, urban-industrial, urban-marine and rural environments. The corrosion rates and the sequence of corrosion product formation are presented and discussed in relation with climatic and atmospheric pollution parameters. Chemical compositions of corrosion products were found to depend on environments and duration of exposure. In all environments, cuprite was the predominating corrosion product that formed first and continuously increased during the exposure. Among the sulphur-containing corrosion products, posnjakite and brochantite were more frequently found and the first formed earlier. Nantokite was the most common chlorine-containing products for most cases, except the high-chloride environment, where atacamite was detected instead. The corrosion rate of copper was well indicated by the colour of patina. The red-purple colour corresponded to the high corrosion rate and the greenish grey colour corresponded to the low corrosion rate. Corrosion rate of sheltered copper in urban-marine environment increased with the exposure time.

  19. PERFORMACE OF MULTI-PROBE CORROSION MONITORING SYSTEMS AT THE HANFORD SITE

    Energy Technology Data Exchange (ETDEWEB)

    CAROTHERS KD; BOOMER KD; ANDA VS; DAHL MM; EDGEMON GL

    2010-01-14

    Between 2007 and 2009, several different multi-probe corrosion monitoring systems were designed and installed in high-level nuclear waste tanks at the U.S. Department of Energy's Hanford Site in WaShington State. The probe systems are being monitored to ensure waste tanks operate in regions that minimize localized corrosion (i.e., pitting) and stress corrosion cracking. The corrosion monitoring systems have been installed in wastes with different chemistry types. An ongoing effort during the same time period has generated non-radioactive simulants that are tested in the laboratory to establish baseline corrosion monitoring system performance and characterize data to allow interpretation of readings from the multiple corrosion monitoring systems. Data collection from these monitoring systems has reached the point where the results allow comparison with the laboratory testing. This paper presents analytical results from the corrosion monitoring system development program.

  20. TEST PLAN AND PROCEDURE FOR THE EXAMINATION OF TANK 241-AY-101 MULTI-PROBE CORROSION MONITORING SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    WYRWAS RB; PAGE JS; COOKE GS

    2012-04-19

    This test plan describes the methods to be used in the forensic examination of the Multi-probe Corrosion Monitoring System (MPCMS) installed in the double-shell tank 241-AY-101 (AY-101). The probe was designed by Applied Research and Engineering Sciences (ARES) Corporation. The probe contains four sections, each of which can be removed from the tank independently (H-14-107634, AY-101 MPCMS Removable Probe Assembly) and one fixed center assembly. Each removable section contains three types of passive corrosion coupons: bar coupons, round coupons, and stressed C-rings (H-14-l07635, AY-101 MPCMS Details). Photographs and weights of each coupon were recorded and reported on drawing H-14-107634 and in RPP-RPT-40629, 241-AY-101 MPCMS C-Ring Coupon Photographs. The coupons will be the subject of the forensic analyses. The purpose of this examination will be to document the nature and extent of corrosion of the 29 coupons. This documentation will consist of photographs and photomicrographs of the C-rings and round coupons, as well as the weights of the bar and round coupons during corrosion removal. The total weight loss of the cleaned coupons will be used in conjunction with the surface area of each to calculate corrosion rates in mils per year. The bar coupons were presumably placed to investigate the liquid-air-interface. An analysis of the waste level heights in the waste tank will be investigated as part of this examination.

  1. Experiences with the KEMA Corrosion Probe in waste incineration plants and coal fired boilers

    Energy Technology Data Exchange (ETDEWEB)

    Jong, M.P. de; Leferink, R.G.I. [KEMA Nederland B.V. Arnhem, (Netherlands)

    2001-07-01

    Fireside corrosion is still a major cause of concern in coal- fired power plants and municipal waste incineration plants. In a highly competitive electricity market, the demand for a method to determine the quality or protectiveness of the oxide layers on evaporator walls, in boilers of power plants with low-NO{sub x} firing techniques, will increase. Moreover, co-firing of new fuels (RDF, pulverised wood and other residual fractions) has as yet unknown consequences for corrosion in evaporator walls and super heaters in boiler installations and waste incinerators. Corrosion monitoring enables operators of coal fired power plants to measure and act when corrosion problems are likely to occur. If done properly corrosion monitoring allows the plant operator to adjust the (co-) firing conditions to less corrosive conditions with the highest possible plant efficiency. Recently KEMA developed the KEMA Corrosion Probe (KEMCOP) which enables plant owners to determine fireside corrosion in different locations in their boiler. A good example is the 540 MWe E.on Maasvlakte power plant, which was recently fitted for the exposure of 144 probes simultaneously. The probes can also be used for material testing by exposing different materials under actual firing conditions. Aside from corrosion monitoring also slagging behaviour and condensation of heavy metals can be monitored. In the Netherlands KEMCOP probes are used for several purposes and are more and more becoming common practice for coal fired boilers and waste incinerators. Until now almost 300 probes have been mounted in coal fired boilers and waste incineration plants. (orig.)

  2. CORROSION MONITORING IN HANFORD NUCLEAR WASTE STORAGE TANKS DESIGN AND DATA FROM 241-AN-102 MULTI-PROBE CORROSION MONITORING SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    ANDA VS; EDGEMON GL; HAGENSEN AR; BOOMER KD; CAROTHERS KG

    2009-01-08

    In 2008, a new Multi-Probe Corrosion Monitoring System (MPCMS) was installed in double-shell tank 241-AN-102 on the U.S. Department of Energy's Hanford Site in Washington State. Developmental design work included laboratory testing in simulated tank 241-AN-102 waste to evaluate metal performance for installation on the MPCMS as secondary metal reference electrodes. The MPCMS design includes coupon arrays as well as a wired probe which facilitates measurement of tank potential as well as corrosion rate using electrical resistance (ER) sensors. This paper presents the MPCMS design, field data obtained following installation of the MPCMS in tank 241-AN-102, and a comparison between laboratory potential data obtained using simulated waste and tank potential data obtained following field installation.

  3. Corrosion circumstance in the Tokai Reprocessing Plant and evaluation of the corrosion rate

    Energy Technology Data Exchange (ETDEWEB)

    Maki, Akira [Japan Nuclear Cycle Development Inst., Tokai Works, Tokai Reprocessing Center, Tokai, Ibaraki (Japan)

    2002-03-01

    In the reprocessing plant, corrosive circumstances arise, because the major equipment contains a high concentration of the metal ions that originate from the fission products. They are also equipped in the various concentrations of nitric acid and various temperatures. Based on failed experiments due to corrosion, repairing the equipment and exchanging materials, the corrosion rate of stainless steel containing Nb was measured over 1 mm/yr in the heat transfer surface of the dissolver. Pin-holes in the weld zone of the heat conduction surface of the dissolver and the acid recovery evaporator were observed. Although the corrosion rate of Ti-5Ta in the vapor zone of the plutonium solution evaporator reached 0.1 - 0.3 mm/yr, no local attacks were confirmed. On the other hand, the corrosion of Ti-5Ta was not observed in the acid recovery evaporator. This report presents the survey result of the corrosion equipment and an outline of the corrosion tests, with the wall thickness measurement result obtained as a soundness confirmation of the equipment. (author)

  4. Corrosion monitoring in a straw-fired power plant using an electrochemical noise probe

    DEFF Research Database (Denmark)

    Cappeln, Frederik Vilhelm; Bjerrum, Niels; Petrushina, Irina

    2007-01-01

    Electrochemical Noise Measurements have been carried out in situ in a straw-fired power plant using an experimental probe constructed from alumina and AlSl 347 steel. Based on a framework of controlled laboratory experiments it has been found that electrochemical noise has the unique ability...... to provide in-situ monitoring of intergranular corrosion in progress. The probe had a lifetime of two months. It was shown that down-time corrosion in the boiler was negligible. Electrochemical noise data indicated that metal temperatures around 590 degrees C should be avoided as the intergranular corrosion...

  5. Assessment of corrosion rate in prestressed concrete with acoustic emission

    Science.gov (United States)

    Mangual, Jesé; ElBatanouny, Mohamed K.; Vélez, William; Ziehl, Paul; Matta, Fabio; González, Miguel

    2011-04-01

    Acoustic Emission (AE) sensing was employed to assess the rate of corrosion of steel strands in small scale concrete block specimens. The corrosion process was accelerated in a laboratory environment using a potentiostat to supply a constant potential difference with a 3% NaCl solution as the electrolyte. The embedded prestressing steel strand served as the anode, and a copper plate served as the cathode. Corrosion rate, half-cell potential measurements, and AE activity were recorded continuously throughout each test and examined to assess the development of corrosion and its rate. At the end of each test the steel strands were cleaned and re-weighed to determine the mass loss and evaluate it vis-á-vis the AE data. The initiation and propagation phases of corrosion were correlated with the percentage mass loss of steel and the acquired AE signals. Results indicate that AE monitoring may be a useful aid in the detection and differentiation of the steel deterioration phases, and estimation of the locations of corroded areas.

  6. On-line corrosion monitoring in geothermal district heating systems. I. General corrosion rates

    DEFF Research Database (Denmark)

    Richter, S.; Hilbert, Lisbeth Rischel; Thorarinsdottir, R.I.

    2006-01-01

    General corrosion rates in the geothermal district heating systems in Iceland are generally low, of the magnitude 1 mu m/y. The reason is high pH (9.5), low-conductivity (200 mu m/y) and negligible dissolved oxygen. The geothermal hot water is either used directly from source or to heat up cold...... ground water. The fluid naturally contains sulphide, which helps keeping the fluid oxygen-free but complicates the electrochemical environment. In this research on-line techniques for corrosion monitoring were tested and evaluated in this medium. Electrochemical methods worked well as long as frequency...

  7. Scanning probe microscopy at video-rate

    Directory of Open Access Journals (Sweden)

    Georg Schitter

    2008-01-01

    Full Text Available Recent results have demonstrated the feasibility of video-rate scanning tunneling microscopy and video-rate atomic force microscopy. The further development of this technology will enable the direct observation of many dynamic processes that are impossible to observe today with conventional Scanning Probe Microscopes (SPMs. Examples are atom and molecule diffusion processes, the motion of molecular motors, real-time film growth, and chemical or catalytic reactions. Video-rate scanning probe technology might also lead to the extended application of SPMs in industry, e.g. for process control. In this paper we discuss the critical aspects that have to be taken into account for improving the imaging speed of SPMs. We point out the required instrumentation efforts, give an overview of the state of the art in high-speed scanning technology and discuss the required future developments for imaging at video-rates.

  8. Thin layer activation for probing flow accelerated corrosion of carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, H.; Madasamy, P. [Water and Steam Chemistry Division, BARC Facilities, Kalpakkam 603 102, Tamil Nadu (India); Kumawat, H.; Thomas, R.G. [Nuclear Physics Division, BARC, Mumbai 400 085, Maharashtra (India); Krishnamohan, T.V. [Water and Steam Chemistry Division, BARC Facilities, Kalpakkam 603 102, Tamil Nadu (India); Velmurugan, S., E-mail: svelu@igcar.gov.in [Water and Steam Chemistry Division, BARC Facilities, Kalpakkam 603 102, Tamil Nadu (India); Narasimhan, S.V. [Water and Steam Chemistry Division, BARC Facilities, Kalpakkam 603 102, Tamil Nadu (India)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer Corrosion rate in certain locations of feeder piping exceeds the design allowance. Black-Right-Pointing-Pointer Online measurement of localized wall thinning in a short time. Black-Right-Pointing-Pointer Velocity and pH dependence of corrosion rates predicted by Sanchez-Caldera model. Black-Right-Pointing-Pointer Surface roughness corrections mandatory for extrapolation of experimental results. - Abstract: Carbon steel feeder elbows and feeder piping of the primary coolant system of pressurized heavy water reactors undergo significant wall thinning due to flow accelerated corrosion. The rate of corrosion in certain locations exceeds the design corrosion allowance. Corrosion rate is dependent on several parameters like pH, temperature, dissolved oxygen, chromium content in material, pipe geometry, etc. Thin layer activation, utilizing the {sup 57}Fe(p,n){sup 57}Co reaction, enabled rapid online measurement of wall thinning in a simulated straight feeder pipe. Significant velocity and pH dependence was observed for corrosion rates and the same were compared with the predictions by Sanchez-Caldera model.

  9. Corrosion

    Science.gov (United States)

    Slabaugh, W. H.

    1974-01-01

    Presents some materials for use in demonstration and experimentation of corrosion processes, including corrosion stimulation and inhibition. Indicates that basic concepts of electrochemistry, crystal structure, and kinetics can be extended to practical chemistry through corrosion explanation. (CC)

  10. Corrosion

    Science.gov (United States)

    Slabaugh, W. H.

    1974-01-01

    Presents some materials for use in demonstration and experimentation of corrosion processes, including corrosion stimulation and inhibition. Indicates that basic concepts of electrochemistry, crystal structure, and kinetics can be extended to practical chemistry through corrosion explanation. (CC)

  11. TANK 241-AN-102 MULTI-PROBE CORROSION MONITORING SYSTEM PROJECT LESSONS LEARNED

    Energy Technology Data Exchange (ETDEWEB)

    TAYLOR T; HAGENSEN A; KIRCH NW

    2008-07-07

    During 2007 and 2008, a new Multi-Probe Corrosion Monitoring System (MPCMS) was designed and fabricated for use in double-shell tank 241-AN-102. The system was successfully installed in the tank on May 1, 2008. The 241-AN-102 MPCMS consists of one 'fixed' in-tank probe containing primary and secondary reference electrodes, tank material electrodes, Electrical Resistance (ER) sensors, and stressed and unstressed corrosion coupons. In addition to the fixed probe, the 241-AN-102 MPCMS also contains four standalone coupon racks, or 'removable' probes. Each rack contains stressed and unstressed coupons made of American Society of Testing and Materials A537 CL1 steel, heat-treated to closely match the chemical and mechanical characteristics of the 241-AN-102 tank wall. These coupon racks can be removed periodically to facilitate examination of the attached coupons for corrosion damage. Along the way to successful system deployment and operation, the system design, fabrication, and testing activities presented a number of challenges. This document discusses these challenges and lessons learned, which when applied to future efforts, should improve overall project efficiency.

  12. Corrosion detection of steel reinforced concrete using combined carbon fiber and fiber Bragg grating active thermal probe

    Science.gov (United States)

    Li, Weijie; Ho, Siu Chun Michael; Song, Gangbing

    2016-04-01

    Steel reinforcement corrosion is one of the dominant causes for structural deterioration for reinforced concrete structures. This paper presents a novel corrosion detection technique using an active thermal probe. The technique takes advantage of the fact that corrosion products have poor thermal conductivity, which will impede heat propagation generated from the active thermal probe. At the same time, the active thermal probe records the temperature response. The presence of corrosion products can thus be detected by analyzing the temperature response after the injection of heat at the reinforcement-concrete interface. The feasibility of the proposed technique was firstly analyzed through analytical modeling and finite element simulation. The active thermal probe consisted of carbon fiber strands to generate heat and a fiber optic Bragg grating (FBG) temperature sensor. Carbon fiber strands are used due to their corrosion resistance. Wet-dry cycle accelerated corrosion experiments were performed to study the effect of corrosion products on the temperature response of the reinforced concrete sample. Results suggest a high correlation between corrosion severity and magnitude of the temperature response. The technique has the merits of high accuracy, high efficiency in measurement and excellent embeddability.

  13. Corrosion rate of construction materials in hot phosphoric acid with the contribution of anodic polarization

    DEFF Research Database (Denmark)

    Kouril, M.; Christensen, Erik; Eriksen, S.;

    2011-01-01

    ). Several grades of stainless steels were tested as well as tantalum, niobium, titanium, nickel alloys and silicon carbide. The corrosion rate was evaluated by means of mass loss at free corrosion potential as well as under various levels of polarization. The only corrosion resistant material in 85...

  14. Development and evaluation of an instantaneous atmospheric corrosion rate monitor

    Science.gov (United States)

    Mansfeld, F.; Jeanjaquet, S. L.; Kendig, M. W.; Roe, D. K.

    1985-06-01

    A research program was carried out in which a new instantaneous atmospheric corrosion rate monitor (ACRM) was developed and evaluated, and equipment was constructed which will allow the use of many sensors in an economical way in outdoor exposures. In the first task, the ACRM was developed and tested in flow chambers in which relative humidity and gaseous and particulate pollutant levels can be controlled. Diurnal cycles and periods of rain were simulated. The effects of aerosols were studied. A computerized system was used for collection, storage, and analysis of the electrochemical data. In the second task, a relatively inexpensive electronics system for control of the ACRM and measurement of atmospheric corrosion rates was designed and built. In the third task, calibration of deterioration rates of various metallic and nonmetallic materials with the response of the ACRMs attached to these materials was carried out under controlled environmental conditions using the system developed in the second task. A Quality Assurance project plan was prepared with inputs from the Rockwell International Environmental Monitoring and Service Center and Quality Assurance System audits were performed.

  15. Thermodynamic Development of Corrosion Rate Modeling in Iron Phosphate Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Schlesinger, Mark [Missouri Univ. of Science and Technology, Rolla, MO (United States); Brow, Richard [Missouri Univ. of Science and Technology, Rolla, MO (United States)

    2011-10-31

    A two-year research program investigated links between the thermodynamic properties of phosphate glasses and their corrosion rates in different solutions. Glasses in the Na2O-CaO-P2O5 and Na2O-Fe2O3-PO5 systems were prepared and characterized. These glasses were then exposed in bulk and powder form to acid (0.1M HCl), basic (0.1M KOH) and neutral (deionized water) solutions at varying exposure times and temperatures. Analysis of the solution and the glass after exposure determined the rate and type of corrosion that occurred. Simultaneously, efforts were made to determine the thermodynamic properties of solid iron phosphate compounds. This included measurement of low temperature (5-300 K) heat capacities, measured at Brigham Young University; the attempted use of a Parr calorimeter to measure ambient temperature enthalpies of formation; and attempted measurement of temperature heat capacities. Only the first of the three tasks was successfully accomplished. In lieu of experimental measurement of enthalpies of formation, first-principles calculation of enthalpies of formation was performed at Missouri S&T; these results will be used in subsequent modeling efforts.

  16. The effect of corrosion induced surface morphology changes on ultrasonically monitored corrosion rates

    Science.gov (United States)

    Gajdacsi, Attila; Cegla, Frederic

    2016-11-01

    Corrosion rates obtained by very frequent (daily) measurements with permanently installed ultrasonic sensors have been shown to be highly inaccurate when changes in surface morphology lead to ultrasonic signal distortion. In this paper the accuracy of ultrasonically estimated corrosion rates (mean wall thickness loss) by means of standard signal processing methods (peak to peak—P2P, first arrival—FA, cross correlation—XC) was investigated and a novel thickness extraction algorithm (adaptive cross-correlation—AXC) is presented. All of the algorithms were tested on simulated ultrasonic data that was obtained by modelling the surface geometry evolution coupled with a fast ultrasonic signal simulator based on the distributed point source method. The performance of each algorithm could then be determined by comparing the actual known mean thickness losses of the simulated surfaces to the values that each algorithm returned. The results showed that AXC is the best of the investigated processing algorithms. For spatially random thickness loss 90% of AXC estimated thickness trends were within -10 to +25% of the actual mean loss rate (e.g. 0.75-1.1 mm year-1 would be measured for a 1 mm year-1 actual mean loss rate). The other algorithms (P2P, FA, XC) exhibited error distributions that were 5-10 times larger. All algorithms performed worse in scenarios where wall loss was not distributed randomly in space (spatially correlated thickness loss occured) and where the overall rms of the surface was either growing or declining. However, on these surfaces AXC also outperformed the other algorithms and showed almost an order of magnitude improvement compared to them.

  17. Analyzing the effect of high repetition laser shock peening on dynamic corrosion rate of magnesium

    Science.gov (United States)

    Caralapatti, Vinodh Krishna; Narayanswamy, Sivakumar

    2017-08-01

    Magnesium as implant material is being investigated extensively due to its superior suitability. With corrosion rate being the major obstacle, this paper aims to determine the effects of high repetition laser shock peening (HRLSP) on the dynamic corrosion rate of magnesium. While there is lot of research on corrosion of magnesium, in this work, a specially designed test bench was used for characterization of dynamic corrosion to mimic the physiological conditions experienced by the implant inside human body. From the results, it can be inferred that corrosion rate of peened samples reduced by at least 6 times compared to unpeened sample and sample peened with 66% overlap 1 scans exhibited the least corrosion. The wettability of the samples was also determined as a measure to analyze the effects of HRLSP on biocompatibility. In addition, peening is seen to induce surface corrosion, which minimizes the risks of implant failure.

  18. Risk Analysis using Corrosion Rate Parameter on Gas Transmission Pipeline

    Science.gov (United States)

    Sasikirono, B.; Kim, S. J.; Haryadi, G. D.; Huda, A.

    2017-05-01

    In the oil and gas industry, the pipeline is a major component in the transmission and distribution process of oil and gas. Oil and gas distribution process sometimes performed past the pipeline across the various types of environmental conditions. Therefore, in the transmission and distribution process of oil and gas, a pipeline should operate safely so that it does not harm the surrounding environment. Corrosion is still a major cause of failure in some components of the equipment in a production facility. In pipeline systems, corrosion can cause failures in the wall and damage to the pipeline. Therefore it takes care and periodic inspections or checks on the pipeline system. Every production facility in an industry has a level of risk for damage which is a result of the opportunities and consequences of damage caused. The purpose of this research is to analyze the level of risk of 20-inch Natural Gas Transmission Pipeline using Risk-based inspection semi-quantitative based on API 581 associated with the likelihood of failure and the consequences of the failure of a component of the equipment. Then the result is used to determine the next inspection plans. Nine pipeline components were observed, such as a straight pipes inlet, connection tee, and straight pipes outlet. The risk assessment level of the nine pipeline’s components is presented in a risk matrix. The risk level of components is examined at medium risk levels. The failure mechanism that is used in this research is the mechanism of thinning. Based on the results of corrosion rate calculation, remaining pipeline components age can be obtained, so the remaining lifetime of pipeline components are known. The calculation of remaining lifetime obtained and the results vary for each component. Next step is planning the inspection of pipeline components by NDT external methods.

  19. Sensitivity Analysis of Corrosion Rate Prediction Models Utilized for Reinforced Concrete Affected by Chloride

    Science.gov (United States)

    Siamphukdee, Kanjana; Collins, Frank; Zou, Roger

    2013-06-01

    Chloride-induced reinforcement corrosion is one of the major causes of premature deterioration in reinforced concrete (RC) structures. Given the high maintenance and replacement costs, accurate modeling of RC deterioration is indispensable for ensuring the optimal allocation of limited economic resources. Since corrosion rate is one of the major factors influencing the rate of deterioration, many predictive models exist. However, because the existing models use very different sets of input parameters, the choice of model for RC deterioration is made difficult. Although the factors affecting corrosion rate are frequently reported in the literature, there is no published quantitative study on the sensitivity of predicted corrosion rate to the various input parameters. This paper presents the results of the sensitivity analysis of the input parameters for nine selected corrosion rate prediction models. Three different methods of analysis are used to determine and compare the sensitivity of corrosion rate to various input parameters: (i) univariate regression analysis, (ii) multivariate regression analysis, and (iii) sensitivity index. The results from the analysis have quantitatively verified that the corrosion rate of steel reinforcement bars in RC structures is highly sensitive to corrosion duration time, concrete resistivity, and concrete chloride content. These important findings establish that future empirical models for predicting corrosion rate of RC should carefully consider and incorporate these input parameters.

  20. High Count Rate Electron Probe Microanalysis

    Science.gov (United States)

    Geller, Joseph D.; Herrington, Charles

    2002-01-01

    Reducing the measurement uncertainty of quantitative analyses made using electron probe microanalyzers (EPMA) requires a careful study of the individual uncertainties from each definable step of the measurement. Those steps include measuring the incident electron beam current and voltage, knowing the angle between the electron beam and the sample (takeoff angle), collecting the emitted x rays from the sample, comparing the emitted x-ray flux to known standards (to determine the k-ratio) and transformation of the k-ratio to concentration using algorithms which includes, as a minimum, the atomic number, absorption, and fluorescence corrections. This paper discusses the collection and counting of the emitted x rays, which are diffracted into the gas flow or sealed proportional x-ray detectors. The representation of the uncertainty in the number of collected x rays collected reduces as the number of counts increase. The uncertainty of the collected signal is fully described by Poisson statistics. Increasing the number of x rays collected involves either counting longer or at a higher counting rate. Counting longer means the analysis time increases and may become excessive to get to the desired uncertainty. Instrument drift also becomes an issue. Counting at higher rates has its limitations, which are a function of the detector physics and the detecting electronics. Since the beginning of EPMA analysis, analog electronics have been used to amplify and discriminate the x-ray induced ionizations within the proportional counter. This paper will discuss the use of digital electronics for this purpose. These electronics are similar to that used for energy dispersive analysis of x rays with either Si(Li) or Ge(Li) detectors except that the shaping time constants are much smaller. PMID:27446749

  1. A study of microbial population dynamics associated with corrosion rates influenced by corrosion control materials

    NARCIS (Netherlands)

    Chang, Yu Jie; Hung, Chun Hsiung; Lee, Jyh Wei; Chang, Yi Tang; Lin, Fen Yu; Chuang, Chun Jie

    2015-01-01

    This research aims to analyze the variations of microbial community structure under anaerobic corrosive conditions, using molecular fingerprinting method. The effect of adding various materials to the environment on the corrosion mechanism has been discussed. In the initial experiment, sulfate-re

  2. A study of microbial population dynamics associated with corrosion rates influenced by corrosion control materials

    NARCIS (Netherlands)

    Chang, Yu Jie; Hung, Chun Hsiung; Lee, Jyh Wei; Chang, Yi Tang; Lin, Fen Yu; Chuang, Chun Jie

    2015-01-01

    This research aims to analyze the variations of microbial community structure under anaerobic corrosive conditions, using molecular fingerprinting method. The effect of adding various materials to the environment on the corrosion mechanism has been discussed. In the initial experiment,

  3. When can Electrochemical Techniques give Reliable Corrosion Rates on Carbon Steel in Sulfide Media?

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Hemmingsen, Tor; Nielsen, Lars Vendelbo

    2005-01-01

    Effects of film formation on carbon steel in hydrogen sulfide media may corrupt corrosion rate monitoring by electrochemical techniques. Electrochemical data from hydrogen sulfide solutions, biological sulfide media and natural sulfide containing geothermal water have been collected and the process...... corrosion rates, but this effect may not be detected if rates are already overestimated. It is concluded that electrochemical techniques can be used for corrosion rate monitoring in som hydrogen sulfide media, but care must be taken when choosing the scan rates, and it is important to realize when direct...... in combination with ferrous sulfide corrosion products cover the steel surface. Corrosion rates can be overestimated by a factor of 10 to 100 with electrochemical techniques - both by linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS). Oxygen entering the system accelerates...

  4. Corrosion rate estimations of microscale zerovalent iron particles via direct hydrogen production measurements.

    Science.gov (United States)

    Velimirovic, Milica; Carniato, Luca; Simons, Queenie; Schoups, Gerrit; Seuntjens, Piet; Bastiaens, Leen

    2014-04-15

    In this study, the aging behavior of microscale zerovalent iron (mZVI) particles was investigated by quantifying the hydrogen gas generated by anaerobic mZVI corrosion in batch degradation experiments. Granular iron and nanoscale zerovalent iron (nZVI) particles were included in this study as controls. Firstly, experiments in liquid medium (without aquifer material) were performed and revealed that mZVI particles have approximately a 10-30 times lower corrosion rate than nZVI particles. A good correlation was found between surface area normalized corrosion rate (RSA) and reaction rate constants (kSA) of PCE, TCE, cDCE and 1,1,1-TCA. Generally, particles with higher degradation rates also have faster corrosion rates, but exceptions do exists. In a second phase, the hydrogen evolution was also monitored during batch tests in the presence of aquifer material and real groundwater. A 4-9 times higher corrosion rate of mZVI particles was observed under the natural environment in comparison with the aquifer free artificial condition, which can be attributed to the low pH of the aquifer and its buffer capacity. A corrosion model was calibrated on the batch experiments to take into account the inhibitory effects of the corrosion products (dissolved iron, hydrogen and OH(-)) on the iron corrosion rate.

  5. Corrosion Rate of Hydrogenation to C110 Casing in High H2S Environment

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhi; LI Changjin; ZHANG Jiyin; SHI Taihe

    2012-01-01

    The corrosion behavior of C110 bushing at high temperature and high pressure with a high H2S / CO2 was studied,and a basis for the materials selection of sour gas well bushing was provided in H2S,CO2 and saline coexisting environment.Under acidic condiction,hydrogen atoms greatly entered into the material and caused the material properties changed.Weight loss method was used to study the corrosion rate of hydrogen charging samples and original untreated samples in simulated oil field environment.PAR2273 electrochemical workstation was used to examine the electrochemical performance of samples untreated,hydrogen charging after reacting in autoclave.The corrosion product film was observed through SEM.The experimental results show that sample with hydrogen charging has a much more obvious partial corrosion and pitting corrosion than the untreated blank sample even the downhole corrosion speed of bushing is increased after being used for a period of time.Polarization curve shows the corrosion tendency is the same between sample with or without hydrogen charging and corrosion tendency is reduced by corrosion product film.A layer of dense product film formed on the surface of samples provides a certain protective effect to the matrix,but cracked holes which will accelerate partial corrosion of the sample were also observed.

  6. Corrosion rate of steel in concrete - from laboratory to reinforced structures

    Energy Technology Data Exchange (ETDEWEB)

    Elsener, B. [Swiss Federal Inst. of Tech., Zurich (Switzerland). Inst. of Mater. Chem. and Corrosion

    1997-12-31

    Measuring corrosion rate of rebars in reinforced concrete is essential for establishing service life prediction of structures and controlling the efficiancy of repair methods. Different electrochemical techniques, all based on measuring the polarization resistance, are used in the laboratory and on site. In calculating corrosion rate from the experimentally determined Rp value, two main problems arise: current distribution between the small counter electrode and the rebars on real structures and localized corrosion attacks. In this work results from laboratory experiments on macrocell corrosion are presented, showing the influence of resistivity and geometrical arrangement on the macrocell corrosion rate under open circuit conditions and under an external anodic pulse. From the results it can be concluded that the polarization resistance measured experimentally corresponds to the corrosion rate of the anode in the macrocell. Most of the imposed current is flowing to the local anode and thus signal confinement for local corrosion attacks is not necessary. The segmented counter electrode opens a way to determined localized corrosion rates. (orig.) 30 refs.

  7. When can Electrochemical Techniques give Reliable Corrosion Rates on Carbon Steel in Sulfide Media?

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Hemmingsen, Tor; Nielsen, Lars Vendelbo

    2005-01-01

    in combination with ferrous sulfide corrosion products cover the steel surface. Corrosion rates can be overestimated by a factor of 10 to 100 with electrochemical techniques - both by linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS). Oxygen entering the system accelerates...

  8. Reliability of Electrochemical Techniques for Determining Corrosion Rates on Carbon Steel in Sulfide Media

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Hemmingsen, T.; Nielsen, Lars Vendelbo

    2007-01-01

    if the biofilm in combination with ferrous sulfide corrosion products cover the steel surface. Corrosion rates can be overestimated by a factor of 10 to 100 with electrochemical techniques - both by linear polarization resistance (LPR) and electrochemicel impedance spectroscopy (EIS). Oxygen entering the system...

  9. Reliability of Electrochemical Techniques for Determining Corrosion Rates on Carbon Steel in Sulfide Media

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Hemmingsen, T.; Nielsen, Lars Vendelbo

    2007-01-01

    accelerates corrosion rates, but this effect may not be detected if rates are already overestimated. It is concluded that electrochemical techniques can be used for corrosion reate monitoring in some H2S media, but care must be taken in the choice of scan ratre; it is important to realize when direct......Effects of film formation on carbon steel in hydrogen sulfide (H2S) media may corrupt corrosion rate monitoring by electrochemical techniques. Electrochemical data from H2S solutions, biological sulfide media, and natural sulfide containing geothermal water have been collected, and the process...... techniques like electrical resistance or mass loss should be used instead....

  10. The corrosion rate of copper in a bentonite test package measured with electric resistance sensors

    Energy Technology Data Exchange (ETDEWEB)

    Rosborg, Bo [Division of Surface and Corrosion Science, KTH, Stockholm (Sweden); Kosec, Tadeja; Kranjc, Andrej; Kuhar, Viljem; Legat, Andraz [Slovenian National Building and Civil Engineering Institute, Ljubljana (Slovenia)

    2012-12-15

    LOT1 test parcel A2 was exposed for six years in the Aespoe Hard Rock Laboratory, which offers a realistic environment for the conditions that will prevail in a deep repository for high-level radioactive waste disposal in Sweden. The test parcel contained copper electrodes for real-time corrosion monitoring in bentonite ring 36, where the temperature was 24 deg C, and copper coupons in bentonite rings 22 and 30, where the temperature was higher. After retrieval of the test parcel in January 2006, a bentonite test package consisting of bentonite rings 35 - 37 was placed in a container and sealed with a thick layer of paraffin. Later the same year new copper electrodes were installed in the test package. In January 2007 electric resistance (ER) sensors of pure copper with a thickness of 35 {mu}m were also installed in the test package mainly to facilitate the interpretation of the results from the real-time corrosion monitoring with electrochemical techniques. The ER measurements have shown that the corrosion rate of pure copper exposed in an oxic bentonite/ saline groundwater environment at room temperate decreases slowly with time to low but measurable values. The corrosion rates estimated from the regularly performed EIS measurements replicate the ER data. Thus, for this oxic environment in which copper acquires corrosion potentials of the order of 200 mV (SHE) or higher, electrochemical measurements provide believable data. Comparing the recorded ER data with an estimate of the average corrosion rate based on comparing cross-sections from exposed and protected sensor elements, it is obvious that the former overestimates the actual corrosion rate, which is understandable. It seems as if electrochemical measurements can provide a better estimate of the corrosion rate; however, this is quite dependent on the use of proper measuring frequencies and evaluation methods. In this respect ER measurements are more reliable. It has been shown that real-time corrosion

  11. FIELD VALIDATION OF CORROSION RATES FOR LOW-LEVEL WASTE DISPOSAL PERFORMANCE ASSESSMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Flitton, M.K. Adler; Seitz, R.R.

    2003-02-27

    Research is being conducted at the Idaho National Engineering and Environmental Laboratory to assess corrosion rates of metals in the subsurface environment in direct support of waste management operations and environmental restoration activities. This research addresses a need identified by Department of Energy-Headquarters when reviewing the performance assessment for the low-level waste disposal facility at the Radioactive Waste Management Complex. Corrosion rates are a key factor determining release rates of long-lived radionuclides from activated metal waste streams. Radionuclide releases from these wastes are key contributors to the projected long-term dose associated with the disposal facility. Short-term results from the corrosion samples buried for one and three years suggest that the corrosion rates assumed for the assessments are conservative. However, the rates appear to be increasing, thus, future retrievals of coupons will be used to identify whether the increasing trend continues.

  12. Cellulose acetate layer effect toward aluminium corrosion rate in hydrochloric acid media

    Science.gov (United States)

    Andarany, K. S.; Sagir, A.; Ahmad, A.; Deni, S. K.; Gunawan, W.

    2017-09-01

    Corrosion occurs due to the oxidation and reduction reactions between the material and its environment. The oxidation reaction defined as reactions that produce electrons and reduction is between two elements that bind the electrons. Corrosion cannot be inevitable in life both within the industry and household. Corrosion cannot eliminate but can be control. According to the voltaic table, Aluminum is a metal that easily corroded. This study attempts to characterize the type of corrosion by using a strong acid media (HCl). Experiment using a strong acid (HCl), at a low concentration that occurs is pitting corrosion, whereas at high concentrations that occurs is corrosion erosion. One of prevention method is by using a coating method. An efforts are made to slow the rate of corrosion is by coating the metal with “cellulose acetate” (CA). cellulose acetate consisted of cellulose powder dissolved in 99% acetic acid, and then applied to the aluminum metal. Soaking experiments using hydrochloric acid, cellulose acetate is able to slow down the corrosion rate of 47 479%.

  13. A practical method for calculating the corrosion rate of uniformly depassivated reinforcing bars in concrete

    Energy Technology Data Exchange (ETDEWEB)

    Ghods, P.; Isgor, O.B.; Pour-Ghaz, M. [Carleton University, Department of Civil and Environmental Engineering, Mackenzie Engineering Building, Ottawa, K1S 5B6 ON (Canada)

    2007-04-15

    The quantification of active corrosion rate of steel in concrete structures through nondestructive methods is a crucial task for scheduling maintenance/repair operations and for achieving accurate service life predictions. Measuring the polarization resistance of corroding systems and using the Stern-Geary equation to calculate the corrosion current density of active steel is a widely-used method for this purpose. However, these measurements are greatly influenced by environmental factors; therefore, accurate monitoring of corrosion requires integrating the instantaneous corrosion rates over time. Although advanced numerical models are helpful in research settings, they remain to be computationally expensive and complex to be adopted by general engineering community. In this paper, a practical numerical model for predicting corrosion rate of uniformly depassivated steel in concrete is developed. The model is built on Stern's earlier work that an optimum anode-to-cathode ratio exists for which the corrosion current on the metal surface reaches a maximum value. The developed model, which represents the corrosion rate as a function of concrete resistivity and oxygen concentration, is validated using experimental data obtained from the literature. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  14. Study on an On-line Measurement System of Corrosion Rate by Linear Polarization Resistance

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Jeon Soo; Lee, Jae Kun; Lee, Jae Bong; Park, Pyl Yang [Korea Electric Power Research Institute, Daejeon (Korea, Republic of)

    2012-04-15

    The linear polarization resistance method is one of the widely used techniques for the corrosion rate monitoring in the water circulating systems of plants. The measurement is simple and rapid, so that a continuous on-line monitoring is possible without any shutdown of plants. A 2-electrode polarization corrosion rate measurement system was installed in a laboratory using a data acquisition board and PC. The signal processing parameters were optimized for the accurate corrosion rate measurement, and the polarization resistance was compensated with the solution resistance measured by the high frequency sine wave signal of an output channel. The precision of corrosion rate data was greatly improved by removing the initial noise signals on measuring the polarization resistance.

  15. The Electrochemical Investigation of the Corrosion Rates of Welded Pipe ASTM A106 Grade B

    Directory of Open Access Journals (Sweden)

    Trinet Yingsamphancharoen

    2016-08-01

    Full Text Available The aim of this work was to investigate the corrosion rate of welded carbon steel pipe (ASTM (American Society for Testing and Materials A106 Grade B by GTAW under the currents of 60, 70, and 80 A. All welded pipes satisfied weld procedure specifications and were verified by a procedure qualification record. The property of used materials was in agreement with the ASME standard: section IX. The welded pipe was used for schematic model corrosion measurements applied in 3.5 wt % NaCl at various flow rates and analyzed by using the electrochemical technique with Tafel’s equation. The results showed the correlation between the flow rate and the corrosion rate of the pipe; the greater the flow rate, the higher corrosion rate. Moreover, the welded pipe from the welding current of 70 A exhibited higher tensile strength and corrosion resistance than those from currents of 60 and 80 A. It indicated that the welding current of 70 A produced optimum heat for the welding of A106 pipe grade B. In addition, the microstructure of the welded pipe was observed by SEM. The phase transformation and crystallite size were analyzed by XRD and Sherrer’s equation. The results suggested that the welding current could change the microstructure and phase of the welded pipe causing change in the corrosion rate.

  16. Theoretical considerations on the supposed linear relationship between concrete resistivity and corrosion rate of steel reinforcement

    Energy Technology Data Exchange (ETDEWEB)

    Gulikers, J. [Research Department, Rijkswaterstaat Bouwdienst, Ministry of Transport, Public Works and Water Management, P.O. Box 20000, 3502 LA Utrecht (Netherlands)

    2005-06-01

    Traditionally, the assessment of service life of steel reinforced concrete structures has been focused on the prediction of the time required to achieve a transition from passive to active corrosion rather than to accurately estimate the subsequent corrosion rates. However, the propagation period, i.e. the time during which the reinforcing steel is actively corroding, may add significantly to the service life. Consequently, ignoring the propagation period may prove to be a conservative approach. On the other hand the prediction of the corrosion rate may result in a very complex task in view of the electrochemical nature of corrosion and the numerous parameters involved. In order to account for the various influences an essentially empirical model has been introduced in which the electrolytic resistivity of the concrete environment serves as the major parameter. This model will be discussed for carbonation-induced corrosion based on the commonly accepted theory of aqueous corrosion. An alternative model for microcell corrosion is proposed which is based on the commonly accepted view that anodic and cathodic sites are microscopic and their locations change randomly with time. In line with this view electrolytic resistivity can be incorporated and thus may play a significant role in the kinetics of the corrosion process. For a wide range of corrosion current densities the relationship between corrosion current density, log(i{sub corr}), and concrete resistance, log(R{sub con}), can then be approximated by an almost ideal linear relationship. Assuming a fixed geometrical arrangement of anodic and cathodic sites on the steel surface, this linear relationship is also valid for concrete resistivity, {rho}{sub con}. However, from the theoretical treatment of the electrochemical processes underlying reinforcement corrosion it becomes evident that a linear relationship between corrosion current density and concrete resistivity does not necessarily imply that concrete

  17. Corrosion product identification and relative rates of corrosion of candidate metals in an irradiated air-steam environment

    Energy Technology Data Exchange (ETDEWEB)

    Reed, D.T.; Swayambunathan, V.; Tani, B.S. (Argonne National Lab., IL (USA)); Van Konynenburg, R.A. (Lawrence Livermore National Lab., CA (USA))

    1989-11-03

    Previously reported work by others indicates that dicopper trihydroxide nitrate, Cu{sub 2}NO{sub 3}(OH){sub 3}, forms on copper and copper alloys subjected to irradiated moist air near room temperature. We have performed experiments over a range of temperature and humidity, and have found that this species is formed at temperatures up to at least 150{degree}C if low to intermediate relative humidities are present. At 150{degree}C and 100% relative humidity, only Cu{sub 2}O and CuO were observed. The relative general corrosion rates of the copper materials tested in 1-month experiments at dose rates of 0.7 and 2.0 kGy/h were Cu > 70/30 Cu--Ni > Al-bronze. High-nickel alloy 825 showed no observable corrosion. 29 refs., 4 tabs.

  18. Recorded corrosion rates on copper electrodes in the Prototype Repository at the Aespoe HRL

    Energy Technology Data Exchange (ETDEWEB)

    Rosborg, Bo [Rosborg Consulting, Nykoeping (Sweden)

    2013-04-15

    Real-time corrosion monitoring by means of electrochemical methods has been applied in an effort to measure corrosion rates of pure copper in the Prototype Repository at the Aspo Hard Rock Laboratory. Copper electrodes were installed in bentonite blocks on top of the electrically heated copper canisters in two deposition holes (dh). Three nominally identical cylindrical copper electrodes were installed in dh 1 and another three in dh 5 a few days before the heat was turned on to the canisters in September 2001 and in May 2003 respectively. The temperature of the copper electrodes has been around 30 deg C in dh 1 and somewhat below 35 deg C in dh 5. Real-time corrosion monitoring for both electrode setups was first applied in January 2004, and then periodically in 2005, 2006, 2008, and most recently in the end of 2010 just before work to open the outer section of the Prototype Repository was started. The recorded corrosion rates fall below 1.3 {mu}m/year (using a default value of n=2 in the software to convert the corrosion current density to a penetration rate by means of Faraday's law, and with no correction applied for the used measuring frequency of 0.01 Hz; also disregarding highly scattered data obtained for the copper electrodes in dh 1 during 2010). While the recorded rates on the electrodes in dh 5 first increased from about 0.2 {mu}m/year in 2004 up to a maximum of 1.3 {mu}m/year a year later (the drainage of the inner and outer sections was temporary closed in the end of 2004), and then gradually decreased to 0.7 {mu}m/year in the end of 2010, the recorded rates on the electrodes in dh 1 show a quite different picture. The recorded rates fall in the range 0.4-0.7 {mu}m/year and do not reflect any obvious decrease. However, it is anticipated that a similar time dependence as observed for the electrodes in dh 5 could have been present early on in the exposure; the electrodes were installed in 2001 but the first measurements were performed in 2004. Also

  19. Frequency dependence of fatigue and corrosion fatigue crack growth rate

    Energy Technology Data Exchange (ETDEWEB)

    Marvasti, Mohammad Hassan; Chen, Weixing [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB (Canada); Kania, Richard; Worthingham, Robert [TransCanada Pipelines Limited, Calgary, AB (Canada); Van Boven, Gregory [Spectra Energy Transmission Limited, Vancouver, BC (Canada)

    2010-07-01

    It was in the mid-1980s that stress corrosion cracking (SCC) was first found in near-neutral pH conditions on the TransCanada pipeline system. Since then, there have been many reports of pipeline cracking in Canada in these conditions. The huge quantity of pipelines in Canada and the number of failures have brought great interest in investigation of this cracking. A study was conducted on one X52 pipeline steel. It used compact tension specimens for corrosion fatigue and fatigue tests in air. The following conclusions were drawn: 1) crack growth in near-neutral pH conditions can be explained by a factor, which reflects the combined action of the mechanical driving force and the hydrogen effects; 2) mechanical dormancy can be common when oil and gas pipelines are in operation; 3) hydrogen is a determining factor of crack growth when pipeline steels are exposed to near-neutral pH conditions.

  20. Electrochemical Meaning of Cumulative Corrosion Rate for Reinforced Concrete in a Tropical Natural Marine Environment

    Directory of Open Access Journals (Sweden)

    Pedro Castro-Borges

    2017-01-01

    Full Text Available The objective of this paper is to discuss the meaning of cumulative corrosion rate (iCCR of reinforced concrete in a tropical marine microclimate of the Yucatan Peninsula identifying four stages that correspond to passivation, beginning of depassivation, breakdown and formation of subsequent corrosion layers, and nucleation and development of cracks. Sixty Portland cement concrete cylinders were exposed in a tropical marine environment at 50 m from the seashore. One-half of the samples had a reinforcing bar embedded at the center of the sample (corrosion measurements and the other half was made with plain concrete (chloride measurements. Five water/cement (w/c ratios and three times of curing (CT were tested representing the common practices of this region. The corrosion rate was monitored using the linear polarization resistance technique (Rp which enables calculating the apparent and cumulative corrosion rate. Representative results indicated that iCCR was effective not only to detect the beginning and duration of the reported stages but also to find the right influence of CT and w/c ratios on the corrosion performance of reinforced concrete.

  1. Electrochemical Corrosion Studies for Modeling Metallic Waste Form Release Rates

    Energy Technology Data Exchange (ETDEWEB)

    Poineau, Frederic [Univ. of Nevada, Las Vegas, NV (United States); Tamalis, Dimitri [Florida Memorial Univ., Miami Gardens, FL (United States)

    2016-08-01

    The isotope 99Tc is an important fission product generated from nuclear power production. Because of its long half-life (t1/2 = 2.13 ∙ 105 years) and beta-radiotoxicity (β⁻ = 292 keV), it is a major concern in the long-term management of spent nuclear fuel. In the spent nuclear fuel, Tc is present as an alloy with Mo, Ru, Rh, and Pd called the epsilon-phase, the relative amount of which increases with fuel burn-up. In some separation schemes for spent nuclear fuel, Tc would be separated from the spent fuel and disposed of in a durable waste form. Technetium waste forms under consideration include metallic alloys, oxide ceramics and borosilicate glass. In the development of a metallic waste form, after separation from the spent fuel, Tc would be converted to the metal, incorporated into an alloy and the resulting waste form stored in a repository. Metallic alloys under consideration include Tc–Zr alloys, Tc–stainless steel alloys and Tc–Inconel alloys (Inconel is an alloy of Ni, Cr and iron which is resistant to corrosion). To predict the long-term behavior of the metallic Tc waste form, understanding the corrosion properties of Tc metal and Tc alloys in various chemical environments is needed, but efforts to model the behavior of Tc metallic alloys are limited. One parameter that should also be considered in predicting the long-term behavior of the Tc waste form is the ingrowth of stable Ru that occurs from the radioactive decay of 99Tc (99Tc → 99Ru + β⁻). After a geological period of time, significant amounts of Ru will be present in the Tc and may affect its corrosion properties. Studying the effect of Ru on the corrosion behavior of Tc is also of importance. In this context, we studied the electrochemical behavior of Tc metal, Tc-Ni alloys (to model Tc-Inconel alloy) and Tc-Ru alloys in acidic media. The study of Tc-U alloys has also been performed in order to better understand the

  2. Possibility of improvement of potentiodynamic method for monitoring corrosion rate of steel reinforcement in concrete

    Indian Academy of Sciences (India)

    V Živica

    2001-10-01

    Quantitative data on corroding steel reinforcement in reinforced concrete structures are undoubtedly very useful for evaluation of their service life and timely repairs. The method of electrode potential measurement is a convenient and simple test for this purpose, but it provides no quantitative data on corrosion rate and only information regarding active or passive state of steel reinforcement can be obtained. We show here the possibility of obtaining quantitative data on degree of corrosion of steel reinforcement by a potentiodynamic method. The developed method is based on experimentally estimated mathematical relation between the results of potentiodynamic method and degree of corrosion of steel reinforcement. It is possible to calculate the degree of corrosion of steel reinforcement using this mathematical relation and the measured values of current density by the potentiodynamic method.

  3. Mathematical Model for Predicting Corrosion Rates in Furnace Internal Wall Tubes of The Refinery Boiler

    Directory of Open Access Journals (Sweden)

    Edori, E. S

    2016-08-01

    Full Text Available A model for predicting the corrosion rates in the furnace internal wall tubes of the refinery boiler was resolved, using the first order differential equation derived from the material balance equation of the system. The mathematical model was able to predict the metal loss recorded by ultrasonic thickness scanning technique (UTS, and the results shows an agreement. The results from both the model and UTS shows that in the various tubes of the furnace, internal wall of the refinery boiler were between the same range. The percentage deviation which was calculated to ascertain the acceptability of the model result as compared to that from UTS proved that the model is effective. The inhibitor model result show that corrosion will drastically reduce in the presence of corrosion inhibitors under proper chemical treatment and management. The model developed can be used to monitor furnace internal wall corrosion even when the system is in operation by extrapolating the result to further years.

  4. Employment of Electrochemical Sensors in Determination of Corrosion Rate In Situ in Formation Water Petroleum

    Directory of Open Access Journals (Sweden)

    Juan Hilario Davis Harriett

    2016-04-01

    Full Text Available The electrochemical corrosion is a spontaneous process that causes deterioration or destruction of aninstallation or pipes, shortening therefore the useful life of the same ones. So, it is necessary to know themechanism of electrochemical corrosion that is developed, and subsequently monitored the corrosionrate in the facilities. The purpose of this investigation was to determine “in situ” the corrosion of the ductsconstruction steel which is in contact with the accompanying water of the petroleum. In the determinationof the corrosion rate a sensor of three electrodes was used and with the help of the electrochemical techniqueof resistance of lineal polarization (LPR the kinetics of corrosion was valued. The tests were carriedout under dynamic conditions with a fl ow velocity of the formation water of 100 m3/h and the temperatureof 70 oC and pH 10. The electrochemical technique of LPR allowed to obtain through the parameterof polarization resistance, the value of the corrosion rate of the steel of the ducts in the formation water.

  5. Factors affecting the corrosion rates of ceramics in coal combustion systems

    Energy Technology Data Exchange (ETDEWEB)

    Hurley, J.P. [Univ. of North Dakota, Grand Forks, ND (United States)

    1995-08-01

    The concentrations of approximately a dozen elements in the products of coal combustion affect the corrosion rates of ceramics used to construct the combustion system. The elements, including H, O, Na, Mg, Al, Si, P, S, Cl, K, Ca, and Fe, affect corrosion rates in three ways: as primary corrodants of the materials, as secondary corrodants that affect the activities of the primary corrodants, and by affecting the mass transport rate of the primary corrodants. A full factorial study of corrosion rates performed by varying the concentrations of these elements would involve X{sup n} tests, where X is the number of variations of each element and n is the number of different elements. For three variations (low, medium, and high concentrations) of each of 12 elements, the number of tests is 531,441 for a single temperature and pressure condition. The numbers can be reduced with the use of a fractional factorial test matrix, but the most effective way to perform corrosion tests is to base them on realistic system conditions. In this paper, the effects of the composition and physical state of the products of coal combustion on ceramic corrosion rates are given along with suggestions of appropriate test conditions for specific system components.

  6. Conditions for testing the corrosion rates of ceramics in coal gasification systems

    Energy Technology Data Exchange (ETDEWEB)

    Hurley, J.P.; Nowok, J.W. [Univ. of North Dakota, Grand Forks, ND (United States)

    1996-08-01

    Coal gasifier operating conditions and gas and ash compositions affect the corrosion rates of ceramics used for construction in three ways: (1) through direct corrosion of the materials, (2) by affecting the concentration and chemical form of the primary corrodents, and (3) by affecting the mass transport rate of the primary corrodents. To perform an accurate corrosion test on a system material, the researcher must include all relevant corrodents and simulate conditions in the gasifier as closely as possible. In this paper, the authors present suggestions for conditions to be used in such corrosion tests. Two main types of corrosion conditions are discussed: those existing in hot-gas cleanup systems where vapor and dry ash may contribute to corrosion and those experienced by high-temperature heat exchangers and refractories where the main corrodent will be coal ash slag. Only the fluidized-bed gasification systems such as the Sierra Pacific Power Company Pinon Pine Power Project system are proposing the use of ceramic filters for particulate cleanup. The gasifier is an air-blown 102-MWe unit employing a Westinghouse{trademark} ceramic particle filter system operating at as high as 1100{degrees}F at 300 psia. Expected gas compositions in the filter will be approximately 25% CO, 15% H{sub 2}, 5% CO{sub 2}, 5% H{sub 2}O, and 50% N{sub 2}. Vapor-phase sodium chloride concentrations are expected to be 10 to 100 times the levels in combustion systems at similar temperatures, but in general the concentrations of the minor primary and secondary corrodents are not well understood. Slag corrosiveness will depend on its composition as well as viscosity. For a laboratory test, the slag must be in a thermodynamically stable form before the beginning of the corrosion test to assure that no inappropriate reactions are allowed to occur. Ideally, the slag would be flowing, and the appropriate atmosphere must be used to assure realistic slag viscosity.

  7. Significance and influence of the ambient temperature as a rate factor of steel reinforcement corrosion

    Indian Academy of Sciences (India)

    V Živica

    2002-10-01

    The rate of corrosion of reinforcement being an electrochemical process, undoubtedly is dependent even on the level of the ambient temperature. Therefore, the ambient temperature seems to be an important factor of the corrosion rate and the durability of the reinforced concrete structures in aggressive environment. The present data on the influence and significance of the ambient temperature in the process of corrosion of reinforcement of the reinforced structures are surprisingly limited and poor. It seems that it is supposed to be a simple increase of corrosion rate when the ambient temperature is increased. The lack of information was a motivation for the present study. It was aimed at the experimental research of the influence of the increase of the ambient temperature on the rate of chloride induced corrosion of steel reinforcement. The results obtained show that the influence of the studied factor is more complex showing an acceleration effect till a temperature of 40°C diversified by the inhibition effects with further increase of the ambient temperature.

  8. Preliminary Simulation of the Corrosion Rate of Archaeological Glass

    Energy Technology Data Exchange (ETDEWEB)

    Steefel, Carl

    2014-01-06

    In this study, we make use of a micro-continuum modeling approach (the Kinetic-Microscopic-Continuum Model or K{micro}C model) to capture the spatial distribution and identity of reaction products developing over time as a result of the archaeological glass corrosion, while also matching the time scales of alteration where possible. Since the glass blocks sat on the Mediterranean seafloor for 1800 years, the physical and chemical boundary conditions are largely constant. We focus on a fracture within the glass block identified by Verney-Carron et al. (2008) and simulate it as a 1D system, with a fixed concentration (Dirichlet) boundary corresponding to the interior of the fracture.

  9. Correlation Between Microstructure and Corrosion Resistance of Magnesium Alloys Prepared by High Strain Rate Rolling

    Science.gov (United States)

    Chen, Jihua; Chen, Guanqing; Yan, Hongge; Su, Bin; Gong, Xiaole; Zhou, Bo

    2017-09-01

    Microstructure and corrosion resistance in Hank's solution of four magnesium alloys (pure Mg, ZK60, Mg-4Zn and Mg-4Zn-0.3Ca) prepared by high strain rate rolling (HSRR) and conventional rolling (CR) are comparatively investigated. The HSRR alloy exhibits better bio-corrosion resistance than the CR alloy. The HSRR ZK60 alloy has finer grains, higher dynamic recrystallization (DRX) extent, lower twin fraction, coarser residual second-phase particles, finer and denser nanometer β 1 precipitates, lower residual compressive stress and stronger basal texture than the CR alloy. The average corrosion rate of the HSRR ZK60 sheet after 90-day immersion in Hank's solution is 0.17 mg cm-2 d-1, about 19% lower than that of the CR sheet. Its corrosion current density is 30.9 μA/cm2, about 45% lower than that of the CR sheet. Bio-corrosion resistance enhancement by HSRR can be mainly ascribe to the reduced grain size, the relatively adequate DRX, non-twinning, the coarser residual second-phase particles, the finer and denser nanometer precipitates and the slightly stronger (0001) texture.

  10. Elevated corrosion rates and hydrogen sulfide in homes with 'Chinese Drywall'

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Joseph G.; MacIntosh, David L. [Environmental Health and Engineering, Inc., 117 Fourth Avenue, Needham, MA (United States); Harvard School of Public Health, 677 Huntington Avenue, Boston, MA (United States); Saltzman, Lori E. [U.S. Consumer Product Safety Commission, Bethesda, MD (United States); Baker, Brian J. [Environmental Health and Engineering, Inc., 117 Fourth Avenue, Needham, MA (United States); Matheson, Joanna M.; Recht, Joel R. [U.S. Consumer Product Safety Commission, Bethesda, MD (United States); Minegishi, Taeko; Fragala, Matt A.; Myatt, Theodore A. [Environmental Health and Engineering, Inc., 117 Fourth Avenue, Needham, MA (United States); Spengler, John D.; Stewart, James H. [Environmental Health and Engineering, Inc., 117 Fourth Avenue, Needham, MA (United States); Harvard School of Public Health, 677 Huntington Avenue, Boston, MA (United States); McCarthy, John F., E-mail: jmcccarthy@eheinc.com [Environmental Health and Engineering, Inc., 117 Fourth Avenue, Needham, MA (United States)

    2012-06-01

    In December 2008, the U.S. Consumer Product Safety Commission (CPSC) began receiving reports about odors, corrosion, and health concerns related to drywall originating from China. In response, a detailed environmental health and engineering evaluation was conducted of 41 complaint and 10 non-complaint homes in the Southeast U.S. Each home investigation included characterization of: 1) drywall composition; 2) indoor and outdoor air quality; 3) temperature, moisture, and building ventilation; and 4) copper and silver corrosion rates. Complaint homes had significantly higher hydrogen sulfide concentrations (mean 0.82 vs. < LOD {mu}g/m{sup 3}, p < 0.05), and significantly greater rates of copper sulfide and silver sulfide corrosion compared to non-complaint homes (Cu{sub 2}S: 476 vs. < 32 A/30 d, p < 0.01; Ag{sub 2}S: 1472 vs. 389 A/30 d, p < 0.01). The abundance of carbonate and strontium in drywall was also elevated in complaint homes, and appears to be useful objective marker of problematic drywall in homes that meet other screening criteria (e.g., constructed or renovated in 2006-2007, reports of malodor and accelerated corrosion). This research provides empirical evidence of the direct association between homes constructed with 'Chinese Drywall' in 2006-2007 and elevated corrosion rates and hydrogen sulfide concentrations in indoor air. - Highlights: Black-Right-Pointing-Pointer Environmental measurements in homes with and without 'Chinese Drywall' Black-Right-Pointing-Pointer Homes with 'Chinese Drywall' had higher hydrogen sulfide concentrations Black-Right-Pointing-Pointer Homes with 'Chinese Drywall' had elevated corrosion rates Black-Right-Pointing-Pointer Study provides empirical evidence of reported associations.

  11. Oil field chemicals synergistic effects on the corrosion rate of L-80 steel in sea and formation waters

    Energy Technology Data Exchange (ETDEWEB)

    Al Hashem, A.; Carew, J. [Petroleum Research and Studies Center, Kuwait Institute for Scientific Research, P.O. Box 24885, 13109 Safat Kuwait (Kuwait); Al-Borno, A. [Charter Coating Service (2000) Ltd., no 6, 4604, 13 Street N.E., Calgary, AB T2E 6P1 (Canada)

    2004-07-01

    The corrosion rate of tubular grade L-80 carbon steel under downhole conditions of a northern oil field of Kuwait was investigated. This was done using the injection seawater, formation water and a 50:50 mixture of both waters in the presence of commercially available corrosion inhibitor, scale inhibitor, and biocide products separately and in combination with each other. The main objective of this study was to investigate the effect of the corrosion inhibitor and its interaction with the scale inhibitor and the biocide, as seen in the corrosion rate of L80 carbon steel. This was done using the manufacturers' recommended dosage levels of the corrosion inhibitor, scale inhibitor and biocide. The corrosion rates were measured by linear polarization. Tests were conducted using the rotating cylinder electrode method with rotational speeds of 1000 and 2000 rpm at 80 deg. C. The seawater results indicated that the corrosion-scale inhibitor and biocide-scale inhibitor combinations provided the best protection at both rotation speeds. In formation water, the effects of rotation speed were more apparent with higher corrosion rates of L-80 carbon steel accompanying higher shear forces. In the 50: 50 mix waters and the formation water, the corrosion-scale inhibitors-biocide combination provided the best protection at both rotational speeds under downhole conditions of a northern oil field of Kuwait. (authors)

  12. Effect of Drag Reducing Polymer and Suspended Solid on the Rate of Diffusion Controlled Corrosion in 90° Copper Elbow

    Science.gov (United States)

    Fouad, Mohamed Ahmed; Zewail, Taghreed Mohamed; Amine, Nieven Kamal Abbes

    2016-06-01

    Rate of diffusion controlled corrosion in 90° Copper Elbow acidified dichromate has been investigated in relation to the following parameters: effect of solution velocity in the absence and presence of drag- reducing polymer on the rate of diffusion controlled corrosion, and effect of the presence of suspended solids on the rate of diffusion controlled corrosion. It was found that the presence of drag reducing polymer inhibited the rate of mass transfer, while the presence of suspended solid increased significantly the rate of mass transfer.

  13. [Measurement of low corrosion rate of coronary stents-made of 316L and 317L stainless steel].

    Science.gov (United States)

    Liang, Chenghao; Guo, Liang; Chen, Wan

    2006-08-01

    Electrochemical constant current linear polarization and atomic absorption spectroscopy were used to measure the corrosion rate of coronary stents made of 316L and 317L stainless steel in 30 degrees C Tyrode's solution. The results indicated that the corrosion rate of 316L and 317L stainless steel was 21 X 10(-3) microm/a, 9.8 X 10(-3) microm/a and 0.8 X 10(-3) m/a, 0.6 X 10(-3) microm/a, respectively. All corrosion rates were lower than the medical materials corrosion rate criteria, i.e. 0.25 microm/a. Moreover the corrosion resistance of 317L stainless steel was much higher than that of 316L stainless steel. The results from atomic absorption spectroscopy may correctly reflect the quantity of releasing metal ions in the solution.

  14. High temperature corrosion investigation in an oxyfuel combustion test rig

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Bjurman, M.; Hjörnhede, A

    2014-01-01

    (perhaps carburized) zone was used as a measure of corrosion rates. The lowest alloyed steel had the highest corrosion rate, and the other austenitic and nickel alloys had much lower corrosion rates. Precipitates in the alloy adjacent the corrosion front were revealed for both Sanicro 28 and C‐276. However...... constructed by Brandenburg Technical University to gain understanding into oxyfuel firing. Two air‐cooled corrosion probes were exposed in this oxyfuel combustion chamber where the fuel was lignite. Gas composition was measured at the location of testing. Various alloys from a 2½ Cr steel, austenitic steels...

  15. Monitoring the impact of the indoor air quality on silver cultural heritage objects using passive and continuous corrosion rate assessments

    Science.gov (United States)

    `t Hart, Lucy; Storme, Patrick; Anaf, Willemien; Nuyts, Gert; Vanmeert, Frederik; Dorriné, Walter; Janssens, Koen; de Wael, Karolien; Schalm, Olivier

    2016-10-01

    There is a long tradition in evaluating industrial atmospheres by measuring the corrosion rate of exposed metal coupons. The heritage community also uses this method, but the interpretation of the corrosion rate often lacks clarity due to the low corrosivity in indoor museum environments. This investigation explores the possibilities and drawbacks of different silver corrosion rate assessments. The corrosion rate is determined by three approaches: (1) chemical characterization of metal coupons using analytical techniques such as electrochemical measurements, SEM-EDX, XRD, and µ-Raman spectroscopy, (2) continuous corrosion monitoring methods based on electrical resistivity loss of a corroding nm-sized metal wire and weight gain of a corroding silver coated quartz crystal, and (3) characterization of the visual degradation of the metal coupons. This study confirms that subtle differences in corrosivity between locations inside a museum can be determined on condition that the same corrosion rate assessment is used. However, the impact of the coupon orientation with respect to the prevailing direction of air circulation can be substantially larger than the impact of the coupon location.

  16. Effect of cold work on the growth rates of stress corrosion cracks in structural materials of nuclear systems

    Energy Technology Data Exchange (ETDEWEB)

    Magdowski, R.; Speidel, M.O. [Swiss Federal Inst. of Tech., Zurich (Switzerland). Inst. of Metallurgy

    1996-10-01

    The growth rates of stress corrosion cracks in austenitic stainless steels and nickel base alloy 600 exposed to simulated boiling water reactor coolant were measured by fracture mechanics testing techniques. Cold work may increase the crack growth rates up to one hundred times. In both, the annealed condition and the cold worked condition, the stress corrosion crack growth rates are independent of stress intensity over a wide K-range and crack growth rates correlate well with yield strength and hardness. In the annealed condition the fracture path is intergranular, but higher degrees of cold work introduce higher proportions of transgranular stress corrosion cracking.

  17. Microbial consortium influence upon steel corrosion rate, using polarisation resistance and electrochemical noise techniques

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez Gayosso, M.J.; Zavala Olivares, G.; Ruiz Ordaz, N.; Juarez Ramirez, C.; Garcia Esquivel, R.; Padilla Viveros, A

    2004-10-01

    The microbiologically influenced corrosion (MIC) is a process, which affects the oil industry, particularly the hydrocarbons extraction, transport and storage. MIC evaluation has been normally based upon microbiological tests, and just a few references mention alternating methods, such as the electrochemical techniques, which can be used as criteria for their evaluation. In this work, two different electrochemical laboratory techniques, polarisation resistance and electrochemical noise were used, in order to determine the corrosion behaviour of a microbial consortium, obtained from a gas transporting pipeline, located in the southeast of Mexico. The bacteria population growth was found to be different for sessile and plancktonic microorganisms. Moreover, long incubation times were required to reach the maximum concentration of sessile bacteria. The electrochemical techniques used in this study exhibited a similar tendency on the corrosion rate behaviour with time, and values above 0.3 mm year{sup -1} were observed at the end of the experiments. The experiments were complemented with surface analysis. Scanning electron microscope observation of APIXL52 steel coupons, exposed to the consortium action, revealed bacteria presence, as well as a damaged steel surface. A type of localized corrosion was observed on the metal surface, and it was associated to the bacteria effect.

  18. Slow strain rate corrosion and fracture characteristics of X-52 and X-70 pipeline steels

    Energy Technology Data Exchange (ETDEWEB)

    Contreras, A. [Instituto Mexicano del Petroleo, Programa de Investigacion y Desarrollo de Ductos, Eje Central Lazaro Cardenas 152, San Bartolo Atepehuacan, C.P. 07730, Mexico, D.F. (Mexico)]. E-mail: acontrer@imp.mx; Albiter, A. [Instituto Mexicano del Petroleo, Programa de Investigacion y Desarrollo de Ductos, Eje Central Lazaro Cardenas 152, San Bartolo Atepehuacan, C.P. 07730, Mexico, D.F. (Mexico); Salazar, M. [Instituto Mexicano del Petroleo, Programa de Investigacion y Desarrollo de Ductos, Eje Central Lazaro Cardenas 152, San Bartolo Atepehuacan, C.P. 07730, Mexico, D.F. (Mexico); Perez, R. [Instituto Mexicano del Petroleo, Programa de Investigacion y Desarrollo de Ductos, Eje Central Lazaro Cardenas 152, San Bartolo Atepehuacan, C.P. 07730, Mexico, D.F. (Mexico)

    2005-10-25

    The susceptibility to stress corrosion cracking (SCC) in a NACE solution saturated with H{sub 2}S, of the X-52 and X-70 steels was studied using slow strain rate tests (SSRT) and electrochemical evaluations. SCC tests were performed in samples which include the longitudinal weld bead of the pipeline steels and were carried out in the NACE solution at both room temperature and 50 deg. C. After failure, the fracture surfaces were observed in a scanning electron microscope (SEM) and the chemical analysis were obtained using X-rays energy dispersive (EDXs) techniques. The specimens tested in air, exhibited a ductile type of failure, and whereas, those tested in the corrosive solution showed a brittle fracture. Specimens tested in the NACE solution saturated with H{sub 2}S presented high susceptibility to SCC. Corrosion was found to be an important factor in the initiation of some cracks. In addition, the effect of the temperature on the corrosion attack was explored. The susceptibility to SCC was manifested as a decrease in the mechanical properties. Potentiodynamic polarization curves and hydrogen permeation measurements were made. The diffusion of atomic hydrogen was related to this fracture forms. The hydrogen permeation flux increased with the increasing of temperature.

  19. RESULTS OF EXPERIMENT TO DETERMINE CORROSION RATES FOR 304L IN HB-LINE DISSOLVER VESSEL VENTILATION SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Mickalonis, J; Kathryn Counts, K

    2008-02-22

    Radioactive material being processed as part of the DE3013 program for HB-Line will result in the presence of chlorides, and in some cases fluorides, in the dissolver. Material Science and Technology developed an experimental plan to evaluate the impact of chloride on corrosion of the dissolver vessel ventilation system. The plan set test variables from the proposed operating parameters, previous test results, and a desired maximum chloride concentration for processing. The test variables included concentrations of nitric acid, fluorides and chlorides, and the presence of a welded and stressed metal coupon. Table 1 contains expected general corrosion rates in the HB-Line vessel vent system from dissolution of 3013 contents of varying nitric acid and chloride content. These general corrosion rates were measured upstream of the condenser in the experiment's offgas system near the entrance to the dissolver. However, they could apply elsewhere in the offgas system, depending on factors not simulated in the testing, including offgas system temperatures and airflow. Localized corrosion was significant in Tests One, Two, and Three. This corrosion is significant because it will probably be the first mode of penetration of the 304L steel in several places in the system. See Table 2. For Tests One and Three, the penetration rate of localized corrosion was much higher than that for general corrosion. It was approximately four times higher in Test One and at least 45 times higher in Test Three, penetrating an entire coupon thickness of 54 mils in 186 hours or less. There was no significant difference in corrosion between welded areas and un-welded areas on coupons. There was also no significant attack on stressed portions of coupons. It is probable that the lack of corrosion was because the stressed areas were facing downwards and offered no place for condensation or deposits to form. Had deposits formed, pitting may have occurred and led to stress corrosion cracking. The

  20. Corrosion and runoff rates of Cu and three Cu-alloys in marine environments with increasing chloride deposition rate.

    Science.gov (United States)

    Odnevall Wallinder, Inger; Zhang, Xian; Goidanich, Sara; Le Bozec, Nathalie; Herting, Gunilla; Leygraf, Christofer

    2014-02-15

    Bare copper sheet and three commercial Cu-based alloys, Cu15Zn, Cu4Sn and Cu5Al5Zn, have been exposed to four test sites in Brest, France, with strongly varying chloride deposition rates. The corrosion rates of all four materials decrease continuously with distance from the coast, i.e. with decreasing chloride load, and in the following order: Cu4Sn>Cu sheet>Cu15Zn>Cu5Al5Zn. The patina on all materials was composed of two main layers, Cu2O as the inner layer and Cu2(OH)3Cl as the outer layer, and with a discontinuous presence of CuCl in between. Additional minor patina constituents are SnO2 (Cu4Sn), Zn5(OH)6(CO3)2 (Cu15Zn and Cu5Al5Zn) and Zn6Al2(OH)16CO3·4H2O/Zn2Al(OH)6Cl·2H2O/Zn5Cl2(OH)8·H2O and Al2O3 (Cu5Al5Zn). The observed Zn- and Zn/Al-containing corrosion products might be important factors for the lower sensitivity of Cu15Zn and Cu5Al5Zn against chloride-induced atmospheric corrosion compared with Cu sheet and Cu4Sn. Decreasing corrosion rates with exposure time were observed for all materials and chloride loads and attributed to an improved adherence with time of the outer patina to the underlying inner oxide. Flaking of the outer patina layer was mainly observed on Cu4Sn and Cu sheet and associated with the gradual transformation of CuCl to Cu2(OH)3Cl of larger volume. After three years only Cu5Al5Zn remains lustrous because of a patina compared with the other materials that appeared brownish-reddish. Significantly lower release rates of metals compared with corresponding corrosion rates were observed for all materials. Very similar release rates of copper from all four materials were observed during the fifth year of marine exposure due to an outer surface patina that with time revealed similar constituents and solubility properties. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

  1. Effect of steam corrosion on core post strength loss: I. Low, chronic steam ingress rates. [HTGR

    Energy Technology Data Exchange (ETDEWEB)

    Wichner, R.P.

    1976-10-01

    The purpose of the study was to assess the effect of chronic, low levels of steam ingress into the primary system of the HTGR on the corrosion, and consequent strength loss of the core support posts. The assessment proceeded through the following three steps: (1) The impurity composition in the primary system was estimated as a function of a range of steady ingress rates of from 0.001 to 1.0 g/sec, both by means of an analysis of the Dragon steam ingress experiment and a computer code, TIMOX, which treats the primary system as a well-mixed pot. (2) The core post burnoffs which result from 40-year exposures to these determined impurity atmospheres were then estimated using a corrosion rate expression derived from published ATJ-graphite corrosion rate data. Burnoffs were determined for both the core posts at the nominal and the maximum sustained temperature, estimated to be 90/sup 0/C above nominal. (3) The final step involved assessment of the degree of strength loss resulting from the estimated burnoffs. An empirical equation was developed for this purpose which compares reasonably well with strength loss data for a number of different graphites and specimen geometries.

  2. Stress corrosion-controlled rates of mode I fracture propagation in calcareous bedrock

    Science.gov (United States)

    Voigtlaender, Anne; Leith, Kerry; Krautblatter, Michael

    2014-05-01

    Surface bedrock on natural rock slopes is subject to constant and cyclic environmental stresses (wind, water, wave, ice, seismic or gravitational). Studies indicate that these stresses range up to several hundred kPa, generally too low to cause macroscopic changes in intact rock, although clear evidence of fracture generation, crack propagation and weathering of bedrock illustrates the effect of environmental stresses at the Earth's surface. We suggest that material degradation and its extent, is likely to be controlled by the rate of stress corrosion cracking (SCC). Stress corrosion is a fluid-material reaction, where fluids preferentially react with strained atomic bonds at the tip of developing fractures. Stress corrosion in ferrous and siliceous materials is often accepted as the fracture propagation and degradation rate-controlling process where materials are subject to stresses and fluids. Although evidence for chemical weathering in propagating bedrock fractures is clear in natural environments, the physical system and quantification of stress corrosion in natural rocks is yet to be addressed. Here, we present preliminary data on the relationship between stresses at levels commonly present on natural rock slopes, and material damage resulting from stress corrosion under constant or cyclic tensile loading. We undertake single notch three-point bending tests (SNBT) on fresh calcareous bedrock specimens (1100x100x100mm) over a two-month period. Two beams containing an artificial notch are stressed to 75% of their ultimate strength, and a constant supply of weak acid is applied at the notch tip to enhance chemical reactions. A third, unloaded, beam is also exposed to weak acid in order to elucidate the contribution of stress corrosion cracking to the material degradation. Stresses at the tip of propagating cracks affect the kinetics of the chemical reaction in the specimen exposed to both loading and corrosion, leading to an increase in degradation, and greater

  3. Corrosion product monitoring using an on-line X-ray fluorescence probe

    Energy Technology Data Exchange (ETDEWEB)

    Stauffer, C.C.; Connolly, D.J. [Babcock & Wilcox Research, Alliance, OH (United States); Millett, P. [Electric Power Research Institute, Palo Alto, CA (United States)

    1995-01-01

    The need for monitoring corrosion products is becoming increasingly important as power plants strive to minimize the effects of corrosion products on plant availability. Current methodology for monitoring corrosion products involves collection of samples using membrane filters followed by analysis of the membranes in the laboratory. This technique is labor intensive and provides only average values over lengthy sampling intervals. Recently, a laboratory tool, x-ray fluorescence spectroscopy, has been combined with on-line sampling capability resulting in an on-line instrument capable of measuring iron oxide particulates in a flowing stream at the ppb level and below. After development in the laboratory, the instrument was successfully field tested in a power plant and is currently undergoing a second field test at another plant. This paper will discuss the design and operation of the instrument, and field data obtained from plant service will be presented. Results show that this instrument will provide on-line measurements of iron oxides at the ppb level with minimal operator involvement.

  4. Automated Methods Of Corrosion Measurements

    DEFF Research Database (Denmark)

    Bech-Nielsen, Gregers; Andersen, Jens Enevold Thaulov; Reeve, John Ch

    1997-01-01

    The chapter describes the following automated measurements: Corrosion Measurements by Titration, Imaging Corrosion by Scanning Probe Microscopy, Critical Pitting Temperature and Application of the Electrochemical Hydrogen Permeation Cell.......The chapter describes the following automated measurements: Corrosion Measurements by Titration, Imaging Corrosion by Scanning Probe Microscopy, Critical Pitting Temperature and Application of the Electrochemical Hydrogen Permeation Cell....

  5. Corrosion rates of fasteners in treated wood exposed to 100% relative humidity

    Science.gov (United States)

    Samuel L. Zelinka; Douglas R. Rammer

    2009-01-01

    In the past, gravimetric corrosion data for fasteners exposed to treated wood has been reported as a percent weight loss. Although percent weight loss is a valid measure of corrosion for comparing identical fasteners, it can distort the corrosion performance of fasteners with different geometries and densities. This report reevaluates a key report on the corrosiveness...

  6. Measuring the corrosion rate of steel in concrete – effect of measurement technique, polarisation time and current

    DEFF Research Database (Denmark)

    Nygaard, Peter Vagn; Geiker, Mette Rica

    2012-01-01

    Both on-site investigations and laboratory studies have shown that different corrosion rates are obtained when different commercially available corrosion rate instruments are used. The different electrochemical techniques and the measurement parameters used, i.e. polarisation current and time......, are in some studies considered the main reasons for the variations. This paper presents an experimental study on the quantitative effect of polarisation time and current on the measured polarisation resistance – and thus the corrosion current density – of passively and actively corroding steel. Two...... electrochemical techniques often used in instruments for on-site corrosion rate measurements are investigated. On passively corroding reinforcement the measured polarisation resistance was for both techniques found to be highly affected by the polarisation time and current and no plateaus at either short or long...

  7. Scanning Probe Investigation of Pitting Corrosion on Aluminum 5083 H131

    Science.gov (United States)

    2014-05-01

    AFM, SKPM, SEM, and EDS for AA5083 and typically iron (Fe)-rich phases are known to be local cathodes whereas silicon (Si)-containing precipitates act...performance at the U.S. Army Research Laboratory (ARL). For example, the corrosion performance of AA5083 in the neutral salt fog exposure test, ASTM...to 1200, then polished in a stepwise fashion from 9 to 3 to 1 µm using aqueous diamond suspensions (MetaDi). The final size of AA5083 substrates for

  8. Influence of / ratio on rate of chloride induced corrosion of steel reinforcement and its dependence on ambient temperature

    Indian Academy of Sciences (India)

    V Živica

    2003-08-01

    The permeability of the embedding cement material for the rate of chloride induced corrosion when the ambient temperature is increased has found a dominant position. The importance of the given permeability in the process is based on the fact that it represents a factor conditioning the possibility of the escaping of the unambiguous reaction partners, oxygen and water vapour, from the system embedding cement material-steel, as the ambient temperature is increased. The resulting effect is a slowing down of the corrosion rate when the / ratio over the value 0.6 and the ambient temperature over the value 40°C are increased. Due to the similarity of the chemism of the corrosion process of steel reinforcement, independent of the action of aggressive species, the found relationships are generally valid, e.g. for the corrosion due to carbonation.

  9. Metabolomic and Metagenomic Analysis of Two Crude Oil Production Pipelines Experiencing Differential Rates of Corrosion

    Science.gov (United States)

    Bonifay, Vincent; Wawrik, Boris; Sunner, Jan; Snodgrass, Emily C.; Aydin, Egemen; Duncan, Kathleen E.; Callaghan, Amy V.; Oldham, Athenia; Liengen, Turid; Beech, Iwona

    2017-01-01

    Corrosion processes in two North Sea oil production pipelines were studied by analyzing pig envelope samples via metagenomic and metabolomic techniques. Both production systems have similar physico-chemical properties and injection waters are treated with nitrate, but one pipeline experiences severe corrosion and the other does not. Early and late pigging material was collected to gain insight into the potential causes for differential corrosion rates. Metabolites were extracted and analyzed via ultra-high performance liquid chromatography/high-resolution mass spectrometry with electrospray ionization (ESI) in both positive and negative ion modes. Metabolites were analyzed by comparison with standards indicative of aerobic and anaerobic hydrocarbon metabolism and by comparison to predicted masses for KEGG metabolites. Microbial community structure was analyzed via 16S rRNA gene qPCR, sequencing of 16S PCR products, and MySeq Illumina shotgun sequencing of community DNA. Metagenomic data were used to reconstruct the full length 16S rRNA genes and genomes of dominant microorganisms. Sequence data were also interrogated via KEGG annotation and for the presence of genes related to terminal electron accepting (TEA) processes as well as aerobic and anaerobic hydrocarbon degradation. Significant and distinct differences were observed when comparing the ‘high corrosion’ (HC) and the ‘low corrosion’ (LC) pipeline systems, especially with respect to the TEA utilization potential. The HC samples were dominated by sulfate-reducing bacteria (SRB) and archaea known for their ability to utilize simple carbon substrates, whereas LC samples were dominated by pseudomonads with the genetic potential for denitrification and aerobic hydrocarbon degradation. The frequency of aerobic hydrocarbon degradation genes was low in the HC system, and anaerobic hydrocarbon degradation genes were not detected in either pipeline. This is in contrast with metabolite analysis, which

  10. Long Term Corrosion/Degradation Test Six Year Results

    Energy Technology Data Exchange (ETDEWEB)

    M. K. Adler Flitton; C. W. Bishop; M. E. Delwiche; T. S. Yoder

    2004-09-01

    The Subsurface Disposal Area (SDA) of the Radioactive Waste Management Complex (RWMC) located at the Idaho National Engineering and Environmental Laboratory (INEEL) contains neutron-activated metals from non-fuel, nuclear reactor core components. The Long-Term Corrosion/Degradation (LTCD) Test is designed to obtain site-specific corrosion rates to support efforts to more accurately estimate the transfer of activated elements to the environment. The test is using two proven, industry-standard methods—direct corrosion testing using metal coupons, and monitored corrosion testing using electrical/resistance probes—to determine corrosion rates for various metal alloys generally representing the metals of interest buried at the SDA, including Type 304L stainless steel, Type 316L stainless steel, Inconel 718, Beryllium S200F, Aluminum 6061, Zircaloy-4, low-carbon steel, and Ferralium 255. In the direct testing, metal coupons are retrieved for corrosion evaluation after having been buried in SDA backfill soil and exposed to natural SDA environmental conditions for times ranging from one year to as many as 32 years, depending on research needs and funding availability. In the monitored testing, electrical/resistance probes buried in SDA backfill soil will provide corrosion data for the duration of the test or until the probes fail. This report provides an update describing the current status of the test and documents results to date. Data from the one-year and three-year results are also included, for comparison and evaluation of trends. In the six-year results, most metals being tested showed extremely low measurable rates of general corrosion. For Type 304L stainless steel, Type 316L stainless steel, Inconel 718, and Ferralium 255, corrosion rates fell in the range of “no reportable” to 0.0002 mils per year (MPY). Corrosion rates for Zircaloy-4 ranged from no measurable corrosion to 0.0001 MPY. These rates are two orders of magnitude lower than those specified in

  11. Corrosion rate of API 5L Gr. X60 multipurpose steel pipeline under combined effect of water and crude oil

    Science.gov (United States)

    Miao, Jian; Wang, Qiang

    2016-09-01

    Multipurpose pipeline is often seriously corroded during its service life, and the phenomenon is more prominent once the transportation medium is changed. Electrochemical polarization curves and impedance spectroscopy of the API 5L Gr. X60 steel pipeline's corrosion process in sedimentary water with different ion types and their concentrations have been studied in this work. The results showed that the corrosion rates were found to be 0.00418 and 0.00232 mm/a for pure water and crude oil, respectively. However, for the mixtures of water and crude oil (with water content increased from 0.2 vol% to 10 vol%), the corrosion rate increased consistently and reached a maximum value of 0.15557 mm/a for 10 vol% water in crude oil. The effect of the concentration of various ions, namely, chloride, bicarbonate and sulfate in (oil/water) mixtures on the corrosion rate was characterized by weight-loss method. The results showed that with increasing the ions' concentrations, the corresponding exchange current density increased significantly. The results were further supported by the observations of corrosion morphology using scanning electron microscopy and are helpful in devising guidelines which would help in reducing corrosion in multipurpose transport pipelines involving a change of transported medium during their service life.

  12. Determination of corrosion rate of reinforcement with a modulated guard ring electrode; analysis of errors due to lateral current distribution

    Energy Technology Data Exchange (ETDEWEB)

    Wojtas, H

    2004-07-01

    The main source of errors in measuring the corrosion rate of rebars on site is a non-uniform current distribution between the small counter electrode (CE) on the concrete surface and the large rebar network. Guard ring electrodes (GEs) are used in an attempt to confine the excitation current within a defined area. In order to better understand the functioning of modulated guard ring electrode and to assess its effectiveness in eliminating errors due to lateral spread of current signal from the small CE, measurements of the polarisation resistance performed on a concrete beam have been numerically simulated. Effect of parameters such as rebar corrosion activity, concrete resistivity, concrete cover depth and size of the corroding area on errors in the estimation of polarisation resistance of a single rebar has been examined. The results indicate that modulated GE arrangement fails to confine the lateral spread of the CE current within a constant area. Using the constant diameter of confinement for the calculation of corrosion rate may lead to serious errors when test conditions change. When high corrosion activity of rebar and/or local corrosion occur, the use of the modulated GE confinement may lead to significant underestimation of the corrosion rate.

  13. The effect of CO{sub 2} on the corrosion rate in simulated combustion atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Maekipaeae, Martti [VTT Processes, P.O. Box 1601, FIN-02044 VTT, Espoo (Finland); Sroda, Szymon [European Commission, Joint Research Centre, Institute for Energy, P.O. Box 2, NL-1755 ZG Petten (Netherlands)

    2004-07-01

    The aim of the study is to improve the understanding of the corrosion mechanism in biomass and waste combustion processes. Laboratory, pilot and full scale testing of materials are performed. The obtained results are discussed, e.g., with reference to thermodynamic modelling calculations. The laboratory experiments in JRC Plant Simulation Test Laboratory are focused mainly on common ferritic and austenitic steels (X10, X20, 2.25Cr1Mo, AC66, Sanicro28, Esshette 1250 etc), which are used as superheater steel tube materials in such applications. The main aim of this part of the project is to understand the effect of deposition as well as the CO{sub 2} or/and CO/CO{sub 2} content in combustion atmospheres on corrosion rate and mechanism of studied materials. Laboratory tests include the thermogravimetric studies using Cahn thermo-balances and long exposure tests in horizontal/autoclave multi-sample furnaces. Post experimental analyses are made using SEM/EDS + XRD techniques and optical microscopy. The experiments are carried out at isothermal temperature - 535 deg. C in various simulated combustion atmospheres (22%H{sub 2}O + 5%O{sub 2} + xCO{sub 2} + N{sub 2}) with different CO{sub 2} content vary from 0 to 25 vol. % for the samples without deposit and with filter/cyclone ash deposition (long exposure tests). In this stage, following conclusions can be made: - Corrosion rate, for the alloys with and without the deposit, increase with increasing CO{sub 2} content, especially for the ferritic steels; - Corrosion rate for samples with the deposit increase significantly and in this case the internal oxidation of the studied samples was observed; - Thermodynamic model calculations performed resulted, a.o., to the following propositions still of preliminary nature; - Various carbides of metallic alloying elements become less stable at oxide scale-metallic alloy phase boundary with increasing partial pressure of carbon dioxide; - Carbides and oxides of various alloying

  14. Impact of iron-reducing bacteria on the corrosion rate of carbon steel under simulated geological disposal conditions.

    Science.gov (United States)

    Schütz, Marta K; Schlegel, Michel L; Libert, Marie; Bildstein, Olivier

    2015-06-16

    The current projects for the disposal of high-level radioactive waste rely on underground burial and confinement by metallic envelopes that are susceptible to corrosion processes. The impact of microbial activity must be fully clarified in order to provide biological parameters for predictive reactive transport models. This study investigates the impact of hydrogenotrophic iron-reducing bacteria (Shewanella oneidensis strain MR-1) on the corrosion rate of carbon steel under simulated geological disposal conditions by using a geochemical approach. It was found that corrosion damage changes mostly according to the experimental solution (i.e., chemical composition). Magnetite and vivianite were identified as the main corrosion products. In the presence of bacteria, the corrosion rate increased by a factor of 1.3 (according to weight loss analysis) to 1.8 (according to H2 measurements), and the detected amount of magnetite diminished. The mechanism likely to enhance corrosion is the destabilization and dissolution of the passivating magnetite layer by reduction of structural Fe(III) coupled to H2 oxidation.

  15. Electrial Resistance Probe Corrosion Sensors for In-Situ Assessment for Waterfront Structures, FY09 OSD Project F09NV04

    Science.gov (United States)

    2013-02-13

    saltwater and protect the connection from corrosion (Figures 2-3 and 2-4). 4 Figure 2-2. Schematic of ER probe installation Figure 2-3...to prevent water intrusion into the conduit system (Figure 2-6). The intent of this process was to ensure that this assembly would be installed such...that an open end of the conduit system would not be submerged below water during installation, thereby minimizing water intrusion into the conduit

  16. Effects of scan rate on the corrosion behavior SS 304 stainless steel in the nanofluid measured by Tafel polarization methods

    Energy Technology Data Exchange (ETDEWEB)

    Prajitno, Djoko Hadi [PSTNT-BATAN Jl. Tamansari 71 Bandung 40132, Indonesia, djokohp@batan.go.id (Indonesia)

    2015-09-30

    The Effects of scan rate on the Tafel polarization curve that is obtained to determine corrosion rate are conducted. The tafel polarization curves are obtained at different scan rates for Stainless Steel 304 in nanofluids contain 0.01 gpl nano particle ZrO{sub 2}. The corrosion stainless steel in nanofluid contains adm+0.01 gpl ZrO{sub 2} nanoparticles at different scan rate was performed by Tafel polarization. The results show that according corrosion potential examination of the stainless steel in nanofluid media 0.01gpl ZrO{sub 2} nanoparticle was actively corroded. The value of cathodic Tafel slope stainless steel in nanofluid at different scan rate relatively unchanged after polarization testing. Mean while the value of anodic Tafel slope stainless steel in nanofluid increase at different scan rate. The results of Tafel polarization technique show that corrosion rate of stainless steel in nanofluid increase with increasing scan rate. X ray diffraction examination of stainless steel after Tafel polarization depict that γ Fe phase is major phase in the surface of alloy.

  17. INTERNAL CORROSION MONITORING IN OFFSHORE PLATFORMS

    Directory of Open Access Journals (Sweden)

    Fernando Benedicto Mainier

    2008-08-01

    Full Text Available Corrosion is one of the main causes of failures in equipment and pipes in off-shore oil production. These failures harm the process, slow the production operational chronogram, and generate high costs of maintenance, beyond generation risks to health and environment. Due to the fact that most of the equipment, tubing and pipes of production platforms are made of steel, in general, carbon steel, the industry of petroleum exploration will always coexist with the corrosive process. The use of a Corrosion Monitoring Plan to diagnostic, to control and to manage the evolution of corrosives process in off-shore oil platforms is the strategy proposed in this work to prevent problems as described above. The Internal Corrosion Monitoring Plan (ICMP, is based on lab analysis of the corrosively of fluids and residues showed periodically in off-shore operational platform; in the corrosion rate determined by the periodic use of test bodies installed inside off-shore oil platforms tubing systems, as mass loss coupons and electric resistance probes; and finally, in periodic operational data collect obtained during the off-shore oil platform systems operation. The ICMP will direct and manage the actions to be taken in case of aggravation of a corrosive process, quickly identifying to the corrosive mechanisms and its localization in the various systems of the platforms. The optimized use of the corrosion inhibitor and other chemical products are one of the main advantages of the ICMP.

  18. Markov chain model helps predict pitting corrosion depth and rate in underground pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Caleyo, F.; Velazquez, J.C.; Hallen, J. M. [ESIQIE, Instituto Politecnico Nacional, Mexico D. F. (Mexico); Esquivel-Amezcua, A. [PEMEX PEP Region Sur, Villahermosa, Tabasco (Mexico); Valor, A. [Universidad de la Habana, Vedado, La Habana (Cuba)

    2010-07-01

    Recent reports place pipeline corrosion costs in North America at seven billion dollars per year. Pitting corrosion causes the higher percentage of failures among other corrosion mechanisms. This has motivated multiple modelling studies to be focused on corrosion pitting of underground pipelines. In this study, a continuous-time, non-homogenous pure birth Markov chain serves to model external pitting corrosion in buried pipelines. The analytical solution of Kolmogorov's forward equations for this type of Markov process gives the transition probability function in a discrete space of pit depths. The transition probability function can be completely identified by making a correlation between the stochastic pit depth mean and the deterministic mean obtained experimentally. The model proposed in this study can be applied to pitting corrosion data from repeated in-line pipeline inspections. Case studies presented in this work show how pipeline inspection and maintenance planning can be improved by using the proposed Markovian model for pitting corrosion.

  19. A prediction method for the general corrosion behavior of Alloy 690 steam generator tube using eddy current testing

    Energy Technology Data Exchange (ETDEWEB)

    Shim, Hee-Sang; Choi, Myung Sik; Lee, Deok Hyun; Hur, Do Haeng, E-mail: dhhur@kaeri.re.kr

    2016-02-15

    Highlights: • A corrosion test for the tubes with different levels of eddy current noise was conducted. • A relationship between the corrosion rate and the eddy current noise of tubes was explored. • Corrosion rate was closely correlated to the tube noise of a rotating pancake probe. • Corrosion rate was not related to the tube noise measured using a bobbin probe. - Abstract: The purpose of this work is to develop an eddy current testing method to predict the general corrosion behavior of Alloy 690 steam generator tubes. A corrosion test was conducted for tubes with different levels of eddy current noise in simulated primary water at 330 °C, and their corrosion behavior was correlated with the tube noise measured using bobbin and rotating probes. The corrosion behavior was closely correlated with the tube noise measured using a rotating probe. However, there was no correlation between the corrosion behavior and the tube noise measured using a bobbin probe. The tube noise value measured using a rotating pancake coil probe is suggested to be a significant parameter in estimating the general corrosion behavior of tubes.

  20. SAVANNAH RIVER SITE TANK CLEANING: CORROSION RATE FOR ONE VERSUS EIGHT PERCENT OXALIC ACID SOLUTION

    Energy Technology Data Exchange (ETDEWEB)

    Ketusky, E.; Subramanian, K.

    2011-01-20

    Until recently, the use of oxalic acid for chemically cleaning the Savannah River Site (SRS) radioactive waste tanks focused on using concentrated 4 and 8-wt% solutions. Recent testing and research on applicable dissolution mechanisms have concluded that under appropriate conditions, dilute solutions of oxalic acid (i.e., 1-wt%) may be more effective. Based on the need to maximize cleaning effectiveness, coupled with the need to minimize downstream impacts, SRS is now developing plans for using a 1-wt% oxalic acid solution. A technology gap associated with using a 1-wt% oxalic acid solution was a dearth of suitable corrosion data. Assuming oxalic acid's passivation of carbon steel was proportional to the free oxalate concentration, the general corrosion rate (CR) from a 1-wt% solution may not be bound by those from 8-wt%. Therefore, after developing the test strategy and plan, the corrosion testing was performed. Starting with the envisioned process specific baseline solvent, a 1-wt% oxalic acid solution, with sludge (limited to Purex type sludge-simulant for this initial effort) at 75 C and agitated, the corrosion rate (CR) was determined from the measured weight loss of the exposed coupon. Environmental variations tested were: (a) Inclusion of sludge in the test vessel or assuming a pure oxalic acid solution; (b) acid solution temperature maintained at 75 or 45 C; and (c) agitation of the acid solution or stagnant. Application of select electrochemical testing (EC) explored the impact of each variation on the passivation mechanisms and confirmed the CR. The 1-wt% results were then compared to those from the 8-wt%. The immersion coupons showed that the maximum time averaged CR for a 1-wt% solution with sludge was less than 25-mils/yr for all conditions. For an agitated 8-wt% solution with sludge, the maximum time averaged CR was about 30-mils/yr at 50 C, and 86-mils/yr at 75 C. Both the 1-wt% and the 8-wt% testing demonstrated that if the sludge was removed

  1. Ultrasonic monitoring of erosion/corrosion thinning rates in industrial piping systems.

    Science.gov (United States)

    Honarvar, Farhang; Salehi, Farzaneh; Safavi, Vahid; Mokhtari, Arman; Sinclair, Anthony N

    2013-09-01

    Monitoring pipe wall erosion/corrosion thinning rates is an important issue in petrochemical and power generation industries. In this paper, two signal processing techniques are utilized for estimating the thinning rate based on ultrasonic pipe wall thickness data collected over a short period of time. The first is a combination of cross-correlation and polynomial curve fitting and the second is a model-based estimation (MBE) scheme. These techniques are applied to data collected from an accelerated thinning rate apparatus and both show that they are capable of estimating the thinning rates quickly in short time periods with good accuracy. In laboratory applications, thinning rates as low as 10 μm/year were measured within 15 days with an uncertainty of ±1.5 μm/year by both techniques. Although the MBE technique can yield marginally better accuracy, the greater stability and computational speed of the cross-correlation technique make it the preferred choice for industrial use.

  2. Study of mechanical properties, microstructures and corrosion behavior of al 7075 t651 alloy with varying strain rate

    Science.gov (United States)

    Mukherjee, A.; Ghosh, M.; Mondal, K.; Venkitanarayanan, P.; Moon, A. P.; Varshney, A.

    2015-02-01

    Compression test of Al 7075 T651 was carried out at high strain rates (1138 - 2534 s-1) using Split Hopkinson Pressure Bar and at slow strain rate (10-4s-1) in 100KN Universal Testing machine to understand the improvement in mechanical properties and associated changes in microstructures. Cylindrical specimens of 6 mm height and 6 mm diameter were compressed dynamically. The influence of strain rates on mechanical properties, microstructure evolution and corrosion behavior after immersion test in 3.5% NaCl solution was also investigated. Strain rate, withdrawal stress and yield stress were observed to increase with impact velocity in high strain rate tests, while in slow strain rate tests, n value was observed to increase with increasing total strain. Microstructural observations revealed that after high strain rate test, grains of Al matrix were elongated. It was observed that corrosion resistance decreased with increase in impact velocity.

  3. Comparison between the corrosion forecast based on the potential measurement and the determination of the corrosion rate of the reinforcement bar by means of electrochemical techniques

    Directory of Open Access Journals (Sweden)

    Castaneda, A.

    2003-12-01

    Full Text Available The ASTA4 876-91 standard establishes a corrosion forecast of concrete reinforced bar by measuring the electrochemical potential. This forecast is based on thermodynamic considerations without taking into account the kinetic of the corrosion process. A comparison was made between the results obtained based on this standard and others using electrochemical techniques (Tafel, Rp, EIS, Electrochemical Noise. These techniques allows to obtain the corrosion rate in samples having 0.4, 0.5 and 0.66 water/cement ratios submitted to salt spray outdoors and by immersion in 3% saline solution during a test time of 20 months. Differences were detected between the results obtained using the ASTM standard and the electrochemical techniques used. The main difference is that samples submitted to immersion shows a higher probability of corrosion than samples submitted to salt spray; however, the electrochemical techniques showed the contrary concerning the corrosion kinetic process .A comparison respecting corrosion rate was also made between the results obtained by the different electrochemical techniques. It is very well known that all electrochemical techniques supposed always general corrosion except electrochemical noise. Using the technique the pitting index can be calculated. It shows that localized corrosion is the most predominant

    La norma ASTM 876-91 establece un pronóstico de corrosión de la barra de refuerzo del hormigón armado mediante la determinación de potenciales electroquímicos. Este pronóstico se basa en consideraciones termodinámicas, sin tener en cuenta la cinética del proceso de corrosión. Se comparan los resultados obtenidos aplicando esta norma con técnicas electroquímicas (Tafel, Rp, EIS, Ruido Electroquímico que permiten calcular la velocidad de corrosión en probetas con relaciones agua/cemento 0,4, 0,5 y 0,66 sometidas a niebla salina en condiciones naturales y en inmersión en solución salina al 3% durante un

  4. Correlation of Process Data and Electrochemical Noise to Assess Kraft Digester Corrosion: Kamloops Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Pawel, SJ

    2002-05-09

    Electrochemical noise (ECN) probes were deployed in a carbon steel continuous kraft digester at five locations roughly equi-spaced from top to bottom of the vessel. Current and potential noise, the temperature at each probe location, and the value of about 60 process parameters (flow rates, liquor chemistry, etc.) were monitored continuously for a period of one year. Historical vessel inspection data, including inspections accomplished immediately prior to and immediately following probe deployment, and post-test evaluation of the probe components were used to assess/compare corrosion indications from the probes with physical changes in wall thickness and corrosion patterns on the digester shell. The results indicate that furnish composition is a significant variable influencing digester corrosion, with increasing amounts of Douglas fir in the nominal furnish correlating directly with increased corrosion activity on the ECN probes. All five probes detected changes in furnish composition approximately simultaneously, indicating rapid chemical communication through the liquor, but the effect was strongest and persisted longest relatively high in the digester. The ECN probes also indicate significant corrosion activity occurred at each probe position during shutdown/restart transients. Little or no correlation between ECN probe corrosion activity and other operational variables was observed. Post-test evaluation of the probes confirmed general corrosion of a magnitude that closely agreed with corrosion current sums calculated for each probe over the exposure period and with historical average corrosion rates for the respective locations. Further, no pitting was observed on any of the electrodes, which is consistent with the ECN data, relevant polarization curves developed for steel in liquor removed from the digester, and the post-test inspection of the digester.

  5. Evaluation of electrochemical techniques for measurement of fireside corrosion in thermal power plants; Utvaerdering av elektrokemiska tekniker foer maetning av roekgassidig hoegtemperaturkorrosion i pannor

    Energy Technology Data Exchange (ETDEWEB)

    Hjorrnhede, Anders

    2007-12-15

    The possibility to measure the corrosion rate on-line, in situ, is getting more and more interesting due to increased corrosion. The worsening may be a result of lower fuel quality or increased steam data due to raised efficiency demands. Also the use of inhibitors can be improved and the lifetime of important components can be increased. Today, virtually all corrosion measurements of materials used for waterwalls, superheaters, economisers and other heat-transferring surfaces are based on in-situ probe tests of coupons or rings. The aim of the project is to evaluate the practicability of commercial or semicommercial on-line in-situ corrosion probes for use in waste fired boilers. The target groups are owners of boilers, operators, service personnel but also boiler manufacturer and material producers. Since the use of on-line, in situ, corrosion probes is substantial, some of the most promising corrosion probes have been tested in a waste fired boiler in Hamburg, Germany. Tests in waste fired boiler have never before been performed. The MECO CB, a Linear Polarisation Resistance (LPR) corrosion probe from Coresto Oy, Finland was tested and from Lehrstuhl fuer Umweltverfahrenstechnik und Anlagentechnik (LUAT) der Universitaet Duisburg-Essen, Germany an Electrochemical Noise (EN) - probe was tested. From Pepperl + Fuchs both EN- and LPR-CorrTran corrosion sensors were tested. The test periods were lasting from 1050h to 3750h. The test materials were the low alloyed steel 15Mo3, the Ni-based super alloys Sanicro 63 and Haynes Hastelloy C-2000. The fluegas temperatures were 635 deg C or 520 deg C. The material temperatures were 440 deg C, 420 deg, 350 deg C and was swept from 400 deg C to 300 deg C. All probes are measuring a signal which has a correlation to the corrosion process, but the quantification procedure is not working well. The results achieved from the corrosion probes must be calibrated against corrosion rates measured by means of conventional corrosion

  6. Evaluation of electrochemical techniques for measurement of fireside corrosion in thermal power plants; Utvaerdering av elektrokemiska tekniker foer maetning av roekgassidig hoegtemperaturkorrosion i pannor

    Energy Technology Data Exchange (ETDEWEB)

    Hjorrnhede, Anders

    2007-12-15

    The possibility to measure the corrosion rate on-line, in situ, is getting more and more interesting due to increased corrosion. The worsening may be a result of lower fuel quality or increased steam data due to raised efficiency demands. Also the use of inhibitors can be improved and the lifetime of important components can be increased. Today, virtually all corrosion measurements of materials used for waterwalls, superheaters, economisers and other heat-transferring surfaces are based on in-situ probe tests of coupons or rings. The aim of the project is to evaluate the practicability of commercial or semicommercial on-line in-situ corrosion probes for use in waste fired boilers. The target groups are owners of boilers, operators, service personnel but also boiler manufacturer and material producers. Since the use of on-line, in situ, corrosion probes is substantial, some of the most promising corrosion probes have been tested in a waste fired boiler in Hamburg, Germany. Tests in waste fired boiler have never before been performed. The MECO CB, a Linear Polarisation Resistance (LPR) corrosion probe from Coresto Oy, Finland was tested and from Lehrstuhl fuer Umweltverfahrenstechnik und Anlagentechnik (LUAT) der Universitaet Duisburg-Essen, Germany an Electrochemical Noise (EN) - probe was tested. From Pepperl + Fuchs both EN- and LPR-CorrTran corrosion sensors were tested. The test periods were lasting from 1050h to 3750h. The test materials were the low alloyed steel 15Mo3, the Ni-based super alloys Sanicro 63 and Haynes Hastelloy C-2000. The fluegas temperatures were 635 deg C or 520 deg C. The material temperatures were 440 deg C, 420 deg, 350 deg C and was swept from 400 deg C to 300 deg C. All probes are measuring a signal which has a correlation to the corrosion process, but the quantification procedure is not working well. The results achieved from the corrosion probes must be calibrated against corrosion rates measured by means of conventional corrosion

  7. The role of solidification rate in the corrosion resistance of a directionally solidified novel aluminium-lanthanum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Dzib-Perez, L. [Programa de Corrosion del Golfo de Mexico, Universidad Autonoma de Campeche, Av. Agustin Melgar s/n, Col. Buenavista, CP 24030 Campeche, Campeche (Mexico); Gonzalez-Sanchez, J. [Programa de Corrosion del Golfo de Mexico, Universidad Autonoma de Campeche, Av. Agustin Melgar s/n, Col. Buenavista, CP 24030 Campeche, Campeche (Mexico)]. E-mail: jagonzal@uacam.mx; Perez, T. [Programa de Corrosion del Golfo de Mexico, Universidad Autonoma de Campeche, Av. Agustin Melgar s/n, Col. Buenavista, CP 24030 Campeche, Campeche (Mexico); Bartolo-Perez, P. [Programa de Corrosion del Golfo de Mexico, Universidad Autonoma de Campeche, Av. Agustin Melgar s/n, Col. Buenavista, CP 24030 Campeche, Campeche (Mexico); CINVESTAV-Merida, Applied Physics Department, Carr. antigua a Progreso, km 6, CP 97310 Merida, Yucatan (Mexico); Juarez, A. [CIATEQ. Calzada del Retablo 150, CP 76150 Queretaro, Queretaro (Mexico)

    2006-08-15

    The corrosion resistance of a novel Al-12.6 wt.%La alloy manufactured using unidirectional solidification was studied by sensitive electrochemical techniques. It was found that the electrochemical behaviour of the alloy depends upon the formation of non-passive corrosion product layers. Different solidification rates produced dissimilar microstructures which promoted selective dissolution when the alloy was anodically polarized in distilled water. A model for the electrochemical behaviour of this alloy was proposed based on an equivalent circuit that simulated the impedance results.

  8. Effect of contents oil temperature and flow rate in the electrochemical corrosion of the AISI-SAE1020-steel

    Science.gov (United States)

    Cedeño, M. L.; L, E. Vera; Pineda T, Y.

    2017-01-01

    Primary causes of corrosion in components and equipment used in the petroleum industry are due to the density differences present in the multiphase system Water/Hydrocarbon/CO2 as well as the presence of weak particles of carbonic acid. The present research is focus on the study of the corrosion rate of the steel AISI-SAE 1020 under a saturated CO2 multiphase system. The effects of fluid speed, temperature and oil content on the steel corrosion were carried out in an electrode of rotator cylinder and also using electrochemical impedance spectroscopy, and potentiodynamic polarization measurements. The results show that the effect of oil content in the rate of steel corrosion is inversely proportional with the speed of the rotor. Our observations indicate that increasing the rotor speed in systems containing 60% oil or higher produce a simultaneous increase in the degradation rate of materials. Similarly, temperatures higher than 60°C generate layers of siderite that reduce the electrochemical effect.

  9. Phase Separation in Ti-6Al-4V Alloys with Boron Additions for Biomedical Applications: Scanning Kelvin Probe Force Microscopy Investigation of Microgalvanic Couples and Corrosion Initiation

    Science.gov (United States)

    Davis, P. H.; Robles, K.; Livingston, K.; Johns, S.; Ravi, V. A.; Graugnard, E.; Hurley, M. F.

    2017-08-01

    To investigate the effect of boron additions on the corrosion behavior of Ti-6Al-4V for potential use in biomedical implants and devices, cast samples of Ti-6Al-4V were alloyed with 0.01% to 1.09% boron by weight and subjected to hot isostatic pressing. Subsequent analysis via scanning Kelvin probe force microscopy and scanning electron microscopy/energy-dispersive spectroscopy revealed the presence of both alpha ( α) and beta ( β) phase titanium, enriched in aluminum and vanadium, respectively. At all concentrations, boron additions affected the grain structure and were dispersed throughout both phases, but above the solubility limit, needle-like TiB structures also formed. The TiB needles and β phase exhibited similar surface potentials, whereas that of the α phase was found to be significantly lower. Nevertheless, when subjected to high applied electrochemical potentials in saline solutions, corrosion initiation was observed exclusively within the more noble β phase.

  10. Calculation of Radioactivity and Dose Rate of Activated Corrosion Products in Water-Cooled Fusion Reactor

    Directory of Open Access Journals (Sweden)

    Jingyu Zhang

    2016-01-01

    Full Text Available In water-cooled reactor, the dominant radioactive source term under normal operation is activated corrosion products (ACPs, which have an important impact on reactor inspection and maintenance. A three-node transport model of ACPs was introduced into the new version of ACPs source term code CATE in this paper, which makes CATE capable of theoretically simulating the variation and the distribution of ACPs in a water-cooled reactor and suitable for more operating conditions. For code testing, MIT PWR coolant chemistry loop was simulated, and the calculation results from CATE are close to the experimental results from MIT, which means CATE is available and credible on ACPs analysis of water-cooled reactor. Then ACPs in the blanket cooling loop of water-cooled fusion reactor ITER under construction were analyzed using CATE and the results showed that the major contributors are the short-life nuclides, especially Mn-56. At last a point kernel integration code ARShield was coupled with CATE, and the dose rate around ITER blanket cooling loop was calculated. Results showed that after shutting down the reactor only for 8 days, the dose rate decreased nearly one order of magnitude, which was caused by the rapid decay of the short-life ACPs.

  11. Stress corrosion cracking of alloy 600 using the constant strain rate test

    Energy Technology Data Exchange (ETDEWEB)

    Bulischeck, T. S.; van Rooyen, D.

    1980-01-01

    The most recent corrosion problems experienced in nuclear steam generators tubed with Inconel alloy 600 is a phenomenon labeled ''denting''. Denting has been found in various degrees of severity in many operating pressurized water reactors. Laboratory investigations have shown that Inconel 600 exhibits intergranular SCC when subjected to high stresses and exposed to deoxygenated water at elevated temperatures. A research project was initiated at Brookhaven National Laboratory in an attempt to improve the qualitative and quantitative understanding of factors influencing SCC in high temperature service-related environments. An effort is also being made to develop an accelerated test method which could be used to predict the service life of tubes which have been deformed or are actively denting. Several heats of commercial Inconel 600 tubing were procured for testing in deaerated pure and primary water at temperatures from 290 to 365/sup 0/C. U-bend type specimens were used to determine crack initiation times which may be expected for tubes where denting has occurred but is arrested and provide baseline data for judging the accelerating effects of the slow strain rate method. Constant extension rate tests were employed to determine the crack velocities experienced in the crack propagation stage and predict failure times of tubes which are actively denting. 8 refs., 17 figs., 5 tabs.

  12. Dynamic tafel factor adaption for the evaluation of instantaneous corrosion rates on zinc by using gel-type electrolytes

    Science.gov (United States)

    Babutzka, M.; Heyn, A.

    2017-03-01

    Electrochemical corrosion measurements allow calculation of the instantaneous zinc corrosion rate via polarization resistances by using tafel factors. However, the determination of the actual tafel factor is problematic since it depends on the state of the formed zinc layers and the corrosion reactions taking place. Therefore, valid tafel factors are either determined in additional experiments via dynamic polarization or estimated by calculation. In most cases a constant value for tafel factors is assumed for simplification, without regard to the real conditions of the corroding system. Since naturally formed zinc layers are unstable using conventional test electrolyte solutions determination of tafel factors is hindered additionally and inaccurate interpretations can result. For some time now, the use of gel-type electrolytes in corrosion research has enabled minimally invasive investigation of zinc surface layers and thus offers new approaches to a scientifically proven determination of tafel factors. The paper presents a new method for the determination and evaluation of tafel factors using gel-type electrolytes and electrochemical frequency modulation technique (EFM). This relatively new electrochemical method offers the possibility to determine both polarization resistances and tafel factors within one measurement and in short measuring intervals. Starting from a comprehensive parameter study it is shown that a direct relationship between the two values exists that can be described mathematically. This contribution presents the determined tafel factors for the system gel-type electrolyte/zinc and discusses their applicability and their limits.

  13. Estimation on gas generation and corrosion rates of carbon steel, stainless steel and zircaloy in alkaline solutions under low oxygen condition

    Energy Technology Data Exchange (ETDEWEB)

    Mihara, Morihiro; Honda, Akira [Japan Nuclear Cycle Development Inst., Tokai Works, Tokai, Ibaraki (Japan); Nishimura, Tsutomu; Wada, Ryutaro [Kobe Steel Ltd., Engineering Company, Energy and Nuclear System Center, Osaka (Japan)

    2002-06-01

    Hydrogen gas generated by corrosion of metals in TRU waste repository may degrade the function of the engineered barrier system for nuclide migration. Therefore, estimation of gas generation rates of metals under the repository condition is important. In this study, we obtained gas generation rates of carbon steel, stainless steel and zircaloy in alkaline solutions under low oxygen conditions and evaluated the corrosion rates based on these data in order to compare with the published data. The magnitude of corrosion rates of carbon steel, stainless steel and zircaloy were 10{sup -1} {mu}m/y, 10{sup -2} {mu}m/y and 10{sup -3} {mu}m/y, respectively. These values agreed with the published corrosion rates from gas generation rates by others. (author)

  14. INFLUENCE OF CONCRETE COVER ON CORROSION MECHANISM AND CORROSION RATE OF STEEL BARS%混凝土保护层对钢筋腐蚀机理及腐蚀速率的影响

    Institute of Scientific and Technical Information of China (English)

    余波; 毋铭; 杨绿峰

    2014-01-01

    混凝土保护层的厚度、电阻率和孔隙水饱和度对混凝土中钢筋的腐蚀机理及腐蚀速率具有重要影响。基于混凝土中钢筋宏电池腐蚀模型,定量分析了混凝土保护层的厚度、电阻率和孔隙水饱和度对钢筋腐蚀机理及腐蚀速率的影响。分析结果表明,混凝土保护层的电阻率和孔隙水饱和度对钢筋腐蚀的控制方式及腐蚀速率影响显著:当钢筋腐蚀受电阻控制时,钢筋腐蚀速率将随着混凝土保护层电阻率的增加而减小,随保护层厚度的增大而增大,但不受混凝土孔隙水饱和度的影响;当钢筋腐蚀受阴极控制时,钢筋腐蚀速率将随着混凝土保护层的孔隙水饱和度和厚度的增大而降低,但不受混凝土电阻率的影响。%The thickness , resistivity and degree of pore saturation of concrete cover have significant influences on the corrosion mechanism and corrosion rate of steel bar embedded in concrete .The influences of the thickness , resistivity and degree of pore saturation of concrete cover on the corrosion mechanism and corrosion rate of steel bar were investigated quantitatively , based on the macro-cell corrosion model of steel bar .The results show that the thickness and degree of pore saturation of concrete cover significantly affect the corrosion mechanism and corrosion rate of steel bar corrosion .If the corrosion of steel bar is under the control of resistivity , the corrosion rate diminishes with the increase of resistivity and accelerates with the increase of cover thickness , while the degree of pore saturation of concrete cover has negligible effect .When the cathodic reaction prevails , however , the corrosion rate decelerates with the increase of the degree of pore saturation and thickness of concrete cover while the effect of resistivity can be neglected .

  15. Influence of the Environment on the General Corrosion Rate of Alloy 22 (N06022)

    Energy Technology Data Exchange (ETDEWEB)

    Rebak, R B; Crook, P

    2004-04-19

    Nickel (Ni) can dissolve a large amount of alloying elements while still maintaining its desirable austenitic microstructure. The resulting alloys are generally divided in families depending on the type of alloying elements they contain. Each one of these families is aimed to specific applications. Corrosive environments in industrial applications are generally divided for example in reducing acids, oxidizing acids, contaminated acids, caustic environments, oxidizing salts, etc. Depending on the application and the environment (electrolyte composition and temperature) several or single alloys may be recommended to fabricate components. The Nichromium-molybdenum (Ni-Cr-Mo) series contains a balanced selection of beneficial alloying elements so it can handle a variety of aggressive environments. By design, Alloy 22 or N06022 is one of the most versatile corrosion resistant nickel alloys since it has an outstanding corrosion resistance both in reducing and oxidizing conditions.

  16. In-situ corrosion measurements of WWII shipwrecks in Chuuk Lagoon, quantification of decay mechanisms and rates of deterioration

    Directory of Open Access Journals (Sweden)

    Ian Donald Macleod

    2016-03-01

    Full Text Available This paper is based on a series of measurements taken on WWII historic shipwrecks that resulted from the effects of Operation Hailstone in February 1944 on the Japanese merchant fleet which was assembled in Chuuk lagoon, Federated States of Micronesia. More than 65 shipwrecks and 250 aircraft were sunk during two main bombing raids. The vessels lost covered a wide range of underwater orientation and water depths and so provided a perfect suite of corrosion experiments. Since the fuel on board the aircraft was either readily burnt at the time or was lost through volatilisation, the wrecked planes present no pollution problems today. However the bunker fuel kept inside on-board storage tanks does present a real conservation management crisis. In-situ measurements on many vessels have determined how water depth, the localised wreck topography, dissolved oxygen levels, temperature and salinity affects the corrosion rate of cast iron and mild steel. Thus corrosion rates can be calculated with confidence.

  17. Measurement of Localized Corrosion Rates at Inclusion Particles in AA7075 by In Situ Three Dimensional (3D) X-ray Synchrotron Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Sudhanshu S.; Williams, Jason J.; Stannard, Tyler J.; Xiao, Xianghui; De Carlo, Francesco; Chawla, Nikhilesh

    2016-03-01

    In situ X-ray synchrotron tomography was used to measure the localized corrosion rate of Mg2Si particles present in 7075 aluminum alloys in deionized ultra-filtered (DIUF) water. The evolution of hydrogen bubbles was captured as a function of time and the measured volume was used to calculate the local corrosion rate of Mg2Si particles. It was shown that in the absence of chloride ions, stress was needed to create fresh particle surfaces, either by fracture or debonding, to initiate corrosion at the particles.

  18. A method to evaluate the diffusion rate of drugs from a microdialysis probe through brain tissue

    NARCIS (Netherlands)

    Westerink, B.H.C.; de Vries, J.B

    2001-01-01

    For interpretation of microdialysis experiments in which compounds are applied retrodialysis, it is important to have information about the migration rate of the infused compounds. Here we describe a dual-probe microdialysis method that can be used to evaluate the penetration rate of the infused dru

  19. Predictive Model for Corrosion Rate of Oil Tubes in CO2/H2 S Coexistent Environment Part Ⅰ :Building of Model

    Institute of Scientific and Technical Information of China (English)

    李全安; 白真权; 黄得志; 张清; 文九巴; 李鹤林

    2004-01-01

    Based on an analysis of the existing models of CO2 corrosion in literatures and the autoclave simulative experiments, a predictive model of corrosion rate (rcorr) in CO2/H2 S corrosion for oil tubes has been established, in which rcorr is expressed as a function of pH, temperature ( T), pressure of CO2 ( Pco2 ) and pressure of H2S ( PH2S ). The model has been verified by experimental data obtained on N80 steel. The improved features of the predictive model include the following aspects: ( 1 ) The influence of temperature on the protectiveness of corrosion film is taken into consideration for establishment of predictive model of the rcorr in CO2/H2S corrosion. The Equations of scale temperature and scale factor are put forward, and they fit the experimental result very well. (2)The linear relationship still exists between In rcorr and In Pco2 in CO2/H2S corrosion (as same as that in CO2 corrosion). Therefore,a correction factor as a function of PH2S has been introduced into the predictive model in CO2/H2S corrosion. (3) The model is compatible with the main existing models.

  20. Influence of wind and topography on distribution of H2S concentration at Cirata hydropower plant and its impact on corrosion rate

    Science.gov (United States)

    Suryaningsih, Sri; Mindara, Jajat Y.

    2016-01-01

    Emission of hydrogen sulfide (H2S) gas by diffusion and by bubbling into the atmosphere at tailrace of Cirata hydropower plant give an environmental impact on surrounding area, especially on corrosion of metal surfaces. Field study shows that the highest H2S concentration and the highest corrosion rate are located at the location of Tailrace, with an average concentration of 152.63x10-3 µg.m-3, and corrosion rate of 0.5010 mm.yr-1. Computational Fluid Dynamics is used to develop a simulation model that replicates the function of wind in the distribution of H2S concentration over the complex three dimensional terrain. Results from this simulation are presented and compared with field study data to determine its impact on corrosion rate.

  1. Stress corrosion study of PH13-8Mo stainless steel using the Slow Strain Rate Technique

    Science.gov (United States)

    Torres, Pablo D.

    1989-01-01

    The need for a fast and reliable method to study stress corrosion in metals has caused increased interest in the Slow Strain Rate Technique (SSRT) during the last few decades. PH13-8MoH950 and H1000 round tensile specimens were studied by this method. Percent reduction-in-area, time-to-failure, elongation at fracture, and fracture energy were used to express the loss in ductility, which has been used to indicate susceptibility to stress corrosion cracking (SCC). Results from a 3.5 percent salt solution (corrosive medium) were compared to those in air (inert medium). A tendency to early failure was found when testing in the vicinity of 1.0 x 10(-6) mm/mm/sec in the 3.5 percent salt solution. PH13-8Mo H1000 was found to be less likely to suffer SCC than PH13-8Mo H950. This program showed that the SSRT is promising for the SCC characterization of metals and results can be obtained in much shorter times (18 hr for PH steels) than those required using conventional techniques.

  2. Analytical correlation between varying corrosion parameters and corrosion rate of Al-4.5Cu/10%ZrSiO{sub 4} composite in hydrochloric acid by rare earth chloride

    Energy Technology Data Exchange (ETDEWEB)

    Oloche, O.B.; Yaro, S.A. [Department of Metallurgical Engineering Ahmadu Bello University, Zaria (Nigeria); Okafor, E.G. [Department of Metallurgical Engineering Ahmadu Bello University, Zaria (Nigeria)], E-mail: ekeneokafor@yahoo.com

    2009-03-20

    The effect of varying temperature, time and inhibitor concentration on the corrosion rate of Al-4.5Cu/ZrSiO{sub 4} composite in 0.5 M hydrochloric acid without and with lanthanide chloride salt have been investigated. 10%ZrSiO{sub 4} was used for the production of the Al-4.5Cu/zircon sand composite. The time, temperature and concentration of inhibitor were varied in the range of 6-10 h at 2 h interval, 30-75 deg. C at 15 deg. C interval and 250-1000 ppm at 250 ppm interval respectively. Factorial design, standard deviation, effect of variables at 95% confidence interval and Arrhenius kinetics approach were used to correlate the corrosion parameter and corrosion rate. Results show that increase in temperature, inhibitor concentration above 250 ppm and decrease in time enhance corrosion rate. Also, temperature and anti-corrosion agent concentration are the most important control parameters. The kinetic and statistical approaches were in good agreement.

  3. How few and far between? Examining the effects of probe rate on self-reported mind wandering.

    Science.gov (United States)

    Seli, Paul; Carriere, Jonathan S A; Levene, Merrick; Smilek, Daniel

    2013-01-01

    We examined whether the temporal rate at which thought probes are presented affects the likelihood that people will report periods of mind wandering. To evaluate this possibility, we had participants complete a sustained-attention task (the Metronome Response Task; MRT) during which we intermittently presented thought probes. Critically, we varied the average time between probes (i.e., probe rate) across participants, allowing us to examine the relation between probe rate and mind-wandering rate. We observed a positive relation between these variables, indicating that people are more likely to report mind wandering as the time between probes increases. We discuss the methodological implications of this finding in the context of the mind-wandering literature, and suggest that researchers include a range of probe rates in future work to provide more insight into this methodological issue.

  4. How few and far between? Examining the effects of probe rate on self-reported mind wandering

    Directory of Open Access Journals (Sweden)

    Paul eSeli

    2013-07-01

    Full Text Available We examined whether the temporal rate at which thought probes are presented affects the likelihood that people will report periods of mind wandering. To evaluate this possibility, we had participants complete a sustained-attention task (the Metronome Response Task; MRT during which we intermittently presented thought probes. Critically, we varied the average time between probes (i.e., probe rate across participants, allowing us to examine the relation between probe rate and mind-wandering rate. We observed a positive relation between these variables, indicating that people are more likely to report mind wandering as the time between probes increases. We discuss the methodological implications of this finding in the context of the mind-wandering literature, and suggest that researchers include a range of probe rates in future work to provide more insight into this methodological issue.

  5. Effective rates from thermodynamically consistent coarse-graining of models for molecular motors with probe particles.

    Science.gov (United States)

    Zimmermann, Eva; Seifert, Udo

    2015-02-01

    Many single-molecule experiments for molecular motors comprise not only the motor but also large probe particles coupled to it. The theoretical analysis of these assays, however, often takes into account only the degrees of freedom representing the motor. We present a coarse-graining method that maps a model comprising two coupled degrees of freedom which represent motor and probe particle to such an effective one-particle model by eliminating the dynamics of the probe particle in a thermodynamically and dynamically consistent way. The coarse-grained rates obey a local detailed balance condition and reproduce the net currents. Moreover, the average entropy production as well as the thermodynamic efficiency is invariant under this coarse-graining procedure. Our analysis reveals that only by assuming unrealistically fast probe particles, the coarse-grained transition rates coincide with the transition rates of the traditionally used one-particle motor models. Additionally, we find that for multicyclic motors the stall force can depend on the probe size. We apply this coarse-graining method to specific case studies of the F(1)-ATPase and the kinesin motor.

  6. Evaluation of susceptibility of high strength steels to delayed fracture by using cyclic corrosion test and slow strain rate test

    Energy Technology Data Exchange (ETDEWEB)

    Li Songjie [School of Materials Science and Engineering, University of Science and Technology Beijing, No. 30 Xueyuan Road, Hidian Zone, Beijing 100083 (China); Structural Metals Center, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Zhang Zuogui [Structural Metals Center, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Akiyama, Eiji [Structural Metals Center, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)], E-mail: AKIYAMA.Eiji@nims.go.jp; Tsuzaki, Kaneaki [Structural Metals Center, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Zhang Boping [School of Materials Science and Engineering, University of Science and Technology Beijing, No. 30 Xueyuan Road, Hidian Zone, Beijing 100083 (China)

    2010-05-15

    To evaluate susceptibilities of high strength steels to delayed fracture, slow strain rate tests (SSRT) of notched bar specimens of AISI 4135 with tensile strengths of 1300 and 1500 MPa and boron-bearing steel with 1300 MPa have been performed after cyclic corrosion test (CCT). During SSRT the humidity around the specimen was kept high to keep absorbed diffusible hydrogen. The fracture stresses of AISI 4135 steels decreased with increment of diffusible hydrogen content which increased with CCT cycles. Their delayed fracture susceptibilities could be successfully evaluated in consideration of both influence of hydrogen content on mechanical property and hydrogen entry.

  7. Methodology to evaluate the crack growth rate by stress corrosion cracking in dissimilar metals weld in simulated environment of PWR nuclear reactor

    Energy Technology Data Exchange (ETDEWEB)

    Paula, Raphael G.; Figueiredo, Celia A.; Rabelo, Emerson G., E-mail: raphaelmecanica@gmail.com, E-mail: caf@cdtn.br, E-mail: egr@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2013-07-01

    Inconel alloys weld metal is widely used to join dissimilar metals in nuclear reactors applications. It was recently observed failures of weld components in plants, which have triggered an international effort to determine reliable data on the stress corrosion cracking behavior of this material in reactor environment. The objective of this work is to develop a methodology to determine the crack growth rate caused by stress corrosion in Inconel alloy 182, using the specimen (Compact Tensile) in simulated PWR environment. (author)

  8. Probe Measurements of Ash Deposit Formation Rate and Shedding in a Biomass Suspension-Fired boiler

    DEFF Research Database (Denmark)

    Shafique Bashir, Muhammad; Jensen, Peter Arendt; Frandsen, Flemming;

    The aim of this study was to investigate ash deposit formation rate, heat uptake reduction and deposit removal by using advanced online ash deposition and sootblowing probes in a 350 MWth suspension-fired boiler, utilizing wood and straw pellets as fuel. The influence of fuel type (straw share...

  9. A rapid, non-destructive methodology to monitor activity of sulfide-induced corrosion of concrete based on H2S uptake rate.

    Science.gov (United States)

    Sun, Xiaoyan; Jiang, Guangming; Bond, Philip L; Wells, Tony; Keller, Jurg

    2014-08-01

    Many existing methods to monitor the corrosion of concrete in sewers are either very slow or destructive measurements. To overcome these limitations, a rapid, non-invasive methodology was developed to monitor the sulfide-induced corrosion process on concrete through the measurement of the H2S uptake rates of concrete at various corrosion stages. The H2S uptake rate for a concrete coupon was determined by measuring the gaseous H2S concentrations over time in a temperature- and humidity-controlled gas-tight reactor. The reliability of this method was evaluated by carrying out repeated tests on different concrete coupons previously exposed to 50 ppm of H2S, at 30 °C and 100% relative humidity for over 32 months. The H2S uptake measurements showed good reproducibility. It was also shown that a severely corroded coupon exhibited higher sulfide uptake rates than a less corroded coupon. This could be explained by the corrosion layer in the more corroded coupon having a higher biological sulfide oxidation activity than the less corroded coupon. Additionally, temperature changes had a stronger effect on the uptake rate of the heavily corroded coupon compared to the less corroded coupon. A corrosion rate of 8.9 ± 0.5 mm/year, estimated from the H2S uptake results, agreed well with the corrosion rate observed in real sewers under similar conditions. The method could be applied to investigate important factors affecting sulfide-induced concrete corrosion, particularly temperature, fluctuating gaseous H2S concentrations, oxygen concentrations, surface pH and relative humidity.

  10. Comparison of Galileo Probe and Earth-Based Translation Rates of Jupiter's Equatorial Clouds

    Science.gov (United States)

    Beebe; Simon; Huber

    1996-05-10

    The Doppler wind speeds derived from Galileo probe data are comparable with the maximum translation speeds observed in the equatorial zone by Voyager 1 and the Hubble Space Telescope. Slower published values of east-west winds are based on measurements of larger features and should be interpreted as translation rates of large weather systems interacting with the wind. The nature of the hot-spot region that the Galileo probe entered is compatible with a high-speed jet at 6 degrees north. The hot spot is associated with an equatorial weather system that spans 5 degrees of latitude and translates at 103 meters per second.

  11. Impact of additives on corrosion rate of cans filled with pieces of apricot

    Directory of Open Access Journals (Sweden)

    Tošković D.V.

    2005-01-01

    Full Text Available Polarization techniques are used for testing the impact of different compounds (additives on tinplate corrosion, using pieces of apricot dipped in syrup with and without nitrate addition as electrolyte solution, at the same time using filled cans as electrolytic cell and operating electrode. This procedure determined the intensity of inhibiting tin dissolving with some of the used additives like sodium-benzoate, potassium-sorbate sodium-lauril-sulphate and p-aminobenzoate acid. Adding these additives to canned pieces of apricot in syrup led to inhibiting of tin dissolving, which was experimentally proved.

  12. Field test corrosion experiences when co-firing straw and coal: 10 year status within Elsam

    DEFF Research Database (Denmark)

    Frandsen, Rasmus Berg; Montgomery, Melanie; Larsen, Ole Hede

    2007-01-01

    to 575 degrees C and for the flue gas from 1025 to 1300 degrees C. All these test tubes have been removed during the last three years at one year intervals for corrosion studies. The corrosion studies performed on all investigated tubes included measurements of the corrosion attack, light optical...... sulphate on superheater tubes resulting in increased corrosion rates. From field experimental results this paper show, that by co-firing straw with coal, corrosion rates can be brought down to an acceptable level. This paper firstly deals with the results from a demonstration program co-firing coal...... and straw at the 150 MW pulverized coal fired boiler Studstrup unit 1. Two exposure series lasting 3000 hours each were performed for co-firing 10 and 20% of straw (% energy basis) with coal. Using built in test tubes in the hot end of the actual superheaters and air/water cooled corrosion probes...

  13. Scanning reference electrode techniques in localized corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Isaacs, H.S.; Vyas, B.

    1979-04-01

    The principles, advantages, and implementations of scanning reference electrode techniques are reviewed. Data related to pitting, intergranular corrosion, welds and stress corrosion cracking are presented. The technique locates the position of localized corrosion and can be used to monitor the development of corrosion and changes in the corrosion rate under a wide range of conditions.

  14. Effects of pH and carbonate concentration on dissolution rates of the lead corrosion product PbO(2).

    Science.gov (United States)

    Xie, Yanjiao; Wang, Yin; Singhal, Vidhi; Giammar, Daniel E

    2010-02-01

    Lead(IV) oxide is a corrosion product that can develop on lead pipes and affect lead concentrations in drinking water. Continuously stirred flow-though reactors were used to quantify the dissolution rates of plattnerite (beta-PbO(2)) at different pH values and dissolved inorganic carbon (DIC) concentrations. Organic pH buffers were not used, because several were found to be reductants for PbO(2) that accelerated its dissolution. Most plattnerite dissolution rates were on the order of 10(-10) mol/min-m(2). The rate of dissolution increased with decreasing pH and with increasing DIC. The effect of DIC is consistent with a reductive dissolution mechanism that involves the reduction of Pb(IV) to Pb(II) at the plattnerite surface followed by the formation of soluble Pb(II)-carbonate complexes that accelerate Pb(II) release from the surface. Under the experimental conditions, dissolved lead concentrations were controlled by the dissolution rate of plattnerite and not by its equilibrium solubility. A dissolution rate model was developed and can be used to predict dissolution rates of plattnerite as a function of pH and DIC.

  15. Fretting and Corrosion Between a Metal Shell and Metal Liner May Explain the High Rate of Failure of R3 Modular Metal-on-Metal Hips.

    Science.gov (United States)

    Ilo, Kevin C; Derby, Emma J; Whittaker, Robert K; Blunn, Gordon W; Skinner, John A; Hart, Alister J

    2017-05-01

    The R3 acetabular system used with its metal liner has higher revision rates when compared to its ceramic and polyethylene liner. In June 2012, the medical and healthcare products regulatory agency issued an alert regarding the metal liner of the R3 acetabular system. Six retrieved R3 acetabular systems with metal liners underwent detailed visual analysis using macroscopic and microscopic techniques. Visual analysis discovered corrosion on the backside of the metal liners. There was a distinct border to the areas of corrosion that conformed to antirotation tab insertions on the inner surface of the acetabular shell, which are for the polyethylene liner. Scanning electron microscopy indicated evidence of crevice corrosion, and energy-dispersive X-ray analysis confirmed corrosion debris rich in titanium. The high failure rate of the metal liner option of the R3 acetabular system may be attributed to corrosion on the backside of the liner which appear to result from geometry and design characteristics of the acetabular shell. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Corrosion rate of steel embedded in blended Portland and fluid catalytic cracking catalyst residue (FC3R cement mortars

    Directory of Open Access Journals (Sweden)

    Payá, J.

    2008-12-01

    Full Text Available This paper reports on a study of the corrosion levels in steel bars embedded in mortars made with a blend of Portland cement and (0-20% spent fluid catalytic cracking catalyst residue (FC3R, with a variable (0.3-0.7 water/binder (w/b ratio. The specimens were stored in the following conditions: relative humidity of 40, 80 or 100% and CO2 concentrations of 5 and 100%. The steel corrosion rate was measured with polarization resistance techniques. In the absence of aggressive agents, the steel was found to remain duly passivated in mortars with an FC3R content of up to 15% under all the conditions of relative humidity tested. The reinforcement corrosion level in mortars with a w/b ratio of 0.3 and 15% FC3R subjected to accelerated carbonation was similar to the level observed in the unblended Portland cement control mortar.En este trabajo se ha estudiado el nivel de corrosión de barras de acero embebidas en morteros de cemento Portland con relación agua/material cementante (a/mc variable (0,3-0,7, en los que parte del cemento (0-20% se sustituyó por catalizador de craqueo usado (FC3R. Las condiciones de conservación de las probetas elaboradas fueron las siguientes: distintas humedades relativas (40, 80 y 100% y dos concentraciones de CO2 (5 y 100%. La velocidad de corrosión de los aceros se midió mediante la técnica de resistencia de polarización. Se ha podido determinar que, bajo las distintas condiciones de humedad relativa y ausencia de agresivo, los aceros se mantuvieron correctamente pasivados en los morteros con contenidos de FC3R de hasta el 15%. El nivel de corrosión que presenta el refuerzo embebidos en morteros con sustitución de un 15% de cemento por FC3R y relación a/mc 0,3, al ser sometidos a un proceso de carbonatación acelerada, era muy similar al mostrado por el mortero patrón, sin FC3R.

  17. Monitoring Microbially Influenced Corrosion

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    and diffusional effects and unreliable corrosion rates, when biofilm and ferrous sulphide corrosion products cover the steel surface. Corrosion rates can be overestimated by a factor of 10 to 100 by electrochemical techniques. Weight loss coupons and ER are recommended as necessary basic monitoring techniques....... EIS might be used for detection of MIC as the appearance of very large capacitances can be attributed to the combined ferrous sulphide and biofilm formation. Capacitance correlates directly with sulphide concentration in sterile sulphide media. Keywords: Corrosion monitoring, carbon steel, MIC, SRB...

  18. Monitoring Microbially Influenced Corrosion

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    Abstract Microbially influenced corrosion (MIC) of carbon steel may occur in media with microbiological activity of especially sulphate-reducing bacteria (SRB). The applicability and reliability of a number of corrosion monitoring techniques for monitoring MIC has been evaluated in experiments...... and diffusional effects and unreliable corrosion rates, when biofilm and ferrous sulphide corrosion products cover the steel surface. Corrosion rates can be overestimated by a factor of 10 to 100 by electrochemical techniques. Weight loss coupons and ER are recommended as necessary basic monitoring techniques....... EIS might be used for detection of MIC as the appearance of very large capacitances can be attributed to the combined ferrous sulphide and biofilm formation. Capacitance correlates directly with sulphide concentration in sterile sulphide media. Keywords: Corrosion monitoring, carbon steel, MIC, SRB...

  19. Establishing empirical relationships to predict porosity level and corrosion rate of atmospheric plasma-sprayed alumina coatings on AZ31B magnesium alloy

    Directory of Open Access Journals (Sweden)

    D. Thirumalaikumarasamy

    2014-06-01

    Full Text Available Plasma sprayed ceramic coatings are successfully used in many industrial applications, where high wear and corrosion resistance with thermal insulation are required. In this work, empirical relationships were developed to predict the porosity and corrosion rate of alumina coatings by incorporating independently controllable atmospheric plasma spray operational parameters (input power, stand-off distance and powder feed rate using response surface methodology (RSM. A central composite rotatable design with three factors and five levels was chosen to minimize the number of experimental conditions. Within the scope of the design space, the input power and the stand-off distance appeared to be the most significant two parameters affecting the responses among the three investigated process parameters. A linear regression relationship was also established between porosity and corrosion rate of the alumina coatings. Further, sensitivity analysis was carried out and compared with the relative impact of three process parameters on porosity level and corrosion rate to verify the measurement errors on the values of the uncertainty in estimated parameters.

  20. Studies on the Construction Parameter of an Artificial Occluded Cell for In-situ Inspection of the Propagation Rate of Localized Corrosion

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An artificial localized corrosion system is assembled and some parameters related to the localized corrosion in active dissolution state(i.e.,non-passive state)have been studied.The results showed that the developed electrochemical system can satisfactorily imitate a naturally formed localized corrosion and the coupling current can indicate the maximum localized propagating rate.In this artificial system, the anodic dissolution reaction followed the auto-catalytic mechanism.The localized corrosion current density was dependent on the area ratio R of the cathode tothe occluded anode. While R was equal to or more than 6, the coupling current reached at a maximum value and did not alter with the increase in R-value. Therefore, R=7 is chosen as one of these optimum parameters used in constructing the system, with which the biggest galvanic current might be obtained. In contrast, the thickness of the polymer filler separating the occluded anode area from the bulk electrolyte solution and the volume of the occluded anode area did not affect the corrosion current obviously. They might affect the response time to approach a steady state.

  1. Electrochemical corrosion studies

    Science.gov (United States)

    Knockemus, W. W.

    1986-01-01

    The objective was to gain familiarity with the Model 350 Corrosion Measurement Console, to determine if metal protection by grease coatings can be measured by the polarization-resistance method, and to compare corrosion rates of 4130 steel coated with various greases. Results show that grease protection of steel may be determined electrochemically. Studies were also conducted to determine the effectiveness of certain corrosion inhibitors on aluminum and steel.

  2. In-situ corrosion investigation at Masnedø CHP plant - a straw-fired power plant

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Karlsson, Asger

    1999-01-01

    Various austenitic and ferritic steels were exposed on a water-cooled probe in the superheater area of a straw-fired CHP plant. The temperature of the probe ranged from 450-600°C and the period of exposure was 1400 hours. The rate of corrosion was assessed based on unattacked metal remaining...

  3. Corrosion testing of urea-formaldehyde foam insulating material

    Energy Technology Data Exchange (ETDEWEB)

    Weil, R.; Graviano, A.; Sheppard, K.

    1980-09-01

    Two tests of the corrosiveness of urea-formaldehyde (UF) foam insulating materials were compared. One test, the Timm test, had test coupons foamed in place. In the second, the Canadian test, blocks of foam already set were placed in contact with test coupons. The Timm test uses 10 gage thick coupons, while the Canadian test specifies 3 mil thick ones. Two samples of UF foam were tested by the Timm and the Canadian tests. The electrical-resistance probes showed that the corrosion rate against steel was initially quite high, of the order of 12 to 20 mpy (mils per year). After about 20 days, the rate was almost zero. In the Timm test, the corrosion rates of steel coupons were of the order to 0.5 to 2 mpy when averaged over the 28 or 56 day test period. The greater corrosion rate of the thick coupons in the Canadian test as well as poor reproducibility of the corrosion rates was attributed primarily to variations in the contact areas between the sample and the UF foam. The corrosion rates of galvanized steel coupons in the Canadian test in several cases exceeded the failure value. In the Timm test, the corrosion rates averaged over the whole test period were quite low. The corrosion rates of copper and aluminum in both tests were quite low. On the basis of the results of this study the following recommendations for a corrosion-test procedure for UF foam were made: two corrosion tests should be conducted, one for foam while curing and one after it has stabilized; the Timm test for corrosiveness while curing should be used, but for only 1 to 2 days; the test for corrosiveness after stabilizing should be of the accelerated type such as the Canadian one. To insure a constant-contact area, thicker coupons should be used; and the coupons for both tests should have a controlled part of the area not in contact with the foam to simulate field conditions.

  4. Corrosion of steel structures in sea-bed sediment

    Indian Academy of Sciences (India)

    Xiutong Wang; Jizhou Duan; Yan Li; Jie Zhang; Shide Ma; Baorong Hou

    2005-04-01

    Seabed sediment (SBS) is a special soil that is covered by seawater. With the developments in marine oil exploitation and engineering, more and more steel structures have been buried in SBS. SBS corrosion has now become a serious problem in marine environment and an important issue in corrosion science. In this paper, approach in the field of SBS corrosion is reviewed. Electrochemical and microbial corrosion factors, corrosion mechanism, measurement of metal corrosion rate, corrosion evaluation and prediction of corrosion are also discussed here.

  5. Microfluidic multifunctional probe array dielectrophoretic force spectroscopy with wide loading rates.

    Science.gov (United States)

    Park, In Soo; Eom, Kilho; Son, Jongsang; Chang, Woo-Jin; Park, Kidong; Kwon, Taeyun; Yoon, Dae Sung; Bashir, Rashid; Lee, Sang Woo

    2012-10-23

    The simultaneous investigation of a large number of events with different types of intermolecular interactions, from nonequilibrium high-force pulling assays to quasi-equilibrium unbinding events in the same environment, can be very important for fully understanding intermolecular bond-rupture mechanisms. Here, we describe a novel dielectrophoretic force spectroscopy technique that utilizes microsized beads as multifunctional probes for parallel measurement of intermolecular forces with an extremely wide range of force rate (10(-4) to 10(4) pN/s) inside a microfluidic device. In our experiments, various forces, which broadly form the basis of all molecular interactions, were measured across a range of force loading rates by multifunctional probes of various diameters with a throughput of over 600 events per mm(2), simultaneously and in the same environment. Furthermore, the individual bond-rupture forces, the parameters for the characterization of entire energy landscapes, and the effective stiffness of the force spectroscopy were determined on the basis of the measured results. This method of determining intermolecular forces could be very useful for the precise and simultaneous examination of various molecular interactions, as it can be easily and cost-effectively implemented within a microfluidic device for a range of applications including immunoassays, molecular mechanics, chemical and biological screening, and mechanobiology.

  6. Can giant radio halos probe the merging rate of galaxy clusters?

    CERN Document Server

    Cassano, R; Giocoli, C; Ettori, S

    2016-01-01

    Radio and X-ray observations of galaxy clusters probe a direct link between cluster mergers and giant radio halos (RH), suggesting that these sources can be used as probes of the cluster merging rate with cosmic time. In this paper we carry out an explorative study that combines the observed fractions of merging clusters (fm) and RH (fRH) with the merging rate predicted by cosmological simulations and attempt to infer constraints on merger properties of clusters that appear disturbed in X-rays and of clusters with RH. We use morphological parameters to identify merging systems and analyze the currently largest sample of clusters with radio and X-ray data (M500>6d14 Msun, and 0.2

  7. Correlation of Process Data and Electrochemical Noise to Assess Kraft Digester Corrosion: Spring Grove Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Pawel, SJ

    2003-06-18

    Electrochemical noise (ECN) probes were deployed in a carbon steel continuous kraft digester at four locations and at one location in the bottom cone of the associated flash tank. The probes consisted of carbon steel electrodes, representing the vessel construction material, and 309LSi stainless steel overlay electrodes, representing the weld overlay repair in a portion of the vessel. Current and potential noise, the temperature at each probe location, and the value of about 32 process parameters (flow rates, liquor chemistry, etc.) were monitored continuously for a period of almost one year. Historical vessel inspection data and post-test evaluation of the probe components were used to assess/compare ECN corrosion activity with physical changes in wall thickness and corrosion patterns on the digester shell. In addition, attempts were made to correlate ECN activity from each electrode type with process parameters. The results indicate the high general corrosion rates of steel observed just below the extraction screens--on the order of 35 mils/y for the past few years--accelerated further during the period of probe deployment. The maximum wastage of steel (normalized to one full year exposure) was about 85 mils/y at the ring 6N probe just below the extraction screens. Consistent with recent historical observations, the steel corrosion rate at the ring 6S probe--at the same elevation but directly across the digester from ring 6N--was significantly lower at about 50 mils/y. Just prior to probe deployment, the digester shell below the extraction screens was overlaid with 309LSi stainless steel, which was observed to be essentially immune to corrosion at this location. While the ECN probes detected differences in electrochemical behavior between steel probes and between 309LSi probes at rings 6N and 6S, there was only poor quantitative correlation of current sums with actual corrosion rates at these locations. A significant contribution of redox reactions on both steel

  8. Field test corrosion experiments in Denmark with biomass fuels Part II Co-firing of straw and coal

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Larsen, OH

    2002-01-01

    superheaters. A range of austenitic and ferritic steels was exposed in the steam temperature range of 520-580°C. The flue gas temperature ranged from 925-1100°C. The rate of corrosion was assessed by precision measurement of material loss and measurement of oxide thickness. Corrosion rates are lower than...... and potassium sulphate. These components give rise to varying degrees of accelerated corrosion. This paper concerns co-firing of straw with coal to reduce the corrosion rate from straw to an acceptable level. A field investigation at Midtkraft Studstrup suspension-fired power plant in Denmark has been...... undertaken where coal has been co-fired with 10% straw and 20% straw (% energy basis) for up to approx. 3000 hours. Two types of exposure were undertaken to investigate corrosion: a) the exposure of metal rings on water/air cooled probes, and b) the exposure of a range of materials built into the existing...

  9. Origins of Negative Strain Rate Dependence of Stress Corrosion Cracking Initiation in Alloy 690, and Intergranular Crack Formation in Thermally Treated Alloy 690

    Science.gov (United States)

    Kim, Young Suk; Kim, Sung Soo

    2016-09-01

    We show that enhanced stress corrosion cracking (SCC) initiation in cold-rolled Alloy 690 with decreasing strain rate is related to the rate of short-range ordering (SRO) but not to the time-dependent corrosion process. Evidence for SRO is provided by aging tests on cold-rolled Alloy 690 at 623 K and 693 K (350 °C and 420 °C), respectively, which demonstrate its enhanced lattice contraction and hardness increase with aging temperature and time, respectively. Secondary intergranular cracks formed only in thermally treated and cold-rolled Alloy 690 during SCC tests, which are not SCC cracks, are caused by its lattice contraction by SRO before SCC tests but not by the orientation effect.

  10. Correlation between General Corrosion Behavior and Eddy Current Noise of Alloy 690 Steam Generator Tube

    Energy Technology Data Exchange (ETDEWEB)

    Hur, Do Haeng; Choi, Myung Sik; Lee, Deok Hyun; Shim, Hee-Sang [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    Nickel and its oxides are released from the surface of steam generator tubes into the primary water. Released nickel and cobalt is activated to Co-58 and Co-60 in the reactor core by a neutron flux, respectively. These activated corrosion products are the main source of high radiation fields and occupational radiation exposure. In addition, some of the corrosion products redeposit on the fuel cladding, hinder the heat transfer, increase the corrosion rate of the fuel cladding, and finally induce an axial offset anomaly. This phenomenon can decrease core shutdown margin, and thus lead to a down-rating of a plant. Recently, many researchers have reported that the surface states of Alloy 690 tubes affect the corrosion product formation and its release in simulated primary water environments. Meanwhile, the surface states of steam generator tubes affect the noise level of eddy current testing. Noise signals arising from the tubes degrade the probability of detection and sizing accuracy of the defects. The corrosion behavior was closely correlated to the tube noise measured using a rotating probe, while it was not related to the noise measured using a bobbin probe. It is suggested that the tube noise value measured using a rotating pancake coil probe can be a decisive measure to estimate the corrosion behavior of tubing.

  11. Probing polymer crystallization at processing-relevant cooling rates with synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Cavallo, Dario, E-mail: Dario.cavallo@unige.it [University of Genoa, Dept. of Chemistry and Industrial Chemistry, Via Dodecaneso 31, 16146 Genoa (Italy); Portale, Giuseppe [ESRF, Dubble CRG, Netherlands Organization of Scientific Research (NWO), 38043 Grenoble (France); Androsch, René [Martin-Luther-University Halle-Wittenberg, Center of Engineering Sciences, D-06099 Halle/S. (Germany)

    2015-12-17

    Processing of polymeric materials to produce any kind of goods, from films to complex objects, involves application of flow fields on the polymer melt, accompanied or followed by its rapid cooling. Typically, polymers solidify at cooling rates which span over a wide range, from a few to hundreds of °C/s. A novel method to probe polymer crystallization at processing-relevant cooling rates is proposed. Using a custom-built quenching device, thin polymer films are ballistically cooled from the melt at rates between approximately 10 and 200 °C/s. Thanks to highly brilliant synchrotron radiation and to state-of-the-art X-ray detectors, the crystallization process is followed in real-time, recording about 20 wide angle X-ray diffraction patterns per second while monitoring the instantaneous sample temperature. The method is applied to a series of industrially relevant polymers, such as isotactic polypropylene, its copolymers and virgin and nucleated polyamide-6. Their crystallization behaviour during rapid cooling is discussed, with particular attention to the occurrence of polymorphism, which deeply impact material’s properties.

  12. Inverse method for the instantaneous measure of wall shear rate magnitude and direction using electrodiffusion probes

    Science.gov (United States)

    Lamarche-Gagnon, Marc-Etienne; Vetel, Jerome

    2016-11-01

    Several methods can be used when one needs to measure wall shear stress in a fluid flow. Yet, it is known that a precise shear measurement is seldom met, mostly when both time and space resolutions are required. The electrodiffusion method lies on the mass transfer between a redox couple contained in an electrolyte and an electrode flush mounted to a wall. Similarly to the heat transfer measured by a hot wire anemometer, the mass transfer can be related to the fluid's wall shear rate. When coupled with a numerical post-treatment by the so-called inverse method, precise instantaneous wall shear rate measurements can be obtained. With further improvements, it has the potential to be effective in highly fluctuating three-dimensional flows. We present developments of the inverse method to two-component shear rate measurements, that is shear magnitude and direction. This is achieved with the use of a three-segment electrodiffusion probe. Validation tests of the inverse method are performed in an oscillating plane Poiseuille flow at moderate pulse frequencies, which also includes reverse flow phases, and in the vicinity of a separation point where the wall shear stress experiences local inversion in a controlled separated flow.

  13. Determination of Erosion/Corrosion Rates in Hanford Tank Farms Radioactive Waste Transfer System Pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Washenfelder, D. J.; Girardot, C. L.; Wilson, E. R.; Page, J. A.; Engeman, J. K.; Gunter, J. R.; Johnson, J. M.; Baide, D. G.; Cooke, G. A.; Larson, J. D.; Castleberry, J. L.; Boomer, K. D.

    2015-11-05

    The twenty-eight double-shell underground radioactive waste storage tanks at the U. S. Department of Energy’s Hanford Site near Richland, WA are interconnected by the Waste Transfer System network of buried steel encased pipelines and pipe jumpers in below-grade pits. The pipeline material is stainless steel or carbon steel in 51 mm to 152 mm (2 in. to 6 in.) sizes. The pipelines carry slurries ranging up to 20 volume percent solids and supernatants with less than one volume percent solids at velocities necessary to prevent settling. The pipelines, installed between 1976 and 2011, were originally intended to last until the 2028 completion of the double-shell tank storage mission. The mission has been subsequently extended. In 2010 the Tank Operating Contractor began a systematic evaluation of the Waste Transfer System pipeline conditions applying guidelines from API 579-1/ASME FFS-1 (2007), Fitness-For-Service. Between 2010 and 2014 Fitness-for-Service examinations of the Waste Transfer System pipeline materials, sizes, and components were completed. In parallel, waste throughput histories were prepared allowing side-by-side pipeline wall thinning rate comparisons between carbon and stainless steel, slurries and supernatants and throughput volumes. The work showed that for transfer volumes up to 6.1E+05 m3 (161 million gallons), the highest throughput of any pipeline segment examined, there has been no detectable wall thinning in either stainless or carbon steel pipeline material regardless of waste fluid characteristics or throughput. The paper describes the field and laboratory evaluation methods used for the Fitness-for-Service examinations, the results of the examinations, and the data reduction methodologies used to support Hanford Waste Transfer System pipeline wall thinning conclusions.

  14. Influence of Portland Cement Class on the Corrosion Rate of Steel Reinforcement in Cement Mortar Caused by Penetrating Chloride and Sulfate from the Environment

    OpenAIRE

    Bikić, F.; Cacan, M.; Rizvanović, M.

    2013-01-01

    The influence of portland cement class on the corrosion rate of steel reinforcement in cement mortar caused by penetrating chloride or sulfate from the environment in already hardened cement mortar is investigated in this paper. Three classes of portland cement have been used for the tests, PC 35, PC 45 and PC 55. Cylindrical samples of cement mortar with steel reinfor- cement in the middle were treated 6 months at room temperature in the follow...

  15. Some peculiarities of corrosion of wheel steel

    Directory of Open Access Journals (Sweden)

    Alexander SHRAMKO

    2009-01-01

    Full Text Available Corrosion mechanism and rate of different chemical composition and structural condition of wheel steel were investigated. It was shown that “white layers”, variation in grain size and banding of wheel steel structure results in corrosion rate. Microstructure of steel from different elements of railway wheels after operation with corrosion was investigated. Wheel steel with addition of vanadium corroded more quickly than steel without vanadium. Non-metallic inclusions are the centre of corrosion nucleation and their influence on corrosion depends on type of inclusion. Mechanism of corrosion of wheel steel corrosion was discussed.

  16. Effect of Silane Flow Rate on Structure and Corrosion Resistance of Ti-Si-N Thin Films Deposited by a Hybrid Cathodic Arc and Chemical Vapour Process

    Institute of Scientific and Technical Information of China (English)

    YIN Long-Cheng; LUAN Sen; LV Guo-Hua; WANG Xing-Quan; HUANG Jun; JIN Hui; FENG Ke-Cheng; YANG Si-Ze

    2008-01-01

    Ti-Si-N thin films with different silicon contents are deposited by a cathodic arc technique in an Ar+N2+SiH4mixture atmosphere. With the increase of silane flow rate, the content of silicon in the Ti-Si-N films varies from2.0 at. % to 12.2 at.%. Meanwhile, the cross-sectional morphology of these films changes from an apparent columnar microstructure to a dense fine-grained structure. The x-ray diffractometer (XRD) and x-ray photoelectron spectroscopy (XPS) results show that the Ti-Si-N film consists of TiN crystallites and SiNx amorphous phase.The corrosion resistance is improved with the increase of silane flow rate. Growth defects in the films produced play a key role in the corrosion process, especially for the local corrosion. The porosity of the films decreases from 0.13% to 0.00032% by introducing silane at the flow rate of 14 sccm.

  17. Contribution of archaeological analogs to the estimation of average corrosion rates and long term corrosion mechanisms of low carbon steel in soil; Apport des analogues archeologiques a l'estimation des vitesses moyennes et a l'etude des mecanismes de corrosion a tres long terme des aciers non allies dans les sols

    Energy Technology Data Exchange (ETDEWEB)

    Neff, D

    2003-11-15

    identified. This corrosion form, constituted among others by a siderite layer is due to a particular environment: waterlogged soil containing wood. In the whole, analyses conducted in the TM show that it is composed of goethite badly crystallized in comparison with those of the DPL. Moreover, in this zone, the average elemental iron amount decreases progressively from the metal to the soil in which it stabilizes. In order to know the behaviour of the identified phases in soil water, some thermodynamic data have been involved to calculate their solubility in function of pH, potential and various water composition. The first conclusion concerns the influence of the composition and the structure of the material which is not important for the corrosion behaviour. From the results, some hypothesis have been formulated on the long term corrosion mechanisms of hypo-eutectoids steels in the considered environment. The role of the cracks formed in the DPL during the burial was evidenced. Moreover, these corrosion products undertake a dissolution in the soil water and a reprecipitation, explaining the progressive decrease of the iron amount in the TM. Lastly, some average corrosion rates have been measured with the help of the analytical and thermodynamic results: they do not exceed 4 {mu}m/year. (author)

  18. Measurement of phytoplankton photosynthesis rate using a pump-and-probe fluorometer

    Directory of Open Access Journals (Sweden)

    Taras K. Antal

    2001-09-01

    Full Text Available In this work we have studied the possibility of determining the rate of phytoplankton photosynthesis in situ using a submersible pump-and-probe fluorometer in water areas differing in their trophic level, as well as in climatic and hydrophysical characteristics. A biophysical model was used to describe the relationship between photosynthesis, underwater irradiance, and the intensity of phytoplankton fluorescence excited by an artificial light source. Fluorescence intensity was used as a measure of light absorption by phytoplankton and for assessing the efficiency of photochemical energy conversion at photosynthetic reaction centers. Parameters of the model that could not be measured experimentally were determined by calibrating fluorescence and irradiance data against the primary production measured in the Baltic Sea with the radioactive carbon method. It was shown that the standard deviation of these parameters in situ did not exceed 20%, and the use of their mean values to estimate the phytoplankton photosynthetic rate showed a good correlation between the calculated and meas

  19. High resolution in situ ultrasonic corrosion monitor

    Science.gov (United States)

    Grossman, R.J.

    1984-01-10

    An ultrasonic corrosion monitor is provided which produces an in situ measurement of the amount of corrosion of a monitoring zone or zones of an elongate probe placed in the corrosive environment. A monitoring zone is preferably formed between the end of the probe and the junction of the zone with a lead-in portion of the probe. Ultrasonic pulses are applied to the probe and a determination made of the time interval between pulses reflected from the end of the probe and the junction referred to, both when the probe is uncorroded and while it is corroding. Corresponding electrical signals are produced and a value for the normalized transit time delay derived from these time interval measurements is used to calculate the amount of corrosion.

  20. Corrosion of Metal-Matrix Composites with Aluminium Alloy Substrate

    Directory of Open Access Journals (Sweden)

    B. Bobic

    2010-03-01

    Full Text Available The corrosion behaviour of MMCs with aluminium alloy matrix was presented. The corrosion characteristics of boron-, graphite-, silicon carbide-, alumina- and mica- reinforced aluminium MMCs were reviewed. The reinforcing phase influence on MMCs corrosion rate as well as on various corrosion forms (galvanic, pitting, stress corrosion cracking, corrosion fatique, tribocorrosion was discussed. Some corrosion protection methods of aluminium based MMCs were described

  1. Effect of Small Variation in the Composition of Plates and Weld Filler Wires on the General Corrosion Rate of Ni-Cr-Mo Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Fix, D V; Estill, J C; Rebak, R B

    2005-02-05

    The ASTM standard B 575 provides the requirements for the chemical composition of Nickel-Chromium-Molybdenum (Ni-Cr-Mo) alloys such as Alloy 22 (N06022) and Alloy 686 (N06686). The compositions of each element are given in a range. For example, the content of Mo is specified from 12.5 to 14.5 weight percent for Alloy 22 and from 15.0 to 17.0 weight percent for Alloy 686. It was important to determine how the corrosion rate of welded plates of Alloy 22 using Alloy 686 weld filler metal would change if heats of these alloys were prepared using several variations in the composition of the elements even though still in the range specified in B 575. All the material used in this report were especially prepared at Allegheny Ludlum Co. Seven heats of plate were welded with seven heats of wire. Immersion corrosion tests were conducted in a boiling solution of sulfuric acid plus ferric sulfate (ASTM G 28 A) using both as-welded (ASW) coupons and solution heat-treated (SHT) coupons. Results show that the corrosion rate was not affected by the chemistry of the materials within the range of the standards.

  2. Review on Stress Corrosion and Corrosion Fatigue Failure of Centrifugal Compressor Impeller

    Institute of Scientific and Technical Information of China (English)

    SUN Jiao; CHEN Songying; QU Yanpeng; LI Jianfeng

    2015-01-01

    Corrosion failure, especially stress corrosion cracking and corrosion fatigue, is the main cause of centrifugal compressor impeller failure. And it is concealed and destructive. This paper summarizes the main theories of stress corrosion cracking and corrosion fatigue and its latest developments, and it also points out that existing stress corrosion cracking theories can be reduced to the anodic dissolution (AD), the hydrogen-induced cracking (HIC), and the combined AD and HIC mechanisms. The corrosion behavior and the mechanism of corrosion fatigue in the crack propagation stage are similar to stress corrosion cracking. The effects of stress ratio, loading frequency, and corrosive medium on the corrosion fatigue crack propagation rate are analyzed and summarized. The corrosion behavior and the mechanism of stress corrosion cracking and corrosion fatigue in corrosive environments, which contain sulfide, chlorides, and carbonate, are analyzed. The working environments of the centrifugal compressor impeller show the behavior and the mechanism of stress corrosion cracking and corrosion fatigue in different corrosive environments. The current research methods for centrifugal compressor impeller corrosion failure are analyzed. Physical analysis, numerical simulation, and the fluid-structure interaction method play an increasingly important role in the research on impeller deformation and stress distribution caused by the joint action of aerodynamic load and centrifugal load.

  3. The use of slow strain rate technique for studying stress corrosion cracking of an advanced silver-bearing aluminum-lithium alloy

    Science.gov (United States)

    Frefer, Abdulbaset Ali; Abosdell, Alajale M.; Raddad, Bashir S.

    2013-12-01

    In the present study, stress corrosion cracking (SCC) behavior of naturally aged advanced silver-bearing Al-Li alloy in NaCl solution was investigated using slow strain rate test (SSRT) method. The SSRT's were conducted at different strain rates and applied potentials at room temperature. The results were discussed based on percent reductions in tensile elongation in a SCC-causing environment over those in air tended to express the SCC susceptbility of the alloy under study at T3. The SCC behavior of the alloy was also discussed based on the microstructural and fractographic examinations.

  4. The use of slow strain rate technique for studying stress corrosion cracking of an advanced silver-bearing aluminum-lithium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Frefer, Abdulbaset Ali; Raddad, Bashir S. [Department of Mechanical and Industrial Engineering/Tripoli University, Tripoli (Libya); Abosdell, Alajale M. [Department of Mechanical Engineering/Mergeb University, Garaboli (Libya)

    2013-12-16

    In the present study, stress corrosion cracking (SCC) behavior of naturally aged advanced silver-bearing Al-Li alloy in NaCl solution was investigated using slow strain rate test (SSRT) method. The SSRT’s were conducted at different strain rates and applied potentials at room temperature. The results were discussed based on percent reductions in tensile elongation in a SCC-causing environment over those in air tended to express the SCC susceptbility of the alloy under study at T3. The SCC behavior of the alloy was also discussed based on the microstructural and fractographic examinations.

  5. 混凝土中钢筋腐蚀速率模型研究进展%Models for Corrosion Rate of Steel in Concrete——a Short Review

    Institute of Scientific and Technical Information of China (English)

    施锦杰; 孙伟

    2012-01-01

    The prediction of steel corrosion rate in concrete is of great importance in the corrosion propagation stage,which also characterizes the time to corrosion-induced crack of concrete cover.The existing corrosion rate models,i.e.,empirical models,reac-tion-controlled models(oxygen diffusion and concrete resistivity) and electrochemical models,for corrosion rate of steel in reinforced concrete structures were reviewed.In addition,some features for steel corrosion such as time-varying,localized corrosion and prob-ability of corrosion were summarized,and some critical issues need to be resolved for the accurately prediction of the corrosion rate of steel were proposed.%预测混凝土中钢筋的腐蚀速率对腐蚀扩展阶段的发展非常重要,同时也能表征腐蚀导致的混凝土保护层开裂的时间。讨论了已有的钢筋腐蚀速率模型,包括经验模型、反应(氧气扩散与混凝土电阻率)控制模型和电化学模型。此外,根据以前的研究成果总结了钢筋腐蚀的时变性、局部腐蚀性与随机性等特征,并提出了准确预测腐蚀速率所需要解决的关键问题。

  6. 电位、电阻率与钢筋腐蚀率关系研究%POTENTIAL, RESISTIVITY AND THE RELATIONSHIP BETWEEN THE CORROSION RATE OF STEEL

    Institute of Scientific and Technical Information of China (English)

    聂志虎; 吴瑾

    2011-01-01

    the half-cell potential and concrete resistivity can only qualitatively estimate the reinforcement corrosion in the concrete, but it can' t quantitative detect the corrosion level of steel rebar. Quantitative relationship of potential, resistivity and steel corrosion rate is researched with the help of these two methods. By studying and analysising on the concrete, the new evaluation based on potential method and resistivity is proposed, and tested in engineering practice.%半电池电位法、电阻率法都是定性地估计混凝土结构中钢筋腐蚀的状态,而不能定量检测钢筋腐蚀率.本文借助这两种方法来研究电位、电阻率与钢筋腐蚀率之间的定量关系.通过对混凝土构件进行的试验研究和分析总结,得出电位法、电阻率法新的评价方法,并在工程实践中得到验证.

  7. A non-destructive test method to monitor corrosion products and corrosion-induced cracking in reinforced cement based materials

    DEFF Research Database (Denmark)

    Michel, Alexander; Pease, Bradley Justin; Peterova, Adela;

    2011-01-01

    ) was conducted to describe the impact of water-to-cement ratio and corrosion current density (i.e., corrosion rate) on the reinforcement corrosion process. Focus was placed, in particular on the determination of the corrosion accommodating region (CAR) and time to corrosion-induced cracking. Experimental results...

  8. Corrosion inhibition of a hygroscopic inorganic dust-depressor

    Institute of Scientific and Technical Information of China (English)

    Longzhe Jin; Lu Wang; Dongke Chen

    2006-01-01

    Metallic corrosion is a serious problem in the application of a hygroscopic inorganic dust-depressor. The basic characteristics of a hygroscopic inorganic dust-depressor and its corrosivity, corrosion mechanism, as well as the principle of corrosion inhibition were analyzed. The static mass-loss test was carried out to investigate the corrosion behavior and the effect of the dustdepressor. The static corrosion rates of steel specimens were measured in six different corrosion inhibitor solutions of the dustdepressor, and the suitable corrosion inhibitors for the dust-depressor to reduce the corrosivity were found out.

  9. Corrosion protection

    Science.gov (United States)

    Brown, Donald W.; Wagh, Arun S.

    2003-05-27

    There has been invented a chemically bonded phosphate corrosion protection material and process for application of the corrosion protection material for corrosion prevention. A slurry of iron oxide and phosphoric acid is used to contact a warm surface of iron, steel or other metal to be treated. In the presence of ferrous ions from the iron, steel or other metal, the slurry reacts to form iron phosphates which form grains chemically bonded onto the surface of the steel.

  10. Synergy effect of naphthenic acid corrosion and sulfur corrosion in crude oil distillation unit

    Science.gov (United States)

    Huang, B. S.; Yin, W. F.; Sang, D. H.; Jiang, Z. Y.

    2012-10-01

    The synergy effect of naphthenic acid corrosion and sulfur corrosion at high temperature in crude oil distillation unit was studied using Q235 carbon-manganese steel and 316 stainless steel. The corrosion of Q235 and 316 in corrosion media containing sulfur and/or naphthenic acid at 280 °C was investigated by weight loss, scanning electron microscope (SEM), EDS and X-ray diffractometer (XRD) analysis. The results showed that in corrosion media containing only sulfur, the corrosion rate of Q235 and 316 first increased and then decreased with the increase of sulfur content. In corrosion media containing naphthenic acid and sulfur, with the variations of acid value or sulfur content, the synergy effect of naphthenic acid corrosion and sulfur corrosion has a great influence on the corrosion rate of Q235 and 316. It was indicated that the sulfur accelerated naphthenic acid corrosion below a certain sulfur content but prevented naphthenic acid corrosion above that. The corrosion products on two steels after exposure to corrosion media were investigated. The stable Cr5S8 phases detected in the corrosion products film of 316 were considered as the reason why 316 has greater corrosion resistance to that of Q235.

  11. Optimising corrosion monitoring in district heating systems

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Thorarinsdottir, R.I.; Andersen, A.

    2002-01-01

    A three-year project - financially supported by the Nordic Industrial Fund - on monitoring of corrosion in district heating systems has been initiated with participation of researchers and industrial partners in Denmark, Finland, Iceland, Norway and Sweden. The primary objective of the project...... is to improve the quality control in district heating systems by corrosion monitoring. In Danish systems electrochemical impedance spectroscopy (EIS), linear polarisation resistance (LPR), high-sensitive electrical resistance (ER) technology, crevice corrosion probes, as well as weight loss coupons...

  12. Corrosion, ion release and Mott-Schottky probe of chromium oxide coatings in saline solution with potential for orthopaedic implant applications

    Science.gov (United States)

    Ogwu, A. A.; Oje, A. M.; Kavanagh, J.

    2016-04-01

    We report our investigation on chromium oxide thin film coatings that show a negligible ion release during electrochemical corrosion testing in saline solution. The chemical constituents of the films prepared by reactive magnetron sputtering were identified to be predominantly Cr2O3 based on Raman spectroscopy anti-symmetric stretching vibration modes for CrIII-O and other peaks and an FTIR spectroscopy E u vibrational mode at 409 cm-1. X-ray photoelectron spectroscopy, multiplet fitting for 2P 3/2 and 2P 1/2 states also confirmed the predominantly Cr2O3 stoichiometry in the films. The prepared chromium oxide coatings showed superior pitting corrosion resistance compared to the native chromium oxide films on bare uncoated stainless steel when tested under open circuit potential, potentiodynamic polarisation and cyclic voltammetry in saline solution. The chromium ion released into solution during the corrosion testing of stainless steel substrates coated with chromium oxide coatings was found to be negligibly small based on atomic absorption spectroscopy measurements. Our Mott-Schottky analysis investigation showed that the negligibly small ion release from the chromium oxide coated steel substrates is most likely due to a much lower defect density on the surface of the deposited coatings compared to the native oxide layer on the uncoated steel substrates. This opens up the opportunity for using chromium oxide surface coatings in hip, knee and other orthopaedic implants where possible metal ion release in vivo still poses a great challenge.

  13. Design and Field Implementation of Auto Tuned Virtual Instrumentation Corrosion Controller

    Science.gov (United States)

    Gopalakrishnan, J.; Agnihotri, Ganga; Deshpande, D. M.

    2016-06-01

    Corrosion in underground metallic pipeline leads to leakage which is hazardous when oil/natural gas is transported. Rate of corrosion in metal pipeline can be controlled by impressing dc current to the gas pipeline and thereby making metal pipeline to act as cathode of corrosion cell. Proportional integral controllers are used in impressed current cathodic protection application; tuning of proportional and integral constants of these controllers requires expertise. Step open, step close and relay tuning methods are compared; relay tuning provided better results for cathodic protection application. Ziegler-Nichols tuning formulas are used to select tuning parameters based on loop response. Virtual instrumentation is used for design, development, testing and field implementation of auto tuned PI controller. Proposed auto tuned proportional integral impressed current cathodic protection controller precisely controls corrosion in pipeline by selecting optimum proportional and integral constants. Controller effectiveness is cross verified using electrical resistance probe.

  14. Design and Field Implementation of Auto Tuned Virtual Instrumentation Corrosion Controller

    Science.gov (United States)

    Gopalakrishnan, J.; Agnihotri, Ganga; Deshpande, D. M.

    2017-02-01

    Corrosion in underground metallic pipeline leads to leakage which is hazardous when oil/natural gas is transported. Rate of corrosion in metal pipeline can be controlled by impressing dc current to the gas pipeline and thereby making metal pipeline to act as cathode of corrosion cell. Proportional integral controllers are used in impressed current cathodic protection application; tuning of proportional and integral constants of these controllers requires expertise. Step open, step close and relay tuning methods are compared; relay tuning provided better results for cathodic protection application. Ziegler-Nichols tuning formulas are used to select tuning parameters based on loop response. Virtual instrumentation is used for design, development, testing and field implementation of auto tuned PI controller. Proposed auto tuned proportional integral impressed current cathodic protection controller precisely controls corrosion in pipeline by selecting optimum proportional and integral constants. Controller effectiveness is cross verified using electrical resistance probe.

  15. Deposition and high temperature corrosion in a 10 MW straw

    DEFF Research Database (Denmark)

    Michelsen, Hanne Philbert; Frandsen, Flemming; Dam-Johansen, Kim

    1998-01-01

    Deposition and corrosion measurements were conducted at a 10 MW wheat straw fired stoker boiler used for combined power and heat production. The plant experiences major problems with deposits on the heat transfer surfaces, and test probes have shown enhanced corrosion due to selective corrosion...

  16. Migrating corrosion inhibitor protection of concrete

    Energy Technology Data Exchange (ETDEWEB)

    Bjegovic, D.; Miksic, B.

    1999-11-01

    Migrating corrosion inhibitors (MCI) were developed to protect steel rebar from corrosion in concrete. They were designed to be incorporated as an admixture during concrete batching or used for surface impregnation of existing concrete structures. Two investigations are summarized. One studied the effectiveness of MCIs as a corrosion inhibitor for steel rebar when used as an admixture in fresh concrete mix. The other is a long-term study of MCI concrete impregnation that chronicles corrosion rates of rebar in concrete specimens. Based on data from each study, it was concluded that migrating corrosion inhibitors are compatible with concrete and effectively delay the onset of corrosion.

  17. Solutions of corrosion Problems in advanced Technologies

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Karlsson, Asger

    1999-01-01

    Austenitic and ferritic steels were exposed in the superheater area of a straw-fired CHP plant. The specimens were exposed for 1400 hours at 450-600°C. The rate of corrosion was assessed based on unattacked metal remaining. The corrosion products and course of corrosion for the various steel types...... were investigated using light optical and scanning electron microscopy. The ferritic steels suffered from corrosion mainly via material loss. The austenitic steels suffered from predominantly selective corrosion resulting in chromium depletion from the alloy. A clear trend was observed that selective...... corrosion increased with increasing chromium content of the alloy....

  18. Soil corrosion monitoring near a pipeline under CP

    Energy Technology Data Exchange (ETDEWEB)

    Bullard, Sophie J.; Covino, Bernard S., Jr.; Cramer, Stephen D.; Holcomb, Gordon R.; Ziomek-Moroz, Margaret; Locke, M.L. (NW Natural); Warthen, M.R. (NW Natural); Kane, Russell D. (Intercorr International Inc.); Eden, Dawn C. (Intercorr International Inc.)

    2005-01-01

    Electrochemical noise (EN), linear polarization resistance (LPR), and harmonic distortion analysis (HDA) were used with three-electrode probes to monitor the corrosion occurring in soil in dry and wet conditions near a gas pipeline under cathodic protection. The test site was a cathodic protection (CP) test station where impressed current CP was applied to a 2 in. (5.1 cm) diameter FBE coated steel pipe using an 84 in. (0.2 m) TA-2 high-silicon cast iron anode. Electrochemical measurements were made at three locations, two inside the CP field and one outside the CP field. Electrochemical measurements were first made with the CP system off to establish the baseline corrosion and then with increasing levels of CP. The degree of protection was based on polarized potential and the adequacy of protection was determined by depolarization measurements. CP of an adjacent pipeline did not affect the measurement of either corrosion rate or pitting factor when using buried soil corrosion probes and the EN, LPR, and HDA techniques.

  19. Corrosion Engineering.

    Science.gov (United States)

    White, Charles V.

    A description is provided for a Corrosion and Corrosion Control course offered in the Continuing Engineering Education Program at the General Motors Institute (GMI). GMI is a small cooperative engineering school of approximately 2,000 students who alternate between six-week periods of academic study and six weeks of related work experience in…

  20. Automated methods of corrosion measurement

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov; Bech-Nielsen, Gregers; Reeve, John Ch

    1997-01-01

    Measurements of corrosion rates and other parameters connected with corrosion processes are important, first as indicators of the corrosion resistance of metallic materials and second because such measurements are based on general and fundamental physical, chemical, and electrochemical relations....... Hence improvements and innovations in methods applied in corrosion research are likeliy to benefit basic disciplines as well. A method for corrosion measurements can only provide reliable data if the beckground of the method is fully understood. Failure of a method to give correct data indicates a need...... to revise assumptions regarding the basis of the method, which sometimes leads to the discovery of as-yet unnoticed phenomena. The present selection of automated methods for corrosion measurements is not motivated simply by the fact that a certain measurement can be performed automatically. Automation...

  1. Corrosion inhibitors from expired drugs.

    Science.gov (United States)

    Vaszilcsin, Nicolae; Ordodi, Valentin; Borza, Alexandra

    2012-07-15

    This paper presents a method of expired or unused drugs valorization as corrosion inhibitors for metals in various media. Cyclic voltammograms were drawn on platinum in order to assess the stability of pharmaceutically active substances from drugs at the metal-corrosive environment interface. Tafel slope method was used to determine corrosion rates of steel in the absence and presence of inhibitors. Expired Carbamazepine and Paracetamol tablets were used to obtain corrosion inhibitors. For the former, the corrosion inhibition of carbon steel in 0.1 mol L(-1) sulfuric acid solution was about 90%, whereas for the latter, the corrosion inhibition efficiency of the same material in the 0.25 mol L(-1) acetic acid-0.25 mol L(-1) sodium acetate buffer solution was about 85%.

  2. Automated methods of corrosion measurement

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov; Bech-Nielsen, Gregers; Reeve, John Ch

    1997-01-01

    Measurements of corrosion rates and other parameters connected with corrosion processes are important, first as indicators of the corrosion resistance of metallic materials and second because such measurements are based on general and fundamental physical, chemical, and electrochemical relations....... Hence improvements and innovations in methods applied in corrosion research are likeliy to benefit basic disciplines as well. A method for corrosion measurements can only provide reliable data if the beckground of the method is fully understood. Failure of a method to give correct data indicates a need...... to revise assumptions regarding the basis of the method, which sometimes leads to the discovery of as-yet unnoticed phenomena. The present selection of automated methods for corrosion measurements is not motivated simply by the fact that a certain measurement can be performed automatically. Automation...

  3. Corrosion sensor

    Science.gov (United States)

    Glass, Robert S.; Clarke, Jr., Willis L.; Ciarlo, Dino R.

    1994-01-01

    A corrosion sensor array incorporating individual elements for measuring various elements and ions, such as chloride, sulfide, copper, hydrogen (pH), etc. and elements for evaluating the instantaneous corrosion properties of structural materials. The exact combination and number of elements measured or monitored would depend upon the environmental conditions and materials used which are subject to corrosive effects. Such a corrosion monitoring system embedded in or mounted on a structure exposed to the environment would serve as an early warning system for the onset of severe corrosion problems for the structure, thus providing a safety factor as well as economic factors. The sensor array is accessed to an electronics/computational system, which provides a means for data collection and analysis.

  4. Evolutionary Computation Techniques for Predicting Atmospheric Corrosion

    Directory of Open Access Journals (Sweden)

    Amine Marref

    2013-01-01

    Full Text Available Corrosion occurs in many engineering structures such as bridges, pipelines, and refineries and leads to the destruction of materials in a gradual manner and thus shortening their lifespan. It is therefore crucial to assess the structural integrity of engineering structures which are approaching or exceeding their designed lifespan in order to ensure their correct functioning, for example, carrying ability and safety. An understanding of corrosion and an ability to predict corrosion rate of a material in a particular environment plays a vital role in evaluating the residual life of the material. In this paper we investigate the use of genetic programming and genetic algorithms in the derivation of corrosion-rate expressions for steel and zinc. Genetic programming is used to automatically evolve corrosion-rate expressions while a genetic algorithm is used to evolve the parameters of an already engineered corrosion-rate expression. We show that both evolutionary techniques yield corrosion-rate expressions that have good accuracy.

  5. On-line Measurement of Boiler Tube Corrosion Rates using Dedicated EMAT (HT-EMAT) Phase 1

    Energy Technology Data Exchange (ETDEWEB)

    Borggreen, Kjeld (SydTek AB, Malmoe (Sweden))

    2009-06-15

    The project includes development of prototype HT-EMAT (High Temperature Electro Magnetic Acoustic Transducer) probes and testing of these in laboratory environment at high temperatures. The following results were obtained: Standard Alnico (Al-Ni-Co-Fe) magnets are sufficiently strong to drive a HT-EMAT probe in the magnetostrictive mode at temperatures up to 550 deg C. With a standard (diam)20 x 40 mm Alnico magnet, the number of turns in the coil using a 0.25 mm wire should be 25 - 30 to give optimum response and highest accuracy. The velocity of shear type sound waves in metals varies linearly with temperature in the interval considered. The prototype HT-EMAT only needs to be calibrated at room temperature, which is a simple procedure. If the temperature dependence of the velocity of the sound waves in steels is taking into account, the prototype probe gives excellent results at temperatures up to 550 deg C. The coil and the connection wire should preferably have a high electric conductivity to minimize damping, skin effects, and impedance mismatch, and also a high oxidation resistance. Pure copper and fine silver are the candidate materials for the HT-EMAT. Deposition of magnetostrictive layers on steel surfaces has been resolved. Magnetite seems as the only useful material until further. Thin layers of natural grown magnetite can be made by long term heat treatments. Thicker layers of artificial magnetite can be made by thermal spraying. Most of the reduction in efficiency of the HT-EMAT probe at high temperatures may be explained by the thermal dependence of the magnetostrictive constant for magnetite. Because the magnetostriction of magnetite disappears at its Curie temperature, the theoretical temperature limit for the HT-EMAT probe is foreseen to be 575 deg C. The prototype HT-EMAT performed well up to 550 deg C both during long time testing and at dynamic testing. The electronic and mechanical stabilities were excellent

  6. Effect of Sulfate-reducing Bacteria on Corrosion Behavior of Mild Steel in Sea Mud

    Institute of Scientific and Technical Information of China (English)

    Xiaodong ZHAO; Jizhou DUAN; Baorong HOU; Suru WU

    2007-01-01

    Microbiologically influenced corrosion (MIC) is very severe corrosion for constructions buried under sea mud environment. Therefore it is of great importance to carry out the investigation of the corrosion behavior of marine steel in sea mud. In this paper, the effect of sulfate-reducing bacteria (SRB) on corrosion behavior of mild steel in sea mud was studied by weight loss, dual-compartment cell, electronic probe microanalysis (EPMA), transmission electron microscopy (TEM) combined with energy dispersive X-ray analysis (EDX) and electrochemical impedance spectroscopy (EIS). The results showed that corrosion rate and galvanic current were influenced by the metabolic activity of SRB. In the environment of sea mud containing SRB, the original corrosion products, ferric (oxyhydr) oxide, transformed to iron sulfide. With the excess of the dissolved H2S, the composition of the protective layer formed of FeS transformed to FeS2 or other non-stoichiometric polysulphide, which changed the state of the former layer and accelerated the corrosion process.

  7. Fireside corrosion testing of candidate superheater tube alloys, coatings, and claddings - Phase II

    Energy Technology Data Exchange (ETDEWEB)

    Blough, J.L.; Krawchuk, M.T.; Van Weele, S.F. [Foster Wheeler Development Corp., Livingston, NJ (United States)

    1995-08-01

    A number of developmental and commercial tubing alloys and claddings have previously been exposed in Phase I to laboratory fireside corrosion testing simulating a superheater or reheater in a coal-fired boiler. This program is exposing samples of TP 347, RA-85H, HR-3C, 253MA, Fe{sub 3}Al + 5Cr, 310 modified, NF-709, 690 clad, and 671 clad, which showed good corrosion resistance from Phase 1, to the actual operating conditions of a 250-MW, coal-fired boiler. The samples were installed on air-cooled, retractable corrosion probes, installed in the reheater cavity, and are being controlled to the operating metal temperatures of an existing and advanced-cycle coal-fired boiler. The exposure will continue for 4000, 12,000, and 16,000 hours of operation. After the three exposure times, the samples will be metallurgically examined to determine the wastage rates and mode of attack. The probes were commissioned November 16, 1994. The temperatures are being recorded every 15 minutes, and the weighted average temperature calculated for each sample. Each of the alloys is being exposed to a temperature in each of two temperature bands-1150 to 1260{degrees}F and 1260 to 1325{degrees}F. After 2000 hours of exposure, one of the corrosion probes was cleaned and the wall thicknesses were ultrasonically measured. The alloy performance from the field probes will be discussed.

  8. Some observations on use of siliceous mineral waters in reduction of corrosion in RCC structures

    Digital Repository Service at National Institute of Oceanography (India)

    Venugopal, C.

    in the corrosion resistance performance of concrete exposed to sea water. Maximum reduction in the corrosion rate was observed in the concrete mixed with 10% gold tailing together with 10% flyash. The corrosion rate and polarisation resistance of the control...

  9. Polarization-corrosion behavior of commercial gold- and silver-base casting alloys in Fusayama solution.

    Science.gov (United States)

    Johnson, D L; Rinne, V W; Bleich, L L

    1983-12-01

    Based on polarization measurements, high Au alloys are highly corrosion-resistant and exhibit the lowest corrosion rates; intermediate Au, Ag, and Pd alloys with Cu are passive but exhibit higher corrosion rates. Twenty weight percent (w/o) In-Ag alloys exhibit active corrosion behavior at potentials only 100 mV noble to the corrosion potential.

  10. DPC materials and corrosion environments.

    Energy Technology Data Exchange (ETDEWEB)

    Ilgen, Anastasia Gennadyevna; Bryan, Charles R.; Teich-McGoldrick, Stephanie; Hardin, Ernest

    2014-10-01

    After an exposition of the materials used in DPCs and the factors controlling material corrosion in disposal environments, a survey is given of the corrosion rates, mechanisms, and products for commonly used stainless steels. Research needs are then identified for predicting stability of DPC materials in disposal environments. Stainless steel corrosion rates may be low enough to sustain DPC basket structural integrity for performance periods of as long as 10,000 years, especially in reducing conditions. Uncertainties include basket component design, disposal environment conditions, and the in-package chemical environment including any localized effects from radiolysis. Prospective disposal overpack materials exist for most disposal environments, including both corrosion allowance and corrosion resistant materials. Whereas the behavior of corrosion allowance materials is understood for a wide range of corrosion environments, demonstrating corrosion resistance could be more technically challenging and require environment-specific testing. A preliminary screening of the existing inventory of DPCs and other types of canisters is described, according to the type of closure, whether they can be readily transported, and what types of materials are used in basket construction.

  11. Corrosion of boiler tube alloys in refuse firing: Shredded vs bulk refuse

    Energy Technology Data Exchange (ETDEWEB)

    Krause, H.H. (Battelle, Columbus, OH (United States)); Daniel, P.L.; Blue, J.D. (Babcock Wilcox, Barberton, OH (United States))

    1994-08-01

    Results of corrosion probe exposures at two mass burning incinerators were compared with those conducted in a unit burning refuse-derived fuel. Tests were conducted with carbon steel, low-alloy steels, stainless steels, and high nickel-chromium alloys. Corrosion rates at similar metal and gas temperatures were essentially the same for both types of fuel. Boiler tube performance in the waterwalls of other incinerators confirmed these results. Boiler design and operating conditions appear to be more important factors in tube wastage than the extent of refuse processing.

  12. Evaluation of atmospheric corrosion on electroplated zinc and zinc nickel coatings by Electrical Resistance (ER) Monitoring

    DEFF Research Database (Denmark)

    Møller, Per

    2013-01-01

    ER (Electrical Resistance) probes provide a measurement of metal loss, measured at any time when a metal is exposed to the real environment. The precise electrical resistance monitoring system can evaluate the corrosion to the level of nanometers, if the conductivity is compensated for temperature...... for the automotive industry, off-shore construction or component and devices used in harsh industrial environments. The ER monitoring makes it possible to study the corrosion rate on-line in remote locations as a function of temperature, relative humidity and changes in the composition of the atmosphere. Different...

  13. Evaluation of MELTGUARD{sup TM} - a measuring system for control of fireside corrosion in boilers; Utvaerdering av MELTGUARD{sup TM} - ett maetsystem foer kontroll av roekgassidig korrosion i pannor

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, Pamela [Vattenfall Utveckling AB, Stockholm (Sweden)

    2001-10-01

    Studsvik AB has developed and now owns the patent for a product called MELTGUARD. According to information from Studsvik, Meltguard is a measuring probe that shows in real-time how much corrosion is occurring and that can reduce costs and increase the lifetime of power boilers burning biomass. The product consists of a tubular air-cooled probe which is exposed in the flue gas through an existing inspection port. The electrodes in the probe react with the flue gas and ash deposit and corrosion is registered as the short-circuited corrosion current (using the zero resistance method) between rings made of the investigated material. The aim of the project was to independently evaluate Meltguard, compare it with a conventional corrosion probe and to publish the results for the Swedish thermal power industry. Two steels have been compared on the probes (a Meltguard-probe can accommodate a maximum of two test pieces), with about the same temperature. Measurements have been carried out with the steels SS2218 (T22) and Esshete 1250 on a Meltguard probe in the biomass fired boiler at Naessjoe combined heat and power plant during the period November 2000 to March 2001. For a 48 hour period sulphur was added to the fuel supply to change the fuel chemistry and influence the corrosion rate. The corrosion current for SS2218 was unstable, fluctuating considerably throughout the measuring period, and was greatly affected by soot-blowing. Usually, soot-blowing resulted in a marked decrease in the corrosion current. No simple or clear relationship between the boiler load and the average corrosion current could be determined. The corrosion current for Esshete 1250 was mostly stable, about 20{mu}A. The current for SS2218 was a little higher than that for E1250, but the relationship between current and corrosion rate was unclear. It was obviously not a linear function as the corrosion measured in 2218, when the testing was completed, was approximately four times greater than that in E

  14. Probing the impact of loading rate on the mechanical properties of viral nanoparticles

    NARCIS (Netherlands)

    Snijder, J.; Ivanovska, I.L.; Baclayon, M.; Roos, W.H.; Wuite, G.J.L.

    2012-01-01

    The effects of changes in the loading rate during the forced dissociation of single bonds have been studied for a wide variety of interactions. Less is known on the loading rate dependent behaviour of more complex systems that consist of multiple bonds. Here we focus on viral nanoparticles, in

  15. Corrosion in airframes

    OpenAIRE

    PETROVIC ZORAN C.

    2016-01-01

    The introductory chapter provides a brief reference to the issue of corrosion and corrosion damage to aircraft structures. Depending on the nature and dimensions of this non uniformity, three different categories of corrosion are defined: uniform, selective and localized corrosion. The following chapters present the forms of corrosion that can occur in three defined categories of corrosion. Conditions that cause certain types of corrosion in various corrosive environments are discussed. Examp...

  16. CORROSION IN AIRFRAMES

    OpenAIRE

    PETROVIC ZORAN C.

    2016-01-01

    The introductory chapter provides a brief reference to the issue of corrosion and corrosion damage to aircraft structures. Depending on the nature and dimensions of this non uniformity, three different categories of corrosion are defined: uniform, selective and localized corrosion. The following chapters present the forms of corrosion that can occur in three defined categories of corrosion. Conditions that cause certain types of corrosion in various corrosive environments are discussed. Examp...

  17. Star Formation Rates, Metallicities, and Colours as Probes of Merger Timelines

    Science.gov (United States)

    Scudder, J. M.; Patton, D. R.; Ellison, S. L.; Torrey, P.; Mendel, J. T.

    2013-10-01

    Pairs of interacting galaxies show significant alterations to their colours, gas-phase metallicities, and SFRs. By investigating the spectroscopic and photometric properties of a sample of interacting galaxies, these changes can be probed. By exploiting the statistical power of the SDSS DR7, we construct a sample of interacting pairs with stringent selection criteria, and develop a methodology that allows us to significantly detect very small deviations for each pair in our sample, relative to a control sample. These deviations can then be interpreted as a function of projected separation. By subdividing the sample based on visual classifications of morphological disturbance, we are able to further investigate these shifts away from control values. We find that galaxies are affected by their encounter out to projected separations of at least 80 kpc h-1. Metallicities shift to significantly lower values over a broader range of projected separations for the morphologically selected sample. Through a comparison with theoretical models, we interpret the form of these trends as the signature of coalescing galaxies at small separations, and of post-pericentric galaxies blurred by projection effects at wider separations.

  18. A Multifunctional Coating for Autonomous Corrosion Control

    Science.gov (United States)

    Calle, L. M.; Hintze, P. E.; Li, W.; Buhrow, J. W.; Jolley, S. T.

    2011-01-01

    This slide presentation reviews the effects of corrosion on various structures at the Kennedy Space Center, and the work to discover a corrosion control coating that will be autonomous and will indicate corrosion at an early point in the process. Kennedy Space Center has many environmental conditions that are corrosive: ocean salt spray, heat, humidity, sunlight and acidic exhaust from the Solid Rocket Boosters (SRBs). Presented is a chart which shows the corrosion rates of carbon steel at various locations. KSC has the highest corrosion rates with 42.0 mils/yr, leading the next highest Galeta Point Beach, in the Panama Canal Zone with 27 mils/yr corrosion. A chart shows the changes in corrosion rate with the distance from the ocean. The three types of corrosion protective coatings are described: barrier (passive), Barrier plus active corrosion inhibiting components, and smart. A smart coating will detect and respond actively to changes in its environment in a functional and predictable manner and is capable of adapting its properties dynamically. The smart coating uses microcapsules, particles or liquid drops coated in polymers, that can detect and control the corrosion caused by the environment. The mechanism for a pH sensitive microcapsule and the hydrophobic core microcapsule are demonstrated and the chemistry is reviewed. When corrosion begins, the microcapsule will release the contents of the core (indicator, inhibitor, and self healing agent) in close proximity to the corrosion. The response to a pH increase is demonstrated by a series of pictures that show the breakdown of the microcapsule and the contents release. An example of bolt corrosion is used, as an example of corrosion in places that are difficult to ascertain. A comparison of various coating systems is shown.

  19. Titanium corrosion in alkaline hydrogen peroxide environments

    Science.gov (United States)

    Been, Jantje

    1998-12-01

    The corrosion of Grade 2 titanium in alkaline hydrogen peroxide environments has been studied by weight loss corrosion tests, electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) measurements and potentiodynamic polarography. Calcium ions and wood pulp were investigated as corrosion inhibitors. In alkaline peroxide, the titanium corrosion rate increased with increasing pH, temperature, and hydrogen peroxide concentration. The corrosion controlling mechanism is thought to be the reaction of the oxide with the perhydroxyl ion. No evidence of thermodynamically stable calcium titanate was found in the surface film of test coupons exposed to calcium-inhibited alkaline peroxide solutions. Calcium inhibition is probably the result of low local alkali and peroxide concentrations at the metal surface produced by reaction of adsorbed calcium with hydrogen peroxide. It has been shown that the inhibiting effect of calcium is temporary, possibly through an effect of calcium on the chemical and/or physical stability of the surface oxide. Pulp is an effective and stable corrosion inhibitor. Raising the pulp concentration decreased the corrosion rate. The inhibiting effect of pulp may be related to the adsorption and interaction of the pulp fibers with H 2O2, thereby decreasing the peroxide concentration and rendering the solution less corrosive. The presence of both pulp and calcium led to higher corrosion rates than obtained by either one inhibitor alone. Replacement of hydrofluoric acid with alkaline peroxide for pickling of titanium was investigated. Titanium corrosion rates in alkaline peroxide exceeded those obtained in the conventional hydrofluoric acid bath. General corrosion was observed with extensive roughening of the surface giving a dull gray appearance. Preferred dissolution of certain crystallographic planes was investigated through the corrosion of a titanium single crystal. Whereas the overall effect on the corrosion rate was small

  20. Rates of stellar tidal disruption as probes of the supermassive black hole mass function

    Science.gov (United States)

    Stone, Nicholas C.; Metzger, Brian D.

    2016-01-01

    Rates of stellar tidal disruption events (TDEs) by supermassive black holes (SMBHs) due to two-body relaxation are calculated using a large galaxy sample (N ≈ 200) in order to explore the sensitivity of the TDE rates to observational uncertainties, such as the parametrization of galaxy light profiles and the stellar mass function. The largest uncertainty arises due to the poorly constrained occupation fraction of SMBHs in low-mass galaxies, which otherwise dominate the total TDE rate. The detection rate of TDE flares by optical surveys is calculated as a function of SMBH mass and other observables for several physically motivated models of TDE emission. We also quantify the fraction of galaxies that produce deeply penetrating disruption events. If the majority of the detected events are characterized by super-Eddington luminosities (such as disc winds, or synchrotron radiation from an off-axis relativistic jet), then the measured SMBH mass distribution will tightly constrain the low-end SMBH occupation fraction. If Eddington-limited emission channels dominate, however, then the occupation fraction sensitivity is much less pronounced in a flux-limited survey (although still present in a volume-complete event sample). The SMBH mass distribution of the current sample of TDEs, though highly inhomogeneous and encumbered by selection effects, already suggests that Eddington-limited emission channels dominate. Even our most conservative rate estimates appear to be in tension with much lower observationally inferred TDE rates, and we discuss several possible resolutions to this discrepancy.

  1. Benefits from corrosion management of ORBEL-I pipeline; Resultados obtidos com o gerenciamento da corrosao do oleoduto ORBEL-I

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Aline de Souza [PETROBRAS Transporte S.A. (TRANSPETRO), Rio de Janeiro, RJ (Brazil); Fernandes Junior, Anibal Augusto; Viana, Flavio Godinho [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2005-07-01

    This work has for objective to present the results gotten with the management of the implanted internal corrosion in the pipeline Rio de Janeiro - Belo Horizonte I (ORBEL I), with 363 kilometers of extension and 18 inch of diameter. This management has for purpose to prevent and to control the corrosive process in the internal structure of the pipe through the identification of the basic causes of the corrosive process and the implantation of actions adjusted for the control of the process. The applied techniques and actions had been based on the described recommendations in the Communication Technique 116/99 No. - Management of the Corrosion of ORBEL I emitted for the Center of Research of PETROBRAS (CENPES). The applied actions had been: determination of the corrosion rate with the coupon use of loss of mass and probe, races of pig of cleanness, chemical analyses of the pumped product and the residue of corrosion, inhibitor injection and water reduction in the product. The results obtained show the decrease of corrosion rates and of corrosiveness of the products transported. (author)

  2. Accelerated corrosion testing results for specimens containing uncoated reinforcing steel and corrosion inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Kondratova, I. L.; Montes, P.; Bremner, T. W. [New Brunswick Univ., Dept, of Civil Engineering, Fredericton, NB (Canada)

    2000-07-01

    Concrete mixtures (water-cement ratios of 0.25, 0.40. or 0.60) containing uncoated reinforcing bars with a simulated crack, formed transverse to the axis of the bar, and with three commercial corrosion inhibitors added for corrosion protection (organic corrosion inhibitor,calcium nitrate-based corrosion inhibitor, and migratory corrosion inhibitor), were tested for corrosion damage. The objective was to evaluate the effectiveness of the different corrosion inhibitors in uncracked and cracked concrete slabs in a simulated marine environment. The specimens were placed in an accelerated exposure cabinet with four cycles of wetting and drying per day in simulated seawater, and corrosion rates measured using the linear polarization technique. Water-soluble chloride content in the rebars was analyzed at the end of the exposure period. The three corrosion inhibitors were found to show a wide variation in performance. There was a direct correlation between their effectiveness and addition rate. All three appeared to be more effective in reducing corrosion rate in a higher water-to-cement ratio concrete. Consistent performance was provided only by calcium nitrate at an addition rate of 25 litre/cu m of concrete, with water-to-cement ratios of 0.60 and 0.40. Pitting corrosion was observed in all pre-cracked high performance concrete specimens; the depth of the pit tended to be deeper when a corrosion inhibitor was used. 6 refs., 6 tabs., 6 figs.

  3. Plastic deformation effect of the corrosion resistance in case of austenitic stainless steel

    Science.gov (United States)

    Haraszti, F.; Kovacs, T.

    2017-02-01

    The corrosion forms are different in case of the austenitic steel than in case of carbon steels. Corrosion is very dangerous process, because that corrosion form is the intergranular corrosion. The austenitic stainless steel shows high corrosion resistance level. It knows that plastic deformation and the heat treating decrease it’s resistance. The corrosion form in case of this steel is very special and the corrosion tests are difficult. We tested the selected steel about its corrosion behaviour after high rate deformation. We wanted to find a relationship between the corrosion resistance decreasing and the rate of the plastic deformation. We wanted to show this behaviour from mechanical and electrical changing.

  4. Experiments probing the influence of air exchange rates on secondary organic aerosols derived from indoor chemistry

    DEFF Research Database (Denmark)

    Weschler, Charles J.; Shields, H.C.

    2003-01-01

    Reactions between ozone and terpenes have been shown to increase the concentrations of submicron particles in indoor settings. The present study was designed to examine the influence of air exchange rates on the concentrations of these secondary organic aerosols as well as on the evolution...

  5. Real Time Quantification of Ultrafast Photoinduced Bimolecular Electron Transfer Rate: Direct Probing of the Transient Intermediate.

    Science.gov (United States)

    Mukherjee, Puspal; Biswas, Somnath; Sen, Pratik

    2015-08-27

    Fluorescence quenching studies through steady-state and time-resolved measurements are inadequate to quantify the bimolecular electron transfer rate in bulk homogeneous solution due to constraints from diffusion. To nullify the effect of diffusion, direct evaluation of the rate of formation of a transient intermediate produced upon the electron transfer is essential. Methyl viologen, a well-known electron acceptor, produces a radical cation after accepting an electron, which has a characteristic strong and broad absorption band centered at 600 nm. Hence it is a good choice to evaluate the rate of photoinduced electron transfer reaction employing femtosecond broadband transient absorption spectroscopy. The time constant of the aforementioned process between pyrene and methyl viologen in methanol has been estimated to be 2.5 ± 0.4 ps using the same technique. The time constant for the backward reaction was found to be 14 ± 1 ps. These values did not change with variation of concentration of quencher, i.e., methyl viologen. Hence, we can infer that diffusion has no contribution in the estimation of rate constants. However, on changing the solvent from methanol to ethanol, the time constant of the electron transfer reaction has been found to increase and has accounted for the change in solvent reorganization energy.

  6. Probing the Rate-Determining Step of the Claisen-Schmidt Condensation by Competition Reactions

    Science.gov (United States)

    Mak, Kendrew K. W.; Chan, Wing-Fat; Lung, Ka-Ying; Lam, Wai-Yee; Ng, Weng-Cheong; Lee, Siu-Fung

    2007-01-01

    Competition experiments are a useful tool for preliminary study of the linear free energy relationship of organic reactions. This article describes a physical organic experiment for upper-level undergraduates to identify the rate-determining step of the Claisen-Schmidt condensation of benzaldehyde and acetophenone by studying the linear free…

  7. Waste of cleaning emulsion sewage as inhibitors of steel corrosion

    Science.gov (United States)

    Fazullin, D. D.; Mavrin, G. V.; Shaikhiev, I. G.

    2016-06-01

    The article describes the corrosion test of steel of the brand 20 in the stratal water. To increase corrosion resistance as a corrosion inhibitor the concentrate waste emulsion of the mark "Incam- 1" was provided. The article presents studies of the corrosion rate with different dosages of corrosion inhibitor in the stratal water. Based on these research results are revealed that the degree of protection of steel is 27% at a dosage of 3.8 g / dm3.

  8. General Corrosion and Localized Corrosion of Waste Package Outer Barrier

    Energy Technology Data Exchange (ETDEWEB)

    K.G. Mon

    2004-10-01

    The waste package design for the License Application is a double-wall waste package underneath a protective drip shield (BSC 2004 [DIRS 168489]; BSC 2004 [DIRS 169480]). The purpose and scope of this model report is to document models for general and localized corrosion of the waste package outer barrier (WPOB) to be used in evaluating waste package performance. The WPOB is constructed of Alloy 22 (UNS N06022), a highly corrosion-resistant nickel-based alloy. The inner vessel of the waste package is constructed of Stainless Steel Type 316 (UNS S31600). Before it fails, the Alloy 22 WPOB protects the Stainless Steel Type 316 inner vessel from exposure to the external environment and any significant degradation. The Stainless Steel Type 316 inner vessel provides structural stability to the thinner Alloy 22 WPOB. Although the waste package inner vessel would also provide some performance for waste containment and potentially decrease the rate of radionuclide transport after WPOB breach before it fails, the potential performance of the inner vessel is far less than that of the more corrosion-resistant Alloy 22 WPOB. For this reason, the corrosion performance of the waste package inner vessel is conservatively ignored in this report and the total system performance assessment for the license application (TSPA-LA). Treatment of seismic and igneous events and their consequences on waste package outer barrier performance are not specifically discussed in this report, although the general and localized corrosion models developed in this report are suitable for use in these scenarios. The localized corrosion processes considered in this report are pitting corrosion and crevice corrosion. Stress corrosion cracking is discussed in ''Stress Corrosion Cracking of the Drip Shield, the Waste Package Outer Barrier, and the Stainless Steel Structural Material'' (BSC 2004 [DIRS 169985]).

  9. Growth rate of matter perturbations as a probe of large-scale magnetism

    CERN Document Server

    Giovannini, Massimo

    2011-01-01

    The growth rate of matter perturbations is computed in a magnetized environment for the LambdaCDM and wCDM paradigms. It is argued that the baryons do not necessarily follow into the dark matter potential wells after they are released from the drag of the photons. The baryonic evolution equations inherit a forcing term whose explicit form depends on the plasma description and can be deduced, for instance, in the resistive magnetohydrodynamical approximation. After deriving an analytical expression for the growth rate applicable when dark energy does not cluster, the effects of relativistic corrections and of the inhomogeneities associated with the other species of the plasma are taken into account numerically. The spectral amplitudes and slopes of the stochastic magnetic background are selected to avoid appreciable distortions in the measured temperature and polarization anisotropies of the Cosmic Microwave Background. The growth of structures in the current paradigms of structure formation represents a compl...

  10. Probing the interplay between factors determining reaction rates on silica gel using termolecular systems.

    Science.gov (United States)

    Kirkpatrick, Iain; Worrall, David R; Williams, Siân L; Buck, Craig J T; Meseguer, Rafael G

    2012-10-01

    In this study we have compared energy and electron transfer reactions in termolecular systems using a nanosecond diffuse reflectance laser flash photolysis technique. We have previously investigated these processes on silica gel surfaces for bimolecular systems and electron transfer in termolecular systems. The latter systems involved electron transfer between three arene molecules with azulene acting as a molecular shuttle. In this study we present an alternative electron transfer system using trans β-carotene as an electron donor in order to effectively immobilise all species except the shuttle, providing the first unambiguous evidence for radical ion mobility. In the energy transfer system we use naphthalene, a structural isomer of azulene, as the shuttle, facilitating energy transfer from a selectively excited benzophenone sensitiser to 9-cyanoanthracene. Bimolecular rate constants for all of these processes have been measured and new insights into the factors determining the rates of these reactions on silica gel have been obtained.

  11. Self-heating probe instrument and method for measuring high temperature melting volume change rate of material

    Science.gov (United States)

    Wang, Junwei; Wang, Zhiping; Lu, Yang; Cheng, Bo

    2013-03-01

    The castings defects are affected by the melting volume change rate of material. The change rate has an important effect on running safety of the high temperature thermal storage chamber, too. But the characteristics of existing measuring installations are complex structure, troublesome operation and low precision. In order to measure the melting volume change rate of material accurately and conveniently, a self-designed measuring instrument, self-heating probe instrument, and measuring method are described. Temperature in heating cavity is controlled by PID temperature controller; melting volume change rate υ and molten density are calculated based on the melt volume which is measured by the instrument. Positive and negative υ represent expansion and shrinkage of the sample volume after melting, respectively. Taking eutectic LiF+CaF2 for example, its melting volume change rate and melting density at 1 123 K are -20.6% and 2 651 kg·m-3 measured by this instrument, which is only 0.71% smaller than literature value. Density and melting volume change rate of industry pure aluminum at 973 K and analysis pure NaCl at 1 123 K are detected by the instrument too. The measure results are agreed with report values. Measuring error sources are analyzed and several improving measures are proposed. In theory, the measuring errors of the change rate and molten density which are measured by the self-designed instrument is nearly 1/20-1/50 of that measured by the refitted mandril thermal expansion instrument. The self-designed instrument and method have the advantages of simple structure, being easy to operate, extensive applicability for material, relatively high accuracy, and most importantly, temperature and sample vapor pressure have little effect on the measurement accuracy. The presented instrument and method solve the problems of complicated structure and procedures, and large measuring errors for the samples with high vapor pressure by existing installations.

  12. Corrosion Fatigue in District Heating Water Tanks

    DEFF Research Database (Denmark)

    Maahn, Ernst Emanuel

    1996-01-01

    Three candidate materials for construction of buffer tanks for district heating water have been tested for corrosion fatigue properties in a district heating water environment. The investigation included Slow Strain Rate Testing of plain tensile specimens, crack initiation testing by corrosion...... fatigue of plain tensile specimens and crack growth rate determination for Compact Tensile Specimens under corrosion fatigue conditions. The three materials are equal with respect to stress corrosion sensibility and crack initiation. Crack growth rate is increased with a factor of 4-6 relative to an inert...

  13. Spatial correlations of the spontaneous decay rate as a probe of dense and correlated disordered materials

    CERN Document Server

    Leseur, Olivier; Carminati, Rémi

    2016-01-01

    We study theoretically and numerically a new kind of spatial correlation for waves in disordered media. We define $C_{\\Gamma}$ as the correlation function of the fluorescent decay rate of an emitter at two different positions inside the medium. We show that the amplitude and the width of $C_{\\Gamma}$ provide decoupled information on the structural correlation of the disordered medium and on the local environment of the emitter. This result may stimulate the emergence of new imaging and sensing modalities in complex media.

  14. “Dhoulath's method” – An investigative probe into mortality rate to aid diagnoses

    Directory of Open Access Journals (Sweden)

    J. Dhoulath Beegum

    2016-09-01

    Full Text Available Inspired by the urgent need to save life, during cardiac arrest, time is an important factor, and time factors, if not speeded up, may lead to death. Baby cries proved to be an obstacle for cardiac diagnosis. To speed up the diagnoses, ‘Dhoulath's method’ was proposed and result proved that the data quality of cardiac data, ‘aortic regurgitation sound’ from a mixture of ‘crying baby's cry’ was faithfully separated out. This separation, by utilizing the features of blind source component separation, in the case of medical emergency, can lead to a speedy diagnoses, to reduce the mortality rate.

  15. Probing Mechanisms for Inverse Correlation between Rate Performance and Capacity in K-O2 Batteries.

    Science.gov (United States)

    Xiao, Neng; Ren, Xiaodi; He, Mingfu; McCulloch, William D; Wu, Yiying

    2017-02-08

    Owing to the formation of potassium superoxide (K(+) + O2 + e(-) = KO2), K-O2 batteries exhibit superior round-trip efficiency and considerable energy density in the absence of any electrocatalysts. For further improving the practical performance of K-O2 batteries, it is important to carry out a systematic study on parameters that control rate performance and capacity to comprehensively understand the limiting factors in superoxide-based metal-oxygen batteries. Herein, we investigate the influence of current density and oxygen diffusion on the nucleation, growth, and distribution of potassium superoxide (KO2) during the discharge process. It is observed that higher current results in smaller average sizes of KO2 crystals but a larger surface coverage on the carbon fiber electrode. As KO2 grows and covers the cathode surface, the discharge will eventually end due to depletion of the oxygen-approachable electrode surface. Additionally, higher current also induces a greater gradient of oxygen concentration in the porous carbon electrode, resulting in less efficient loading of the discharge product. These two factors explain the observed inverse correlation between current and capacity of K-O2 batteries. Lastly, we demonstrate a reduced graphene oxide-based K-O2 battery with a large specific capacity (up to 8400 mAh/gcarbon at a discharge rate of 1000 mA/gcarbon) and a long cycle life (over 200 cycles).

  16. Underground pipeline corrosion

    CERN Document Server

    Orazem, Mark

    2014-01-01

    Underground pipelines transporting liquid petroleum products and natural gas are critical components of civil infrastructure, making corrosion prevention an essential part of asset-protection strategy. Underground Pipeline Corrosion provides a basic understanding of the problems associated with corrosion detection and mitigation, and of the state of the art in corrosion prevention. The topics covered in part one include: basic principles for corrosion in underground pipelines, AC-induced corrosion of underground pipelines, significance of corrosion in onshore oil and gas pipelines, n

  17. Effect of corrosion on flexural bond strength

    Directory of Open Access Journals (Sweden)

    Akshatha Shetty

    2014-09-01

    Full Text Available Corrosion is one of the main causes affecting durability of structures. Corrosion effects on structures cannot be ignored and replaced. To understand the performance of structures there is a need to study the rate at which different corrosion levels occur. Hence the present investigation has been taken up to study the behaviour of NBS (National Bureau of Standard beam specimens made up of Ordinary Portland Cement (OPC and Portland Pozzolona Cement (PPC concrete matrix were subjected to accelerated corrosion for different corrosion levels of 2.5 % to 10 % at 2.5 % interval. Results are compared with those for control beam specimen. It is observed that bond stress value decreases with the increase in corrosion levels. Also corrosion leads to the decline of load carrying capacity.

  18. Initial measurements of O-ion and He-ion decay rates observed from the Van Allen probes RBSPICE instrument.

    Science.gov (United States)

    Gerrard, Andrew; Lanzerotti, Louis; Gkioulidou, Matina; Mitchell, Donald; Manweiler, Jerry; Bortnik, Jacob; Keika, Kunihiro

    2014-11-01

    H-ion (∼45 keV to ∼600 keV), He-ion (∼65 keV to ∼520 keV), and O-ion (∼140 keV to ∼1130 keV) integral flux measurements, from the Radiation Belt Storm Probe Ion Composition Experiment (RBSPICE) instrument aboard the Van Allan Probes spacecraft B, are reported. These abundance data form a cohesive picture of ring current ions during the first 9 months of measurements. Furthermore, the data presented herein are used to show injection characteristics via the He-ion/H-ion abundance ratio and the O-ion/H-ion abundance ratio. Of unique interest to ring current dynamics are the spatial-temporal decay characteristics of the two injected populations. We observe that He-ions decay more quickly at lower L shells, on the order of ∼0.8 day at L shells of 3-4, and decay more slowly with higher L shell, on the order of ∼1.7 days at L shells of 5-6. Conversely, O-ions decay very rapidly (∼1.5 h) across all L shells. The He-ion decay time are consistent with previously measured and calculated lifetimes associated with charge exchange. The O-ion decay time is much faster than predicted and is attributed to the inclusion of higher-energy (> 500 keV) O-ions in our decay rate estimation. We note that these measurements demonstrate a compelling need for calculation of high-energy O-ion loss rates, which have not been adequately studied in the literature to date.

  19. Recent Natural Corrosion Inhibitors for Mild Steel: An Overview

    Directory of Open Access Journals (Sweden)

    Marko Chigondo

    2016-01-01

    Full Text Available Traditionally, reduction of corrosion has been managed by various methods including cathodic protection, process control, reduction of the metal impurity content, and application of surface treatment techniques, as well as incorporation of suitable alloys. However, the use of corrosion inhibitors has proven to be the easiest and cheapest method for corrosion protection and prevention in acidic media. These inhibitors slow down the corrosion rate and thus prevent monetary losses due to metallic corrosion on industrial vessels, equipment, or surfaces. Inorganic and organic inhibitors are toxic and costly and thus recent focus has been turned to develop environmentally benign methods for corrosion retardation. Many researchers have recently focused on corrosion prevention methods using green inhibitors for mild steel in acidic solutions to mimic industrial processes. This paper provides an overview of types of corrosion, corrosion process, and mainly recent work done on the application of natural plant extracts as corrosion inhibitors for mild steel.

  20. Corrosion studies in brines of the Salton Sea Geothermal Field

    Energy Technology Data Exchange (ETDEWEB)

    Carter, J.P.; McCawley, F.X.; Cramer, S.D.; Needham, P.B. Jr.

    1979-01-01

    Toward the goal of maximizing minerals and metals recovery from domestic resources, the Bureau of Mines, U.S. Department of the Interior, has conducted in situ corrosion studies at the Salton Sea Known Geothermal Resources Area (KGRA) in the Imperial Valley, Calif., to evaluate and characterize materials of construction for geothermal resources recovery plants. General-, pitting, and crevice-corrosion characteristics of 13 commercially available alloys were investigated for periods of 15 and 30 days in seven process environments expected to be found in typical geothermal resources plants. Stainless steel alloy 29-4, Inconel 625, and the Hastelloys G, S, and C-276 were the most resistant to general corrosion, did not pit, and exhibited little susceptibility to crevice corrosion. Stainless steel alloys 430, E-Brite 26-1, and 6X had low general corrosion rates, but pitted and were susceptible to crevice corrosion. Stainless steel alloy 316 L had a low corrosion rate, but corroded intergranularly, pitted, and was susceptible to crevice corrosion and to stress-corrosion cracking. Titanium--1.5 nickel and TiCode-12 had low corrosion rates, did not pit, and were not susceptible to crevice corrosion. Carbon and 4130 steels had high corrosion rates, pitted, and had high susceptibilities to crevice corrosion. The major scale-forming mineral on the corrosion samples in most of the process environments studied was galena mixed with lesser amounts of other minerals.

  1. Probing the peak of the star formation rate density with the extragalactic background light

    CERN Document Server

    Raue, Martin

    2012-01-01

    The extragalactic background light (EBL), i.e., the diffuse meta-galactic photon field in the ultraviolet to infrared, is dominated by the emission from stars in galaxies. It is, therefore, intimately connected with the integrated star formation rate density (SFRD). In this paper, the SFRD is constrained using recent limits on the EBL density derived from observations of distant sources of high and very-high energy gamma-rays. The stellar EBL contribution is modeled utilizing simple stellar population spectra including dust attenuation and emission. A wide range of values for the different model parameters (SFRD(z), metallicity, dust absorption) is investigated and their impact on the resulting EBL is studied. The calculated EBL densities are compared with the specific EBL density limits and constraints on the SFRD are derived. For the fiducial model, adopting a Chabrier initial mass function (IMF), the SFRD is constrained to ~< 0.1 M_solar yr^-1 Mpc^-3 and < 0.2 M_solar yr^-1 Mpc^-3 for a redshift of z...

  2. The rate of quasiparticle recombination probes the onset of coherence in cuprate superconductors.

    Science.gov (United States)

    Hinton, J P; Thewalt, E; Alpichshev, Z; Mahmood, F; Koralek, J D; Chan, M K; Veit, M J; Dorow, C J; Barišić, N; Kemper, A F; Bonn, D A; Hardy, W N; Liang, Ruixing; Gedik, N; Greven, M; Lanzara, A; Orenstein, J

    2016-04-13

    In the underdoped copper-oxides, high-temperature superconductivity condenses from a nonconventional metallic "pseudogap" phase that exhibits a variety of non-Fermi liquid properties. Recently, it has become clear that a charge density wave (CDW) phase exists within the pseudogap regime. This CDW coexists and competes with superconductivity (SC) below the transition temperature Tc, suggesting that these two orders are intimately related. Here we show that the condensation of the superfluid from this unconventional precursor is reflected in deviations from the predictions of BSC theory regarding the recombination rate of quasiparticles. We report a detailed investigation of the quasiparticle (QP) recombination lifetime, τqp, as a function of temperature and magnetic field in underdoped HgBa2CuO(4+δ) (Hg-1201) and YBa2Cu3O(6+x) (YBCO) single crystals by ultrafast time-resolved reflectivity. We find that τqp(T) exhibits a local maximum in a small temperature window near Tc that is prominent in underdoped samples with coexisting charge order and vanishes with application of a small magnetic field. We explain this unusual, non-BCS behavior by positing that Tc marks a transition from phase-fluctuating SC/CDW composite order above to a SC/CDW condensate below. Our results suggest that the superfluid in underdoped cuprates is a condensate of coherently-mixed particle-particle and particle-hole pairs.

  3. The rate of quasiparticle recombination probes the onset of coherence in cuprate superconductors

    Science.gov (United States)

    Hinton, J. P.; Thewalt, E.; Alpichshev, Z.; Mahmood, F.; Koralek, J. D.; Chan, M. K.; Veit, M. J.; Dorow, C. J.; Barišić, N.; Kemper, A. F.; Bonn, D. A.; Hardy, W. N.; Liang, Ruixing; Gedik, N.; Greven, M.; Lanzara, A.; Orenstein, J.

    2016-04-01

    In the underdoped copper-oxides, high-temperature superconductivity condenses from a nonconventional metallic ”pseudogap” phase that exhibits a variety of non-Fermi liquid properties. Recently, it has become clear that a charge density wave (CDW) phase exists within the pseudogap regime. This CDW coexists and competes with superconductivity (SC) below the transition temperature Tc, suggesting that these two orders are intimately related. Here we show that the condensation of the superfluid from this unconventional precursor is reflected in deviations from the predictions of BSC theory regarding the recombination rate of quasiparticles. We report a detailed investigation of the quasiparticle (QP) recombination lifetime, τqp, as a function of temperature and magnetic field in underdoped HgBa2CuO4+δ (Hg-1201) and YBa2Cu3O6+x (YBCO) single crystals by ultrafast time-resolved reflectivity. We find that τqp(T ) exhibits a local maximum in a small temperature window near Tc that is prominent in underdoped samples with coexisting charge order and vanishes with application of a small magnetic field. We explain this unusual, non-BCS behavior by positing that Tc marks a transition from phase-fluctuating SC/CDW composite order above to a SC/CDW condensate below. Our results suggest that the superfluid in underdoped cuprates is a condensate of coherently-mixed particle-particle and particle-hole pairs.

  4. A novel technique for measuring stress-corrosion crack-growth rates in single-crystal experiments

    Energy Technology Data Exchange (ETDEWEB)

    Lichter, B.D. [Vanderbilt Univ., Nashville, TN (United States)]|[Delft Univ. of Technology (Netherlands); Flanagan, W.F. [Vanderbilt Univ., Nashville, TN (United States)

    1994-12-31

    Crack-growth occurs discontinuously in oriented copper-gold single-crystals during slow-strain rate experiments performed under anodic polarization in aqueous NaCl solutions. Crack advance between major crack arrests is accompanied by load-drops and current-transients which can be quantitatively related to the length of the advance as well as yielding the average instantaneous rate of advance. Two independent but self-consistent methods are used: (1) mechanical analysis of the load-drops, taking into account the elastic displacement of the load-train and of the specimen, due to both the load and the crack advance, and (2) analysis of the current-transients in which it is argued that the current is proportional to the rate of new surface production. Results show that the crack velocity is on the order of 50--400{mu}/s, depending on the environment and potential, too slow to be explained by a running brittle crack, and too fast to be explained by Faradaic dissolution.

  5. TO THE QUESTION ABOUT THE INFLUENCE OF THE STRESSES IN THE ELEMENTS OF THE REINFORCEMENT SHAFTS AT THE RATE OF CORROSION

    Directory of Open Access Journals (Sweden)

    V. V. Kovalenko

    2008-03-01

    Full Text Available On the basis of laboratory explorations the features of conducting the corrosive process in the shaft reinforcement parts under the load from lifting buckets and rock mass were determined.

  6. Site-specific interaction between α-synuclein and membranes probed by NMR-observed methionine oxidation rates.

    Science.gov (United States)

    Maltsev, Alexander S; Chen, Jue; Levine, Rodney L; Bax, Ad

    2013-02-27

    α-Synuclein (αS) is an intrinsically disordered protein that is water-soluble but also can bind negatively charged lipid membranes while adopting an α-helical conformation. Membrane affinity is increased by post-translational N-terminal acetylation, a common modification in all eukaryotic cells. In the presence of lipid vesicles containing a small fraction of peroxidized lipids, the N-terminal Met residues in αS (Met1 and Met5) rapidly oxidize while reducing the toxic lipid hydroperoxide to a nonreactive lipid hydroxide, whereas C-terminal Met residues remain unaffected. Met oxidation can be probed conveniently and quantitatively by NMR spectroscopy. The results show that oxidation of Met1 reduces the rate of oxidation of Met5 and vice versa as a result of decreased membrane affinity of the partially oxidized protein. The effect of Met oxidation on the αS-membrane affinity extends over large distances, as in the V49M mutant, oxidation of Met1 and Met5 strongly impacts the oxidation rate of Met49 and vice versa. When not bound to membrane, oxidized Met1 and Met5 of αS are excellent substrates for methionine sulfoxide reductase (Msr), thereby providing an efficient vehicle for water-soluble Msr enzymes to protect the membrane against oxidative damage.

  7. effect of municipal liquid waste on corrosion susceptibility of ...

    African Journals Online (AJOL)

    DR. AMINU

    The corrosion rate of the galvanized steel pipe was measured using the gravimetric technique. ... three stagnant liquid waste samples collected outside the city (SLW4,SLW5, and ... increased exposure time, a layer of protective corrosion ...

  8. Corrosion-Activated Micro-Containers for Environmentally Friendly Corrosion Protective Coatings

    Science.gov (United States)

    Li, Wenyan; Buhrow, J. W.; Zhang, X.; Johnsey, M. N.; Pearman, B. P.; Jolley, S. T.; Calle, L. M.

    2016-01-01

    This work concerns the development of environmentally friendly encapsulation technology, specifically designed to incorporate corrosion indicators, inhibitors, and self-healing agents into a coating, in such a way that the delivery of the indicators and inhibitors is triggered by the corrosion process, and the delivery of self-healing agents is triggered by mechanical damage to the coating. Encapsulation of the active corrosion control ingredients allows the incorporation of desired autonomous corrosion control functions such as: early corrosion detection, hidden corrosion detection, corrosion inhibition, and self-healing of mechanical damage into a coating. The technology offers the versatility needed to include one or several corrosion control functions into the same coating.The development of the encapsulation technology has progressed from the initial proof-of-concept work, in which a corrosion indicator was encapsulated into an oil-core (hydrophobic) microcapsule and shown to be delivered autonomously, under simulated corrosion conditions, to a sophisticated portfolio of micro carriers (organic, inorganic, and hybrid) that can be used to deliver a wide range of active corrosion ingredients at a rate that can be adjusted to offer immediate as well as long-term corrosion control. The micro carriers have been incorporated into different coating formulas to test and optimize the autonomous corrosion detection, inhibition, and self-healing functions of the coatings. This paper provides an overview of progress made to date and highlights recent technical developments, such as improved corrosion detection sensitivity, inhibitor test results in various types of coatings, and highly effective self-healing coatings based on green chemistry. The NASA Kennedy Space Centers Corrosion Technology Lab at the Kennedy Space Center in Florida, U.S.A. has been developing multifunctional smart coatings based on the microencapsulation of environmentally friendly corrosion

  9. Corrosion Testing Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Corrosion Testing Facility is part of the Army Corrosion Office (ACO). It is a fully functional atmospheric exposure site, called the Corrosion Instrumented Test...

  10. Acoustic Emission Quantification Evaluation Method Research of Tank Bottom Corrosion Based on Risk Corrosion Rate%基于风险腐蚀速率的储罐底板腐蚀声发射量化评价方法研究

    Institute of Scientific and Technical Information of China (English)

    戴光; 邱枫; 张颖; 赵永涛; 刘延军

    2012-01-01

    According to reference [ 8 ], based on the statistical theory, bringing in risk concept, the acoustic emission testing and magnetic flux leakage testing data of tank bottom corrosion were comprehensively analysed, and then the quantification method of the acoustic emission parameter based on the testing data of the magnetic flux leakage which was about tank bottom corrosion was got. Through the analysis of the 6 tanks,the quantification relationship between the acoustic emission typical parameter of a class of tanks which held crude oil medium and tank bottom corrosion was got in an area, the relationship between a-coustic emission activity and risk corrosion rate of CRP is y = 13946. 9758x,the relationship between CRP and actual corrosion rate CTP is y - 12. 0412x. Testing the tanks which need evaluate with acoustic e-mission, using the evaluation model, CRP can be got and then management corrosion rate of CMP can be got, the basis of management and maintenance decision of tank can be provided for.%基于统计理论,引入风险概念,综合分析储罐底板腐蚀的声发射检测和漏磁检测数据,得到基于漏磁检测数据的声发射参量对储罐底板腐蚀的量化方法.通过对6台储罐的分析,得到某一地区介质为原油的一类储罐的声发射典型参量与储罐底板腐蚀的量化关系,即声发射活度与风险腐蚀速率CRP的关系为:y=13946.9758x,得到CRP与实际腐蚀速率CTP的关系为:y=12.0412x.对评估储罐进行声发射检测,利用该评价模型可得到CRP,进而得到管理腐蚀速率CMP,为储罐管理维修决策提供依据.

  11. The oxidation and corrosion of ODS alloys

    Science.gov (United States)

    Lowell, Carl E.; Barrett, Charles A.

    1990-01-01

    The oxidation and hot corrosion of high temperature oxide dispersion strengthened (ODS) alloys are reviewed. The environmental resistance of such alloys are classified by oxide growth rate, oxide volatility, oxide spalling, and hot corrosion limitations. Also discussed are environmentally resistant coatings for ODS materials. It is concluded that ODS NiCrAl and FeCrAl alloys are highly oxidation and corrosion resistant and can probably be used uncoated.

  12. Oxidation And Hot Corrosion Of ODS Alloy

    Science.gov (United States)

    Lowell, Carl E.; Barrett, Charles A.

    1993-01-01

    Report reviews oxidation and hot corrosion of oxide-dispersion-strengthened (ODS) alloys, intended for use at high temperatures. Classifies environmental resistances of such alloys by rates of growth of oxides, volatilities of oxides, spalling of oxides, and limitations imposed by hot corrosion. Also discusses environmentally resistant coatings for ODS materials. Concludes ODS NICrAl and FeCrAl alloys highly resistant to oxidation and corrosion and can be used uncoated.

  13. Influence of Deposit Formation on Corrosion at a Straw Fired boiler

    DEFF Research Database (Denmark)

    Hansen, Lone Aslaug; Michelsen, Hanne Philbert; Frandsen, Flemming;

    2000-01-01

    Straw-fired boilers generally experience severe problems with deposit formation and are expected to suffer from severe superheater corrosion at high steam temperatures due to the large alkali and chlorine content in straw. In this study, deposits collected (1) on air-cooled probes and (2) directly...... at the existing heat transfer surfaces of a straw-fired boiler have been examined. Deposits collected on air-cooled probes were found to consist of an inner layer of KCl and an outer layer of sintered fly ash. Ash deposits formed on the heat transfer surfaces all had a characteristic layered structure......, with a dense layer of K2SO4 present adjacent to the metal surface. It is argued that the K2SO4 layer present adjacent to the metal surface may lead to reduced corrosion rates at this boiler. A discussion of the deposit structure, the K2SO4 layer formation mechanism, and the influence of the inner layer...

  14. Probe Oscillation Shear Elastography (PROSE): A High Frame-Rate Method for Two-Dimensional Ultrasound Shear Wave Elastography.

    Science.gov (United States)

    Mellema, Daniel C; Song, Pengfei; Kinnick, Randall R; Urban, Matthew W; Greenleaf, James F; Manduca, Armando; Chen, Shigao

    2016-09-01

    Ultrasound shear wave elastography (SWE) utilizes the propagation of induced shear waves to characterize the shear modulus of soft tissue. Many methods rely on an acoustic radiation force (ARF) "push beam" to generate shear waves. However, specialized hardware is required to generate the push beams, and the thermal stress that is placed upon the ultrasound system, transducer, and tissue by the push beams currently limits the frame-rate to about 1 Hz. These constraints have limited the implementation of ARF to high-end clinical systems. This paper presents Probe Oscillation Shear Elastography (PROSE) as an alternative method to measure tissue elasticity. PROSE generates shear waves using a harmonic mechanical vibration of an ultrasound transducer, while simultaneously detecting motion with the same transducer under pulse-echo mode. Motion of the transducer during detection produces a "strain-like" compression artifact that is coupled with the observed shear waves. A novel symmetric sampling scheme is proposed such that pulse-echo detection events are acquired when the ultrasound transducer returns to the same physical position, allowing the shear waves to be decoupled from the compression artifact. Full field-of-view (FOV) two-dimensional (2D) shear wave speed images were obtained by applying a local frequency estimation (LFE) technique, capable of generating a 2D map from a single frame of shear wave motion. The shear wave imaging frame rate of PROSE is comparable to the vibration frequency, which can be an order of magnitude higher than ARF based techniques. PROSE was able to produce smooth and accurate shear wave images from three homogeneous phantoms with different moduli, with an effective frame rate of 300 Hz. An inclusion phantom study showed that increased vibration frequencies improved the accuracy of inclusion imaging, and allowed targets as small as 6.5 mm to be resolved with good contrast (contrast-to-noise ratio ≥ 19 dB) between the target and

  15. Influence of the operating parameters over the current efficiency and corrosion rate in the Hall-Heroult aluminum cell with tin oxide anode substrate material

    Institute of Scientific and Technical Information of China (English)

    Virgil Constantin

    2015-01-01

    A systematic laboratory study was conducted on current efficiency and corrosion obtalned in cryolite–alumina melts with SnO2–Sb2O3–CuO ceramic inert anodes. The current efficiency (CE) was determined by measuring the total amount of oxygen evolved at the anode and was found to be~95%. The influence of operating parameters (inter-elec-trode distance, temperature and current density) was evaluated. The quantitative interdependencies as wel as the ranges of CE optimal values were established (2–3 cm, 940–960 °C and 0.7–0.8 A·cm−2). The corrosion process of these anodes was evaluated by the mass loss method. The evaluation also took care of the corrosion data, as the prob-lem of the anode corrosion appeared to be the maln obstacle for the use of those anodes in the commercial cel s. Low-ering of the ACD up to 2 cm did not aggravate anode corrosion.

  16. Relationship between Corrosion Level of Rebar Embedded in Concrete, Corrosion Potential and Current Density Measured by Non-destructive Test Method

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Lan; Cho, Seung Ho; Roh, Young Sook [Dankook University, Seoul (Korea, Republic of); Kim, Joong Koo [Korean Precision Industrial Co., Pohang (Korea, Republic of)

    2004-10-15

    The purpose of this study is to identify corrosion mechanism and develop qualitative measurement method of corrosion level. Fist of all, structural behavior of each different level of corrosion states have been evaluated. And mathematical models that can predict corrosion level in terms of electric potential and corrosion intensity are proposed. Corrosion rate in reinforcing bar was investigated in this study using accelerated corrosion method due to electric potential differences based on Faradays law. Total 288 measurement spots were designed in terms of corrosion rates, diameter of reinforcing bars, and concrete cover thickness. Corrosion current densities and corrosion potentials of concrete were measured on these specimens using Gecor device. This study suggested the relationship between corrosion levels, and measured electric current density as follows.

  17. New corrosion issues in gas sweetening plants

    Energy Technology Data Exchange (ETDEWEB)

    Asperger, R.G. (CLI International and Asperger Technologies, Houston, TX (United States))

    Gas treating plants are experiencing corrosion problems which impact on efficiency and safety. While general corrosion is not particularly hazardous in the gas processing industry, local corrosion is very dangerous since it has several different mechanisms, all of which have dangerously high rates, and it occurs at locations which are hard to find and hard to predict. A newly discovered, velocity-dependent type of corrosion is reported. It is related to yet-undefined species which cause excessively high corrosion in areas of turbulence. This accelerated corrosion is not due to erosion or cavitation, but to a diffusion-limited reaction accelerated by turbulence. A full-flow test loop was built to evaluate the corrosiveness of gas plant solutions at their normal temperature and flow rates. Test runs were conducted with Co[sub 2]-loaded amine solutions for periods of 12 days. Carbon steel specimens mounted in the test loop were examined and corrosion rates calculated. Chromium alloys were shown to be attacked by corrodents in the low-velocity part of the loop and very aggressively attacked in the high-velocity part. The tests demonstrate the need for rigorous monitoring of corrosion in areas of higher velocity such as piping elbows and other points of turbulence. 5 refs., 2 figs., 3 tabs.

  18. Corrosion of oil-fired domestic boilers

    Energy Technology Data Exchange (ETDEWEB)

    Koebel, M.; Elsener, M.

    1989-05-01

    Depending on the surface temperature of the flue gas side the corrosion of oil fired domestic boilers proceeds either mainly by acid corrosion or by oxygen corrosion: (1) At surface temperatures of 60/sup 0/C and higher the corrosion mechanism of acid corrosion prevails and the corrosion rates amount to 0.1-0.3 mm/year (values referred to continuous burner operation). The corrosion products consist of soluble iron(II)- and iron(III)sulfates. Higher corrosion rates can be attributed to an appreciable catalytic formation of sulfur trioxide on the corrosion products formed on the convective heating surfaces. (2) At surface temperatures of 40/sup 0/C the mechanism of oxygen corrosion already dominates and the corrosion rates are about ten times higher (1.5-3 mm/year, referred to continuous burner operation). The high portion of iron oxide hydrates, especially goethit (/alpha/-FeOOH), makes the corrosion products difficult to remove. (3) Distinctly reduced service lives are also expected for the so called reduced temperature boilers ('Niedertemperaturkessel') and low temperature boilers ('Tieftemperaturkessel'): According to the manufacturers these boilers may be operated at boiler water temperatures well below 60/sup 0/C, as they are equipped with constructive measures to enhance the surface temperature on the flue gas side. However, these measures are only fully effective under stationary conditions. Some of the results were obtained from weight loss measurements on test specimen made from St 35.8 and gray cast iron, that were exposed to the flue gases of an fired experimental boiler. Other important results come from field measurements of the sulfuric acid content of about 30 boilers that are in practical use. (orig.).

  19. Effect of silty sand with different sizes on corrosion behavior of 3Cr steel in CO2 aqueous environment

    Science.gov (United States)

    Liu, Wei; Lu, Songle; Zhang, Peng; Dou, Juanjuan; Zhao, Qinghe

    2016-08-01

    Corrosion behavior of 3Cr steel in CO2 aqueous environment containing silty sand was investigated by immersion test. The results show that CO2 corrosion rate and morphology of 3Cr steel were obviously affected by the size of silty sand. 5000 mesh silty sand mixed with corrosion products, forming compact Cr-rich corrosion scale and resulting in low corrosion rate and uniform corrosion. 1000 mesh silty sand mixed with corrosion products, forming porous corrosion scale without Cr enrichment and resulting in high corrosion rate and pitting corrosion. 5000 mesh silty sand enhanced Cr enrichment in corrosion scale, leading to low anodic current. However, 1000 mesh silty sand deteriorated Cr enrichment in corrosion scale, leading to high anodic current. Cathodic current was reduced by silty sand, but was not affected by two sizes of silty sand. Cr enrichment in corrosion scale of 3Cr steel was obviously affected by separation effect of silty sand.

  20. Landau-Squire jet as a versatile probe to measure flow rate through individual nanochannel and nanotubes

    Science.gov (United States)

    Secchi, Eleonora; Marbach, Sophie; Siria, Alessandro; Bocquet, Lyderic

    2015-11-01

    Over the last decade, nanometric sized channels have been intensively investigated since new model of fluid transport are expected due to the flow confinement at the nanometric scale. Nanoconfinement generates new phenomena, such as superfast flows in carbon nanotubes and slippage over smooth surfaces. However, a major challenge of nanofluidics lies in fabricating nanoscale fluidic devices and developing new velocimetry techniques able to measure flow rates down to femtoL/s. In this work we report the experimental study of the velocity fields generated by pressure driven flow from glass nanochannel with a diameter ranging from 1 μm to 100nm. The flow emerging from these channels can be described by the classical Landau-Squire solution of the Navier-Stokes equation for a point jet. We show that due to the peculiarity of this flow, it can be used as an efficient probe to characterize the permeability of nanochannels. Velocity field is measured experimentally seeding the fluid in the reservoir with 500 nm Polystyrene particles and measuring the velocity with a standard PIV algorithm. Predictions are tested for nanochannels of several dimensions and supported by ionic current measurement. This demonstrates that this technique is a powerful tool to characterize the flow through nanochannels. We finally apply this method to the measurement of the flow emerging from a single carbon nanotube inserted in the nanochannels and present first data of permeability measurement through a single nanotube.

  1. Kalman Filtering and Smoothing of the Van Allen Probes Observations to Estimate the Radial, Energy and Pitch Angle Diffusion Rates

    Science.gov (United States)

    Podladchikova, T.; Shprits, Y.; Kellerman, A. C.

    2015-12-01

    The Kalman filter technique combines the strengths of new physical models of the Earth's radiation belts with long-term spacecraft observations of electron fluxes and therefore provide an extremely useful method for the analysis of the state and evolution of the electron radiation belts. However, to get the reliable data assimilation output, the Kalman filter application is confronted with a set of fundamental problems. E.g., satellite measurements are usually limited to a single location in space, which confines the reconstruction of the global evolution of the radiation environment. The uncertainties arise from the imperfect description of the process dynamics and the presence of observation errors, which may cause the failure of data assimilation solution. The development of adaptive Kalman filter that combines the Van Allen Probes data and 3-D VERB code, its accurate customizations in the reconstruction of model describing the phase space density (PSD) evolution, extension of the possibilities to use measurement information, and the model adjustment by developing the identification techniques of model and measurement errors allowed us to reveal hidden and implicit regularities of the PSD dynamics and obtain quantitative and qualitative estimates of radial, energy and pitch angle diffusion characteristics from satellite observations. In this study we propose an approach to estimate radial, energy and pitch angle diffusion rates, as well as the direction of their propagation.

  2. Corrosion in supercritical fluids

    Energy Technology Data Exchange (ETDEWEB)

    Propp, W.A.; Carleson, T.E.; Wai, Chen M.; Taylor, P.R.; Daehling, K.W.; Huang, Shaoping; Abdel-Latif, M.

    1996-05-01

    Integrated studies were carried out in the areas of corrosion, thermodynamic modeling, and electrochemistry under pressure and temperature conditions appropriate for potential applications of supercritical fluid (SCF) extractive metallurgy. Carbon dioxide and water were the primary fluids studied. Modifiers were used in some tests; these consisted of 1 wt% water and 10 wt% methanol for carbon dioxide and of sulfuric acid, sodium sulfate, ammonium sulfate, and ammonium nitrate at concentrations ranging from 0.00517 to 0.010 M for the aqueous fluids. The materials studied were Types 304 and 316 (UNS S30400 and S31600) stainless steel, iron, and AISI-SAE 1080 (UNS G10800) carbon steel. The thermodynamic modeling consisted of development of a personal computer-based program for generating Pourbaix diagrams at supercritical conditions in aqueous systems. As part of the model, a general method for extrapolating entropies and related thermodynamic properties from ambient to SCF conditions was developed. The experimental work was used as a tool to evaluate the predictions of the model for these systems. The model predicted a general loss of passivation in iron-based alloys at SCF conditions that was consistent with experimentally measured corrosion rates and open circuit potentials. For carbon-dioxide-based SCFs, measured corrosion rates were low, indicating that carbon steel would be suitable for use with unmodified carbon dioxide, while Type 304 stainless steel would be suitable for use with water or methanol as modifiers.

  3. Corrosion Mechanism of Corrosion-Resistant Steel Developed for Bottom Plate of Cargo Oil Tanks

    Institute of Scientific and Technical Information of China (English)

    Feilong SUN; Xiaogang LI; Fan ZHANG; Xuequn CHENG; Cheng ZHOU; Nianchun WU; Yuqun YIN

    2013-01-01

    A new type of corrosion-resistant steel consisting of ferrite and bainite phases was developed for cargo oil tanks of crude oil tankers.The corrosion rate of this new steel was 0.22 mm/a,which was equivalent to ca.1/5 of the criterion (≤ 1 mm/a) for corrosion-resistant steels.The composition and element distribution of the corrosion products were investigated by micro-Raman spectrometry and energy dispersive spectrometer.The results demonstrated that the corrosion product was composed of α-FeOOH,Fe3O4 and a continuous Cu enrichment layer.This kind of corrosion product was protective to the steel matrix and accounted for the enhancement of the corrosion resistance of the new developed steel.

  4. Field corrosion characterization of soil corrosion of X70 pipeline steel in a red clay soil

    Institute of Scientific and Technical Information of China (English)

    Shengrong Wang; Cuiwei Dun; Xiaogang Li; Zhiyong Liunn; Min Zhu; Dawei Zhang

    2015-01-01

    The corrosion behavior of X70 pipeline steel buried in red soil environment has been studied. The surface morphology and elemental distribution were determined by scanning electron microscopy (SEM),energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The corrosion kinetics was evaluated by weight loss measurement. The results show that in red soil, the corrosion rate of X70 steel decreases with time, and follows the exponential decay law. General corrosion with non-uniform and localized pitting occurred on the steel surface.α-FeOOH was the dominate products during corrosion in whole buried periods, and the corrosion products exhibited well protective properties. The potentiodynamic polarization tests revealed that icorr decreased with time, indicating the improvement of corrosion resistance. The results of Electrochemical impendence spectroscopy (EIS) are consistent with potentiodynamic polarization tests.

  5. Field corrosion characterization of soil corrosion of X70 pipeline steel in a red clay soil

    Directory of Open Access Journals (Sweden)

    Shengrong Wang

    2015-06-01

    Full Text Available The corrosion behavior of X70 pipeline steel buried in red soil environment has been studied. The surface morphology and elemental distribution were determined by scanning electron microscopy (SEM,energy dispersive X-ray spectroscopy (EDS, and X-ray diffraction (XRD. The corrosion kinetics was evaluated by weight loss measurement. The results show that in red soil, the corrosion rate of X70 steel decreases with time, and follows the exponential decay law. General corrosion with non-uniform and localized pitting occurred on the steel surface. α-FeOOH was the dominate products during corrosion in whole buried periods, and the corrosion products exhibited well protective properties. The potentiodynamic polarization tests revealed that icorr decreased with time, indicating the improvement of corrosion resistance. The results of Electrochemical impendence spectroscopy (EIS are consistent with potentiodynamic polarization tests.

  6. Aircraft Corrosion

    Science.gov (United States)

    1981-08-01

    allowed to dry. The area is then checked for the golden brown color which is produced by the chemical conversion material. If the work area requires...Materials, pp. 258-3074 1968. 41. W. IH. Ailor, "Seven-year exposure at Point leyes , California," "Corrosion in Natural Environments, ASTM STP 558," American... Color Units 3 Turbidity Units 0.7 pH Units 7.6 Temperature OF 76 Sp. Conductivity MMhos 425 B.O.D. (5 days at 206C) 0.2 SjV i;~-- 1201 A .9 8 ~ 8 kl

  7. Electrochemical corrosion testing of metal waste forms

    Energy Technology Data Exchange (ETDEWEB)

    Abraham, D. P.; Peterson, J. J.; Katyal, H. K.; Keiser, D. D.; Hilton, B. A.

    1999-12-14

    Electrochemical corrosion tests have been conducted on simulated stainless steel-zirconium (SS-Zr) metal waste form (MWF) samples. The uniform aqueous corrosion behavior of the samples in various test solutions was measured by the polarization resistance technique. The data show that the MWF corrosion rates are very low in groundwaters representative of the proposed Yucca Mountain repository. Galvanic corrosion measurements were also conducted on MWF samples that were coupled to an alloy that has been proposed for the inner lining of the high-level nuclear waste container. The experiments show that the steady-state galvanic corrosion currents are small. Galvanic corrosion will, hence, not be an important mechanism of radionuclide release from the MWF alloys.

  8. CORROSION MONITORING OF PLUTONIUM OXIDE AND SNF

    Energy Technology Data Exchange (ETDEWEB)

    Douglas, D.G.; Haas, C.M.; Smith, C.M.; Ohl, P.C.

    2003-02-27

    While developing a method to measure pressure in totally sealed stainless steel containers holding spent nuclear fuel at the U.S. DOE Hanford Site, Vista Engineering Technologies, LLC (Vista Engineering) personnel adapted the central concept to corrosion monitoring techniques for the same containers. The ability to monitor corrosion within vessels containing spent nuclear fuel, plutonium and other hazardous materials is imperative for safe storage. Vista Engineering personnel have devised a way to monitor corrosion in a totally sealed stainless steel container using a Magnetically Coupled Corrosion Gauge (MCCG) Patent Pending. The MCCG can be used to detect corrosion as well as measure corrosion rate and does not require any penetration of the containment vessel, which minimizes pressure boundary surface area and sensitive weld materials in the vessels.

  9. Corrosion of carbon-alloyed iron aluminides

    Indian Academy of Sciences (India)

    M Sen; R Balasubramaniam; A V Ramesh Kumar

    2000-10-01

    The corrosion behaviour of two carbon-alloyed intermetallics of composition Fe–28.1Al–2.1C and Fe–27.5Al–3.7C has been studied and compared with that of binary intermetallics. Potentiodynamic polarization studies indicated that the intermetallics exhibited active–passive behaviour in an acidic solution of pH = 1, whereas they exhibited stable passivity in a buffer solution of pH 8.4. Corrosion rates were also obtained by immersion testing. The variation of corrosion rate as a function of time was similar for both the intermetallics. The variation in corrosion rate as a function of time has been explained based on the observed potentiodynamic polarization behaviour. Scanning electron microscopy of corroded surfaces indicated that the carbon-alloyed intermetallics were susceptible to galvanic corrosion, due to the presence of carbides.

  10. Fuel corrosion processes under waste disposal conditions

    Energy Technology Data Exchange (ETDEWEB)

    Shoesmith, D.W. [Univ. of Western Ontario, Dept. of Chemistry, London, Ontario (Canada)

    1999-09-01

    Under the oxidizing conditions likely to be encountered in the Yucca Mountain Repository, fuel dissolution is a corrosion process involving the coupling of the anodic dissolution of the fuel with the cathodic reduction of oxidants available within the repository. The oxidants potentially available to drive fuel corrosion are environmental oxygen, supplied by the transport through the permeable rock of the mountain and molecular and radical species produced by the radiolysis of available aerated water. The mechanism of these coupled anodic and cathodic reactions is reviewed in detail. While gaps in understanding remain, many kinetic features of these reactions have been studied in considerable detail, and a reasonably justified mechanism for fuel corrosion is available. The corrosion rate is determined primarily by environmental factors rather than the properties of the fuel. Thus, with the exception of increase in rate due to an increase in surface area, pre-oxidation of the fuel has little effect on the corrosion rate.

  11. Passive Corrosion Behavior of Alloy 22

    Energy Technology Data Exchange (ETDEWEB)

    Rebak, R B; Payer, J H

    2006-01-10

    Alloy 22 (N06022) was designed to stand the most aggressive industrial applications, including both reducing and oxidizing acids. Even in the most aggressive environments, if the temperature is lower than 150 F (66 C) Alloy 22 would remain in the passive state having particularly low corrosion rates. In multi-ionic solutions that may simulate the behavior of concentrated ground water, even at near boiling temperatures, the corrosion rate of Alloy 22 is only a few nanometers per year because the alloy is in the complete passive state. The corrosion rate of passive Alloy 22 decreases as the time increases. Immersion corrosion testing also show that the newer generation of Ni-Cr-Mo alloys may offer a better corrosion resistance than Alloy 22 only in some highly aggressive conditions such as in hot acids.

  12. Passive Corrosion Behavior of Alloy 22

    Energy Technology Data Exchange (ETDEWEB)

    R.B. Rebak; J.H. Payer

    2006-01-20

    Alloy 22 (NO6022) was designed to stand the most aggressive industrial applications, including both reducing and oxidizing acids. Even in the most aggressive environments, if the temperature is lower than 150 F (66 C) Alloy 22 would remain in the passive state having particularly low corrosion rates. In multi-ionic solutions that may simulate the behavior of concentrated ground water, even at near boiling temperatures, the corrosion rate of Alloy 22 is only a few nano-meters per year because the alloy is in the complete passive state. The corrosion rate of passive Alloy 22 decreases as the time increases. Immersion corrosion testing also show that the newer generation of Ni-Cr-Mo alloys may offer a better corrosion resistance than Alloy 22 only in some highly aggressive conditions such as in hot acids.

  13. Corrosion rate of parent and weld materials of F82H and JPCA steels under LBE flow with active oxygen control at 450 and 500 deg. C

    Energy Technology Data Exchange (ETDEWEB)

    Kikuchi, Kenji [Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan)], E-mail: kikuchi.kenji21@jaea.go.jp; Kamata, Kinya; Ono, Mikinori; Kitano, Teruaki; Hayashi, Kenichi [Mitsui Engineering and Ship-building Co., Ltd., 5-6-4 Tsukiji, Chuo-ku, Tokyo 104-8439 (Japan); Oigawa, Hiroyuki [Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan)

    2008-06-30

    Corrosion behavior of parent and weld materials of F82H and JPCA was studied in the circulating LBE loop under impinging flow. These are candidate materials for Japanese Accelerator Driven System (ADS) beam windows. Maximum temperatures were kept to 450 and 500 deg. C with 100 deg. C constant temperature difference. Main flow velocity was 0.4-0.6 m/s in every case. Oxygen concentration was controlled to 2-4 x 10{sup -5} mass% although there was one exception. Testing time durations were 500-3000 h. Round bar type specimens were put in the circular tube of the loop. An electron beam weld in the middle of specimens was also studied. Optical microscopy, electron microscopy, X-ray element analyses and X-ray diffraction were used to investigate corrosion in these materials. Consequently corrosion depth and stability of those oxide layers were characterized based on the analyses. For a long-term behavior a linear law is recommended to predict corrosion in the ADS target design.

  14. Sewage sludge as additive to reduce the initial fireside corrosion caused by combustion of shredder residues in a waste-fired BFB boiler

    Energy Technology Data Exchange (ETDEWEB)

    Jonsson, T.; Pettersson, J.; Johansson, L.G.; Svensson, J.E. [Chalmers Univ. of Technology, Goeteborg (Sweden). Environmental Inorganic Chemistry; Davidsson, K. [SP Technical Research Institute of Sweden, Boraas (Sweden)

    2010-07-01

    Corrosion/deposition field tests have been carried out in a commercial waste-fired BFB boiler using air-cooled probes. The influence of 20% shredder light fraction (SLF), from recovery of metal scrap material, mixed with waste was studied at different material temperatures (280-420 C). In addition, 3% sewage sludge was added to the 20% SLF/waste mixture. The initial deposit and corrosion products were compared to when the normal waste (municipal solid waste and industrial wastes) fuel was used. After 24 hours exposure, the deposits were analyzed as for elemental composition while the corrosion products were characterised by ESEM/EDX and XRD. The results show that combustion of 20% SLF increased the amount of deposition, which in addition contains a larger fraction chlorine. This causes a higher initial corrosion rate. Adding 3% sewage sludge removes the effect of the SLF and deposits and corrosion products were comparable with the ones formed during the reference exposure. The results indicate that the initial fireside corrosion is chlorine induced and no signs of low-melting heavy metals salts were observed in the corrosion products. (orig.)

  15. On-line Corrosion Monitoring in District Heating Systems

    DEFF Research Database (Denmark)

    Richter, Sonja; Thorarinsdottir, R.I.; Hilbert, Lisbeth Rischel

    2005-01-01

    The corrosion control in district heating systems is today performed primarily with control of the water quality. The corrosion rate is kept low by assuring low dissolved oxygen concentration, high pH and low conductivity. Corrosion failures can occur, e.g. as a result of unknown oxygen ingress...

  16. Online, real-time corrosion monitoring in district heating systems

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Thorarinsdottir, R.I.

    2005-01-01

    The corrosion control in district heating systems is today performed primarily with control of the water quality. The corrosion rate is kept low by assuring low dissolved oxygen concentration, high pH and low conductivity. Corrosion failures can occur, e.g. as a result of unknown oxygen ingress...

  17. Corrosion of graphite composites in phosphoric acid fuel cells

    Science.gov (United States)

    Christner, L. G.; Dhar, H. P.; Farooque, M.; Kush, A. K.

    1986-01-01

    Polymers, polymer-graphite composites and different carbon materials are being considered for many of the fuel cell stack components. Exposure to concentrated phosphoric acid in the fuel cell environment and to high anodic potential results in corrosion. Relative corrosion rates of these materials, failure modes, plausible mechanisms of corrosion and methods for improvement of these materials are investigated.

  18. Migrating corrosion inhibitor blend for reinforced concrete: Part 1 -- Prevention of corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Elsener, B.; Buechler, M.; Stalder, F.; Boehni, H.

    1999-12-01

    The efficiency of a migrating corrosion inhibitor in preventing corrosion of mild steel was investigated in saturated calcium hydroxide (Ca[OH]{sub 2}) solutions and in mortar. The protective effect of the inhibitor against pitting corrosion caused by chloride attack and against uniform corrosion as a result of carbonation was determined. Results showed that high concentrations ({approx}10%) allowed the inhibition of pitting corrosion tritiation in solution containing 1 M/L sodium chloride (NaCl). However, inhibiting properties can be lost by evaporation of the volatile constituent of the inhibitor or by the precipitation of the nonvolatile fraction of the inhibitor in presence of calcium ions. Addition of the inhibitor blend to mortar yielded a retardation of the corrosion initiation in the case of chloride-induced corrosion, but o significant reduction in corrosion rate. No effect was found in carbonated samples, and no influence on the corrosion rate was detected. Additionally, the estimation of the extent of the retarding effect on corrosion initiation on real structures was difficult, as the inhibitor was found to evaporate from the mortar. This evaporation resulted in a loss of inhibiting properties. Hence, the long-term efficiency of the inhibitor could not be guaranteed.

  19. Use of Electrochemical Noise to Assess Corrosion in Kraft Continuous Digesters

    Energy Technology Data Exchange (ETDEWEB)

    Pawel, S.J.

    2004-11-29

    Electrochemical noise (EN) probes were deployed in two continuous kraft digesters at a variety of locations representative of corrosion throughout the vessels. Current and potential noise, the temperature at each probe location, and the value of up to 60 process parameters (flow rates, liquor chemistry, etc.) were monitored continuously during each experiment. The results indicate that changes in furnish composition and process upsets were invariably associated with concurrent substantial changes in EN activity throughout the vessels. Post-test evaluation of the mild steel electrode materials in both vessels confirmed general corrosion of a magnitude consistent with historical trends in the respective vessels as well as values qualitatively (and semi-quantitatively) related to EN current sums for each electrode pair. Stainless steel electrodes representing 309LSi and 312 overlay repairs exhibited zero wastage corrosion--as did the actual overlays--but the EN data indicated periodic redox activity on the stainless steel that varied with time and position within the vessel. Little or no correlation between EN probe activity and other operational variables was observed in either vessel. Additional details for each digester experiment are summarized.

  20. On-line Corrosion Monitoring in District Heating Systems

    DEFF Research Database (Denmark)

    Richter, Sonja; Thorarinsdottir, R.I.; Hilbert, Lisbeth Rischel

    2005-01-01

    The corrosion control in district heating systems is today performed primarily with control of the water quality. The corrosion rate is kept low by assuring low dissolved oxygen concentration, high pH and low conductivity. Corrosion failures can occur, e.g. as a result of unknown oxygen ingress......, precipitation of deposits or crevices. The authors describe methods used for on-line monitoring of corrosion, cover the complications and the main results of a Nordic project....

  1. Online, real-time corrosion monitoring in district heating systems

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Thorarinsdottir, R.I.

    2005-01-01

    The corrosion control in district heating systems is today performed primarily with control of the water quality. The corrosion rate is kept low by assuring low dissolved oxygen concentration, high pH and low conductivity. Corrosion failures can occur, e.g. as a result of unknown oxygen ingress......, precipitation of deposits or crevices. The authors describe methods used for on-line monitoring of corrosion, cover the complications and the main results of a Nordic project....

  2. Recent Natural Corrosion Inhibitors for Mild Steel: An Overview

    OpenAIRE

    Marko Chigondo; Fidelis Chigondo

    2016-01-01

    Traditionally, reduction of corrosion has been managed by various methods including cathodic protection, process control, reduction of the metal impurity content, and application of surface treatment techniques, as well as incorporation of suitable alloys. However, the use of corrosion inhibitors has proven to be the easiest and cheapest method for corrosion protection and prevention in acidic media. These inhibitors slow down the corrosion rate and thus prevent monetary losses due to metalli...

  3. Steam generator corrosion 2007; Dampferzeugerkorrosion 2007

    Energy Technology Data Exchange (ETDEWEB)

    Born, M. (ed.)

    2007-07-01

    Between 8th and 9th November, 2007, SAXONIA Standortentwicklungs- und -verwertungsgesellschaft GmbH (Freiberg, Federal Republic of Germany) performed the 3rd Freiberger discussion conference ''Fireside boiler corrosion''. The topics of the lectures are: (a) Steam generator corrosion - an infinite history (Franz W. Alvert); (b) CFD computations for thermal waste treatment plants - a contribution for the damage recognition and remedy (Klaus Goerner, Thomas Klasen); (c) Experiences with the use of corrosion probes (Siegfried R. Horn, Ferdinand Haider, Barbara Waldmann, Ragnar Warnecke); (d) Use of additives for the limitation of the high temperature chlorine corrosion as an option apart from other measures to the corrosion protection (Wolfgang Spiegel); (e) Current research results and aims of research with respect to chlorine corrosion (Ragnar Warnecke); (f) Systematics of the corrosion phenomena - notes for the enterprise and corrosion protection (Thomas Herzog, Wolfgang Spiegel, Werner Schmidl); (g) Corrosion protection by cladding in steam generators of waste incinerators (Joerg Metschke); (h) Corrosion protection and wear protection by means of thermal spraying in steam generators (Dietmar Bendix); (i) Review of thick film nickelized components as an effective protection against high-temperature corrosion (Johann-Wilhelm Ansey); (j) Fireproof materials for waste incinerators - characteristics and profile of requirement (Johannes Imle); (k) Service life-relevant aspects of fireproof linings in the thermal recycling of waste (Till Osthoevener and Wolfgang Kollenberg); (l) Alternatives to the fireproof material in the heating space (Heino Sinn); (m) Cladding: Inconal 625 contra 686 - Fundamentals / applications in boiler construction and plant construction (Wolfgang Hoffmeister); (n) Thin films as efficient corrosion barriers - thermal spray coating in waste incinerators and biomass firing (Ruediger W. Schuelein, Steffen Hoehne, Friedrich

  4. A STUDY OF CORROSION AND STRESS CORROSION CRACKING OF CARBON STEEL NUCLEAR WASTE STORAGE TANKS

    Energy Technology Data Exchange (ETDEWEB)

    BOOMER, K.D.

    2007-08-21

    The Hanford reservation Tank Farms in Washington State has 177 underground storage tanks that contain approximately 50 million gallons of liquid legacy radioactive waste from cold war plutonium production. These tanks will continue to store waste until it is treated and disposed. These nuclear wastes were converted to highly alkaline pH wastes to protect the carbon steel storage tanks from corrosion. However, the carbon steel is still susceptible to localized corrosion and stress corrosion cracking. The waste chemistry varies from tank to tank, and contains various combinations of hydroxide, nitrate, nitrite, chloride, carbonate, aluminate and other species. The effect of each of these species and any synergistic effects on localized corrosion and stress corrosion cracking of carbon steel have been investigated with electrochemical polarization, slow strain rate, and crack growth rate testing. The effect of solution chemistry, pH, temperature and applied potential are all considered and their role in the corrosion behavior will be discussed.

  5. Corrosion of High Chromium Ferritic/Martensitic Steels in High Temperature Water. a Literature Review

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, P.; Lapena, J.; Blazquez, F. [Ciemat, Madrid (Spain)

    2000-07-01

    Available literature concerning corrosion of high-chromium ferritic/martensitic steels in high temperature water has been reviewed. The subjects considered are general corrosion, effect of irradiation on corrosion, stress corrosion cracking (SCC) and irradiation-assisted stress corrosion cracking (IASCC). In addition some investigations about radiation induced segregation (RIS) are shown in order to know the compositional changes at grain boundaries of these alloys and their influence on corrosion properties. The data on general corrosion indicate moderate corrosion rates in high temperature water up to 350 degree centigree. Considerably larger corrosion rates were observed under neutron irradiation. The works concerning to the behaviour of these alloys to stress corrosion cracking seem to conclude that in these materials is necessary to optimize the temper temperature and to carry out the post-weld heat treatments properly in order to avoid stress corrosion cracking. (Author) 40 refs.

  6. Evaluation of oxygen corrosion in waterflood and disposal water systems

    Energy Technology Data Exchange (ETDEWEB)

    Conger, H.C.

    1967-01-01

    The case histories presented illustrate how specially polished pipe nipples have been used and examined in the field to evaluate the seriousness of an oxygen corrosion problem. The case histories also illustrate how these test pipe nipples have been used to evaluate actual, not relative, effectiveness of a chemical treatment program to control oxygen corrosion. Data are presented and discussed showing the relationship between corrosion rates of test pipe nipples and actual in-service equipment. The case histories show how corrosion rates based on pipe test nipple data were used to project equipment life under no chemical treatment vs. chemical treatment. A comparative study of corrosion rates between the use of pipe nipples and coupons as a means of measuring oxygen corrosion is discussed. A further comparative study is made between coupon corrosion rates based on weight loss and pit depth penetration.

  7. Optimising corrosion monitoring in district heating systems

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Thorarinsdottir, R.I.; Andersen, A.

    2002-01-01

    is to improve the quality control in district heating systems by corrosion monitoring. In Danish systems electrochemical impedance spectroscopy (EIS), linear polarisation resistance (LPR), high-sensitive electrical resistance (ER) technology, crevice corrosion probes, as well as weight loss coupons......A three-year project - financially supported by the Nordic Industrial Fund - on monitoring of corrosion in district heating systems has been initiated with participation of researchers and industrial partners in Denmark, Finland, Iceland, Norway and Sweden. The primary objective of the project...... will be tested. Laboratory studies as well as on-line measurements in district heating systems using probes in a specially designed sidestream unit are included in the practical part of the project....

  8. Fouling corrosion in aluminum heat exchangers

    Directory of Open Access Journals (Sweden)

    Su Jingxin

    2015-06-01

    Full Text Available Fouling deposits on aluminum heat exchanger reduce the heat transfer efficiency and cause corrosion to the apparatus. This study focuses on the corrosive behavior of aluminum coupons covered with a layer of artificial fouling in a humid atmosphere by their weight loss, Tafel plots, electrochemical impedance spectroscopy (EIS, and scanning electron microscope (SEM observations. The results reveal that chloride is one of the major elements found in the fouling which damages the passive film and initiates corrosion. The galvanic corrosion between the metal and the adjacent carbon particles accelerates the corrosive process. Furthermore, the black carbon favors the moisture uptake, and gives the dissolved oxygen greater chance to migrate through the fouling layer and form a continuous diffusive path. The corrosion rate decreasing over time is conformed to electrochemistry measurements and can be verified by Faraday’s law. The EIS results indicate that the mechanism of corrosion can be interpreted by the pitting corrosion evolution mechanism, and that pitting was observed on the coupons by SEM after corrosive exposure.

  9. NOVEL CORROSION SENSOR FOR VISION 21 SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Heng Ban

    2004-12-01

    Advanced sensor technology is identified as a key component for advanced power systems for future energy plants that would have virtually no environmental impact. This project intends to develop a novel high temperature corrosion sensor and subsequent measurement system for advanced power systems. Fireside corrosion is the metal loss caused by chemical reactions on surfaces exposed to the combustion environment. Such corrosion is the leading mechanism for boiler tube failures and has emerged to be a significant concern for current and future energy plants due to the introduction of technologies targeting emissions reduction, efficiency improvement, or fuel/oxidant flexibility. Corrosion damage can lead to catastrophic equipment failure, explosions, and forced outages. Proper management of corrosion requires real-time indication of corrosion rate. However, short-term, on-line corrosion monitoring systems for fireside corrosion remain a technical challenge to date due to the extremely harsh combustion environment. The overall objective of this proposed project is to develop a technology for on-line corrosion monitoring based on a new concept. This report describes the initial results from the first-year effort of the three-year study that include laboratory development and experiment, and pilot combustor testing.

  10. Graphene: corrosion-inhibiting coating.

    Science.gov (United States)

    Prasai, Dhiraj; Tuberquia, Juan Carlos; Harl, Robert R; Jennings, G Kane; Rogers, Bridget R; Bolotin, Kirill I

    2012-02-28

    We report the use of atomically thin layers of graphene as a protective coating that inhibits corrosion of underlying metals. Here, we employ electrochemical methods to study the corrosion inhibition of copper and nickel by either growing graphene on these metals, or by mechanically transferring multilayer graphene onto them. Cyclic voltammetry measurements reveal that the graphene coating effectively suppresses metal oxidation and oxygen reduction. Electrochemical impedance spectroscopy measurements suggest that while graphene itself is not damaged, the metal under it is corroded at cracks in the graphene film. Finally, we use Tafel analysis to quantify the corrosion rates of samples with and without graphene coatings. These results indicate that copper films coated with graphene grown via chemical vapor deposition are corroded 7 times slower in an aerated Na(2)SO(4) solution as compared to the corrosion rate of bare copper. Tafel analysis reveals that nickel with a multilayer graphene film grown on it corrodes 20 times slower while nickel surfaces coated with four layers of mechanically transferred graphene corrode 4 times slower than bare nickel. These findings establish graphene as the thinnest known corrosion-protecting coating.

  11. Numerical Modeling of Weld Joint Corrosion

    Science.gov (United States)

    Lu, Yongxin; Jing, Hongyang; Han, Yongdian; Xu, Lianyong

    2016-03-01

    A numerical model is presented in this work that predicts the corrosion rate of weld joint. The model is able to track moving boundary of the corroding constituent of weld joint. The corrosion rates obtained from the model are compared with those estimated from mixed potential theory and two experimental techniques, namely immersion test and constant potential polarization test. The corrosion rate predicted using the model is within 10% of the estimate from the mixed potential theory, within 20% of that got from the immersion experiment and within 10% of that got from the constant potential polarization experiment for weld joint.

  12. Predicting concrete corrosion of sewers using artificial neural network.

    Science.gov (United States)

    Jiang, Guangming; Keller, Jurg; Bond, Philip L; Yuan, Zhiguo

    2016-04-01

    Corrosion is often a major failure mechanism for concrete sewers and under such circumstances the sewer service life is largely determined by the progression of microbially induced concrete corrosion. The modelling of sewer processes has become possible due to the improved understanding of in-sewer transformation. Recent systematic studies about the correlation between the corrosion processes and sewer environment factors should be utilized to improve the prediction capability of service life by sewer models. This paper presents an artificial neural network (ANN)-based approach for modelling the concrete corrosion processes in sewers. The approach included predicting the time for the corrosion to initiate and then predicting the corrosion rate after the initiation period. The ANN model was trained and validated with long-term (4.5 years) corrosion data obtained in laboratory corrosion chambers, and further verified with field measurements in real sewers across Australia. The trained model estimated the corrosion initiation time and corrosion rates very close to those measured in Australian sewers. The ANN model performed better than a multiple regression model also developed on the same dataset. Additionally, the ANN model can serve as a prediction framework for sewer service life, which can be progressively improved and expanded by including corrosion rates measured in different sewer conditions. Furthermore, the proposed methodology holds promise to facilitate the construction of analytical models associated with corrosion processes of concrete sewers.

  13. COUPLING NORSOK CO2 CORROSION PREDICTION MODEL WITH PIPELINES THERMAL/HYDRAULIC MODELS TO SIMULATE CO2 CORROSION ALONG PIPELINES

    Directory of Open Access Journals (Sweden)

    MOKHTAR CHE ISMAIL

    2011-12-01

    Full Text Available Pipelines transporting oil and gas are vulnerable to internal corrosion when water forms a part of the transported fluids. The presence of carbon dioxide (CO2 in the fluid accelerates the corrosion rate due to its reaction with water which results in forming carbonic acid, and hence, water pH is reduced. The corrosion rate prediction is an important task needed to manage and control the corrosion. The prediction can be carried on by selecting one of many empirical and mechanistic models that developed for corrosion rate prediction. One of these models is NORSOK model, an empirical model developed by NORSOK Norwegian standard for CO2 corrosion prediction in straight pipes. In this paper NORSOK model has been coupled to thermal and hydraulic models to predict CO2 corrosion rate along pipelines.

  14. High Temperature Corrosion in Biomass-Fired Boilers

    DEFF Research Database (Denmark)

    Henriksen, Niels; Montgomery, Melanie; Hede Larsen, Ole

    2002-01-01

    condense on superheater components. This gives rise to specific corrosion problems not previously encountered in coal-fired power plants. The type of corrosion attack can be directly ascribed to the composition of the deposit and the metal surface temperature. To avoid such high corrosion rates, woodchip...... has also been utilised as a fuel. Combustion of woodchip results in a smaller amount of ash, and potassium and chlorine are present in lesser amounts. However, significant corrosion rates were still seen. A case study of a woodchip fired boiler is described. The corrosion mechanisms in both straw...

  15. Wastewater-Enhanced Microbial Corrosion of Concrete Sewers.

    Science.gov (United States)

    Jiang, Guangming; Zhou, Mi; Chiu, Tsz Ho; Sun, Xiaoyan; Keller, Jurg; Bond, Philip L

    2016-08-02

    Microbial corrosion of concrete in sewers is known to be caused by hydrogen sulfide, although the role of wastewater in regulating the corrosion processes is poorly understood. Flooding and splashing of wastewater in sewers periodically inoculates the concrete surface in sewer pipes. No study has systematically investigated the impacts of wastewater inoculation on the corrosion of concrete in sewers. This study investigated the development of the microbial community, sulfide uptake activity, and the change of the concrete properties for coupons subjected to periodic wastewater inoculation. The concrete coupons were exposed to different levels of hydrogen sulfide under well-controlled conditions in laboratory-scale corrosion chambers simulating real sewers. It was evident that the periodic inoculation induced higher corrosion losses of the concrete in comparison to noninoculated coupons. Instantaneous measurements such as surface pH did not reflect the cumulative corrosion losses caused by long-term microbial activity. Analysis of the long-term profiles of the sulfide uptake rate using a Gompertz model supported the enhanced corrosion activity and greater corrosion loss. The enhanced corrosion rate was due to the higher sulfide uptake rates induced by wastewater inoculation, although the increasing trend of sulfide uptake rates was slower with wastewater. Increased diversity in the corrosion-layer microbial communities was detected when the corrosion rates were higher. This coincided with the environmental conditions of increased levels of gaseous H2S and the concrete type.

  16. Novel Corrosion Sensor for Vision 21 Systems

    Energy Technology Data Exchange (ETDEWEB)

    Heng Ban; Bharat Soni

    2007-03-31

    Advanced sensor technology is identified as a key component for advanced power systems for future energy plants that would have virtually no environmental impact. This project intends to develop a novel high temperature corrosion sensor and subsequent measurement system for advanced power systems. Fireside corrosion is the leading mechanism for boiler tube failures and has emerged to be a significant concern for current and future energy plants due to the introduction of technologies targeting emissions reduction, efficiency improvement, or fuel/oxidant flexibility. Corrosion damage can lead to catastrophic equipment failure, explosions, and forced outages. Proper management of corrosion requires real-time indication of corrosion rate. However, short-term, on-line corrosion monitoring systems for fireside corrosion remain a technical challenge to date due to the extremely harsh combustion environment. The overall goal of this project is to develop a technology for on-line fireside corrosion monitoring. This objective is achieved by the laboratory development of sensors and instrumentation, testing them in a laboratory muffle furnace, and eventually testing the system in a coal-fired furnace. This project successfully developed two types of sensors and measurement systems, and successful tested them in a muffle furnace in the laboratory. The capacitance sensor had a high fabrication cost and might be more appropriate in other applications. The low-cost resistance sensor was tested in a power plant burning eastern bituminous coals. The results show that the fireside corrosion measurement system can be used to determine the corrosion rate at waterwall and superheater locations. Electron microscope analysis of the corroded sensor surface provided detailed picture of the corrosion process.

  17. Analysis of the Influence of Organic Corrosion Inhibitors on Corrosion of Reinforcement in Concrete Bridge Structure Under Simulated Field Service Environment

    OpenAIRE

    Shi, Liang; Ye, J.; C. C. CHEN; Wu, Y; Liu, J. Z.

    2014-01-01

    For concrete bridge projects in marine environments, attention must be paid to the reinforcement corrosion problems caused by chloride intrusion. As kinds of functional admixtures, which can reduce the reinforcement corrosion rate, corrosion inhibitors are becoming very popular in China in new bridge projects. Corrosion inhibitors cover both inorganic and organic inhibitors. Nitrite is representative of inorganic corrosion inhibitors, but its carcinogenicity has hindered its further developme...

  18. Initial measurements of O-ion and He-ion decay rates observed from the Van Allen probes RBSPICE instrument

    OpenAIRE

    Gerrard, Andrew; Lanzerotti, Louis; Gkioulidou, Matina; Mitchell, Donald; Manweiler, Jerry; Bortnik, Jacob; Keika, Kunihiro

    2014-01-01

    H-ion (∼45 keV to ∼600 keV), He-ion (∼65 keV to ∼520 keV), and O-ion (∼140 keV to ∼1130 keV) integral flux measurements, from the Radiation Belt Storm Probe Ion Composition Experiment (RBSPICE) instrument aboard the Van Allan Probes spacecraft B, are reported. These abundance data form a cohesive picture of ring current ions during the first 9 months of measurements. Furthermore, the data presented herein are used to show injection characteristics via the He-ion/H-ion abundance ratio and the ...

  19. Advanced modelling of concrete deterioration due to reinforcement corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Isgor, O.B. [Carleton Univ., Dept. of Civil and Environmental Engineering, Ottawa, Ontario (Canada); Razaqpur, A.G. [McMaster Univ., Dept. of Civil Engineering, Hamilton, Ontario (Canada)

    2006-06-15

    A comprehensive model is presented for predicting the rate of steel corrosion in concrete structures and the consequent formation and propagation of cracks around the steel reinforcement. The corrosion model considers both the initiation and the propagation stages of corrosion. Processes commencing in the initiation stage, such as the transport of chloride ions and oxygen within the concrete and variation in temperature and moisture, are assumed to continue in the propagation stage while active corrosion is occurring contemporaneously. This allows the model to include the effects of changes in exposure conditions on the corrosion rate and the effects of the corrosion reactions on the transport properties of concrete. The corrosion rates are calculated by applying the finite-element solution of the Laplace equation for electrochemical potential, with appropriate boundary conditions. Because these boundary conditions are nonlinear, a nonlinear solution algorithm is used. The results of the analysis are compared with available test data, and the comparison is found to be satisfactory. (author)

  20. Plant applications of online corrosion monitoring: CO2 capture amine plant case study

    NARCIS (Netherlands)

    Kane, R.D.; Srinivasan, S.; Khakharia, P.M.; Goetheer, E.L.V.; Mertens, J.; Vroey, S. de

    2015-01-01

    Over the past several years, there has been a significant effort to bring corrosion monitoring into the realm of online, real-time management with plant process control technology. As part of this new direction in corrosion monitoring, corrosion data (e.g. information on corrosion rate, measured Ste

  1. Modelling on corrosion inhibitor kinetics in carbon steel pipe used in oil industry

    Science.gov (United States)

    Hasmi, A. N.; Nuraini, N.; Wahyuningrum, D.; Sumarti, N.; Bunjali, B.

    2014-02-01

    A model to explain the kinetics of corrosion inhibitor is proposed here. The model is based on Transition State Theory. Our model has many similarities with Michelis-Menten Kinetics. The kinetics difference between uninhibited corrosion and inhibited corrosion is presented. Our model showed the inhibitor could suppress the corrosion rate.

  2. Plant applications of online corrosion monitoring: CO2 capture amine plant case study

    NARCIS (Netherlands)

    Kane, R.D.; Srinivasan, S.; Khakharia, P.M.; Goetheer, E.L.V.; Mertens, J.; Vroey, S. de

    2015-01-01

    Over the past several years, there has been a significant effort to bring corrosion monitoring into the realm of online, real-time management with plant process control technology. As part of this new direction in corrosion monitoring, corrosion data (e.g. information on corrosion rate, measured

  3. Corrosion in Electronic Devices and Sensors to Prevent Corrosion

    Directory of Open Access Journals (Sweden)

    Siddharth Dev

    2014-02-01

    Full Text Available Many types of metal and alloys are used in various electronic devices and components like computers, microchips, printed circuit board (PCB, integrated circuits, transistors, and diodes etc. Such components have variety of applications in the field of medical, aerospace, automotive sectors, telecommunication and defense. These components are exposed to different types of environments. The increased used of electronics has also increased the demand for reliability. The size of electronic equipment is also very significant parameter and it has been decreasing presently at a faster rate. The smaller size of equipment has undetectable failures. Though the corrosion taking place in electronic components is generally of micro level which can not be detected easily but the services of device are seized. The paper deals with the various types of corrosion in electronic components as a case study and an approach towards development of some sensor for corrosion monitoring.

  4. Annual report, spring 2015. Alternative chemical cleaning methods for high level waste tanks-corrosion test results

    Energy Technology Data Exchange (ETDEWEB)

    Wyrwas, R. B. [Savannah River Site (SRS), Aiken, SC (United States)

    2015-07-06

    The testing presented in this report is in support of the investigation of the Alternative Chemical Cleaning program to aid in developing strategies and technologies to chemically clean radioactive High Level Waste tanks prior to tank closure. The data and conclusions presented here were the examination of the corrosion rates of A285 carbon steel and 304L stainless steel when interacted with the chemical cleaning solution composed of 0.18 M nitric acid and 0.5 wt. % oxalic acid. This solution has been proposed as a dissolution solution that would be used to remove the remaining hard heel portion of the sludge in the waste tanks. This solution was combined with the HM and PUREX simulated sludge with dilution ratios that represent the bulk oxalic cleaning process (20:1 ratio, acid solution to simulant) and the cumulative volume associated with multiple acid strikes (50:1 ratio). The testing was conducted over 28 days at 50°C and deployed two methods to invest the corrosion conditions; passive weight loss coupon and an active electrochemical probe were used to collect data on the corrosion rate and material performance. In addition to investigating the chemical cleaning solutions, electrochemical corrosion testing was performed on acidic and basic solutions containing sodium permanganate at room temperature to explore the corrosion impacts if these solutions were to be implemented to retrieve remaining actinides that are currently in the sludge of the tank.

  5. Research on a new type of fiber Bragg grating based corrosion sensor

    Science.gov (United States)

    Li, Peng; Song, Shide; Wang, Xiaona; Zhou, Weijie; Zhang, Zuocai

    2015-08-01

    Investigations of the corrosion of rebars in concrete structures are widely studied because of the serious damage to concrete caused by rebar corrosion. The rebar corrosion products in reinforced concrete take up 2~6 times the volume of the rebar. Based on this principle, a new type of fiber Bragg grating (FBG) corrosion sensor is proposed in this paper, which consists of two sensors, an FBG corrosion measurement sensor to measure the expansion strain caused by rebar corrosion, and a temperature compensation sensor to eliminate the cross-sensitivity of FBG corrosion sensor. The corrosion rate is derived by the wavelength shift of FBG corrosion sensor, so rebar corrosion can be monitored and assessed by the FBG wavelength shift. A customized rebar with epoxy fixing groove is designed to install a corrosion sensor on its surface and an embedded temperature compensation sensor. The corrosion sensor is embedded in cement mortar and subsequently casted in concrete. The performance of the corrosion sensor is studied in an accelerated electrochemical corrosion test. Experimental results show that the new type of corrosion sensor has advantage of relatively large measurement range of corrosion rate. The corrosion sensor is suitable to monitor slightly and moderately corroded rebars.

  6. Monitoring corrosion in prestressed concrete beams using acoustic emission technique

    Science.gov (United States)

    ElBatanouny, Mohamed K.; Mangual, Jesé; Vélez, William; Ziehl, Paul H.; Matta, Fabio; González, Miguel

    2012-04-01

    Early detection of corrosion can help reduce the cost of maintenance and extend the service life of structures. Acoustic emission (AE) sensing has proven to be a promising method for early detection of corrosion in reinforced concrete members. A test program is presented composed of four medium-scale prestressed concrete T-beams. Three of the beams have a length of 16 ft. 4 in. (4.98 m), and one is 9 ft. 8 in. (2.95 m). In order to corrode the specimens a 3% NaCl solution was prepared, which is representative of sea salt concentration. The beams were subjected to wet-dry cycles to accelerate the corrosion process. Two of the specimens were pre-cracked prior to conditioning in order to examine the effect of crack presence. AE data was recorded continuously while half-cell potential measurements and corrosion rate by Linear Polarization Resistance (LPR) were measured daily. Corrosion current was also being acquired constantly to monitor any change in the concrete resistivity. Results indicate that the onset of corrosion may be identified using AE features, and were corroborated with measurements obtained from electrochemical techniques. Corroded areas were located using source triangulation. The results indicate that cracked specimens showed corrosion activity prior to un-cracked specimens and experienced higher corrosion rates. The level of corrosion was determined using corrosion rate results. Intensity analysis was used to link the corrosion rate and level to AE data.

  7. Review of Artificial Neural Networks (ANN) applied to corrosion monitoring

    Science.gov (United States)

    Mabbutt, S.; Picton, P.; Shaw, P.; Black, S.

    2012-05-01

    The assessment of corrosion within an engineering system often forms an important aspect of condition monitoring but it is a parameter that is inherently difficult to measure and predict. The electrochemical nature of the corrosion process allows precise measurements to be made. Advances in instruments, techniques and software have resulted in devices that can gather data and perform various analysis routines that provide parameters to identify corrosion type and corrosion rate. Although corrosion rates are important they are only useful where general or uniform corrosion dominates. However, pitting, inter-granular corrosion and environmentally assisted cracking (stress corrosion) are examples of corrosion mechanisms that can be dangerous and virtually invisible to the naked eye. Electrochemical noise (EN) monitoring is a very useful technique for detecting these types of corrosion and it is the only non-invasive electrochemical corrosion monitoring technique commonly available. Modern instrumentation is extremely sensitive to changes in the system and new experimental configurations for gathering EN data have been proven. In this paper the identification of localised corrosion by different data analysis routines has been reviewed. In particular the application of Artificial Neural Network (ANN) analysis to corrosion data is of key interest. In most instances data needs to be used with conventional theory to obtain meaningful information and relies on expert interpretation. Recently work has been carried out using artificial neural networks to investigate various types of corrosion data in attempts to predict corrosion behaviour with some success. This work aims to extend this earlier work to identify reliable electrochemical indicators of localised corrosion onset and propagation stages.

  8. Slurry Chemical Corrosion and Galvanic Corrosion during Copper Chemical Mechanical Polishing

    Science.gov (United States)

    Kondo, Seiichi; Sakuma, Noriyuki; Homma, Yoshio; Ohashi, Naofumi

    2000-11-01

    Copper (Cu) corrosion during chemical mechanical polishing (CMP) was controlled in order to improve the Cu damascene interconnect process. Slurry chemical corrosion was found to be enhanced when the slurry was diluted by deionized (DI) water during rinsing just after CMP@. Since the corrosion inhibitor, benzotriazole (BTA), reduces the Cu removal rate, adding it to the rinse solution prevents chemical corrosion more effectively than adding it to the slurry. On the other hand, galvanic corrosion occurs at the interface between Cu and the barrier metal, and it can be prevented by selecting appropriate barrier metals. Because the difference between the electrochemical potentials of Cu and the barrier metal is small in the slurry, refractory metals such as Ta, TaN, and TiN were found to be appropriate barrier metals. On the other hand, W, WN, and Ti have large potential differences, so galvanic corrosion was clearly observed when Cu/W damascene interconnects were fabricated.

  9. A high-repetition rate scheme for synchrotron-based picosecond laser pump/x-ray probe experiments on chemical and biological systems in solution.

    Science.gov (United States)

    Lima, Frederico A; Milne, Christopher J; Amarasinghe, Dimali C V; Rittmann-Frank, Mercedes Hannelore; van der Veen, Renske M; Reinhard, Marco; Pham, Van-Thai; Karlsson, Susanne; Johnson, Steven L; Grolimund, Daniel; Borca, Camelia; Huthwelker, Thomas; Janousch, Markus; van Mourik, Frank; Abela, Rafael; Chergui, Majed

    2011-06-01

    We present the extension of time-resolved optical pump/x-ray absorption spectroscopy (XAS) probe experiments towards data collection at MHz repetition rates. The use of a high-power picosecond laser operating at an integer fraction of the repetition rate of the storage ring allows exploitation of up to two orders of magnitude more x-ray photons than in previous schemes based on the use of kHz lasers. Consequently, we demonstrate an order of magnitude increase in the signal-to-noise of time-resolved XAS of molecular systems in solution. This makes it possible to investigate highly dilute samples at concentrations approaching physiological conditions for biological systems. The simplicity and compactness of the scheme allows for straightforward implementation at any synchrotron beamline and for a wide range of x-ray probe techniques, such as time-resolved diffraction or x-ray emission studies.

  10. Design and Validation of a Probe for Spatially and Temporally Resolved Measurements of Vorticity and Strain Rates in Compressible Turbulence Interactions

    Directory of Open Access Journals (Sweden)

    S. Xanthos

    2007-01-01

    Full Text Available A custom-made hot-wire vorticity probe was designed and developed capable of measuring the time-dependent highly fluctuating three dimensional velocity and vorticity vectors, and associated total temperature, in non-isothermal and inhomogeneous flows with reasonable spatial and temporal resolution. These measurements allowed computation of the vorticity stretching/tilting terms, vorticity generation through dilatation terms, full dissipation rate of the kinetic energy term and full rate-of-strain tensor. The probe has been validated experimentally in low-speed boundary layers and used in the CCNY Shock Tube Research Facility, where interactions of planar expansion waves or shock waves with homogeneous and isotropic turbulence have been investigated at several Reynolds numbers. 

  11. Corrosion Evolution of Reinforcing Steel in Concrete under Dry/Wet Cyclic Conditions Contaminated with Chloride

    Institute of Scientific and Technical Information of China (English)

    J. Wei; X.X. Fu; J.H. Dong; W. Ke

    2012-01-01

    The corrosion evolution of rebar in concrete was monitored by electrochemical impedance spectroscopy (EIS) under dry/wet alternated accelerated corrosion test. Four stages with different dynamic characteristics were observed during the corrosion evolution. They were passive stage, local corrosion controlled by the charge transfer step, accelerated corrosion controlled by the mass transfer step, and constant rate corrosion controlled by the mass transfer step through a barrier layer. X-ray diffraction (XRD) analysis showed that the corrosion product of rebar in mortar was composed of α-FeOOH, γ-FeOOH and Fe304. The corrosion mechanisms of all four stages were discussed and the corrosion reactions were proposed according to the corrosion product and corrosion evolution characteristics.

  12. Sulphur recirculation for reduced boiler corrosion; Minskad pannkorrosion med svavelrecirkulation

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Sven; Karlsson, Martin (Goetaverken Miljoe AB, Goeteborg (Sweden)); Blomqvist, Evalena; Baefver, Linda; Claesson, Frida; Davidsson, Kent (SP Sveriges Tekniska Forskningsinstitut, Boraas (Sweden)); Froitzheim, Jan; Pettersson, Jesper; Steenari, Britt-Marie (Chalmers Tekniska Hoegskola, Oorganisk miljoekemi, Goeteborg (Sweden))

    2010-03-15

    Sulphur recirculation is a new technology for reducing boiler corrosion and dioxin formation, which was demonstrated in full-scale tests performed at the Renova Waste to Energy plant at Saevenaes in Goeteborg (Sweden). Sulphur is recirculated from the flue gas cleaning back to the boiler, which reduces the chloride content of the deposits, which in turn reduces boiler corrosion and dioxin formation. Sulphur dioxide was separated from the flue gas in a wet scrubber by adding hydrogen peroxide, producing sulphuric acid. The sulphuric acid was injected into the furnace using nozzles with atomization air, surrounded by recirculated flue gas for improved mixing. By recirculating the sulphur, the sulphur dioxide concentration was increased in the boiler. Each sulphur atom passed the boiler several times and no external sulphur had to be added. Dioxin, ash, deposits and particle samplings together with 1000 h corrosion probe measurements were performed for normal operation (reference) and with sulphur recirculation respectively. During spring 2009, reference measurements were made and the recirculation system was installed and tested. During autumn 2009, a long term test with sulphur recirculation was made. An SO{sub 2} concentration of approximately 800 mg/m3 (n, d.g.) was maintained in the boiler by the system except during a period of extremely low sulphur content in the waste. The sulphur dioxide stack concentrations have been far below the emission limit. Sulphuric acid dew point measurements have shown that the sulphuric acid dosage did not lead to elevated SO{sub 3} concentrations, which may otherwise lead to low temperature corrosion. The chlorine content of both fly ash and boiler ash decreased and the sulphur content increased during the sulphur recirculation tests. The molar chlorine/sulphur ratio (Cl/S) decreased by two thirds in the fly ash as well as in the boiler ash, except for one sample. With sulphur recirculation in operation, the deposit growth was

  13. Experimental Investigation of the Corrosion Behavior of Friction Stir Welded AZ61A Magnesium Alloy Welds under Salt Spray Corrosion Test and Galvanic Corrosion Test Using Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    A. Dhanapal

    2013-01-01

    Full Text Available Extruded Mg alloy plates of 6 mm thick of AZ61A grade were butt welded using advanced welding process and friction stir welding (FSW processes. The specimens were exposed to salt spray conditions and immersion conditions to characterize their corrosion rates on the effect of pH value, chloride ion concentration, and corrosion time. In addition, an attempt was made to develop an empirical relationship to predict the corrosion rate of FSW welds in salt spray corrosion test and galvanic corrosion test using design of experiments. The corrosion morphology and the pit morphology were analyzed by optical microscopy, and the corrosion products were examined using scanning electron microscope and X-ray diffraction analysis. From this research work, it is found that, in both corrosion tests, the corrosion rate decreases with the increase in pH value, the decrease in chloride ion concentration, and a higher corrosion time. The results show the usage of the magnesium alloy for best environments and suitable applications from the aforementioned conditions. Also, it is found that AZ61A magnesium alloy welds possess low-corrosion rate and higher-corrosion resistance in the galvanic corrosion test than in the salt spray corrosion test.

  14. Corrosion Behavior of Low-Alloy Pipeline Steel Exposed to H2S/CO2-Saturated Saline Solution

    Science.gov (United States)

    Liu, Zhenguang; Gao, Xiuhua; Du, Linxiu; Li, Jianping; Li, Ping; Bai, Xiaolei; Misra, R. D. K.

    2017-02-01

    Immersion experiments were carried out to study H2S/CO2 corrosion behavior of low-alloy pipeline steel in terms of microstructure, corrosion kinetics, corrosion phases, microscopic surface morphology, cross-sectional morphology and elemental distribution. The experimental results indicated that the microstructure of designed steel was tempered martensite. The corrosion rate followed exponential behavior. H2S corrosion dominated the corrosion process, and the corrosion products were mackinawite, greigite and troilite. The corrosion products changed from mackinawite/greigite to mackinawite/troilite, and mackinawite dominated the corrosion phases. The corrosion products became more compact with immersion time, which led to decrease in corrosion rate. The chromium and molybdenum content in the corrosion product was higher than that in the steel substrate.

  15. Corrosion Behavior of Low-Alloy Pipeline Steel Exposed to H2S/CO2-Saturated Saline Solution

    Science.gov (United States)

    Liu, Zhenguang; Gao, Xiuhua; Du, Linxiu; Li, Jianping; Li, Ping; Bai, Xiaolei; Misra, R. D. K.

    2017-03-01

    Immersion experiments were carried out to study H2S/CO2 corrosion behavior of low-alloy pipeline steel in terms of microstructure, corrosion kinetics, corrosion phases, microscopic surface morphology, cross-sectional morphology and elemental distribution. The experimental results indicated that the microstructure of designed steel was tempered martensite. The corrosion rate followed exponential behavior. H2S corrosion dominated the corrosion process, and the corrosion products were mackinawite, greigite and troilite. The corrosion products changed from mackinawite/greigite to mackinawite/troilite, and mackinawite dominated the corrosion phases. The corrosion products became more compact with immersion time, which led to decrease in corrosion rate. The chromium and molybdenum content in the corrosion product was higher than that in the steel substrate.

  16. Runoff of copper and zinc caused by atmospheric corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Leuenberger-Minger, A.U.; Faller, M.; Richner, P. [Swiss Federal Labs. for Materials Testing and Research (EMPA), Duebendorf (Switzerland)

    2002-03-01

    Runoff and total corrosion loss for copper and zinc were investigated at seven sites in Switzerland. The exposure sites were chosen near the stations of the national air pollution monitoring network (NABEL), where climatic and air pollution data are measured. Runoff and corrosion rates were investigated after 0.5, 1, 2 and 4 years of exposure. Runoff rates differ from corrosion rates depending on the material, the exposure time and the sampling site. (orig.)

  17. Numerical modelling of corrosion - Theoretical backgrounds -

    Energy Technology Data Exchange (ETDEWEB)

    Warkus, J.; Raupach, M. [ibac, RWTH Aachen (Germany); Gulikers, J. [Ministry of Transport, Rijkswaterstaat, Bouwdienst, Utrecht (Netherlands)

    2006-08-15

    During recent years research projects with different approaches have been carried out to develop models which are suitable to assess the metal removal rate in case of reinforcement corrosion. Some of them are based on empirical methods and correlate the corrosion rate to parameters like concrete resistivity, temperature and relative humidity. Another type of model is based on a quantification of the ongoing electrochemical processes. In this paper the theoretical backgrounds and mathematical descriptions of reinforcement corrosion with regard to a numerical modelling are presented and discussed. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  18. The corrosion and corrosion mechanical properties evaluation for the LBB concept in VVERs

    Energy Technology Data Exchange (ETDEWEB)

    Ruscak, M.; Chvatal, P.; Karnik, D.

    1997-04-01

    One of the conditions required for Leak Before Break application is the verification that the influence of corrosion environment on the material of the component can be neglected. Both the general corrosion and/or the initiation and, growth of corrosion-mechanical cracks must not cause the degradation. The primary piping in the VVER nuclear power plant is made from austenitic steels (VVER 440) and low alloy steels protected with the austenitic cladding (VVER 1000). Inspection of the base metal and heterogeneous weldments from the VVER 440 showed that the crack growth rates are below 10 m/s if a low oxygen level is kept in the primary environment. No intergranular cracking was observed in low and high oxygen water after any type of testing, with constant or periodic loading. In the framework of the LBB assessment of the VVER 1000, the corrosion and corrosion mechanical properties were also evaluated. The corrosion and corrosion mechanical testing was oriented predominantly to three types of tests: stress corrosion cracking tests corrosion fatigue tests evaluation of the resistance against corrosion damage. In this paper, the methods used for these tests are described and the materials are compared from the point of view of response on static and periodic mechanical stress on the low alloyed steel 10GN2WA and weld metal exposed in the primary circuit environment. The slow strain rate tests and static loading of both C-rings and CT specimens were performed in order to assess the stress corrosion cracking characteristics. Cyclic loading of CT specimens was done to evaluate the kinetics of the crack growth under periodical loading. Results are shown to illustrate the approaches used. The data obtained were evaluated also from the point of view of comparison of the influence of different structure on the stress corrosion cracking appearance. The results obtained for the base metal and weld metal of the piping are presented here.

  19. Corrosion of mild steel, copper and brass in crude oil / seawater mixture

    Digital Repository Service at National Institute of Oceanography (India)

    PrabhaDevi, S.; Sawant, S.S.; Wagh, A.B.

    Mild steel, copper and brass coupons were introduced in natural seawater containing varying amount of crude oil. Mild steel showed higher rate of corrosion in seawater containing oil and lower corrosion rate in natural as well as artificial seawater...

  20. Monitoring Techniques for Microbially Influenced Corrosion of Carbon Steel

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    2000-01-01

    Microbially influenced corrosion (MIC) of carbon steel may occur in media with microbiological activity of especially sulphate-reducing bacteria, e.g. on pipelines buried in soil and on marine structures. MIC of carbon steel must be monitored on-line in order to provide an efficient protection...... corrosion and detects localised corrosion, but the sensitivity is not high enough for monitoring initiation of pitting and small attacks. Electrochemical techniques as LPR and EIS give distorted data and unreliable corrosion rates, when biofilm and corrosion products cover the steel surface. However, EIS...... and control the corrosion. A number of monitoring techniques is industrially used today, and the applicability and reliability of these for monitoring MIC is evaluated. Coupons and ER are recommended as necessary basic techniques even though localised corrosion rate cannot be measured. FSM measures general...

  1. Monitoring Techniques for Microbially Influenced Corrosion of Carbon Steel

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    2000-01-01

    and control the corrosion. A number of monitoring techniques is industrially used today, and the applicability and reliability of these for monitoring MIC is evaluated. Coupons and ER are recommended as necessary basic techniques even though localised corrosion rate cannot be measured. FSM measures general......Microbially influenced corrosion (MIC) of carbon steel may occur in media with microbiological activity of especially sulphate-reducing bacteria, e.g. on pipelines buried in soil and on marine structures. MIC of carbon steel must be monitored on-line in order to provide an efficient protection...... corrosion and detects localised corrosion, but the sensitivity is not high enough for monitoring initiation of pitting and small attacks. Electrochemical techniques as LPR and EIS give distorted data and unreliable corrosion rates, when biofilm and corrosion products cover the steel surface. However, EIS...

  2. Corrosion problems with aqueous coolants, final report

    Energy Technology Data Exchange (ETDEWEB)

    Diegle, R B; Beavers, J A; Clifford, J E

    1980-04-11

    The results of a one year program to characterize corrosion of solar collector alloys in aqueous heat-transfer media are summarized. The program involved a literature review and a laboratory investigation of corrosion in uninhibited solutions. It consisted of three separate tasks, as follows: review of the state-of-the-art of solar collector corrosion processes; study of corrosion in multimetallic systems; and determination of interaction between different waters and chemical antifreeze additives. Task 1 involved a comprehensive review of published literature concerning corrosion under solar collector operating conditions. The reivew also incorporated data from related technologies, specifically, from research performed on automotive cooling systems, cooling towers, and heat exchangers. Task 2 consisted of determining the corrosion behavior of candidate alloys of construction for solar collectors in different types of aqueous coolants containing various concentrations of corrosive ionic species. Task 3 involved measuring the degradation rates of glycol-based heat-transfer media, and also evaluating the effects of degradation on the corrosion behavior of metallic collector materials.

  3. Corrosion resistance of monolayer hexagonal boron nitride on copper

    Science.gov (United States)

    Mahvash, F.; Eissa, S.; Bordjiba, T.; Tavares, A. C.; Szkopek, T.; Siaj, M.

    2017-02-01

    Hexagonal boron nitride (hBN) is a layered material with high thermal and chemical stability ideal for ultrathin corrosion resistant coatings. Here, we report the corrosion resistance of Cu with hBN grown by chemical vapor deposition (CVD). Cyclic voltammetry measurements reveal that hBN layers inhibit Cu corrosion and oxygen reduction. We find that CVD grown hBN reduces the Cu corrosion rate by one order of magnitude compared to bare Cu, suggesting that this ultrathin layer can be employed as an atomically thin corrosion-inhibition coating.

  4. Modelling of Corrosion Cracks

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    Modelling of corrosion cracking of reinforced concrete structures is complicated as a great number of uncertain factors are involved. To get a reliable modelling a physical and mechanical understanding of the process behind corrosion in needed.......Modelling of corrosion cracking of reinforced concrete structures is complicated as a great number of uncertain factors are involved. To get a reliable modelling a physical and mechanical understanding of the process behind corrosion in needed....

  5. Controlling internal corrosion of oil and gas pipelines : the corrosion inhibitor selection software (CISS) program

    Energy Technology Data Exchange (ETDEWEB)

    Doiron, A.; Papavinasam, S. [Natural Resources Canada, Ottawa, ON (Canada). CANMET Materials Technology Laboratory

    2009-07-01

    The internal pitting corrosion of oil and gas pipelines can be effectively controlled through the addition of inhibitors. However, simulation of field operating conditions is necessary because the performance of corrosion inhibitors is influenced by several interacting parameters. This paper reviewed the Corrosion Inhibitor Selection Software (CISS) program. The materials transported in production pipelines are often multiphase, containing oil, aqueous (brine), and gas phases. The corrosion rate and inhibitor performance are influenced by composition, temperature, flow and pressure. Steel composition and structure also influence both the rate and type of corrosion. Improvements in corrosion test methodologies are aimed at simulating field corrosion conditions in the laboratory in a compressed time-scale. The parameters that influence the types of corrosion must be simulated in order for laboratory methodology to be relevant. The variables controlled should be quantifiable. There should also be a correlation between the influence of variables controlled in the laboratory and of the same variables in the field. The CISS program evaluates inhibitors in the following 4 steps: (1) pipeline operating conditions, (2) selection of laboratory methodology, (3) determination of operating conditions for the laboratory methodologies, and (4) selection of corrosion inhibitors. The 7 objectives of the CISS program are to optimize the strategies of inhibitor selection for pipeline applications; determine the hydrodynamic parameters of the pipe from field operating conditions; select appropriate laboratory methodologies for evaluating inhibitors; determine flow conditions for high-shear laboratory methodologies; develop a qualitative relationship between corrosion rates of non-shear laboratory methodologies and of pipelines; evaluate corrosion inhibitors based on results from different laboratory methodologies; and design cost-effective inhibitors for future applications. 47 refs

  6. Management of Reinforcement Corrosion

    DEFF Research Database (Denmark)

    Küter, André; Geiker, Mette Rica; Møller, Per

    Reinforcement corrosion is the most important cause for deterioration of reinforced concrete structures, both with regard to costs and consequences. Thermodynamically consistent descriptions of corrosion mechanisms are expected to allow the development of innovative concepts for the management...... of reinforcement corrosion....

  7. Prediction of microsegregation and pitting corrosion resistance of austenitic stainless steel welds by modelling

    Energy Technology Data Exchange (ETDEWEB)

    Vilpas, M. [VTT Manufacturing Technology, Espoo (Finland). Materials and Structural Integrity

    1999-07-01

    solidification, the dendrite cores were predicted to be the weakest link with respect to weld pitting corrosion resistance. In primary ferritic solidification, the second phase austenite in the vicinity of d/g interfaces was predicted to show lowest pitting corrosion resistance. Solidification parameters used in the modelling were verified by cooling rate and dendrite arm spacing measurements as well as by analytical calculations. Experimental investigations using electron probe microanalyses (EPMA, CMA), electron microscopy (SEM, FEG-STEM), microstructural investigations and pitting corrosion tests were used in assessing the calculated microsegregation and CPT-temperatures and showed a reasonably good compatibility with the results of modelling. (orig.)

  8. Influence of Organic Inhibitor on Corrosion Resistance of Steel in Simulated Concrete Pore Solution

    OpenAIRE

    Cai, Jingshun S.; C. C. CHEN; Liu, J. Z.; Liu, J. P.

    2014-01-01

    Organic corrosion inhibitor is one of lower cost technologies that limit the deterioration of concrete structures. The influence of a newly prepared organic corrosion inhibitor on the corrosion behavior of carbon steel in simulated concrete pore solution was investigated by polarization curves, electrochemical impedance spectroscopy, and so on. The effect of organic corrosion inhibitors on concrete working performance was also studied. The results show that the corrosion rate decreases with t...

  9. Influence of Zinc Addition on Corrosion Rate of AP65 Anodes%Zn元素对AP65镁阳极材料腐蚀速率的影响

    Institute of Scientific and Technical Information of China (English)

    彭文静; 金和喜; 刘伟成

    2015-01-01

    Mg⁃6%Al⁃5%Pb⁃Zn anodes were prepared by fusion metallurgy and homogenization treatment. The effect of zinc content on the corrosion rate of AP65 anode was studied by the methods of immersion, constant current polarization and potentiodynamic scanning. The experimental results showed that the AP65 anode had shorter activation time, enhanced electrochemical activity and higher corrosion rate after the addition of zinc. The corrosion current density of APZ1.5 anode was 0.020 mA/cm2, while the APZ1.0 anode with the open circuit potential up to -1.643 V(vs SCE) had the corrosion current density of 0.018 mA/cm2 , indicating a good comprehensive performance. The addition of zinc made the open circuit potential of AP65 magnesium anode obviously changed. However, the positive or negative change trend has no linear relationship with zinc content.%经熔炼、均匀化处理制备了Mg⁃6%Al⁃5%Pb⁃Zn镁阳极材料。采用浸泡法、恒电流极化法和动电位扫描法研究不同Zn含量对AP65镁阳极腐蚀速率的影响。结果表明:添加Zn元素后,AP65镁阳极激活时间变短、电化学活性增强、自腐蚀速率增大。 APZ1.5阳极的腐蚀电流密度为0.020 mA/cm2。 APZ1.0合金开路电位达-1.643 V(vs SCE),腐蚀电流密度为0.018 mA/cm2,具有相对较好的综合性能。 Zn元素的加入使AP65镁阳极开路电位发生明显改变,但正向或负向移动趋势与Zn元素含量并不成线性对应关系。

  10. Corrosion inhibitors; Los inhibidores de corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Godinez, L. A.; Meas, Y.; Ortega-Borges, R.; Corona, A.

    2003-07-01

    In this paper, we briefly describe the characteristics, cost and electrochemical nature of the corrosion phenomena as well as some of the technologies that are currently employed to minimize its effect. The main subject of the paper however, deals with the description, classification and mechanism of protection of the so-called corrosion inhibitors. Examples of the use of these substances in different aggressive environments are also presented as means to show that these compounds, or their combination, can in fact be used as excellent and relatively cheap technologies to control the corrosion of some metals. In the last part of the paper, the most commonly used techniques to evaluate the efficiency and performance of corrosion inhibitors are presented as well as some criteria to make a careful and proper selection of a corrosion inhibitor technology in a given situation. (Author) 151 refs.

  11. Non-destructive elecrochemical monitoring of reinforcement corrosion

    DEFF Research Database (Denmark)

    Nygaard, Peter Vagn

    been widely accepted as a non-destructive ”state of the art” technique for detection of corrosion in concrete structures. And, over the last decade, the trend in corrosion monitoring has moved towards quantitative non-destructive monitoring of the corrosion rate of the steel reinforcement. A few...... corrosion rate measurement instruments have been developed and are commercially available. The main features of these instruments are the combined use of an electrochemical technique for determining the corrosion rate and a so-called ”confinement technique”, which in principle controls the polarised surface...... area of the reinforcement, i.e. the measurement area. Both on-site investigations and laboratory studies have shown that varying corrosion rates are obtained when the various commercially available instruments are used. And in the published studies, conflicting explanations are given illustrating...

  12. Effect of combinative addition of strontium and rare earth elements on corrosion resistance of AZ91D magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    NIU Jie-xin; CHEN Qiu-rong; XU Nai-xin; WEI Zhong-ling

    2008-01-01

    The influence of strontium(Sr) and rare earth(RE) elements on the corrosion behavior of AZ91D magnesium alloy was investigated by conventional corrosion testing and electrochemical measurements in 3.5% NaCI solution. After comparing the mass loss and hydrogen evolution of the samples, the microstruetures of the alloys and the morphologies of their corrosion product films were characterized by electron probe microanalysis-energy dispersive spectrometry(EPMA-EDS) and Auger electron spectroscopy(AES). Compared with individual addition of Sr or RE to AZ91D, the combinative addition of 0.5% Sr and 1% RE to AZ91D successfully decreases the corrosion rate further, which can be attributed to the depression of micro-galvanic couples, as well as the formation of more protective film due to aluminum enrichment. The combinative addition of strontium and rare earth elements to AZ91D magnesium alloy appears to he a promising approach to increase its corrosion resistance.

  13. A NOVEL MODEL FOR PREDICTING FLOW ACCELERATED CORROSION RATE IN REDUCER%一种预测异径管流动加速腐蚀速率的新模型

    Institute of Scientific and Technical Information of China (English)

    陆晓峰; 朱晓磊; 凌祥

    2011-01-01

    A new prediction model was proposed to calculate the flow accelerated corrosion (FAC) rate in reducer, which was coupled the steady-state mass transfer model electrochemical theory and one-dimensional galvanic corrosion model. Firstly, the steady-state mass transfer model was used to obtain the distribution of concentration polarization current density and the concentration polarization corrosion potential of velocity extreme point near the wall of reducer. The galvanic corrosion current density was calculated by substituting the potential into one-dimensional galvanic corrosion model. The new model was employed to calculate the reducer; the results showed that the corrosion current density of large-end was larger two orders than that of small-end. Compared with the FAC rate calculated by the wall shear stress theory, presented by Efird and Cheng, or by purely steady-state mass transfer theory, the results obtained by the new model have good agreement with the practical situation which were counted 2000 pipe fittings in Taiwan nuclear power plant by Kuen Ting. The statistical result showed that the large-end of reducer appeared the maximum of reduction of thickness.%通过将稳态传质模型和一维电偶腐蚀模型耦合,提出了预测异径管流动加速腐蚀速率的新模型。该模型先由稳态传质模型得到异径管近壁面处的自腐蚀电流密度分布和速度极值点处的自腐蚀电位,而后将极值点处自腐蚀电位代入到一维电偶腐蚀模型中,计算该壁面处的电偶腐蚀电流密度。应用此新模型对某一异径管流动加速腐蚀速率进行计算,发现异径管大端的腐蚀电流密度比小端腐蚀电流密度大两个数量级,据此可以解释台湾某核电站蒸汽冷凝水管线统计得出异径管大端出现最大减薄量的现象。与壁面剪切应力理论和稳态传质理论计算流动加速腐蚀速率分布相比,该模型的计算结果更贴近实际情况。

  14. Effects of Cr, Ni and Cu on the Corrosion Behavior of Low Carbon Microalloying Steel in a Cl-Containing Environment

    Institute of Scientific and Technical Information of China (English)

    Yanlei Zhou; Jun Chen; Yang Xu; Zhenyu Liu

    2013-01-01

    The effects of Cr,Ni and Cu on the corrosion behavior of low carbon microalloying steel in a Cl-containing environment were investigated.The results revealed that the corrosion process could be divided into the initial stage in which the corrosion rate increased with accumulation of corrosion products and the later stage in which homogeneous and compact inner rust layers started to protect steel substrate out of corrosion mediums.The results of X-ray diffraction (XRD) indicated that the rust layers of the three-group steels (Cr,Cr-Ni and Cr-Ni-Cu steels) were composed of α-FeOOH,β-FeOOH,γ-FeOOH,Fe3O4 and large amounts of amorphous compounds.The content of amorphous compounds of Cr-Ni-Cu steel was about 2%-3% more than that of Cr-Ni steel.The results of electron probe microanalysis (EPMA) showed that Cr concentrated mainly in the inner region of the rust of Cr-Ni-Cu steel,inner/outer interface especially,whereas Ni was uniformly distributed all over the rust and Cu was noticed rarely after 73 wet/dry cycles.The addition of Cr and Ni was beneficial to the formation of dense and compact inner rust layer,which was the most important reason for the improvement of corrosion resistance of experimental steel.

  15. Reliability Model of Corrosion Fatigue Crack Growth Rate Evaluation of LD10CS Aluminum Alloy%LD10CS腐蚀疲劳裂纹扩展速率评价的可靠性模型

    Institute of Scientific and Technical Information of China (English)

    贾明明; 李旭东; 吕航

    2014-01-01

    腐蚀损伤会加速疲劳载荷下的飞机铝合金结构裂纹的萌生和扩展,威胁结构安全性。针对腐蚀影响下的疲劳裂纹扩展的随机性本质,对预腐蚀 LD10CS 合金的预腐蚀疲劳试验进行了数据分析,提出了基于可靠性的腐蚀裂纹扩展速率表征方法,与试验结果对比表明,该方法可以给出 LD10CS 腐蚀疲劳裂纹扩展速率的上下限,进而给出该种材料铝合金构件的疲劳裂纹扩展寿命的上下限,为评估铝合金构件的寿命提供了依据。%Fatigue loadings and environmental corrosion damage can decrease the mechanical properties of LD10CS alu-minum alloy.The paper made a research on the fatigue crack growth rate (FCG)of AA LD10CS with corrosion damage, and proposed a reliability-based method to evaluate FCG.Compare of predicted FCG and experimental results indicated that the proposed method was able to give the lower and upper limit of FCG of LD10CS with corrosion damage,which provided the basis of aluminum alloy component safe life prediction.

  16. Corrosion inhibitors for intermediate cooling systems

    Energy Technology Data Exchange (ETDEWEB)

    Falk, I.; Suhr, L.

    1985-04-01

    The selected inhibitors were tested for heat and radiation stability and corrosion protection on the bench scale. Based on the results from these tests two of the products were selected, Bycoguard 81 and Bycoguard MP4S for continuing corrosion tests in an autoclave loop at 90 degrees C and 120 degrees C. Oxygen saturated deionized water with an addition of 1 ppm chloride was recirculated in the loop. Samples of copper and carbon steel were exposed to the water in the autoclave for periods up to 10 weeks. The purpose of this project was to find a substitute for hydrazine and chromates. Besides good corrosion protection qualities the toxic and environmental effect of the inhibitors should be minimal. The investigation has shown that the copper inhibitor BTA (benzotriazole) loses its corrosion protection qualities at a water temperature of 120 degrees C. The protection effects at 90 degrees C were satisfactory for both of the materials. The corrosion rates measured were 0.01 mm/y or less for the copper and carbon steel samples. The environment in the autoclave during the testing was more corrosive than is to be found in intermediate cooling systems. Due to the low corrosion rates measured the two inhibitors are to be recommended as alternatives to hydrazine and chromates.

  17. Marine atmospheric corrosion of carbon steels

    Energy Technology Data Exchange (ETDEWEB)

    Morcillo, M.; Alcantara, J.; Diaz, I.; Chico, B.; Simancas, J.; Fuente, D. de la

    2015-07-01

    Basic research on marine atmospheric corrosion of carbon steels is a relatively young scientific field and there continue to be great gaps in this area of knowledge. The presence of akaganeite in the corrosion products that form on steel when it is exposed to marine atmospheres leads to a notable increase in the corrosion rate. This work addresses the following issues: (a) environmental conditions necessary for akaganeite formation; (b) characterisation of akaganeite in the corrosion products formed; (c) corrosion mechanisms of carbon steel in marine atmospheres; (d) exfoliation of rust layers formed in highly aggressive marine atmospheres; (e) long-term corrosion rate prediction; and (f) behaviour of weathering steels. Field research has been carried out at Cabo Vilano wind farm (Camarinas, Galicia) in a wide range of atmospheric salinities and laboratory work involving the use of conventional atmospheric corrosion techniques and near-surface and bulk sensitive analytical techniques: scanning electron microscopy (SEM)/energy dispersive spectrometry (EDS), X-ray diffraction (XRD), Mossbauer spectroscopy and SEM/μRaman spectroscopy. (Author)

  18. Evaluation of zinc addition on fuel cladding corrosion at the Halden test reactor. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kolstad, E.; Symons, W.J.; Bryhn-Integrigtsen, K.; Oberlaender, B.C.

    1996-08-01

    Experimental studies have shown that addition of zinc to a PWR environment reduces the general corrosion rates of materials in the primary system and delays the initiation of primary water stress corrosion cracking (PWSCC) in Alloy 600. In order to provide an early warning of any potential adverse effects on the fuel cladding, corrosion studies were initiated at the Halden test reactor. These tests were carried out in a PWR rig inserted in the Halden reactor core. The rig simulated thermal hydraulic and coolant conditions typical of a MR. It had two flow channels where the fuel rod segments were exposed to the coolant under irradiation flux. Selected pre-characterized rodlets with fresh and pre-irradiated standard and low-tin Zircaloy-4 material were irradiated for three cycles. First cycle lasted for 110 effective full power days (EFPDs), the second for 95 EFPDs and the last 62 EFPDs. The cladding corrosion behavior was monitored by initial, interim and final oxide thickness measurements by eddy current lift-off probe. Crud sampling was performed in both channels after cycle 1 and 2. Destructive post-irradiation examinations (PIE) of two rodlets, irradiated during cycle 1 and 2, have also been completed at the conclusion of the in-pile testing. This report presents the results on oxide thickness measurements, irradiation history and water chemistry data, and the PIE.

  19. Internal corrosion of carbon steel piping in hot aquifers service

    Directory of Open Access Journals (Sweden)

    Simičić Miloš V.

    2011-01-01

    Full Text Available Internal corrosion of carbon steel pipelines is a major problem encountered in water service. In terms of prediction of the remaining lifetime for water pipelines based on the corrosion allowance, the three main approaches are corrosion modelling, corrosion inhibitor availability, and corrosion monitoring. In this study we used two theoretical corrosion models, CASSANDRA and NORSOK M-506 of quite different origin in order to predict uniform corrosivity of hot aquifers in eight different pipelines. Because of the varying calculation criteria for the different models, these can give very different corrosion rate predictions for the same data input. This is especially true under conditions where the formation of protective films may occur, such as at elevated temperatures. The evaluation of models was conducted by comparison using weight-loss coupons and three corrosion inhibitors were obtained from commercial suppliers. The tests were performed during the 60-day period. Even though inhibitors’ efficiencies of 98% had been achieved in laboratory testing, inhibitors’ availabilities of 85% have been used due to logistics problems and other issues. The results, given in mmpy, i.e. millimeter per year, are very consistent with NORSOK M-506 prediction. This is presumably because the model considers the effect of the formation of a passive iron carbonate film at temperatures above 80 °C and significant reduction in corrosion rate. Corrosion inhibitor A showed a better performance than inhibitors B and C in all cases but the target corrosion rates of less than 0.1 mmpy were achieved for all inhibitors. The chemical type of corrosion inhibitor A is based on quaternary amines mixed with methanol, isopropyl alcohol, xylene and ethylbenzene. Based on the obtained results the carbon steel lifetime of 30 years, provided proper inhibitors are present and 3mm corrosion allowance, can be achieved for hot aquifers service with presented water compositions.

  20. Launch Pad Coatings for Smart Corrosion Control

    Science.gov (United States)

    Calle, Luz M.; Hintze, Paul E.; Bucherl, Cori N.; Li, Wenyan; Buhrow, Jerry W.; Curran, Jerome P.; Whitten, Mary C.

    2010-01-01

    Corrosion is the degradation of a material as a result of its interaction with the environment. The environment at the KSC launch pads has been documented by ASM International (formerly American Society for Metals) as the most corrosive in the US. The 70 tons of highly corrosive hydrochloric acid that are generated by the solid rocket boosters during a launch exacerbate the corrosiveness of the environment at the pads. Numerous failures at the pads are caused by the pitting of stainless steels, rebar corrosion, and the degradation of concrete. Corrosion control of launch pad structures relies on the use of coatings selected from the qualified products list (QPL) of the NASA Standard 5008A for Protective Coating of Carbon Steel, Stainless Steel, and Aluminum on Launch Structures, Facilities, and Ground Support Equipment. This standard was developed to establish uniform engineering practices and methods and to ensure the inclusion of essential criteria in the coating of ground support equipment (GSE) and facilities used by or for NASA. This standard is applicable to GSE and facilities that support space vehicle or payload programs or projects and to critical facilities at all NASA locations worldwide. Environmental regulation changes have dramatically reduced the production, handling, use, and availability of conventional protective coatings for application to KSC launch structures and ground support equipment. Current attrition rate of qualified KSC coatings will drastically limit the number of commercial off the shelf (COTS) products available for the Constellation Program (CxP) ground operations (GO). CxP GO identified corrosion detection and control technologies as a critical, initial capability technology need for ground processing of Ares I and Ares V to meet Constellation Architecture Requirements Document (CARD) CxP 70000 operability requirements for reduced ground processing complexity, streamlined integrated testing, and operations phase affordability

  1. Corrosion protection with eco-friendly inhibitors

    Science.gov (United States)

    Shahid, Muhammad

    2011-12-01

    Corrosion occurs as a result of the interaction of a metal with its environment. The extent of corrosion depends on the type of metal, the existing conditions in the environment and the type of aggressive ions present in the medium. For example, CO3-2 and NO-3 produce an insoluble deposit on the surface of iron, resulting in the isolation of metal and consequent decrease of corrosion. On the other hand, halide ions are adsorbed selectively on the metal surface and prevent formation of the oxide phase on the metal surface, resulting in continuous corrosion. Iron, aluminum and their alloys are widely used, both domestically and industrially. Linear alkylbenzene and linear alkylbenzene sulfonate are commonly used as detergents. They have also been found together in waste water. It is claimed that these chemicals act as inhibitors for stainless steel and aluminum. Release of toxic gases as a result of corrosion in pipelines may lead in certain cases to air pollution and possible health hazards. Therefore, there are two ways to look at the relationship between corrosion and pollution: (i) corrosion of metals and alloys due to environmental pollution and (ii) environmental pollution as a result of corrosion protection. This paper encompasses the two scenarios and possible remedies for various cases, using 'green' inhibitors obtained either from plant extracts or from pharmaceutical compounds. In the present study, the effect of piperacillin sodium as a corrosion inhibitor for mild steel was investigated using a weight-loss method as well as a three-electrode dc electrochemical technique. It was found that the corrosion rate decreased as the concentration of the inhibitor increased up to 9×10-4 M 93% efficiency was exhibited at this concentration.

  2. In vitro corrosion of Mg-Ca alloy — The influence of glucose content

    Science.gov (United States)

    Cui, Lan-Yue; Li, Xiao-Ting; Zeng, Rong-Chang; Li, Shuo-Qi; Han, En-Hou; Song, Liang

    2017-09-01

    Influence of glucose on corrosion of biomedical Mg-1.35Ca alloy was made using hydrogen evolution, pH and electrochemical polarization in isotonic saline solution. The corrosion morphologies, compositions and structures were probed by virtue of SEM, EDS, FTIR, XRD and XPS. Results indicate that the glucose accelerated the corrosion of the alloy. The elemental Ca has no visible effect on the corrosion mechanism of glucose for the Mg-1.35Ca alloy in comparison with pure Mg. In addition, the presence of CO2 has beneficial effect against corrosion due to the formation of a layer of carbonatecontaining products.

  3. The Pitting Corrosion Rate Of Super13Cr、15Cr Stainless Steel Under Oil Field Acidizing Environment%油田酸化环境下超级13Cr、15Cr不锈钢的点蚀速率研究

    Institute of Scientific and Technical Information of China (English)

    宋文文; 金伟; 耿海龙; 杜金楠; 高文祥

    2016-01-01

    本文研究了超级13Cr和15Cr马氏体不锈钢分别在120℃和95℃全程酸化(鲜酸+残酸)实验中的耐点蚀性能。结果表明:超级13Cr和15Cr不锈钢在120℃条件下的点蚀速率分别为1.59mm/a和1.35mm/a;在95℃条件下的点蚀速率分别为6.55mm/a 和2.60mm/y;95℃条件下两种材质的点蚀速率高于120℃条件下的点蚀速率;在两种腐蚀条件下15Cr较13Cr表现出更优异的耐点蚀性能。%This paper studied the pitting corrosion resistance performance of super 13Cr and 15Cr stainless steel under the entire acidizing (fresh acid + residual acid) experiment at 120℃ and 95℃.The results showed that pitting corrosion rates of super 13Cr and 15Cr stainless steel were 1.59 mm/a and 1.35mm/aat 120℃; The pitting corrosion rates of super 13Cr and 15Cr stainless steel were 6.5mm/a and 2.6mm/aat 95℃;The pitting corrosion rates of the two materialsat 95℃ were higher than pitting corrosion rates at 120℃;The pitting corrosion resistance of super 15Cr was better than 13Cr stainless steel in the two corrosion conditions.

  4. General Corrosion and Localized Corrosion of Waste Package Outer Barrier

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, J.C.; McCright, R.D.

    2000-01-28

    Alloy 22 is an extremely Corrosion Resistant Material, with a very stable passive film. Based upon exposures in the LTCTF, the GC rates of Alloy 22 are typically below the level of detection, with four outliers having reported rates up to 0.75 #mu#m per year. In any event, over the 10,000 year life of the repository, GC of the Alloy 22 (assumed to be 2 cm thick) should not be life limiting. Because measured corrosion potentials are far below threshold potentials, localized breakdown of the passive film is unlikely under plausible conditions, even in SSW at 120 deg C. The pH in ambient-temperature crevices formed from Alloy 22 have been determined experimentally, with only modest lowering of the crevice pH observed under plausible conditions. Extreme lowering of the crevice pH was only observed under situations where the applied potential at the crevice mouth was sufficient to result in catastrophic breakdown of the passive film above the threshold potential in non-buffered conditions not characteristic of the Yucca Mountain environment. In cases where naturally ocurring buffers are present in the crevice solution, little or no lowering of the pH was observed, even with significant applied potential. With exposures of twelve months, no evidence of crevice corrosion has been observed in SDW, SCW and SAW at temperatures up to 90 deg C. An abstracted model has been presented, with parameters determined experimentally, that should enable performance assessment to account for the general and localized corrosion of this material. A feature of this model is the use of the materials specification to limit the range of corrosion and threshold potentials, thereby making sure that substandard materials prone to localized attack are avoided. Model validation will be covered in part by a companion SMR on abstraction of this model.

  5. CORROSION OF LEAD SHIELDING IN NUCLEAR MATERIALS PACKAGES

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, K; Kerry Dunn, K; Joseph Murphy, J

    2008-07-18

    Inspection of United States-Department of Energy (US-DOE) model 9975 nuclear materials shipping package revealed corrosion of the lead shielding that was induced by off-gas constituents from organic components in the package. Experiments were performed to determine the corrosion rate of lead when exposed to off-gas or degradation products of these organic materials. The results showed that the room temperature vulcanizing (RTV) sealant was the most corrosive organic species used in the construction of the packaging, followed by polyvinyl acetate (PVAc) glue. Fiberboard material, also used in the construction of the packaging induced corrosion to a much lesser extent than the PVAc glue and RTV sealant, and only in the presence of condensed water. The results indicated faster corrosion at temperatures higher than ambient and with condensed water. In light of these corrosion mechanisms, the lead shielding was sheathed in a stainless steel liner to mitigate against corrosion.

  6. METAL CORROSION IN WATERBORNE PRESERVATIVE- TREATED WOOD

    Directory of Open Access Journals (Sweden)

    Krisdianto Sugiyanto

    2010-12-01

    Full Text Available The rigidity and firmness of wooden construction and furniture those are joined by metal screws depend on corrosion rate of these metals. This paper examines the weight-loss percentage of metal screws used in wood samples that have been treated with water-borne preser vative (i.e.3% borax boric acid and 3% diffusol CB and concurrently investigates the effect of brake fluid on preventing metal corrosion. Wood samples tested included three acacia and one eucalypts wood species which were grouped into sapwood and heartwood containing samples. Wood samples fastened with metal screws were freely suspended in glass jars that contained 25 ml of sulphuric acid (H2SO4 to keep the humidity rate above 90%. After 12 months, the metal screws lost their weight due to the corrosion brought about by the related factors either in separate individual or in combination, which comprised brake and fluid-dipping , wood species, wood portion (sapwood and heartwood, kinds of preser vatives used. Corrosion rates of metal screws fastened in eucalypts wood sample as indicated by the screw-weight loss (i.e. 5.8% was more severe than that fastened in acacia wood. Furthermore, corrosion rate of metal screws as fixed firmly in sapwood sample proceeded faster than that in heartwood. This might be caused by the higher moisture content in sapwood. On the other hand, corrosion rate of the screws as fastened in waterborne-preser vative-treated wood samples was greater than that in non-preser ved wood due to electrokinetic characteristics and ionic potential exhibited by the preser vative thereby intensif ying the screw-corrosion process. Meanwhile, less severe corrosion was obser ved and recorded on the screws pre-dipped in brake fluid compared to those on the non-dipped screws

  7. Correlation of Process Data and Electrocheical Noise to Assess Kraft Digester Corrosion: Second Year at Spring Grove

    Energy Technology Data Exchange (ETDEWEB)

    Pawel, SJ

    2004-04-27

    Electrochemical noise (EN) probes were deployed in the carbon steel continuous kraft digester at Spring Grove at four locations and at one location in the bottom cone of the associated flash tank for a second consecutive year of a corrosion study. The probes contained dual electrodes of 309LSi stainless steel overlay--representing a field repair material applied to a portion of the vessel--and dual electrodes of 312 stainless steel overlay. Current and potential noise, the temperature at each probe location, and the value of 23 process parameters (flow rates, liquor chemistry, etc.) were again monitored continuously for a period of almost one year. Historical vessel inspection data and post-test evaluation of the probe components were used to assess/compare EN corrosion activity with physical changes in wall thickness and corrosion patterns on the digester shell. In addition, attempts were made to correlate EN activity from each electrode type with process parameters. The results indicate the corrosion conditions aggressive to mild steel persist within the digester, as post-test inspection of the vessel revealed localized corrosion of mild steel in locations previously free of attack. Further, there was evidence that the depth of localized attack of exposed steel had increased in some locations. Nevertheless, the stainless steel overlay in the digester was essentially immune to corrosion, as evidenced by retained surface relief and heat tint associated with the original deposition process. The 309LSi electrodes also appeared visually pristine, and post-exposure metallographic examination of the 309LSi electrode materials revealed no attack. The 312 electrode materials were similar in appearance, but exhibited very minor interdendritic attack over the exposed surface. The silver electrodes in the probes were consumed (to Ag{sub 2}S) to variable degree over the course of the exposure indicating a useful life of not more than a year in digester service in this vessel

  8. MICROSCOPIC CORROSION STUDIES OF DUPLEX STAINLESS STEELS

    Institute of Scientific and Technical Information of China (English)

    C.Leygraf; J.Pan; M.Femenia

    2004-01-01

    Electrochemical scanning tunneling microscopy and scanning electrochemical microscopy have been used for in situ monitoring of localized corrosion processes of different Duplex stainless steels (DSS) in acidic chloride solutions. The techniques allow imaging of local dissolution events with micrometer resolution, as opposed to conventional electrochemical techniques, which only give an overall view of the corrosion behavior. In addition, combined scanning Kelvin probe force microscopy and magnetic force microscopy were used for mapping the Volta potential variation over the surface of DSSs. A significant difference in Volta potential between the austenite and ferrite phases suggests galvanic interaction between the phases. A compositional gradient appears within 2 micrometers across the phase boundary, as seen with scanning Auger microscopy (SAM). In all, the studies suggest that higher alloyed DSS exhibit a more homogeneous dissolution behavior than lower alloyed DSS, due to higher and more similar corrosion resistance of the two phases, and enhanced resistance of the ferrite/austenite phase boundary regions.

  9. EFFECT OF CHLORIDE ON THE ATMOSPHERIC CORROSION OF SIMULATED ARTIFACT IRON IN NO3-BEARING POLLUTANT ENVIRONMENT

    Institute of Scientific and Technical Information of China (English)

    X. Cao; C.C. Xu

    2006-01-01

    The effect of chloride in nitrogen-bearing pollutant on the atmospheric corrosion of cast iron was investigated by using periodic wet-dry test, electrochemical experiment and surface tension test.Scanning electron microscopy (SEM) with energy disperse atomic X-ray (EDAX) was used to identify the corrosion processes and products. The results of the weight loss measurement showed that the whole corrosion kinetics can be approximately described by: AW=AtB. With the addition of NaC1, B increases. The result presented that Cl- accelerated the corrosion rate obviously during the whole corrosion process. The initial corrosion process was investigated from the viewpoint of surface tension. At the initial corrosion period, the corrosion rate was proportion to the adsorption of anions contained the solutions. And as corrosion went on, the penetration effect of anions and different characteristics of the corrosion products began to dominant the corrosion process, which led to the accelerated effect.

  10. Mobile Probing and Probes

    DEFF Research Database (Denmark)

    2013-01-01

    Mobile probing is a method, developed for learning about digital work situations, as an approach to discover new grounds. The method can be used when there is a need to know more about users and their work with certain tasks, but where users at the same time are distributed (in time and space......). Mobile probing was inspired by the cultural probe method, and was influenced by qualitative interview and inquiry approaches. The method has been used in two subsequent projects, involving school children (young adults at 15-17 years old) and employees (adults) in a consultancy company. Findings point...... to mobile probing being a flexible method for uncovering the unknowns, as a way of getting rich data to the analysis and design phases. On the other hand it is difficult to engage users to give in depth explanations, which seem easier in synchronous dialogs (whether online or face2face). The development...

  11. Mobile Probing and Probes

    DEFF Research Database (Denmark)

    2012-01-01

    Mobile probing is a method, which has been developed for learning about digital work situations, as an approach to discover new grounds. The method can be used when there is a need to know more about users and their work with certain tasks, but where users at the same time are distributed (in time...... and space). Mobile probing was inspired by the cultural probe method, and was influenced by qualitative interview and inquiry approaches. The method has been used in two subsequent projects, involving school children (young adults at 15-17 years old) and employees (adults) in a consultancy company. Findings...... point to mobile probing being a flexible method for uncovering the unknowns, as a way of getting rich data to the analysis and design phases. On the other hand it is difficult to engage users to give in depth explanations, which seem easier in synchronous dialogs (whether online or face2face...

  12. Mobile Probing and Probes

    DEFF Research Database (Denmark)

    2012-01-01

    Mobile probing is a method, which has been developed for learning about digital work situations, as an approach to discover new grounds. The method can be used when there is a need to know more about users and their work with certain tasks, but where users at the same time are distributed (in time...... and space). Mobile probing was inspired by the cultural probe method, and was influenced by qualitative interview and inquiry approaches. The method has been used in two subsequent projects, involving school children (young adults at 15-17 years old) and employees (adults) in a consultancy company. Findings...... point to mobile probing being a flexible method for uncovering the unknowns, as a way of getting rich data to the analysis and design phases. On the other hand it is difficult to engage users to give in depth explanations, which seem easier in synchronous dialogs (whether online or face2face...

  13. Probing the effect of human normal sperm morphology rate on cycle outcomes and assisted reproductive methods selection.

    Directory of Open Access Journals (Sweden)

    Bo Li

    Full Text Available Sperm morphology is the best predictor of fertilization potential, and the critical predictive information for supporting assisted reproductive methods selection. Given its important predictive value and the declining reality of semen quality in recent years, the threshold of normal sperm morphology rate (NSMR is being constantly corrected and controversial, from the 4th edition (14% to the 5th version (4%. We retrospectively analyzed 4756 cases of infertility patients treated with conventional-IVF(c-IVF or ICSI, which were divided into three groups according to NSMR: ≥14%, 4%-14% and <4%. Here, we demonstrate that, with decrease in NSMR(≥14%, 4%-14%, <4%, in the c-IVF group, the rate of fertilization, normal fertilization, high-quality embryo, multi-pregnancy and birth weight of twins gradually decreased significantly (P<0.05, while the miscarriage rate was significantly increased (p<0.01 and implantation rate, clinical pregnancy rate, ectopic pregnancy rate, preterm birth rate, live birth rate, sex ratio, and birth weight(Singleton showed no significant change. In the ICSI group, with decrease in NSMR (≥14%, 4%-14%, <4%, high-quality embryo rate, multi-pregnancy rate and birth weight of twins were gradually decreased significantly (p<0.05, while other parameters had no significant difference. Considering the clinical assisted methods selection, in the NFMR ≥14% group, normal fertilization rate of c-IVF was significantly higher than the ICSI group (P<0.05, in the 4%-14% group, birth weight (twins of c-IVF were significantly higher than the ICSI group, in the <4% group, miscarriage of IVF was significantly higher than the ICSI group. Therefore, we conclude that NSMR is positively related to embryo reproductive potential, and when NSMR<4% (5th edition, ICSI should be considered first, while the NSMR≥4%, c-IVF assisted reproduction might be preferred.

  14. Corrosion behavior of Mg and Mg-Zn alloys in simulated body fluid

    Institute of Scientific and Technical Information of China (English)

    GAO Jia-cheng; WU Sha; QIAO Li-ying; WANG Yong

    2008-01-01

    The corrosion behavior of Mg and Mg-Zn in simulated body fluid was studied.The mass loss of pure Mg,Mg-Zn-Zr and Mg-Zn-Zr-Y in simulated body fluid was measured using photovoltaic scale meter.Corrosion rate was determined through electrochemical tests.Finally,the corrosion mechanism was tbermodynamically studied.The results show that the corrosion rate decreases with the lapse of time for both pure Mg and Mg alloys.The purer the alloy,the borer the corrosion resistance exhibits.The corrosion behavior of Mg alloy is improved by the addition of trace Y.

  15. On Corrosion of Ferrous in Typical Indian Soils-Part II Wrought Iron

    Directory of Open Access Journals (Sweden)

    Brajendra Nath Tripathi

    1965-07-01

    Full Text Available Corrosion of wrought iron in ten Indian soils, employing Schwerdtfeger's soil corrosion cell procedure has been studied. The corrosion of wrought iron n non-acidic solid proceeds through electrochemical mechanism. Usually the rate of corrosion is maximum at the beginning and with the development of the film of the common products, the rate gradually decreases with time until it becomes more or less constant . In most of the cases 'uneven' general or local corrosion with pittings is observed. The maximum penetration is directly proportional to the corrodibility. Soils having moisture equivalent in the range 25-30% are most corrosive. The corrosivity of soils increases with increase in the concentration of soluble electrolytes. Ferric oxide present in laterite soil functions as a cathodic depolariser and hence increase the corrosivity. In and acidic sol the corrosion mainly proceeds through the mechanism of direct chemical reaction . The results have also been analyzed and correlated with various factors.

  16. Erosion--Corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Vyas, B.

    1978-01-01

    The deterioration of materials by corrosion or erosion by itself presents a formidable problem and for this reason investigators have studied these two phenomena independently. In fact, there are very few systematic studies on E-C and the majority of references mention it only in passing. In most real systems, however, the two destructive processes take place simultaneously, hence the purpose of this review is to present the various interactions between the chemical and mechanical agents leading to accelerated degradation of the material. The papers cited in the review are those that lead to a better understanding of the process involved in the accelerated rate of material loss under E-C conditions.

  17. Corrosion behavior of Mg/graphene composite in aqueous electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Selvam, M. [Centre for Nano Science and Technology, KS Rangasamy College of Technology, Tiruchengode, 637215, Tamil Nadu (India); Saminathan, K., E-mail: ksaminath@gmail.com [Centre for Nano Science and Technology, KS Rangasamy College of Technology, Tiruchengode, 637215, Tamil Nadu (India); Siva, P. [Centre for Nano Science and Technology, KS Rangasamy College of Technology, Tiruchengode, 637215, Tamil Nadu (India); Saha, P. [Department of Ceramic Engineering, National Institute of Technology, Rourkela, India-769008 (India); Rajendran, V. [Centre for Nano Science and Technology, KS Rangasamy College of Technology, Tiruchengode, 637215, Tamil Nadu (India)

    2016-04-01

    In the present work, the electrochemical corrosion behavior of magnesium (Mg) and thin layer graphene coated Mg (Mg/graphene) are studied in different salt electrolyte such as NaCl, KCl and Na{sub 2}SO{sub 4}. The phase structure, crystallinity, and surface morphology of the samples are investigated using X-ray diffraction (XRD) analysis, scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM/EDAX), and Raman spectroscopy techniques. The electrochemical corrosion behavior of the Mg and graphene coated Mg are also investigated using Electrochemical Impedance Spectroscopy (EIS) analysis. The tafel plot reveals that the corrosion of Mg drastically drops when coated with thin layer graphene (Mg/graphene) compared to Mg in KCl electrolyte. Moreover, the EIS confirms that Mg/graphene sample shows improve corrosion resistance and lower corrosion rate in KCl solution compare to all other electrolytes studied in the present system. - Highlights: • The corrosion behavior of magnesium alloy (AZ91) was investigated in three different electrolyte solution. • To study the anti-corrosion behavior of graphene coated with magnesium alloy. • To improve the corrosion resistance for magnesium alloy. • Nyquist plots confirms that MgG shows better corrosion resistance and lower corrosion rate in KCl solution.

  18. The corrosion behavior of nanocrystalline nickel based thin films

    Energy Technology Data Exchange (ETDEWEB)

    Danışman, Murat, E-mail: muratdan@gmail.com

    2016-03-01

    In this study, the effect of Cr addition on corrosion behavior of Ni thin films were investigated. Ni thin films and Ni films with three different Cr content were deposited on glass substrates by magnetron sputtering. After deposition process, thin films with different Cr content were thermally treated in a rapid thermal process system. Phase analysis and grain size calculations of the samples were carried out by X-ray diffraction analysis. In order to reveal corrosion properties, potentiodynamic tests were conducted on samples. Analysis revealed that, although Cr addition to pure-Ni thin films improved their corrosion resistance, occurrence of σ-Cr{sub 3}Ni{sub 2} phase at higher Cr contents increased corrosion rate. The corrosion properties of the samples were also investigated by electrochemical impedance spectroscopy and surface related parameters caused by corrosion reactions were calculated. The analysis revealed that at 55% wt. Cr, rapid ion exchange occurred and highest corrosion current, 23.4 nA cm{sup −2} was observed. - Highlights: • Thin film Ni–Cr samples were deposited on glass substrate. • Effect of Cr addition on corrosion behavior of Ni thin films were investigated. • Potentiodynamic tests and electrochemical impedance spectroscopy methods were used. • Cr content in Ni thin films plays and important role on corrosion. • Up to a certain Cr content, Cr addition reduces corrosion rate.

  19. Pre-oxidation and its effect on reducing high-temperature corrosion of superheater tubes during biomass firing

    DEFF Research Database (Denmark)

    Okoro, Sunday Chukwudi; Kvisgaard, M.; Montgomery, Melanie;

    2016-01-01

    Superheater tubes in biomass-fired power plants experience high corrosion rates due to condensation of corrosive alkali chloride-rich deposits. To explore the possibility of reducing the corrosion attack by the formation of an initial protective oxide layer, the corrosion resistance of pre-oxidis...

  20. Corrosion Behavior of S450EW Low-alloy Weathering Steel in Cyclically Alternate Corrosion Environments

    Institute of Scientific and Technical Information of China (English)

    Jun-shan WANG; Pei-yang SHI; Cheng-jun LIU; Mao-fa JIANG

    2015-01-01

    Weathering steel is widely used in various ifelds due to its excellent mechanical properties and high corrosion resistance. The effect of chromium content on the S450EW weathering steel in cyclic immersion test was studied. The results indicated that the corrosion resistance of S450EW weathering steel is closely related to chromium content. The addition of chromium signiif-cantly inhibited the weathering steel corrosion. The corrosion rate of experimental steel after 96 h immersion was 1.101 g·m−2·h−1. The rust of S450EW weathering steel was mainly constituted of FeOOH and Fe3O4 phase, and the elevation of chromium content promoted the formation of α-FeOOH. The ifne precipitates of the two phases contributed to the formation of dense dust layer of test steel. Furthermore, the increase of chromium is beneifcial for the cure of original defects and cracks of the rust layer via the enrich-ment of chromium. The corrosion potential and the resistance of corrosion process were thus increased, protecting the experimental steel from further corrosion. A S450EW steel with corrosion resistance more than 1.5 times of Q450NQR1 steel was prepared.

  1. Low temperature corrosion in bark fuelled, small boilers; Laagtemperaturkorrosion i barkeldade, mindre pannor

    Energy Technology Data Exchange (ETDEWEB)

    Lindau, Leif; Goldschmidt, Barbara [Sycon Energikonsult AB, Malmoe (Sweden)

    2002-04-01

    A number of small (3-12 MW), new biofuel boiler plants in South Sweden, and (at least) in Austria, have suffered a high (wastage of mm/yrs.) corrosion rate on the low temperature boiler side. This problem has been investigated with respect to its occurrence and its character by contacts with operators, by plant inspections, and by analysis of cold side deposits. The plants affected have low feed water temperatures (< 100 deg C ). The plants fire most types of Swedish biofuel: chips, bark, hog fuel, and 'GROT'(=twigs and tops). The results found give basis for a hypothesis that the corrosion results from the presence of an aqueous phase in the deposits, this phase being stabilized by dissolved salts having high solubility. It then follows that for each salt, there is a critical relative humidity (calculated from the flue gas water partial pressure and the cooling surface temperature as is common practice among boiler engineers) for both the presence of the aqueous phase and the corrosion. Some critical single salts, ZnC12 and CaC12 have been identified, and they give critical 'relative humidities' of 5% and 18% respectively. These figures are a lower bound. The corresponding figure, derived from the practical experience and the reported plant operational data, is between 20 and 30%. Corrosion tests have been carried out by exposing an air-cooled probe in the fluegases at a 12 MW boiler at Saevelundsverket in Alingsaas, and the material wastage at different temperatures has been measured with a profilometer. The high corrosion rates were reproduced in the tests for high relative humidities. The corrosion rate was small and not measurable (<0.1 mm/yr) for relative humidity < 22%. The work shows by means of indirect evidence that the corrosion critical components are ZnCl{sub 2} and possibly CaCl{sub 2} as well. The practical engineering design criterion derived from the work is that the relative humidity (calculated from the flue gas water partial

  2. Corrosion Behavior of Titanium in Artificial Saliva by Lactic Acid

    Directory of Open Access Journals (Sweden)

    Qing Qu

    2014-07-01

    Full Text Available As one of the main products produced by oral microorganisms, the role of lactic acid in the corrosion of titanium is very important. In this study, the corrosion behavior of titanium in artificial saliva with and without lactic acid were investigated by open-circuit potentials (OCPs, polarization curves and electrochemical impedance spectroscopy (EIS. OCP firstly increased with the amount of lactic acid from 0 to 3.2 g/L and then tended to decrease from 3.2 to 5.0 g/L. The corrosion of titanium was distinctly affected by lactic acid, and the corrosion rate increased with increasing the amount of lactic acid. At each concentration of lactic acid, the corrosion rate clearly increased with increasing the immersing time. Results of scanning electron microscopy (SEM also indicated that lactic acid accelerated the pitting corrosion in artificial saliva. A probable mechanism was also proposed to explain the experimental results.

  3. Effect of Mixed Corrosion Inhibitors in Cooling Water System

    Directory of Open Access Journals (Sweden)

    Dina Raheem

    2011-01-01

    Full Text Available The effect of mixed corrosion inhibitors in cooling system was evaluated by using carbon steel specimens and weight loss analysis. The carbon steel specimens immersed in mixture of sodium phosphate (Na2 HPO4 used as corrosion inhibitor and sodium glocunate (C6 H11 NaO7 as a scale dispersant at different concentrations (20,40, 60, 80 ppm and at different temperature (25,50,75 and 100ºC for (1-5 days. The corrosion inhibitors efficiency was calculated by using uninhibited and inhibited water to give 98.1%. The result of these investigations indicate that the corrosion rate decreases with the increase the corrosion inhibitors concentration at 80 ppm and at 100ºC for 5 days, (i.e, corrosion rate= 0.014gmd.

  4. CORROSION OF LEAD SHIELDING IN NUCLEAR MATERIALS PACKAGES

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, K; Kerry Dunn, K

    2007-11-16

    Inspection of United States-Department of Energy (US-DOE) model 9975 nuclear materials shipping package revealed corrosion of the lead shielding induced by off-gas constituents from organic components in the package. Experiments were performed to determine the corrosion rate of lead when exposed to off-gas or degradation products of these organic materials. The results showed that the room temperature vulcanizing (RTV) sealant was the most corrosive organic species followed by the polyvinyl acetate (PVAc) glue. The fiberboard material induced corrosion to a much lesser extent than the PVAc glue and RTV, and only in the presence of condensed water. The results indicated faster corrosion at temperatures higher than ambient and with condensed water as expected. A corrosion rate of 0.05 mm/year measured for coupons exposed to the most aggressive conditions was recommended as a conservative estimate for use in package performance calculations.

  5. Characterization of the Reinforcing Steel Corrosion by Potentialdynamic Scan Approach

    Institute of Scientific and Technical Information of China (English)

    QIAO Guofu; LIU Tiejun

    2012-01-01

    Reinforcement corrosion is the major cause of damage and early failure of reinforced concrete structures worldwide with subsequent enormous costs for maintenance,restoration and replacement.Many methods used today for assessment of reinforcement corrosion are based on electrochemical techniques that determine the free corrosion potential or polarization resistance.Most of these methods always consider the B value in Stern-Geary equation as constant.However,B changes with different condition.In this paper,potentialdynamic method is used to characterize the corrosion of reinforcing steel.The corrosion rate of Q235 carbon steel is measured with concrete environment.B is calculated real-time.By this way,the error of reinforcement corrosion rate is minimized.

  6. Novel Corrosion Sensor for Vision 21 Systems

    Energy Technology Data Exchange (ETDEWEB)

    Heng Ban

    2005-12-01

    Advanced sensor technology is identified as a key component for advanced power systems for future energy plants that would have virtually no environmental impact. This project intends to develop a novel high temperature corrosion sensor and subsequent measurement system for advanced power systems. Fireside corrosion is the metal loss caused by chemical reactions on surfaces exposed to the combustion environment. Such corrosion is the leading mechanism for boiler tube failures and has emerged to be a significant concern for current and future energy plants due to the introduction of technologies targeting emissions reduction, efficiency improvement, or fuel/oxidant flexibility. Corrosion damage can lead to catastrophic equipment failure, explosions, and forced outages. Proper management of corrosion requires real-time indication of corrosion rate. However, short-term, on-line corrosion monitoring systems for fireside corrosion remain a technical challenge to date due to the extremely harsh combustion environment. The overall objective of this project is to develop a technology for on-line corrosion monitoring based on a new concept. This objective is to be achieved by a laboratory development of the sensor and instrumentation, testing of the measurement system in a laboratory muffle furnace, and eventually testing the system in a coal-fired furnace. The initial plan for testing at the coal-fired pilot-scale furnace was replaced by testing in a power plant, because the operation condition at the power plant is continuous and more stable. The first two-year effort was completed with the successful development sensor and measurement system, and successful testing in a muffle furnace. Because of the potential high cost in sensor fabrication, a different type of sensor was used and tested in a power plant burning eastern bituminous coals. This report summarize the experiences and results of the first two years of the three-year project, which include laboratory

  7. Probing Neutrino Mass Hierarchy by Comparing the Charged-Current and Neutral-Current Interaction Rates of Supernova Neutrinos

    CERN Document Server

    Lai, Kwang-Chang; Lee, Feng-Shiuh; Lin, Guey-Lin; Liu, Tsung-Che; Yang, Yi

    2016-01-01

    The neutrino mass hierarchy is one of the neutrino fundamental properties yet to be determined. We introduce a method to determine neutrino mass hierarchy by comparing the interaction rate of neutral current (NC) interactions, $\

  8. Environmentally Friendly Coating Technology for Autonomous Corrosion Control

    Science.gov (United States)

    Calle, Luz M.; Li, Wenyan; Buhrow, Jerry W.; Johnsey, Marissa N.; Jolley, Scott T.; Pearman, Benjamin P.; Zhang, Xuejun; Fitzpatrick, Lilliana; Gillis, Mathew; Blanton, Michael; Hanna, Joshua S.; Rawlins, James W.

    2016-01-01

    This work concerns the development of environmentally friendly encapsulation technology, specifically designed to incorporate corrosion indicators, inhibitors, and self-healing agents into a coating, in such a way that the delivery of the indicators and inhibitors is triggered by the corrosion process, and the delivery of self-healing agents is triggered by mechanical damage to the coating. Encapsulation of the active corrosion control ingredients allows the incorporation of desired autonomous corrosion control functions such as: early corrosion detection, hidden corrosion detection, corrosion inhibition, and self-healing of mechanical damage into a coating. The technology offers the versatility needed to include one or several corrosion control functions into the same coating.The development of the encapsulation technology has progressed from the initial proof-of-concept work, in which a corrosion indicator was encapsulated into an oil-core (hydrophobic) microcapsule and shown to be delivered autonomously, under simulated corrosion conditions, to a sophisticated portfolio of micro carriers (organic, inorganic, and hybrid) that can be used to deliver a wide range of active corrosion ingredients at a rate that can be adjusted to offer immediate as well as long-term corrosion control. The micro carriers have been incorporated into different coating formulas to test and optimize the autonomous corrosion detection, inhibition, and self-healing functions of the coatings. This paper provides an overview of progress made to date and highlights recent technical developments, such as improved corrosion detection sensitivity, inhibitor test results in various types of coatings, and highly effective self-healing coatings based on green chemistry.

  9. Erosion-corrosion; Erosionkorrosion

    Energy Technology Data Exchange (ETDEWEB)

    Aghili, B

    1999-05-01

    A literature study on erosion-corrosion of pipings in the nuclear industry was performed. Occurred incidents are reviewed, and the mechanism driving the erosion-corrosion is described. Factors that influence the effect in negative or positive direction are treated, as well as programs for control and inspection. Finally, examples of failures from databases on erosion-corrosion are given in an attachment 32 refs, 16 figs, tabs

  10. Design of multi-function Hanford tank corrosion monitoring system

    Energy Technology Data Exchange (ETDEWEB)

    EDGEMON, G.L.

    1999-04-01

    A multi-fiction corrosion monitoring system has been designed for installation into DST 241-AN-105 at the Hanford Site in fiscal year 1999. The 241-AN-105 system is the third-generation corrosion monitoring system described by TTP RLO-8-WT-21. Improvements and upgrades from the second-generation system (installed in 241-AN-102) that have been incorporated into the third-generation system include: Gasket seating surfaces utilize O-rings instead of a washer type gasket for improved seal; Probe design contains an equally spaced array of 22 thermocouples; Probe design contains an adjustable verification thermocouple; Probe design contains three ports for pressure/gas sampling; Probe design contains one set of strain gauges to monitor probe flexure if flexure occurs; Probe utilizes an adjustable collar to allow depth adjustment of probe during installation; System is capable of periodically conducting LPR scans; System is housed in a climate controlled enclosure adjacent to the riser containing the probe; System uses wireless Ethernet links to send data to Hanford Local Area Network; System uses commercial remote access software to allow remote command and control; and Above ground wiring uses driven shields to reduce external electrostatic noise in the data. These new design features have transformed what was primarily a second-generation corrosion monitoring system into a multi-function tank monitoring system that adds a great deal of functionality to the probe, provides for a better understanding of the relationship between corrosion and other tank operating parameters, and optimizes the use of the riser that houses the probe in the tank.

  11. Coatings and Corrosion Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Purpose: The mission of the Coatings and Corrosion Laboratory is to develop and analyze the effectiveness of innovative coatings test procedures while evaluating the...

  12. Mechanism for Corrosion Prevention by a Mechanical Plating of Uniform Zinc-Iron Alloy

    Science.gov (United States)

    Kasai, Naoya; Kaku, Yoshihiko; Okazaki, Shinji; Hirai, Kuninori

    2016-09-01

    In situ electrochemical monitoring with a three-electrode cell was applied to investigate the anti-corrosion properties of a mechanical zinc-iron alloy plating. Several electron probe microanalyses were also conducted to identify the chemical elements in the plating. The results indicated the formation of a Zn-Fe intermetallic compound, which allowed a mechanism for corrosion prevention to be proposed. In the proposed mechanism, Zn(OH)2 plays a significant role in the corrosion prevention of steel alloys.

  13. Amplified OTDR systems for multipoint corrosion monitoring.

    Science.gov (United States)

    Nascimento, Jehan F; Silva, Marcionilo J; Coêlho, Isnaldo J S; Cipriano, Eliel; Martins-Filho, Joaquim F

    2012-01-01

    We present two configurations of an amplified fiber-optic-based corrosion sensor using the optical time domain reflectometry (OTDR) technique as the interrogation method. The sensor system is multipoint, self-referenced, has no moving parts and can measure the corrosion rate several kilometers away from the OTDR equipment. The first OTDR monitoring system employs a remotely pumped in-line EDFA and it is used to evaluate the increase in system reach compared to a non-amplified configuration. The other amplified monitoring system uses an EDFA in booster configuration and we perform corrosion measurements and evaluations of system sensitivity to amplifier gain variations. Our experimental results obtained under controlled laboratory conditions show the advantages of the amplified system in terms of longer system reach with better spatial resolution, and also that the corrosion measurements obtained from our system are not sensitive to 3 dB gain variations.

  14. Amplified OTDR Systems for Multipoint Corrosion Monitoring

    Directory of Open Access Journals (Sweden)

    Joaquim F. Martins-Filho

    2012-03-01

    Full Text Available We present two configurations of an amplified fiber-optic-based corrosion sensor using the optical time domain reflectometry (OTDR technique as the interrogation method. The sensor system is multipoint, self-referenced, has no moving parts and can measure the corrosion rate several kilometers away from the OTDR equipment. The first OTDR monitoring system employs a remotely pumped in-line EDFA and it is used to evaluate the increase in system reach compared to a non-amplified configuration. The other amplified monitoring system uses an EDFA in booster configuration and we perform corrosion measurements and evaluations of system sensitivity to amplifier gain variations. Our experimental results obtained under controlled laboratory conditions show the advantages of the amplified system in terms of longer system reach with better spatial resolution, and also that the corrosion measurements obtained from our system are not sensitive to 3 dB gain variations.

  15. IMPACT OF NUCLEAR MATERIAL DISSOLUTION ON VESSEL CORROSION

    Energy Technology Data Exchange (ETDEWEB)

    Mickalonis, J.; Dunn, K.; Clifton, B.

    2012-10-01

    Different nuclear materials require different processing conditions. In order to maximize the dissolver vessel lifetime, corrosion testing was conducted for a range of chemistries and temperature used in fuel dissolution. Compositional ranges of elements regularly in the dissolver were evaluated for corrosion of 304L, the material of construction. Corrosion rates of AISI Type 304 stainless steel coupons, both welded and non-welded coupons, were calculated from measured weight losses and post-test concentrations of soluble Fe, Cr and Ni.

  16. Effects of chemical composition on the corrosion of dental alloys

    OpenAIRE

    GALO, Rodrigo; RIBEIRO, Ricardo Faria; RODRIGUES, Renata Cristina Silveira; Rocha, Luís Augusto; Mattos,Maria da Glória Chiarello de

    2012-01-01

    The aim of this study was to determine the effect of the oral environment on the corrosion of dental alloys with different compositions, using electrochemical methods. The corrosion rates were obtained from the current-potential curves and electrochemical impedance spectroscopy (EIS). The effect of artificial saliva on the corrosion of dental alloys was dependent on alloy composition. Dissolution of the ions occurred in all tested dental alloys and the results were strongly dependent on the g...

  17. Corrosion in the oil industry

    Energy Technology Data Exchange (ETDEWEB)

    Brondel, D. (Sedco Forex, Montrouge (France)); Edwards, R. (Schlumberger Well Services, Columbus, OH (United States)); Hayman, A. (Etudes et Productions Schlumberger, Clamart (France)); Hill, D. (Schlumberger Dowell, Tulsa, OK (United States)); Mehta, S. (Schlumberger Dowell, St. Austell (United Kingdom)); Semerad, T. (Mobil Oil Indonesia, Inc., Sumatra (Indonesia))

    1994-04-01

    Corrosion costs the oil industry billions of dollars a year, a fact that makes the role of the corrosion engineer an increasingly important one. Attention is paid to how corrosion affects every aspect of exploration and production, from offshore rigs to casing. Also the role of corrosion agents such as drilling and production fluids is reviewed. Methods of control and techniques to monitor corrosion are discussed, along with an explanation of the chemical causes of corrosion. 21 figs., 32 refs.

  18. Corrosion Studies of 2195 Al-Li Alloy and 2219 Al Alloy with Differing Surface Treatments

    Science.gov (United States)

    Danford, M. D.; Mendrek, M. J.

    1998-01-01

    Corrosion studies of 2195 Al-Li and 2219 Al alloys have been conducted using the scanning reference electrode technique (SRET) and the polarization resistance (PR) technique. The SRET was used to study corrosion mechanisms, while corrosion rate measurements were studied with the PR technique. Plates of Al203 blasted, soda blasted and conversion coated 2219 Al were coated with Deft primer and the corrosion rates studied with the EIS technique. Results from all of these studies are presented.

  19. Power Spectrum Analysis of Heart Rate Fluctuation: A Quantitative Probe of Beat-To-Beat Cardiovascular Control

    Science.gov (United States)

    Akselrod, Solange; Gordon, David; Ubel, F. Andrew; Shannon, Daniel C.; Barger, A. Clifford; Cohen, Richard J.

    1981-07-01

    Power spectrum analysis of heart rate fluctuations provides a quantitative noninvasive means of assessing the functioning of the short-term cardiovascular control systems. We show that sympathetic and parasympathetic nervous activity make frequency-specific contributions to the heart rate power spectrum, and that renin-angiotensin system activity strongly modulates the amplitude of the spectral peak located at 0.04 hertz. Our data therefore provide evidence that the reninangiotensin system plays a significant role in short-term cardiovascular control on the time scale of seconds to minutes.

  20. Mobile Probing and Probes

    DEFF Research Database (Denmark)

    2013-01-01

    to mobile probing being a flexible method for uncovering the unknowns, as a way of getting rich data to the analysis and design phases. On the other hand it is difficult to engage users to give in depth explanations, which seem easier in synchronous dialogs (whether online or face2face). The development...

  1. Effect of inhibitors and coatings on rebar corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Saricimen, H.; Ashiru, O.A.; Jarrah, N.R.; Quddus, A.; Shameem, M. [King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia). Research Inst.

    1997-12-01

    Chloride-induced corrosion of reinforcing steel is a major cause of deterioration of concrete structures in the eastern province of Saudi Arabia. Two of the practical ways of preventing or retarding corrosion of reinforcing steel bars in concrete are by using (a) inhibitor in concrete mix, and (b) coating either on the rebars or on external surfaces of concrete structures. The objective of this study has been to evaluate the effect of two inhibitors, three concrete coatings, and two barrier coatings on corrosion of reinforcing steel bars. Reinforced concrete specimens were monitored by AC and DC electrochemical techniques while undergoing free and accelerated corrosion. Accelerated corrosion tests were performed under 4V impressed anodic potential. Corrosion of the steel bars were evaluated by measuring anodic current, time-to-cracking of concrete specimens, and corrosion rates of the steel bars. The results showed that the specimens with the concrete surface coatings did not perform better than the control specimens. Time-to-cracking was shorter and corrosion rate of steel bars was higher in specimens coated with concrete coatings. The inhibitors and rebar surface coatings reduced the corrosion rate of steel bars significantly and improved the time-to-cracking of the specimens in comparison to control specimens.

  2. The use of permanent corrosion monitoring in new and existing reinforced concrete structures

    Energy Technology Data Exchange (ETDEWEB)

    Broomfield, J.P. [Broomfield (J.P.), London (United Kingdom); Davies, K.; Hladky, K.

    1999-11-01

    Corrosion monitoring systems consisting of linear polarization, concrete resistivity and other probes have been installed in new structures to monitor durability and in existing structures to evaluate rehabilitation strategies such as corrosion inhibitor application and patch repairs. The types of sensors used, data collection techniques, results and interpretation are discussed.

  3. Corrosion electrochemical behavior of brass tubes in circulating cooling seawater

    Institute of Scientific and Technical Information of China (English)

    LU Yu-zhuo; SONG Shi-zhe; YIN Li-hui

    2005-01-01

    Electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN) were used to study the corrosion electrochemical behavior of brass tubes in circulating cooling seawater using the developed sensor. EIS study shows that the inhibitor can lead to the formation of corrosion products on metal surface, which will then inhibit the corrosion process. When the flow rate of the seawater increases, the diffusion of oxygen speeds up and the action of filming on HAl77-2 tube accelerates, resulting in decrease of corrosion rate. EN analysis shows that the flow rate of the seawater has little effect on pitting susceptivity of HSn70-1 tube; however the pitting susceptivity of HAl77-2 tube increases with increasing flow rate. Good agreement is observed between the spectral noise resistance Rsn (f) calculated from EN data and the modulus of impedance. It is shown that the electrochemical noise technique can be used in corrosion monitoring.

  4. Oil ash corrosion; A review of utility boiler experience

    Energy Technology Data Exchange (ETDEWEB)

    Paul, L.D. (Babcock and Wilcox Co., Alliance, OH (United States)); Seeley, R.R. (Babcock and Wilcox Canada Ltd., Cambridge, ON (Canada))

    1991-02-01

    In this paper a review of experience with oil ash corrosion is presented along with current design practices used to avoid excessive tube wastage. Factors influencing oil ash corrosion include fuel chemistry, boiler operation, and boiler design. These factors are interdependent and determine the corrosion behavior in utility boilers. Oil ash corrosion occurs when vanadium-containing ash deposits on boiler tube surfaces become molten. These molten ash deposits dissolve protective oxides and scales causing accelerated tube wastage. Vanadium is the major fuel constituent responsible for oil ash corrosion. Vanadium reacts with sodium, sulfur, and chlorine during combustion to produce lower melting temperature ash compositions, which accelerate tube wastage. Limiting tube metal temperatures will prevent ash deposits from becoming molten, thereby avoiding the onset of oil ash corrosion. Tube metal temperatures are limited by the use of a parallel stream flow and by limiting steam outlet temperatures. Operating a boiler with low excess air has helped avoid oil ash corrosion by altering the corrosive combustion products. Air mixing and distribution are essential to the success of this palliative action. High chromium alloys and coatings form more stable protective scaled on tubing surfaces, which result in lower oil ash corrosion rates. However, there is not material totally resistant to oil ash corrosion.

  5. Irradiation-Accelerated Corrosion of Reactor Core Materials. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, Zhujie [Univ. of Michigan, Ann Arbor, MI (United States); Was, Gary [Univ. of Michigan, Ann Arbor, MI (United States); Bartels, David [Univ. of Notre Dame, IN (United States)

    2015-04-02

    This project aims to understand how radiation accelerates corrosion of reactor core materials. The combination of high temperature, chemically aggressive coolants, a high radiation flux and mechanical stress poses a major challenge for the life extension of current light water reactors, as well as the success of most all GenIV concepts. Of these four drivers, the combination of radiation and corrosion places the most severe demands on materials, for which an understanding of the fundamental science is simply absent. Only a few experiments have been conducted to understand how corrosion occurs under irradiation, yet the limited data indicates that the effect is large; irradiation causes order of magnitude increases in corrosion rates. Without a firm understanding of the mechanisms by which radiation and corrosion interact in film formation, growth, breakdown and repair, the extension of the current LWR fleet beyond 60 years and the success of advanced nuclear energy systems are questionable. The proposed work will address the process of irradiation-accelerated corrosion that is important to all current and advanced reactor designs, but remains very poorly understood. An improved understanding of the role of irradiation in the corrosion process will provide the community with the tools to develop predictive models for in-reactor corrosion, and to address specific, important forms of corrosion such as irradiation assisted stress corrosion cracking.

  6. A Probe into the Mortgage Rates of Land Contract Management Rights Based on Unified Annual Output Value

    Institute of Scientific and Technical Information of China (English)

    Zhongjun; YI

    2013-01-01

    The mortgage of land contract management rights has launched a pilot project in Ningxia,Hubei,Henan,Guizhou,Chongqing and other provinces,municipalities and autonomous regions,which provides a good solution to the problem of funds for rural development and plays a huge role in promoting local rural economic development.In the mortgage financing of land contract management rights implemented in various regions,how to determine a scientific,accurate and reasonable mortgage rate of land contract management rights becomes a difficulty troubling the mortgage financing of land.On the basis of unified annual output value of land,this article uses survey method,income capitalization method,and comparison method to analyze the value of land contract management rights,and finally determine the mortgage rates of land contract management rights.

  7. Comparison of corrosion behavior of ZL104 alloy at as-cast and heat treatment states

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The corrosion behavior of ZL 104 alloy at different states (as-cast and heat treatment) in salt spray corrosion (SSC) was studied. The results show that the sample treated after refinement and modification has the least corrosive resistance compared with the sample bearing as-cast structure at the beginning of the corrosion. As the corrosion process continued, however, the trend reversed itself. After 44 h continuous corrosion, the corrosive rates of all samples tend to be stable. After experiments, the sample bearing as-cast structure had the most corrosive products on the surface whereas the sample being refined and modified had the least products. The Fourier transformation infrared spectroscopy (FTIR)analyses of the corrosion products show that these products are composed of hydroxyl-containing substances.

  8. Probing neutrino mass hierarchy by comparing the charged-current and neutral-current interaction rates of supernova neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Kwang-Chang [Center for General Education, Chang Gung University,Kwei-Shan, Taoyuan, 333, Taiwan (China); Leung Center for Cosmology and Particle Astrophysics (LeCosPA), National Taiwan University, Taipei, 106, Taiwan (China); Lee, Fei-Fan [Institute of Physics, National Chiao Tung University,Hsinchu, 300, Taiwan (China); Lee, Feng-Shiuh [Department of Electrophysics, National Chiao Tung University,Hsinchu, 300, Taiwan (China); Lin, Guey-Lin [Leung Center for Cosmology and Particle Astrophysics (LeCosPA), National Taiwan University, Taipei, 106, Taiwan (China); Institute of Physics, National Chiao Tung University,Hsinchu, 300, Taiwan (China); Liu, Tsung-Che [Leung Center for Cosmology and Particle Astrophysics (LeCosPA), National Taiwan University, Taipei, 106, Taiwan (China); Yang, Yi [Department of Electrophysics, National Chiao Tung University,Hsinchu, 300, Taiwan (China)

    2016-07-22

    The neutrino mass hierarchy is one of the neutrino fundamental properties yet to be determined. We introduce a method to determine neutrino mass hierarchy by comparing the interaction rate of neutral current (NC) interactions, ν(ν-bar)+p→ν(ν-bar)+p, and inverse beta decays (IBD), ν-bar{sub e}+p→n+e{sup +}, of supernova neutrinos in scintillation detectors. Neutrino flavor conversions inside the supernova are sensitive to neutrino mass hierarchy. Due to Mikheyev-Smirnov-Wolfenstein effects, the full swapping of ν-bar{sub e} flux with the ν-bar{sub x} (x=μ, τ) one occurs in the inverted hierarchy, while such a swapping does not occur in the normal hierarchy. As a result, more high energy IBD events occur in the detector for the inverted hierarchy than the high energy IBD events in the normal hierarchy. By comparing IBD interaction rate with the mass hierarchy independent NC interaction rate, one can determine the neutrino mass hierarchy.

  9. Atmosphere corrosion behavior of plasma sprayed and laser remelted coatings on copper

    Institute of Scientific and Technical Information of China (English)

    Gongying Liang; T. T. Wong; Geng An; J. M. K. MacAlpine

    2006-01-01

    Nickel and chromium coatings were produced using plasma spraying and laser remelting on the copper sheet. The corrosion test was carried out in an acidic atmosphere, and the corrosive behaviors of both coatings and original copper samples were investigated by using an impedance comparison method. Experimental results show that nickel and chromium coatings display better corrosion resistance properties relative to the original pure copper sample. The corrosion rate of chromium coating is less than that of nickel coating, and corrosion resistances of laser remelted nickel and chromium samples are better thanthose of plasma sprayed samples. The corrosion deposit film of copper is loose compared with nickel and chromium.

  10. Effect of Ca2+ and Mg2+ on CO2 Corrosion Behavior of Tube Steel

    Institute of Scientific and Technical Information of China (English)

    ZHAO Guo-xian; LI Jian-ping; HAO Shi-ming; L(U) Xiang-hong; LI He-lin

    2005-01-01

    Effects of Ca2+ and Mg2+ on the CO2 corrosion behaviors of tube steel were studied in simulated oil-fieldenvironment. The influence of Ca2+ and Mg2+ on the corrosion rate and morphologies of corrosion product layerwas determined by scanning electron microscope and measuring mass loss. Potentiodynamic polarization and im-pedance spectroscopy were used to investigate the change of electrochemical characteristic parameters of corrosionproduct layer and corrosion dynamic process. The results show that with Ca2+ and Mg2+ in electrolyte, the mor-phologies and microstructures of corrosion product layer changed obviously, thus affecting the corrosion process.

  11. Review of Corrosion Modes for Alloy 22 Regarding Lifetime Expectancy of Nuclear Waste Containers

    Energy Technology Data Exchange (ETDEWEB)

    Rebak, R B; Estill, J C

    2002-11-15

    Alloy 22 (UNS N06022) was selected to fabricate the corrosion resistant outer barrier of a two-layer waste package container for nuclear waste at the designated repository site in Yucca Mountain in Nevada (USA). A testing program is underway to characterize and quantify three main modes of corrosion that may occur at the site. Current results show that the containers would perform well under general corrosion, localized corrosion and environmentally assisted cracking (EAC). For example, the general corrosion rate is expected to be below 100 nm/year and the container is predicted to be outside the range of potential for localized corrosion and environmentally assisted cracking.

  12. Atom-Probe Tomography, TEM and ToF-SIMS study of borosilicate glass alteration rim: A multiscale approach to investigating rate-limiting mechanisms

    Science.gov (United States)

    Gin, S.; Jollivet, P.; Barba Rossa, G.; Tribet, M.; Mougnaud, S.; Collin, M.; Fournier, M.; Cadel, E.; Cabie, M.; Dupuy, L.

    2017-04-01

    Significant efforts have been made into understanding the dissolution of silicate glasses and minerals, but there is still debate about the formation processes and the properties of surface layers. Here, we investigate glass coupons of ISG glass - a 6 oxide borosilicate glass of nuclear interest - altered at 90 °C in conditions close to saturation and for durations ranging from 1 to 875 days. Altered glass coupons were characterized from atomic to macroscopic levels to better understand how surface layers become protective. With this approach, it was shown that a rough interface, whose physical characteristics have been modeled, formed in a few days and then propagated into the pristine material at a rate controlled by the reactive transport of water within the growing alteration layer. Several observations such as stiff interfacial B, Na, and Ca profiles and damped profiles within the rest of the alteration layer are not consistent with the classical inter-diffusion model, or with the interfacial dissolution-precipitation model. A new paradigm is proposed to explain these features. Inter-diffusion, a process based on water ingress into the glass and ion-exchange, may only explain the formation of the rough interface in the early stage of glass corrosion. A thin layer of altered glass is formed by this process, and as the layer grows, the accessibility of water to the reactive interface becomes rate-limiting. As a consequence, only the most easily accessible species are dissolved. The others remain undissolved in the alteration layer, probably fixed in highly hydrolysis resistant clusters. A new estimation of water diffusivity in the glass when covered by the passivating layer was determined from the shift between B and H profiles, and was 10-23 m2.s-1, i.e. approximately 3 orders of magnitude lower than water diffusivity in the pristine material. Overall, in the absence of secondary crystalline phases that could consume the major components of the alteration

  13. Carbon Dioxide Corrosion:

    DEFF Research Database (Denmark)

    Fosbøl, Philip Loldrup

    2008-01-01

    CO2 corrosion is a general problem in the industry and it is expensive. The focus of this study is an oil gas production related problem. CO2 corrosion is observed in offshore natural gas transportation pipelines. A general overview of the problem is presented in chapter 1. The chemical system co...

  14. Corrosion evaluation technology

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Uh Chul; Han, Jeong Ho; Nho, Kye Ho; Lee, Eun Hee; Kim, Hong Pyo; Hwang, Seong Sik; Lee, Deok Hyun; Hur, Do Haeng; Kim, Kyung Mo

    1997-09-01

    A multifrequency ACPD system was assembled which can measure very small crack. Stress corrosion cracking test system with SSRT operating high temperature was installed. Stress corrosion cracking test of newly developed alloy 600 and existing alloy 600 was carried out in steam atmosphere of 400 deg C. No crack was observed in both materials within a test period of 2,000 hrs. Corrosion fatigue test system operating at high temperature was installed in which fatigue crack was measured by CDPD. Lead enhanced the SCC of the Alloy 600 in high temperature water, had a tendency to modify a cracking morphology from intergranular to transgranular. Pit initiation preferentially occurred at Ti-rich carbide. Resistance to pit initiation decreased with increasing temperature up to 300 deg C. Test loop for erosion corrosion was designed and fabricated. Thin layer activation technique was very effective in measuring erosion corrosion. Erosion corrosion of a part of secondary side pipe was evaluated by the Check Family Codes of EPRI. Calculated values of pipe thickness by Check Family Codes coincided with the pipe thickness measured by UT with an error of {+-} 20%. Literature review on turbine failure showed that failure usually occurred in low pressure turbine rotor disc and causes of failure are stress corrosion cracking and corrosion fatigue. (author). 12 refs., 20 tabs., 77 figs.

  15. Avionics Corrosion Control Study

    Science.gov (United States)

    1974-01-01

    found at seacoast (harsn) environnents is the most destructive. Differences in electrolte concentration and oxygen concentration promote corrosion...against corrosion by acting as moisture and gas barriers. CMCVIT B0.4ID *COATINGS Polyurethane’s, cprxies, silicones, and polystyrenes are the most

  16. Marine corrosion of mild steel at Lumut, Perak

    Science.gov (United States)

    Ting, Ong Shiou; Potty, Narayanan Sambu; Liew, Mohd. Shahir

    2012-09-01

    The corrosion rate of structural steels in the adverse marine and offshore environments affects the economic interest of offshore structures since the loss of steel may have significant impact on structural safety and performance. With more emphasis to maintain existing structures in service for longer time and hence to defer replacement costs, there is increasing interest in predicting corrosion rate at a given location for a given period of exposure once the protection coating or cathodic protection is lost. The immersion depth, salinity, steel composition and water pollution will be taken into account. Various corrosion allowances are prescribed for structural members by different standards. There are no studies to determine the appropriate corrosion allowance for steel structures in marine environment in Malaysia. The objectives of the research are to determine the nature and rate of corrosion in mm/year for steel structures in marine environment. It also tries to identify whether the corrosion rate is affected by differences in the chemical composition of the steels, and microalgae. Two sets of corrosion coupons of Type 3 Steel consisting of mild steel were fabricated and immersed in seawater using steel frames. The corrosion rate of the coupon in mm/ per year is estimated based on the material weight loss with time in service. The results are compared with recommendations of the code.

  17. A new corrosion sensor to determine the start and development of embedded rebar corrosion process at coastal concrete.

    Science.gov (United States)

    Xu, Chen; Li, Zhiyuan; Jin, Weiliang

    2013-09-30

    The corrosion of reinforcements induced by chloride has resulted to be one of the most frequent causes of their premature damage. Most corrosion sensors were designed to monitor corrosion state in concrete, such as Anode-Ladder-System and Corrowatch System, which are widely used to monitor chloride ingress in marine concrete. However, the monitoring principle of these corrosion sensors is based on the macro-cell test method, so erroneous information may be obtained, especially from concrete under drying or saturated conditions due to concrete resistance taking control in macro-cell corrosion. In this paper, a fast weak polarization method to test corrosion state of reinforcements based on electrochemical polarization dynamics was proposed. Furthermore, a new corrosion sensor for monitoring the corrosion state of concrete cover was developed based on the proposed test method. The sensor was tested in cement mortar, with dry-wet cycle tests to accelerate the chloride ingress rate. The results show that the corrosion sensor can effectively monitor chloride penetration into concrete with little influence of the relative humidity in the concrete. With a reasonable corrosion sensor electrode arrangement, it seems the Ohm-drop effect measured by EIS can be ignored, which makes the tested electrochemical parameters more accurate.

  18. A New Corrosion Sensor to Determine the Start and Development of Embedded Rebar Corrosion Process at Coastal Concrete

    Directory of Open Access Journals (Sweden)

    Weiliang Jin

    2013-09-01

    Full Text Available The corrosion of reinforcements induced by chloride has resulted to be one of the most frequent causes of their premature damage. Most corrosion sensors were designed to monitor corrosion state in concrete, such as Anode-Ladder-System and Corrowatch System, which are widely used to monitor chloride ingress in marine concrete. However, the monitoring principle of these corrosion sensors is based on the macro-cell test method, so erroneous information may be obtained, especially from concrete under drying or saturated conditions due to concrete resistance taking control in macro-cell corrosion. In this paper, a fast weak polarization method to test corrosion state of reinforcements based on electrochemical polarization dynamics was proposed. Furthermore, a new corrosion sensor for monitoring the corrosion state of concrete cover was developed based on the proposed test method. The sensor was tested in cement mortar, with dry-wet cycle tests to accelerate the chloride ingress rate. The results show that the corrosion sensor can effectively monitor chloride penetration into concrete with little influence of the relative humidity in the concrete. With a reasonable corrosion sensor electrode arrangement, it seems the Ohm-drop effect measured by EIS can be ignored, which makes the tested electrochemical parameters more accurate.

  19. A New Corrosion Sensor to Determine the Start and Development of Embedded Rebar Corrosion Process at Coastal Concrete

    Science.gov (United States)

    Xu, Chen; Li, Zhiyuan; Jin, Weiliang

    2013-01-01

    The corrosion of reinforcements induced by chloride has resulted to be one of the most frequent causes of their premature damage. Most corrosion sensors were designed to monitor corrosion state in concrete, such as Anode-Ladder-System and Corrowatch System, which are widely used to monitor chloride ingress in marine concrete. However, the monitoring principle of these corrosion sensors is based on the macro-cell test method, so erroneous information may be obtained, especially from concrete under drying or saturated conditions due to concrete resistance taking control in macro-cell corrosion. In this paper, a fast weak polarization method to test corrosion state of reinforcements based on electrochemical polarization dynamics was proposed. Furthermore, a new corrosion sensor for monitoring the corrosion state of concrete cover was developed based on the proposed test method. The sensor was tested in cement mortar, with dry-wet cycle tests to accelerate the chloride ingress rate. The results show that the corrosion sensor can effectively monitor chloride penetration into concrete with little influence of the relative humidity in the concrete. With a reasonable corrosion sensor electrode arrangement, it seems the Ohm-drop effect measured by EIS can be ignored, which makes the tested electrochemical parameters more accurate. PMID:24084117

  20. Monitoring Techniques for Microbially Influenced Corrosion of Carbon Steel

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    2000-01-01

    Abstract Monitoring Techniques for Microbially Influenced Corrosion of Carbon Steel Microbially influenced corrosion (MIC) of carbon steel may occur in media with microbiological activity of especially sulphate-reducing bacteria, e.g. on pipelines buried in soil and on marine structures. MIC...... of carbon steel must be monitored on-line in order to provide an efficient protection and control the corrosion. A number of monitoring techniques is industrially used today, and the applicability and reliability of these for monitoring MIC is evaluated. Coupons and ER are recommended as necessary basic...... techniques even though localised corrosion rate cannot be measured. FSM measures general corrosion and detects localised corrosion, but the sensitivity is not high enough for monitoring initiation of pitting and small attacks. Electrochemical techniques as LPR and EIS give distorted data and unreliable...

  1. Monitoring Techniques for Microbially Influenced Corrosion of Carbon Steel

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    2000-01-01

    of carbon steel must be monitored on-line in order to provide an efficient protection and control the corrosion. A number of monitoring techniques is industrially used today, and the applicability and reliability of these for monitoring MIC is evaluated. Coupons and ER are recommended as necessary basic......Abstract Monitoring Techniques for Microbially Influenced Corrosion of Carbon Steel Microbially influenced corrosion (MIC) of carbon steel may occur in media with microbiological activity of especially sulphate-reducing bacteria, e.g. on pipelines buried in soil and on marine structures. MIC...... techniques even though localised corrosion rate cannot be measured. FSM measures general corrosion and detects localised corrosion, but the sensitivity is not high enough for monitoring initiation of pitting and small attacks. Electrochemical techniques as LPR and EIS give distorted data and unreliable...

  2. Comparison of corrosion monitoring techniques in district heating systems

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Nielsen, Lars Vendelbo; Thorarinsdottir, R.I.

    2004-01-01

    Investigations aimed at evaluating monitoring techniques as a function of the specific water chemistry has been conducted as a part of a Nordic project focused on improving the quality of corrosion monitoring in municipal district heating. A combination of techniques has been selected to measure...... both general and localised corrosion. Electrochemical techniques (LPR, EIS) as well as direct techniques (high sensitive ER, weight loss, local crevice corrosion current) have been applied. The data show that the water quality in Danish systems is high resulting in low corrosion rates, but changes...... in the water quality induce localised corrosion. Useful monitoring results have been obtained with high sensitive ER technique (MetriCorr) and crevice corrosion measurements with the LOCORR cell (FORCE TECHNOLOGY)....

  3. Diffusion model for acid corrosion of cemented materials

    Energy Technology Data Exchange (ETDEWEB)

    Van Dijk, J.C.; De Moel, P.J.; Nooyen, W.F.; Nuiten, P.C.

    1986-09-25

    The acid corrosion of cemented materials is an important aspect in engineering practice. Corrosion affects the strength of materials and may cause a deterioration of water quality. This article deals with corrosion due to non-erosive acid attacks. A diffusion model is presented in which the depth of attack increases in proportion to the square root of both time, the hydronium ion concentration in the water, and the inverse of the total concentration of lime in the solid phase. Experiments verifying the model are presented. The experiments also reveal that the corrosion of asbestos cement proceeds faster as compared to concrete because of desintegration of the structure of asbestos cement. The diffusion model also worked out to be applicable for corrosion by agressive CO/sub 2/. The lower corrosion rate due to the formation of CaCO/sub 3/ can for this case be described by a lower diffusion coefficient. 4 tabs., 6 figs., 9 refs.

  4. Bond Strength Degradation of Corrosive Reinforced Lightweight Concrete

    Institute of Scientific and Technical Information of China (English)

    CHEN Yueshun; LU Yiyan; LI Houxiang; ZENG Sanhai

    2007-01-01

    The influence of reinforced bar corrosion on the bond degradation in lightweight concrete was studied. Accelerated constant current corrosion tests were performed on lightweight reinforced concrete samples, and the influential factors, such as protective layer thickness, reinforced bar diameter and corrosive level were investigated. The constant current step method was used to measure the electric resistance of the concrete protective cover, which was used to characterize the corrosion level of the rebar. Experimental results indicated that the corrosive resistance increased with increasing the cover dimension and decreasing the reinforced bar diameter, and the rate of decrease in the specimen impedance after cracking depended on the cover dimension. A new medium was offered for the further research on the performance degradation of corrosion lightweight concrete.

  5. Corrosion behaviour of construction materials for high temperature steam electrolysers

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey; Petrushina, Irina; Christensen, Erik;

    2011-01-01

    Different types of commercially available stainless steels, Ni-based alloys as well as titanium and tantalum were evaluated as possible metallic bipolar plates and construction materials. The corrosion resistance was measured under simulated conditions corresponding to the conditions in high...... to corrosion under strong anodic polarisation. Among alloys, Ni-based showed the highest corrosion resistance in the simulated PEM electrolyser medium. In particular, Inconel 625 was the most promising among the tested corrosion-resistant alloys for the anodic compartment in high temperature steam electrolysis....... Tantalum showed outstanding resistance to corrosion in selected media. On the contrary, passivation of titanium was weak, and the highest rate of corrosion among all tested materials was observed for titanium at 120 degrees C....

  6. Corrosion of copper alloys in sulphide containing district heting systems

    DEFF Research Database (Denmark)

    Thorarinsdottir, R.I.; Maahn, Ernst Emanuel

    1999-01-01

    Copper and some copper alloys are prone to corrosion in sulphide containing geothermal water analogous to corrosion observed in district heating systems containing sulphide due to sulphate reducing bacteria. In order to study the corrosion of copper alloys under practical conditions a test...... was carried out at four sites in the Reykjavik District Heating System. The geothermal water chemistry is different at each site. The corrosion rate and the amount and chemical composition of deposits on weight loss coupons of six different copper alloys are described after exposure of 12 and 18 months...

  7. Influence of bacteria on film formation inhibiting corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Gunasekaran, G.; Chongdar, Shobhana; Gaonkar, S.N.; Kumar, Pradeep

    2004-08-01

    Mild steel coupons were incubated separately in two bacterial cultures namely Pseudomonas flava and Pseudomonas stutzeri. A significant reduction in the corrosion rate was observed in presence of P. flava. With a view to understand the mechanisms of microbially influenced corrosion/corrosion inhibition, various electrochemical and biological experiments such as weight change measurements and electrochemical impedance spectroscopy (EIS) measurements were made. The exposed surfaces were examined using scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDAX). The scraped surface film was also examined using FT-IR (Fourier transform infra red) spectroscopy. The results suggest that P. flava have enhancing effect on corrosion inhibitive properties of phosphate film.

  8. Effect of pellicle on galvanic corrosion of amalgam.

    Science.gov (United States)

    Holland, R I

    1984-02-01

    Galvanic corrosion of amalgam, induced by contact with a type IV dental casting gold alloy, was determined under simulated oral conditions in an electrochemical cell. The effect of a pellicle layer formed by 1 h exposure to saliva in the oral cavity was determined. Pellicle on the amalgam had no effect on the maximum corrosion rate or the 2 h corrosion charge, whereas pellicle on the gold alloy substantially reduced both these parameters of the conventional low-copper amalgam; the corrosion of the high-copper amalgam was less and was not influenced by pellicle formation.

  9. An experimental investigation on the slow strain rate corrosion of 316L stainless steel containing H2S and Cl-%316L钢在含H2S、Cl-水溶液中的慢应变速率腐蚀试验研究

    Institute of Scientific and Technical Information of China (English)

    董绍平; 袁军国; 方德明; 高增梁; 张庆; 刘富胜

    2001-01-01

    通过慢应变速率法(SSRT)应力腐蚀试验,得到了316L钢的应力腐蚀敏感性指数,回归出计算应力腐蚀敏感性指数的方程,表明水溶液中Cl-对316L钢的应力腐蚀影响较大,而H2S的影响小。%Through the stress corrosion test of slow strain rate test, the sensitive indexes of the stress corrosion of 316L stainless steel was derived, the regression equation was given for calculating the sensitive indexes of stress corrosion of 316L stainless steel. It shows that the influence of Cl- in solution on the stress corrosion of 316L stsinless steel was some strong and the influence of H2S in solution on the stress corrosion of 316L stainless steel was small.

  10. Modeling the Time-to Corrosion Cracking of the Cover Concrete in Chloride Contaminated Reinforced Concrete Structures

    OpenAIRE

    Liu, Youping

    1996-01-01

    Significant factors on steel corrosion in chloride contaminated reinforced concrete and time-to-corrosion cracking were investigated in this study. Sixty specimens were designed with seven admixed chloride contents, three concrete cover depths, two reinforcing steel bar diameters, two exposure conditions, and a typical concrete with water to cement ratio of 0.45. Corrosion current density (corrosion rate), corrosion potential, ohmic resistance of concrete and temperature were measured monthly...

  11. Spin Dephasing as a Probe of Mode Temperature, Motional State Distributions, and Heating Rates in a 2D Ion Crystal

    CERN Document Server

    Sawyer, Brian C; Bollinger, John J

    2014-01-01

    We employ spin-dependent optical dipole forces to characterize the transverse center-of-mass (COM) motional mode of a two-dimensional Wigner crystal of hundreds of $^9$Be$^+$. By comparing the measured spin dephasing produced by the spin-dependent force with the predictions of a semiclassical dephasing model, we obtain absolute mode temperatures in excellent agreement with both the Doppler laser cooling limit and measurements obtained from a previously published technique (B. C. Sawyer et al. Phys. Rev. Lett. \\textbf{108}, 213003 (2012)). Furthermore, the structure of the dephasing histograms allows for discrimination between initial thermal and coherent states of motion. We also apply the techniques discussed here to measure, for the first time, the ambient heating rate of the COM mode of a 2D Coulomb crystal in a Penning trap. This measurement places an upper limit on the anomalous single-ion heating rate due to electric field noise from the trap electrode surfaces of $\\frac{d\\bar{n}}{dt}\\sim 5$ s$^{-1}$ fo...

  12. Theoretical Analysis of Reinforcement Tunnel Lining Corrosion

    Directory of Open Access Journals (Sweden)

    ZhiQiang Zhangand

    2013-05-01

    Full Text Available The main cause of ageing damage in reinforced concrete structures is reinforcement corrosion. Damage can be detected visually as coincident cracks along the reinforcement bar, which are significant of both reduction of the re-bar, cross-section and loss of bond strength for reinforced concrete. The reinforced concrete is one of the most widely used engineering materials as final lining of tunnels. The corrosion is common durability problems that have significant effect on the tunnel performance. This study intends to analysis reinforcement concrete corrosion at the tunnel lining by applying temperature expansion theory on steel through numerical simulation process, with expansive force effect. The thickness of concrete cover and the diameter of steel bar have an impact on the stress for reinforcement concrete during propagation of corrosion process. The corrosion cracks appear at the corner of a tunnel lining then in invert and vault because the maximum stress will be in the corner then in invert and vault. The internal force in the concrete lining changes differently when the corrosion rate change.

  13. Corrosion detection and monitoring in steam generators by means of ultrasound; Deteccion y monitoreo de corrosion por medio de ultrasonido en generadores de vapor

    Energy Technology Data Exchange (ETDEWEB)

    Chacon Nava, Jose G.; Calva, Mauricio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico); Fuentes Samaniego, Raul [Universidad Autonoma de Nuevo Leon (Mexico); Peraza Garcia, Alejandro [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1987-12-31

    The tube and component failures in steam generators due to corrosion cause huge economical losses. In this article the internal corrosion processes (hydrogen attack) and high temperature corrosion are described, as well as the ultrasound techniques used for its detection. The importance of obtaining corrosion rates, which are fundamental parameters for the detection of the tube`s residual life. The purpose is to prevent possible failures that would diminish the power plant availability. [Espanol] Las fallas de tuberia en componentes de generadores de vapor debidas a corrosion ocasionan considerables perdidas economicas. En este articulo se describen los procesos de corrosion interna (ataque por hidrogeno) y corrosion en alta temperatura, asi como tecnicas de ultrasonido empleadas para su deteccion. Se destaca la importancia de obtener valores de velocidad de corrosion, que es un parametro fundamental para la determinacion de la vida residual de tuberias. El proposito es poder prevenir posibles fallas que disminuyan la disponibilidad de centrales termoelectricas.

  14. Superheater corrosion in biomass boiler - theories and tests in Vaestermalmsverket, Falun; Oeverhettarkorrosion i bioeldad panna - teorier och prov i Vaestermalmsverket, Falun

    Energy Technology Data Exchange (ETDEWEB)

    Roennquist, Eva-Marie

    2000-10-01

    It has lately been evident that a number of biomass-fired plants are experiencing major problems with corrosion of their superheaters. The major aim with this project is to contribute with increased knowledge in this area. The efforts to build up experience around different materials applicable for superheaters with high steam data is of great importance for future plants in Sweden. The main objective for 'Vaermeforsk' has been to transfer the experiences from this investigation to other boilers or plants with different types of fuel. This investigation has therefore been focused on the verification of SYCON's assumptions regarding the roles of chloride and alkali and the possibility of influencing/minimising superheater corrosion by optimisation of the fuel mix. Another important part was to verify that the boiler design, as such, does not create an unfavourable environment for the superheaters by producing reducing zones due to plume formation. Based on the above, the investigation has been divided into three loosely connected parts. (1) The role and reaction by chlorides in the deposits on a superheater, (2) Reducing environment - plume formation of non-combusted fuel, and (3) Choice of materials in the superheater. Serious corrosion has been detected in the superheater tubes of 'Vaestermalmsverket' in Falun. The material temperature was below 530 deg C. No serious inhomogeneous combustion problems or areas with reducing environments have been detected. The corrosion was therefore judged to be caused by alkali chlorides which condense on the superheater tubes. Tests with minor amounts of sulphur added to the biomass fuel have been shown to suppress the generation of alkali chlorides and their condensation on the superheater surfaces. A good correlation between calculated and measured values have been achieved. Very low corrosion rates have been measured on the test probes, constructed with different superheater material and placed in the

  15. Corrosion monitoring as an integral component of an effective corrosion management program

    Energy Technology Data Exchange (ETDEWEB)

    Bich, N.N. [FORCE Technology Canada Inc., Calgary, AB (Canada)

    2004-07-01

    This paper presented 6 case studies of oil and sour gas transmission pipelines where the use of corrosion monitoring devices led to the early identification of ineffective mitigation measures. The field signature method inspection tool (FSM-IT) was used in all 6 cases. FSM-IT is a non-intrusive corrosion monitoring tool that consists of a geometric matrix of sensing pins that are permanently attached to an outer pipe wall. The sensing matrix wiring is coupled to a sensing matrix interface (SMI) to form an interface. With the occurrence of internal corrosion or erosion, the electrical field is changed and compared against the signature. Computer software is used to compare the new measurements against the original signature to produce metal loss values. The software is capable of trending the metal loss over time, calculating corrosion rates and creating 3D plots to illustrate accumulated wall loss over the whole matrix. The orientation of the corrosion can be determined from an evaluation of the plots. Case studies included details of pipeline length, corrosion mechanisms, and repair activities. Mitigation measures in the case studies included batching; continuous injection; and pigging. It was concluded that the FSM-IT corrosion mitigation tool is effective in monitoring mitigation effectiveness. 7 refs., 1 tab., 12 figs.

  16. Corrosion of Carbon Steel and Corrosion-Resistant Rebars in Concrete Structures Under Chloride Ion Attack

    Science.gov (United States)

    Mohamed, Nedal; Boulfiza, Mohamed; Evitts, Richard

    2013-03-01

    Corrosion of reinforced concrete is the most challenging durability problem that threatens reinforced concrete structures, especially structures that are subject to severe environmental conditions (i.e., highway bridges, marine structures, etc.). Corrosion of reinforcing steel leads to cracking and spalling of the concrete cover and billions of dollars are spent every year on repairing such damaged structures. New types of reinforcements have been developed to avoid these high-cost repairs. Thus, it is important to study the corrosion behavior of these new types of reinforcements and compare them to the traditional carbon steel reinforcements. This study aimed at characterizing the corrosion behavior of three competing reinforcing steels; conventional carbon steel, micro-composite steel (MMFX-2) and 316LN stainless steel, through experiments in carbonated and non-carbonated concrete exposed to chloride-laden environments. Synthetic pore water solutions have been used to simulate both cases of sound and carbonated concrete under chloride ions attack. A three-electrode corrosion cell is used for determining the corrosion characteristics and rates. Multiple electrochemical techniques were applied using a Gamry PC4™ potentiostat manufactured by Gamry Instruments (Warminster, PA). DC corrosion measurements were applied on samples subjected to fixed chloride concentration in the solution.

  17. Diagnosing, Measuring and Monitoring Microbiologically Influenced Corrosion (MIC)

    Science.gov (United States)

    2011-01-01

    to determine the presence of specific groups of bacteria in the bulk medium ( planktonic cells) or associated with corrosion products (sessile cells...ESEM to study marine biofilms on stainless steel surfaces. They observed a gelatinous layer in which bacteria and microalgae were embedded...monitoring planktonic bacteria was not effective at predicting microbial fouling or MIC. Additionally, general corrosion rates were low throughout

  18. Mitigation of Corrosion on Magnesium Alloy by Predesigned Surface Corrosion

    OpenAIRE

    Xuming Zhang; Guosong Wu; Xiang Peng; Limin Li; Hongqing Feng; Biao Gao; Kaifu Huo; Chu, Paul K.

    2015-01-01

    Rapid corrosion of magnesium alloys is undesirable in structural and biomedical applications and a general way to control corrosion is to form a surface barrier layer isolating the bulk materials from the external environment. Herein, based on the insights gained from the anticorrosion behavior of corrosion products, a special way to mitigate aqueous corrosion is described. The concept is based on pre-corrosion by a hydrothermal treatment of Al-enriched Mg alloys in water. A uniform surface c...

  19. Corrosion Failures in Marine Environment

    Directory of Open Access Journals (Sweden)

    R. Krishnan

    1985-04-01

    Full Text Available This paper gives a brief description of typical marine environments and the most common form of corrosion of materials used in this environment. Some typical case histories of failures pertaining to pitting, bimetallic corrosion, dealloying, cavitation and stress corrosion cracking are illustrated as typical examples of corrosion failures.

  20. Corrosion Inhibitors for Reinforced Concrete

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    Steel corrosion in reinforced concrete structures has been a major problem across the U.S. Steel-reinforced concrete structures are continually subject to attack by corrosion brought on by naturally occurring environmental conditions. FerroGard, a corrosion inhibitor, developed by Sika Corporation, penetrates hardened concrete to dramatically reduce corrosion by 65% and extend the structure's service life.

  1. Water corrosion of spent nuclear fuel: radiolysis driven dissolution at the UO2/water interface.

    Science.gov (United States)

    Springell, Ross; Rennie, Sophie; Costelle, Leila; Darnbrough, James; Stitt, Camilla; Cocklin, Elizabeth; Lucas, Chris; Burrows, Robert; Sims, Howard; Wermeille, Didier; Rawle, Jonathan; Nicklin, Chris; Nuttall, William; Scott, Thomas; Lander, Gerard

    2015-01-01

    X-ray diffraction has been used to probe the radiolytic corrosion of uranium dioxide. Single crystal thin films of UO(2) were exposed to an intense X-ray beam at a synchrotron source in the presence of water, in order to simultaneously provide radiation fields required to split the water into highly oxidising radiolytic products, and to probe the crystal structure and composition of the UO(2) layer, and the morphology of the UO(2)/water interface. By modeling the electron density, surface roughness and layer thickness, we have been able to reproduce the observed reflectivity and diffraction profiles and detect changes in oxide composition and rate of dissolution at the Ångström level, over a timescale of several minutes. A finite element calculation of the highly oxidising hydrogen peroxide product suggests that a more complex surface interaction than simple reaction with H(2)O(2) is responsible for an enhancement in the corrosion rate directly at the interface of water and UO(2), and this may impact on models of long-term storage of spent nuclear fuel.

  2. DETECTION OF OH{sup +} IN TRANSLUCENT INTERSTELLAR CLOUDS: NEW ELECTRONIC TRANSITIONS AND PROBING THE PRIMARY COSMIC RAY IONIZATION RATE

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, D.; Linnartz, H. [Sackler Laboratory for Astrophysics, Leiden Observatory, University of Leiden, PO Box 9513, 2300 RA Leiden (Netherlands); Galazutdinov, G. A. [Instituto de Astronomia, Universidad Catolica del Norte, Av. Angamos 0610, Antofagasta (Chile); Krełowski, J., E-mail: zhao@strw.leidenuniv.nl [Center for Astronomy, Nicholas Copernicus University, Gagarina 11, Pl-87-100 Toruń (Poland)

    2015-06-01

    We present the detection of rotationally resolved electronic transitions in the OH{sup +} A{sup 3}Π–X{sup 3}Σ{sup −} (0, 0) and (1, 0) bands toward CD-32 4348, HD 63804, HD 78344, and HD 80077. These four translucent clouds have been studied in a recent Very Large Telescope/Ultraviolet and Visual Echelle Spectrograph observational run. In total, seven absorption features of OH{sup +} are detected, and six of them are identified here for the first time, providing a precise tool to trace OH{sup +} in translucent interstellar clouds. An improved set of line positions and oscillator strengths is compiled to support our data interpretation. A dedicated analysis of the observed features in individual targets yields an accurate determination of OH{sup +} column densities. The results are applied to estimate the primary cosmic ray ionization rate in the investigated translucent clouds, which yields a typical value of ∼1.0 × 10{sup −16} s{sup −1}. In addition, following this work, two of the new interstellar features recently reported by Bhatt and Cami, at ∼3572.65 and 3346.96 Å, can be identified as OH{sup +} absorption lines now.

  3. The Corrosion Behavior of Stainless Steels and Copper Alloys Exposed to Natural Seawater

    Science.gov (United States)

    1991-01-01

    significant changes of the corrosion potential (Ecw) or surface properties. Rotating cylinder experiments indicated that both E., and corrosion rates for...and inorganic chloride corrosion layer that contained alloying elements; a biof ilm; and crystalline, spherical phosphate-rich deposits. All copper...nichtrostendem Stahl und bacteria and diatoms that did not cause significant changes of the Titan entstehenden dfinnen Biofilme bestanden aus

  4. The Corrosion and Preservation of Iron Antiques.

    Science.gov (United States)

    Walker, Robert

    1982-01-01

    Discusses general corrosion reactions (iron to rust), including corrosion of iron, sulfur dioxide, chlorides, immersed corrosion, and underground corrosion. Also discusses corrosion inhibition, including corrosion inhibitors (anodic, cathodic, mixed, organic); safe/dangerous inhibitors; and corrosion/inhibition in concrete/marble, showcases/boxes,…

  5. Flow-induced corrosion behavior of absorbable magnesium-based stents.

    Science.gov (United States)

    Wang, Juan; Giridharan, Venkataraman; Shanov, Vesselin; Xu, Zhigang; Collins, Boyce; White, Leon; Jang, Yongseok; Sankar, Jagannathan; Huang, Nan; Yun, Yeoheung

    2014-12-01

    The aim of this work was to study corrosion behavior of magnesium (Mg) alloys (MgZnCa plates and AZ31 stents) under varied fluid flow conditions representative of the vascular environment. Experiments revealed that fluid hydrodynamics, fluid flow velocity and shear stress play essential roles in the corrosion behavior of absorbable magnesium-based stent devices. Flow-induced shear stress (FISS) accelerates the overall corrosion (including localized, uniform, pitting and erosion corrosions) due to the increased mass transfer and mechanical force. FISS increased the average uniform corrosion rate, the localized corrosion coverage ratios and depths and the removal rate of corrosion products inside the corrosion pits. For MgZnCa plates, an increase of FISS results in an increased pitting factor but saturates at an FISS of ∼0.15Pa. For AZ31 stents, the volume loss ratio (31%) at 0.056Pa was nearly twice that (17%) at 0Pa before and after corrosion. Flow direction has a significant impact on corrosion behavior as more severe pitting and erosion corrosion was observed on the back ends of the MgZnCa plates, and the corrosion product layer facing the flow direction peeled off from the AZ31 stent struts. This study demonstrates that flow-induced corrosion needs be understood so that Mg-based stents in vascular environments can be effectively designed.

  6. Corrosion performance of iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.

    1993-03-01

    Iron aluminides are being developed for use as structural materials and/or cladding alloys in fossil energy systems. Extensive development has been in progress on Fe{sub 3}Al-based alloys to improve the engineering ductility of these alloys. This paper describes results from the ongoing program to evaluate the corrosion performance of these alloys. The experimental program at Argonne National Laboratory involvesthermogravimetric analyses of alloys exposed to environments that simulate coal gasification and fluidized-bed combustion. Experiments were conducted at 650--1000{degrees}C in simulated oxygen/sulfur gas mixtures. In addition, oxidation/sulfidation behavior of several alumina-forming Fe-Al and Fe-Cr-Ni-Al alloys was determined for comparison with the corrosion rates obtained on iron aluminides. Other aspects of the program are corrosion evaluation of the aluminides in the presence of HC1-containing gases and in the presence of slag from a slogging gasifier. Results are used to establish threshold Al levels in the alloys for development of protective alumina scales. Thermal cycling tests are used to examine the spalling resistance of the scales.

  7. Corrosion performance of iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.

    1993-03-01

    Iron aluminides are being developed for use as structural materials and/or cladding alloys in fossil energy systems. Extensive development has been in progress on Fe[sub 3]Al-based alloys to improve the engineering ductility of these alloys. This paper describes results from the ongoing program to evaluate the corrosion performance of these alloys. The experimental program at Argonne National Laboratory involvesthermogravimetric analyses of alloys exposed to environments that simulate coal gasification and fluidized-bed combustion. Experiments were conducted at 650--1000[degrees]C in simulated oxygen/sulfur gas mixtures. In addition, oxidation/sulfidation behavior of several alumina-forming Fe-Al and Fe-Cr-Ni-Al alloys was determined for comparison with the corrosion rates obtained on iron aluminides. Other aspects of the program are corrosion evaluation of the aluminides in the presence of HC1-containing gases and in the presence of slag from a slogging gasifier. Results are used to establish threshold Al levels in the alloys for development of protective alumina scales. Thermal cycling tests are used to examine the spalling resistance of the scales.

  8. An overview of the corrosion aspect of dental implants (titanium and its alloys

    Directory of Open Access Journals (Sweden)

    Chaturvedi T

    2009-01-01

    Full Text Available Titanium and its alloys are used in dentistry for implants because of its unique combination of chemical, physical, and biological properties. They are used in dentistry in cast and wrought form. The long term presence of corrosion reaction products and ongoing corrosion lead to fractures of the alloy-abutment interface, abutment, or implant body. The combination of stress, corrosion, and bacteria contribute to implant failure. This article highlights a review of the various aspects of corrosion and biocompatibility of dental titanium implants as well as suprastructures. This knowledge will also be helpful in exploring possible research strategies for probing the biological properties of materials.

  9. Intergranular corrosion testing of austenitic stainless steels in nitric acid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Whillock, G.O.H.; Dunnett, B. F. [British Nuclear Fuels plc, BNFL, B170, Sellafield, Seascale, Cumbria CA20 1PG (United Kingdom)

    2004-07-01

    In hot strong nitric acid solutions, stainless steels exhibit intergranular corrosion. Corrosion rates are often measured from immersion testing of specimens manufactured from the relevant material (e.g. plate or pipe). The corrosion rates, measured from weight loss, are found to increase with time prior to reaching steady state, which can take thousands of hours to achieve. The apparent increase in corrosion rate as a function of time was found to be an artefact due to the surface area of the specimen's being used in the corrosion rate calculations, rather than that of the true area undergoing active corrosion i.e. the grain boundaries. The steady state corrosion rate coincided with the onset of stable grain dropping, where the use of the surface area of the specimen to convert the weight loss measurements to corrosion rates was found to be appropriate. This was confirmed by sectioning of the specimens and measuring the penetration depths. The rate of penetration was found to be independent of time and no induction period was observed. A method was developed to shorten considerably the testing time to reach the steady state corrosion rate by use of a pre-treatment that induces grain dropping. The long-term corrosion rates from specimens which were pre-treated was similar to that achieved after prolonged testing of untreated (i.e. initially ground) specimens. The presence of cut surfaces is generally unavoidable in the simple immersion testing of specimens in test solutions. However, inaccuracy in the results may occur as the measured corrosion rate is often influenced by the orientation of the microstructure, the highest rates typically being observed on the cut surfaces. Two methods are presented which allow deconvolution of the corrosion rates from immersion testing of specimens containing cut surfaces, thus allowing reliable prediction of the long-term corrosion rate of plate surfaces. (authors)

  10. Implication of Atmospheric Wetness Levels on Corrosion at a Coating Defect during Accelerated Testing

    Science.gov (United States)

    2012-08-28

    Outline • Objectives • Atmospheric corrosion • Testing Approach • Effect of RH on corrosion of steel • Effect of inhibitor addition on coated steel... inhibitor migration in the coating . For a given test method, wet and dry times will influence inhibitor mobility, and thus corrosion rate Continuous...Implication of Atmospheric Wetness Levels on Corrosion at a Coating Defect during Accelerated Testing James F. Dante Southwest Research Institute

  11. Quantitative analysis of hydrogen gas formed by aqueous corrosion of metallic uranium

    Energy Technology Data Exchange (ETDEWEB)

    Fonnesbeck, J.

    2000-03-20

    Three unirradiated EBR-II blanket fuel samples containing depleted uranium metal were corrosion tested in simulated J-13 well water at 90 C. The corrosion rate of the blanket uranium metal was then determined relative to H{sub 2} formation. Corrosion of one of the samples was interrupted prior to complete oxidation of the uranium metal and the solid corrosion product was analyzed for UO{sub 2} and UH{sub 3}.

  12. The corrosion of depleted uranium in terrestrial and marine environments.

    Science.gov (United States)

    Toque, C; Milodowski, A E; Baker, A C

    2014-02-01

    Depleted Uranium alloyed with titanium is used in armour penetrating munitions that have been fired in a number of conflict zones and testing ranges including the UK ranges at Kirkcudbright and Eskmeals. The study presented here evaluates the corrosion of DU alloy cylinders in soil on these two UK ranges and in the adjacent marine environment of the Solway Firth. The estimated mean initial corrosion rates and times for complete corrosion range from 0.13 to 1.9 g cm(-2) y(-1) and 2.5-48 years respectively depending on the particular physical and geochemical environment. The marine environment at the experimental site was very turbulent. This may have caused the scouring of corrosion products and given rise to a different geochemical environment from that which could be easily duplicated in laboratory experiments. The rate of mass loss was found to vary through time in one soil environment and this is hypothesised to be due to pitting increasing the surface area, followed by a build up of corrosion products inhibiting further corrosion. This indicates that early time measurements of mass loss or corrosion rate may be poor indicators of late time corrosion behaviour, potentially giving rise to incorrect estimates of time to complete corrosion. The DU alloy placed in apparently the same geochemical environment, for the same period of time, can experience very different amounts of corrosion and mass loss, indicating that even small variations in the corrosion environment can have a significant effect. These effects are more significant than other experimental errors and variations in initial surface area.

  13. Corrosion control in mining technology

    Energy Technology Data Exchange (ETDEWEB)

    Telekesi, J.

    1985-01-01

    An overview of corrosion effects in mining technology and the importance of protection is presented. The most common corrosion processes and effects are summarized and the system and criteria of their avoidance are discussed in detail. Preventive measures are recommended to decrease possible corrosion effects including the selection of corrosion-resistive constructions, to use protective coatings and inhibition techniques and some other protection possibilities where applicable. The organization aspects and the economic impact of corrosion control in mining are discussed.

  14. Engineering considerations for corrosion monitoring of gas gathering pipeline systems

    Energy Technology Data Exchange (ETDEWEB)

    Braga, T.G.; Asperger, R.G.

    1987-01-01

    Proper corrosion monitoring of gas gathering pipelines requires a system review to determine the appropriate monitor locations and types of monitoring techniques. This paper develops and discusses a classification of conditions such as flow regime and gas composition. Also discussed are junction categories which, for corrosion monitoring, need to be considered from two points of view. The first is related to fluid flow in the line and the second is related corrosion inhibitor movement along the pipeline. The appropriate application of the various monitoring techniques such as coupons, hydrogen detectors, electrical resistance probe and linear polarization probes are discussed in relation to flow regime and gas composition. Problems caused by semi-conduction from iron sulfide are considered. Advantages and disadvantages of fluid gathering methods such as pots and flow-through drips are discussed in relation to their reliability as on-line monitoring locations.

  15. Corrosion-resistant uranium

    Science.gov (United States)

    Hovis, V.M. Jr.; Pullen, W.C.; Kollie, T.G.; Bell, R.T.

    1981-10-21

    The present invention is directed to the protecting of uranium and uranium alloy articles from corrosion by providing the surfaces of the articles with a layer of an ion-plated metal selected from aluminum and zinc to a thickness of at least 60 microinches and then converting at least the outer surface of the ion-plated layer of aluminum or zinc to aluminum chromate or zinc chromate. This conversion of the aluminum or zinc to the chromate form considerably enhances the corrosion resistance of the ion plating so as to effectively protect the coated article from corrosion.

  16. Corrosion of magnesium alloys in commercial engine coolants

    Energy Technology Data Exchange (ETDEWEB)

    Song, G.; StJohn, D.H. [CRC for Cast Metals Manufacturing (CAST), Division of Materials, School of Engineering, The University of Queensland, Brisbane, QLD 4072 (Australia)

    2005-01-01

    A number of magnesium alloys show promise as engine block materials. However, a critical issue for the automotive industry is corrosion of the engine block by the coolant and this could limit the use of magnesium engine blocks. This work assesses the corrosion performance of conventional magnesium alloy AZ91D and a recently developed engine block magnesium alloy AM-SC1 in several commercial coolants. Immersion testing, hydrogen evolution measurement, galvanic current monitoring and the standard ASTM D1384 test were employed to reveal the corrosion performance of the magnesium alloys subjected to the coolants. The results show that the tested commercial coolants are corrosive to the magnesium alloys in terms of general and galvanic corrosion. The two magnesium alloys exhibited slightly different corrosion resistance to the coolants with AZ91D being more corrosion resistant than AM-SC1. The corrosivity varied from coolant to coolant. Generally speaking, an organic-acid based long life coolant was less corrosive to the magnesium alloys than a traditional coolant. Among the studied commercial coolants, Toyota long life coolant appeared to be the most promising one. In addition, it was found that potassium fluoride effectively inhibited corrosion of the magnesium alloys in the studied commercial coolants. Both general and galvanic corrosion rates were significantly decreased by addition of KF, and there were no evident side effects on the other engine block materials, such as copper, solder, brass, steel and aluminium alloys, in terms of their corrosion performance. The ASTM D 1384 test further confirmed these results and suggested that Toyota long life coolant with 1%wt KF addition is a promising coolant for magnesium engine blocks. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

  17. Remote measurement of corrosion using ultrasonic techniques

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, K.M.; Porter, A.M.

    1995-02-01

    Supercritical water oxidation (SCWO) technology has the potential of meeting the US Department of Energy`s treatment requirements for mixed radioactive waste. A major technical constraint of the SCWO process is corrosion. Safe operation of a pilot plant requires monitoring of the corrosion rate of the materials of construction. A method is needed for measurement of the corrosion rate taking place during operation. One approach is to directly measure the change in wall thickness or growth of oxide layer at critical points in the SCWO process. In FY-93, a brief survey of the industry was performed to evaluate nondestructive evaluation (NDE) methods for remote corrosion monitoring in supercritical vessels. As a result of this survey, it was determined that ultrasonic testing (UT) methods would be the most cost-effective and suitable method of achieving this. Therefore, the objective for FY-94 was to prove the feasibility of using UT to monitor corrosion of supercritical vessels remotely during operation without removal of the insulation.

  18. A study on species transport in the corrosion products of ferrous archaeological analogues - a contribution to the modelling of iron long term corrosion behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Vega, E.; Dillmann, Ph.; Fluzin, Ph. [LRC CEA DSM 01-27: IRAMAT UMR5060 CNRS et Laboratoire Pierre Sue (CEA/CNRS), CEA Saclay 91191 Gif-sur-Yvette Cedex (France)

    2004-07-01

    One of the main technological and environmental challenges for the next centuries is the safe storage of nuclear wastes. For this purpose, the behaviour during several centuries of every material constituting the barrier between wastes and environment must be predicted. In addition to modelling and laboratory simulations, the only mean to study corrosion systems formed during several centuries is to analyse archaeological ferrous artefacts buried in soil. Precedent studies on this kind of artefacts have shown that the corrosion system is formed by the metallic core, a dense corrosion product layer, a transformed medium constituted of a mix of corrosion products and soil compounds, and the soil itself. Moreover, analytical and electrochemical studies seem to show that the corrosion mechanisms are driven by the species transport in the dense product layer (DPL) and especially by oxygen migration in the DPL pores. Thus, it seems necessary to precise the species transport properties in the DPL. A characterisation study on ferrous artefacts coming from the site of Glinet (16. AD) have been carried out. The rust layers have been studied using several techniques. The composition analyses were performed with Energy Dispersive Spectroscopy (EDS) coupled to the Scanning Electron Microscope, and Electron Probe Microanalysis (EPMA). Structural information have been obtained by X-ray micro-diffraction ({mu}XRD) and micro-Raman spectroscopy. The aim of this communication is to present the results of a study performed with markers in order to better understand the species transport in the DPL. Experiments focus on an archaeological artefact part from Glinet excavation. The migration in the DPL of I and Na ions (which have roughly the same diffusion coefficient in water than oxygen) will be studied by immersion of an archaeological analogue with his DPL in a saturated iodide (NaI) aqueous solution. After different immersion times (1 h, 3 h, 7 h and 168 h), the concentration

  19. Corrosion Behavior of Commercial Magnetic Refrigerant Gadolinium in Water

    Institute of Scientific and Technical Information of China (English)

    Zhang Zeyu; Long Yi; Wen Da; Ye Rongchang; Wan Farong

    2004-01-01

    Gadolinium(Gd) used as magnetic refrigerant always works in water environment.However, its poor corrosion resistance is serious impediment against wider application of Gd.In this paper, the corrosion behavior of two types of commercial Gd ( A, B both are 98.9 at.% pure) with the same oxygen content has been studied.The results show that the corrosion rate of A is 3.226 times higher than that of B in deionized water and 6.039 times in tap water.According to SEM, the different corrosion rate is because of the different distribution of impurity in matrix.In addition,NaOH solution was chosen as inhibitor to prevent Gd from being corroded successfully.No pitting corrosion and weight loss were observed for commercial Gd even after immersion for nearly 2000 h in NaOH solution.

  20. Effect of flow on corrosion in catenary risers and its corrosion inhibitor performance

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Pedro Altoe; Magalhaes, Alvaro Augusto Oliveira; Silva, Jussara de Mello [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil); Kang, Cheolho; More, Parimal P. [Det Norske Veritas (DNV), Oslo (Norway)

    2009-07-01

    In oil and gas production, multiphase flow is often encountered and a range of different flow patterns can be experienced in pipelines. The flow regime transition and flow characteristics can be changed with the change of pipeline topography, which affects the corrosion and the performance of corrosion inhibitor in these multiphase pipelines. This paper outlines on the effect of inclination on the flow characteristics and their subsequent effect on corrosion rates. Also, this paper presents on the performance of three candidate corrosion inhibitors under severe slugging conditions at low water cut. For the simulation of offshore flow lines and risers, the experiments were carried out in a 44 m long, 10 cm diameter, three different pipeline inclinations of 0, 3 and 45 degrees. Light condensate oil with a viscosity of 2.5 cP at room temperature was used and water cut was 20%. The results indicated that the baseline corrosion rate in 45 degrees showed higher than other inclinations. Each corrosion inhibitor showed a different inhibitor performance. (author)

  1. Corrosion Evaluation of RERTR Uranium Molybdenum Fuel

    Energy Technology Data Exchange (ETDEWEB)

    A K Wertsching

    2012-09-01

    As part of the National Nuclear Security Agency (NNSA) mandate to replace the use of highly enriched uranium (HEU) fuel for low enriched uranium (LEU) fuel, research into the development of LEU fuel for research reactors has been active since the late 1970’s. Originally referred to as the Reduced Enrichment for Research and Test Reactor (RERTR) program the new effort named Global Threat Reduction Initiative (GTRI) is nearing the goal of replacing the standard aluminum clad dispersion highly enriched uranium aluminide fuel with a new LEU fuel. The five domestic high performance research reactors undergoing this conversion are High Flux Isotope reactor (HFIR), Advanced Test Reactor (ATR), National Institute of Standards and Technology (NIST) Reactor, Missouri University Research Reactor (MURR) and the Massachusetts Institute of Technology Reactor II (MITR-II). The design of these reactors requires a higher neutron flux than other international research reactors, which to this point has posed unique challenges in the design and development of the new mandated LEU fuel. The new design utilizes a monolithic fuel configuration in order to obtain sufficient 235U within the LEU stoichoimetry to maintain the fission reaction within the domestic test reactors. The change from uranium aluminide dispersion fuel type to uranium molybdenum (UMo) monolithic configuration requires examination of possible corrosion issues associated with the new fuel meat. A focused analysis of the UMo fuel under potential corrosion conditions, within the ATR and under aqueous storage indicates a slow and predictable corrosion rate. Additional corrosion testing is recommended for the highest burn-up fuels to confirm observed corrosion rate trends. This corrosion analysis will focus only on the UMo fuel and will address corrosion of ancillary components such as cladding only in terms of how it affects the fuel. The calculations and corrosion scenarios are weighted with a conservative bias to

  2. Characterization of Corrosion Product Layers from CO2 Corrosion of 13Cr Stainless Steel in Simulated Oilfield Solution

    Science.gov (United States)

    Yin, Z. F.; Wang, X. Z.; Liu, L.; Wu, J. Q.; Zhang, Y. Q.

    2011-10-01

    The influence of temperature and flow rate on the characterization and mechanisms of corrosion product layers from CO2 corrosion of 13Cr stainless steel was carried out in simulated oilfield solution. Cyclic potentiodynamic polarization method as well as weight loss tests in autoclave were utilized to investigate pitting corrosion behavior at various temperatures. Weight loss tests were performed at 100 and 160 °C under dynamic and static flow conditions. At the same time, the significant pitting parameters such as E corr, E pit, E pp, ∆ E, and I pass in cyclic polarization curves at various temperatures were analyzed and compared for revealing the pitting behavior of 13Cr stainless steel. The surface measurement techniques such as SEM, XRD, and XPS were used to detect the corrosion product layers. The results showed that both temperature and flow rate had significant effects on characterization of corrosion product layers or passive films formed on 13Cr stainless steel in CO2 corrosion system. At high temperature, lots of pits were formed at the localized corrosion areas of metal surfaces. Corrosion rates under the condition of 5 m/s were higher than those under the static condition regardless of the test temperatures.

  3. Corrosion and Materials Performance in biomass fired and co-fired power plants

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Larsen, OH; Biede, O

    2003-01-01

    not previously encountered in coal-fired power plants. The type of corrosion attack can be directly ascribed to the composition of the deposit and the metal surface temperature. In woodchip boilers, a similar corrosion rate and corrosion mechanism has on some occasions been observed. Co-firing of straw (10....... Results from 100% straw-firing, woodchip and co-firing of straw with coal will be reported. The corrosion mechanisms observed are summarized and the corrosion rates for 18-8 type stainless steels are compared....

  4. External Corrosion of Pipes in District Heating Systems; Utvaendig korrosion paa fjaerrvaermeroer

    Energy Technology Data Exchange (ETDEWEB)

    Sund, Goeran [Det Norske Veritas, Stockholm (Sweden)

    2002-07-01

    Corrosion damages of pipes in district heating systems can occur both external and internal. The aim with this work has been to clarify external corrosion damages of pipes, and try to correlate the damages to the corrosivity of different soils and waters. For the analysis the Swedish District Heating Association's district heating system statistics has been used. The district heating system statistics shows that the cost for corrosion damages is high, and pipes older than 20 years have increased risk for corrosion. The knowledge about corrosion concerning steel poles and water pipes in soils can not be applied to external corrosion of steel pipes in district heating systems. The corrosion rate of steel poles in soils is low. The corrosion of steel pipes in district heating systems can locally give high rates, up to 0,5 mm/year. The mechanism for this type of corrosion is different compared to the corrosion mechanism of poles in soils. The temperature is higher and aggressive water, with road-salt and chloride content, falls in drops on the steel pipe, and impurities evaporate on the steel surface. These factors increase the corrosion rate. If the material thickness is 5 mm, fracture can occur in the pipe within ten years. The number of copper pipe corrosion damage is limited. The most determining corrosion factors of copper pipes are pH-value and impurities as chloride and sulphate in the water. Stainless steel pipes of type 304 can not be used in soils due to the risk of local corrosion. Higher alloyed stainless steels, with molybdenum and higher chromium content should be used. It is concluded that failures can occur due to external corrosion of steel pipes. This failure is expensive and can lead to human damage. One way to eliminate failures of steel pipes is to carry out risk analysis.

  5. Corrosion Inhibitors for Aluminum.

    Science.gov (United States)

    Muller, Bodo

    1995-01-01

    Describes a simple and reliable test method used to investigate the corrosion-inhibiting effects of various chelating agents on aluminum pigments in aqueous alkaline media. The experiments that are presented require no complicated or expensive electronic equipment. (DDR)

  6. Corrosion of copper containers prior to saturation of a nuclear fuel waste disposal vault

    Energy Technology Data Exchange (ETDEWEB)

    King, F.; Kolar, M

    1997-12-01

    The buffer material surrounding the containers in a Canadian nuclear fuel waste disposal vault will partially desiccate as a result of the elevated temperature at the container surface. This will lead to a period of corrosion in a moist air atmosphere. Corrosion will either take the form of slow oxidation if the container surface remains dry or aqueous electrochemical corrosion if the surface is wetted by a thin liquid film. The relevant literature is reviewed, from which it is concluded that corrosion should be uniform in nature, except if the surface is wetted, in which case localized corrosion is a possibility. A quantitative analysis of the extent and rate of uniform corrosion during the unsaturated period is presented. Two bounding cases are considered: first, the case of slow oxidation in moist air following either logarithmic or parabolic oxide-growth kinetics and, second, the case of electrochemically based corrosion occurring in a thin liquid film uninhibited by the growth of corrosion products. (author)

  7. Study on the Synthesis and Corrosion Inhibition Performance of Mannich-Modified Imidazoline

    Directory of Open Access Journals (Sweden)

    Xiangjun Kong

    2016-07-01

    Full Text Available A novel Mannich-modified imidazoline (MMI as cationic emulsifier was synthesised for corrosion harm reduction, through three steps — acylation, cyclization, and Mannich reaction. The surface activity was characterized by determination of surface tensions and critical micelle concentration (CMC. The corrosion inhibition performance of five types of steels in the simulated corrosion solution in the presence of the MMI was investigated by static weight loss tests. The results showed that the MMI had good surface activities, with CMC of 19.8 μg g−1 and surface tension of 36.4 mN m−1. The corrosion test results indicated that the corrosion rates of different materials were decreased significantly, and degrees of corrosion inhibition were always higher than 80.0 %. The main inhibition mechanism was most likely due to the adsorption of the corrosion inhibitor on the steel surface, leading to the prevention of corrosion medium from the metal surface.

  8. Roles of Radiolytic and Externally Generated H2 in the Corrosion of Fractured Spent Nuclear Fuel.

    Science.gov (United States)

    Liu, Nazhen; Wu, Linda; Qin, Zack; Shoesmith, David W

    2016-11-15

    A 2-D model for the corrosion of spent nuclear fuel inside a failed nuclear waste container has been modified to determine the influence of various redox processes occurring within fractures in the fuel. The corrosion process is driven by reaction of the fuel with the dominant α radiolysis product, H2O2. A number of reactions are shown to moderate or suppress the corrosion rate, including H2O2 decomposition and a number of reactions involving dissolved H2 produced either by α radiolysis or by the corrosion of the steel container vessel. Both sources of H2 lead to the suppression of fuel corrosion, with their relative importance being determined by the radiation dose rate, the steel corrosion rate, and the dimensions of the fractures in the fuel. The combination of H2 from these two sources can effectively prevent corrosion when only micromolar quantities of H2 are present.

  9. Metallic corrosion in the polluted urban atmosphere of Hong Kong.

    Science.gov (United States)

    Liu, Bo; Wang, Da-Wei; Guo, Hai; Ling, Zhen-Hao; Cheung, Kalam

    2015-01-01

    This study aimed to explore the relationship between air pollutants, particularly acidic particles, and metallic material corrosion. An atmospheric corrosion test was carried out in spring-summer 2012 at a polluted urban site, i.e., Tung Chung in western Hong Kong. Nine types of metallic materials, namely iron, Q235 steel, 20# steel, 16Mn steel, copper, bronze, brass, aluminum, and aluminum alloy, were selected as specimens for corrosion tests. Ten sets of the nine materials were all exposed to ambient air, and then each set was collected individually after exposure to ambient air for consecutive 6, 13, 20, 27, 35, 42, 49, 56, 63, and 70 days, respectively. After the removal of the corrosion products on the surface of the exposed specimens, the corrosion rate of each material was determined. The surface structure of materials was observed using scanning electron microscopy (SEM) before and after the corrosion tests. Environmental factors including temperature, relative humidity, concentrations of gaseous pollutants, i.e., sulfur dioxide (SO₂), nitrogen dioxide (NO₂), carbon monoxide (CO), ozone (O₃), and particulate-phase pollutants, i.e., PM₂.₅ (FSP) and PM₁₀ (RSP), were monitored. Correlation analysis between environmental factors and corrosion rate of materials indicated that iron and carbon steel were damaged by both gaseous pollutants (SO₂ and NO₂) and particles. Copper and copper alloys were mainly corroded by gaseous pollutants (SO₂ and O₃), while corrosion of aluminum and aluminum alloy was mainly attributed to NO₂ and particles.

  10. Surface films and corrosion of copper

    Energy Technology Data Exchange (ETDEWEB)

    Hilden, J.; Laitinen, T.; Maekelae, K.; Saario, T.; Bojinov, M. [VTT Manufacturing Technology, Espoo (Finland)

    1999-03-01

    In Sweden and Finland the spent nuclear fuel is planned to be encapsulated in cast iron canisters that have an outer shield made of copper. The copper shield is responsible for the corrosion protection of the canister construction. General corrosion of the copper is not expected to be the limiting factor in the waste repository environment when estimating the life-time of the canister construction. However, different forms of localised corrosion, i.e. pitting, stress corrosion cracking, or environmentally assisted creep fracture may cause premature failure of the copper shield. Of the probable constituents in the groundwater, nitrites, chlorides, sulphides and carbonates have been suggested to promote localised corrosion of copper. The main assumption made in planning this research program is that the surface films forming on copper in the repository environment largely determine the susceptibility of copper to the different forms of localised corrosion. The availability of reactants, which also may become corrosion rate limiting, is investigated in several other research programs. This research program consists of a set of successive projects targeted at characterising the properties of surface films on copper in repository environment containing different detrimental anions. A further aim was to assess the significance of the anion-induced changes in the stability of the oxide films with regard to localised corrosion of copper. This report summarises the results from a series of investigations on properties of surface films forming on copper in water of pH = 8.9 at temperature of 80 deg C and pressure of 2 MPa. The main results gained so far in this research program are as follows: The surface films forming on copper in the thermodynamic stability region of monovalent copper at 80 deg C consist of a bulk part (about 1 mm thick) which is a good ionic and electronic conductor, and an outer, interfacial layer (0.001 - 0.005 mm thick) which shows p-type semiconductor

  11. Corrosion Behavior of 110S Tube Steel in Environments of High H2S and CO2 Content

    Institute of Scientific and Technical Information of China (English)

    LI W en-fei; ZHOU Yan-jun; XUE Yan

    2012-01-01

    The corrosion behavior of the 110S tube steel in the environments of high H2 S and CO2 content was inves- tigated by using a high-temperature and high-pressure autoclave, and the corrosion products were characterized by scanning electron microscopy and X ray diffraction technique. The results showed that all of the corrosion products under the test conditions mainly consisted of different types of iron sulfides such as pyrrhotite of Fe0.95 S, mackinaw- ite of FeS0.9, Fe0. 985 S and FeS, and the absence of iron carbonate in the corrosion scales indicated that the corrosion process was controlled by H2S corrosion. The corrosion rate of the 110S steel decreased firstly and then increased with the rising of temperature. The minimum corrosion rate occurred at 110 ℃. When the H2 S partial pressure PH2s below 9 MPa, the corrosion rate declined with the increase of PH2s. While over 9 MPa, a higher PH2s resulted in a faster corrosion process. With the increasing of the CO2 partial pressure, the corrosion rate had an increasing trend. The morphologies of the corrosion scales had a good accordance with the corrosion rates.

  12. Corrosive wear. Evaluation of wear and corrosive resistant materials; Noetningskorrosion. Utvaerdering av noetnings- och korrosionsbestaendiga material

    Energy Technology Data Exchange (ETDEWEB)

    Persson, H.; Hjertsen, D.; Waara, P.; Prakash, B.; Hardell, J.

    2007-12-15

    With a new purchase of a waste conveyer screw at hand, for the 'A-warehouse' at the combined power and heating plant at E.ON Norrkoeping, the request for improved construction materials was raised. The previous screw required maintenance with very short intervals due to the difficult operation conditions. With the new screw the expectation is to manage 6 months of operation without interruption. The environment for the screw has two main components that sets the demand on the materials, on one hand the corrosive products that comes along and which forms at digestion of the waste and on the other hand the abrasive content in the waste. The term of the mechanism is wear-corrosion and can give considerably higher material loss than the two mechanisms wear and corrosion separately. Combination of a strong corrosive environment together with extensive wear is something that we today have limited knowledge about. The overall objective of the project has been to establish better wear and corrosive resistant construction materials for a waste conveyer screw that will lead to reduced operational disturbance costs. The evaluation has been performed in both controlled laboratory environments and in field tests, which has given us a better understanding of what materials are more suitable in this tough environment and has given us a tool for future predictions of the wear rate of the different material. The new conveyer screw, installed in February 2007 and with which the field test have been performed, has considerably reduced the wear of the construction and the target of 6 month maintenance-free operation is met with this screw for all the evaluated materials. The wear along the screw varies very much and with a clear trend for all the materials to increase towards the feeding direction of the screw. As an example, the wear plate SS2377 (stainless duplex steel) has a useful life at the most affected areas that is calculated to be 1077 days of operation with the

  13. Modelling reinforcement corrosion in concrete

    DEFF Research Database (Denmark)

    Michel, Alexander; Geiker, Mette Rica; Stang, Henrik

    2012-01-01

    A physio-chemical model for the simulation of reinforcement corrosion in concrete struc-tures was developed. The model allows for simulation of initiation and subsequent propaga-tion of reinforcement corrosion. Corrosion is assumed to be initiated once a defined critical chloride threshold...... is reached causing the formation of anodic and cathodic regions along the reinforcement. Critical chloride thresholds, randomly distributed along the reinforcement sur-face, link the initiation and propagation phase of reinforcement corrosion. To demonstrate the potential use of the developed model......, a numerical example is pre-sented, that illustrates the formation of corrosion cells as well as propagation of corrosion in a reinforced concrete structure....

  14. Corrosion and arc erosion in MHD channels

    Energy Technology Data Exchange (ETDEWEB)

    Rosa, R.J. (Montana State Univ., Bozeman, MT (United States). Dept. of Mechanical Engineering); Pollina, R.J. (Montana State Univ., Bozeman, MT (United States). Dept. of Mechanical Engineering EG and G Energy Measurements, Inc., Las Vegas, NV (United States))

    1992-08-01

    The problems connected with gas side corrosion for the design of the lA4 (POC) channel hardware are explored and results of gas side wear rate tests in the Textron Mark VII facility are presented. It is shown that the proposed designs meet a 2000 hour lifetime criterion based upon these materials tests. Improvement in cathode lifetime is demonstrated with lower voltage intercathode gaps. The corrosion of these materials is discussed and it is shown how lifetimes are dependent upon gap voltage and average metal temperature. The importance of uniformity of slagging to the durability of the anode wall is demonstrated. The wear mechanism of the anodes in the MHD channel is analyzed. In addition to gas-side corrosion, the results of specific water corrosion tests of sidewall materials are discussed. All of the tests reported here were carried out to confirm the gas-side performance and the manufacturability of anode and sidewall designs and to address questions posed about the durability of tungsten-copper on the waterside. the results of water corrosion tests of the tungsten copper alloy sidewall material are presented to show that with proper control of waterside pH and, if necessary, dissolved oxygen, one can obtain reliable performance with no degradation of heat transfer with this material. The final choice of materials was determined primarily by the outcome of these tests and also by the question of the manufacturability of the prospective designs.

  15. Handbook of corrosion data, 2nd edition

    Energy Technology Data Exchange (ETDEWEB)

    Craig, B.; Anderson, D. [eds.

    1995-12-31

    As in the prior edition, in one convenient volume this book makes it easy to find what effect environment has on the corrosion of metals and alloys. Coverage on all the environments in the first edition has been updated and expanded and some 80 or more environments have been added, including food products (chocolate, milk, cider, beer, etc.), fruit juices (grape, pineapple, lemon, etc.), soil, blood, gasoline, fertilizers, etc. Presentation of the tabular information for all environments has been standardized throughout the book. The environments are listed alphabetically. Each listing includes a general description of the conditions, a comment on the corrosion characteristics of various alloys in such a situation, a bibliography of recent articles specific to the environment, tables consolidating and comparing corrosion rates at various temperatures and concentrations for various alloys, and graphical information. also included are summaries on the general corrosion characteristics of major metals and alloys. This separate section of the book considers each material group, such as aluminum, stainless steel, zinc and so forth. Additional tables are presented here to give the corrosion characteristics of various alloys in hundreds of environments.

  16. Simulation of Eddy-Current Corrosion Detection Using a Sensor Array

    Science.gov (United States)

    Katyal, V.; Bowler, J. R.

    2003-03-01

    A computer simulation has been developed to evaluate eddy-current probes containing magnetic field sensor arrays for the detection and evaluation of hidden corrosion. The simulation is used to assess probes that incorporate magneto-resistive or Hall devices in a closely-spaced, linear array. These probes will allow rapid data acquisition over a track width determined by the length of the array. The benefit of the simulation is that adjustments to the virtual probe parameters are easily made allowing improvements in sensitivity, imaging capability and resolution. A number of probe designs have been studied in this way including the "racetrack" probe.

  17. Corrosion and Corrosion Control in Light Water Reactors

    Science.gov (United States)

    Gordon, Barry M.

    2013-08-01

    Serious corrosion problems have plagued the light water reactor (LWR) industry for decades. The complex corrosion mechanisms involved and the development of practical engineering solutions for their mitigation will be discussed in this article. After a brief overview of the basic designs of the boiling water reactor (BWR) and pressurized water reactor (PWR), emphasis will be placed on the general corrosion of LWR containments, flow-accelerated corrosion of carbon steel components, intergranular stress corrosion cracking (IGSCC) in BWRs, primary water stress corrosion cracking (PWSCC) in PWRs, and irradiation-assisted stress corrosion cracking (IASCC) in both systems. Finally, the corrosion future of both plants will be discussed as plants extend their period of operation for an additional 20 to 40 years.

  18. Localized corrosion of aluminum alloys for OTEC heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Dexter, S C

    1979-01-01

    The effects of dissolved oxygen, pH and temperature on the rate of initiation and growth of pitting and crevice corrosion of aluminum alloy 5052 and pure aluminum have been determined. Variations in pH and temperature rather than dissolved oxygen are shown to account for increased corrosion rates of 5000 series aluminum alloys that have been reported for deep ocean exposures. The impact of these results on the use of aluminum for OTEC heat exchanger tubing and on possible approaches to corrosion control are discussed.

  19. On-line corrosion monitoring in district heating systems

    DEFF Research Database (Denmark)

    Richter, Sonja; Thorarinsdottir, R.I.; Hilbert, Lisbeth Rischel

    2004-01-01

    Traditionally corrosion monitoring in district heating systems has been performed offline via weight loss coupons. These measurements give information about the past and not the present situation and require long exposure time (weeks or months). The good quality of district heating medium makes...... corrosion monitoring a challenge. Under normal conditions the pH is high (app. 9), conductivity is low (app. 10-200 µS/cm) and the concentration of dissolved oxygen is negligible. The low corrosion rates (in the order of µm/y) are difficult to measure and furthermore, factors such as hydrogen sulphide......), Electrochemical Noise (EN) and Zero Resistance Ammetry (ZRA). Electrochemical Resistance (ER) has also been used to measure corrosion. The method traditionally only measures corrosion off-line but with newly developed high-sensitive ER technique developed by MetriCorr in Denmark, on-line monitoring is possible...

  20. Surface treatment and history-dependent corrosion in lead alloys

    Energy Technology Data Exchange (ETDEWEB)

    Li Ning [Los Alamos National Laboratory, Los Alamos, NM (United States)]. E-mail: ningli@lanl.gov; Zhang Jinsuo [Los Alamos National Laboratory, Los Alamos, NM (United States); Sencer, Bulent H. [Los Alamos National Laboratory, Los Alamos, NM (United States); Koury, Daniel [University of Nevada, Las Vegas, NV (United States)

    2006-06-23

    In oxygen-controlled lead and lead-bismuth eutectic (LBE), steel corrosion may be strongly history dependent. This is due to the competition between liquid metal dissolution corrosion and oxidation as a 'self-healing' protection barrier. Such effects can be observed from corrosion testing of a variety of surface-treated materials, such as cold working, shot peening, pre-oxidation, etc. Shot peening of austenitic steels produces surface-layer microstructural damages and grain compression, which could contribute to increased Cr migration to the surface and enhance the protection through an impervious oxide. Pre-oxidation under conditions different from operating ones may form more protective oxides, reduce oxygen and metal ion migration through the oxides, and achieve better protection for longer durations. Corrosion and oxidation modeling and analysis reveal the potential for significantly reducing long-term corrosion rates by initial and early-stage conditioning of steels for Pb/LBE services.

  1. Electrochemical and Corrosion Inhibition Studies of Cucurbita Maxima

    Directory of Open Access Journals (Sweden)

    K. Anbarasi

    2016-08-01

    Full Text Available The influence of the acid extract of peel of Cucurbita maxima (PCM on the corrosion of mild steel in 1N H2SO4 was investigated by weight loss, polarization and impedance methods and SEM analysis. The inhibition efficiency increases with extract concentration and immersion period. Weight loss and corrosion rates of mild steel decreased as the concentration of inhibitor increased. The results showed that PCM was potential corrosion inhibitor and maximum inhibition efficiency (IE % obtained was 98% for 3%PCM at 1h. Impedance measurement results an increase in charge transfer resistance (Rct, which also confirms the corrosion inhibitive nature of the plant extract. Potentiodynamic study showed that PCM acts as a mixed type of inhibitor, which controls both the anodic and cathodic reactions. Scanning electron microscopic studies provided the evidence of improved surface condition for the corrosion protection, due to the adsorption.

  2. Influence of Heat Treatments on the Corrosion Resistance of Medium -Carbon Steel using Sulfuric Spring Water

    Directory of Open Access Journals (Sweden)

    Ikhlas Basheer

    2013-04-01

    Full Text Available The corrosion is one of the important problems that may be occur to the parts of machinery and equipment after manufactured and when used as a result of exposure to corrosive media. Plain-carbon steel is considered as one of the most common minerals used in industrial applications. Some of heat treatments can have direct effect on the corrosion rate of steel by building up galvanic corrosion cells between its microscopic phases. Therefore, to adopt one of kinds of the plain-carbon steel and the most commonly used in industry to be study subject, that is medium carbon steel and took samples of this steel has been treated thermally in three methods which the normalising, annealing, and hardening .The corrosive media used in the research is Sulfuric Spring, it contains many chemical compounds to show its influence on the corrosion of steel. The weight loss method is used to determine corrosion rate and to compare between the results obtained, show that the greatest corrosion resistance of the annealed steel and the corrosion resistance of the hardened steel is the lowest while the corrosion  resistance of the normalised steel is in-between them.         Calcium carbonate was formed on the metal surface which acts as an isolating layer which decrease corrosion rate with time

  3. Experimental Study on Rebar Corrosion Using the Galvanic Sensor Combined with the Electronic Resistance Technique

    Science.gov (United States)

    Xu, Yunze; Li, Kaiqiang; Liu, Liang; Yang, Lujia; Wang, Xiaona; Huang, Yi

    2016-01-01

    In this paper, a new kind of carbon steel (CS) and stainless steel (SS) galvanic sensor system was developed for the study of rebar corrosion in different pore solution conditions. Through the special design of the CS and SS electronic coupons, the electronic resistance (ER) method and zero resistance ammeter (ZRA) technique were used simultaneously for the measurement of both the galvanic current and the corrosion depth. The corrosion processes in different solution conditions were also studied by linear polarization resistance (LPR) and the measurements of polarization curves. The test result shows that the galvanic current noise can provide detailed information of the corrosion processes. When localized corrosion occurs, the corrosion rate measured by the ER method is lower than the real corrosion rate. However, the value measured by the LPR method is higher than the real corrosion rate. The galvanic current and the corrosion current measured by the LPR method shows linear correlation in chloride-containing saturated Ca(OH)2 solution. The relationship between the corrosion current differences measured by the CS electronic coupons and the galvanic current between the CS and SS electronic coupons can also be used to evaluate the localized corrosion in reinforced concrete. PMID:27618054

  4. Corrosion behavior of friction stir welded AZ31B Mg alloy - Al6063 alloy joint

    Directory of Open Access Journals (Sweden)

    B. Ratna Sunil

    2016-12-01

    Full Text Available In the present work, AZ31B Mg alloy and Al6063 alloy-rolled sheets were successfully joined by friction stir welding. Microstructural studies revealed a sound joint with good mechanical mixing of both the alloys at the nugget zone. Corrosion performance of the joint was assessed by immersing in 3.5% NaCl solution for different intervals of time and the corrosion rate was calculated. The joint has undergone severe corrosion attack compared with both the base materials (AZ31B and Al6063 alloys. The predominant corrosion mechanism behind the high corrosion rate of the joint was found to be high galvanic corrosion. From the results, it can be suggested that the severe corrosion of dissimilar Mg–Al joints must be considered as a valid input while designing structures intended to work in corroding environment.

  5. Corrosion testing using isotopes

    Science.gov (United States)

    Hohorst, Frederick A.

    1995-12-05

    A method for determining the corrosion behavior of a material with respect to a medium in contact with the material by: implanting a substantially chemically inert gas in a matrix so that corrosion experienced by the material causes the inert gas to enter the medium; placing the medium in contact with the material; and measuring the amount of inert gas which enters the medium. A test sample of a material whose resistance to corrosion by a medium is to be tested, composed of: a body of the material, which body has a surface to be contacted by the medium; and a substantially chemically inert gas implanted into the body to a depth below the surface. A test sample of a material whose resistance to corrosion by a medium is to be tested, composed of: a substrate of material which is easily corroded by the medium, the substrate having a surface; a substantially chemically inert gas implanted into the substrate; and a sheet of the material whose resistance to corrosion is to be tested, the sheet being disposed against the surface of the substrate and having a defined thickness.

  6. Severe Environmental Corrosion Erosion Facility

    Data.gov (United States)

    Federal Laboratory Consortium — NETL’s Severe Environment Corrosion Erosion Facility in Albany, OR, allows researchers to safely examine the performance of materials in highly corrosive or erosive...

  7. Integrated sensor network for monitoring steel corrosion in concrete structures

    Directory of Open Access Journals (Sweden)

    José Enrique Ramón

    2016-06-01

    Full Text Available Corrosion is one of the main triggering factors affecting the service life and durability of structures. Several methods are used for corrosion studies but electrochemical techniques are the most commonly applied. Corrosion processes monitoring and control by means of non-destructive techniques, such as the implementation of embedded sensors, has been the target of many works.  It is possible to obtain relevant information of structural corrosion processes in real time. This document describes a system including specific equipment and which allows obtaining relevant information about these corrosion processes. This system is formed by a sensor network. There are several types of electrodes, which are distributed throughout the structure under study and a specific equipment developed by the research group, which is used to determine pertinent parameters such as the corrosion potential (Ecorr and the corrosion density (icorr by applying sequences of potentiostatic pulses. The system allows to reliably determine the corrosion rate in different areas of the structure. The sensor, due to its configuration, provides information of a specific area of the structure, but on the other hand it is involved in the galvanic events that can occur along the structure by differential aeration, galvanic cells, etc. because the sensor is not isolated from the structure.  This system also procures information of buried and submerged elements. Besides, it is possible to obtain information related to temperature, concrete resistance. The system includes specific potentiometric sensors to monitor chloride access and carbonatation processes.

  8. Influence of Paper Surface Compounds on Corrosion of Printing Machines

    Directory of Open Access Journals (Sweden)

    Kresimir Dragcevic

    2013-01-01

    Full Text Available This paper deals with investigation of corrosion processes on construction steel in contact with aqueous solutions of surface coatings of high gloss and standard uncoated papers for sheet-fed printing. During the period of four months, changes in the mass of steel specimens were measured (loss of material, as well as changes in pH values and conductivity of the examined solutions. Formation of corrosion products on the surface was identified by changes of spectrophotometric reemission in the visible portion of the steel spectrum and by FT-IR spectral recordings. In addition, the electrochemical potentiodynamic measurements were carried out with the direct current and the method of linear polarization and Tafel’s extrapolation, by which the corrosion parameters were determined: corrosion potential, corrosion current density, polarization resistance cathodic and anodic inclination of Tafel’s lines, as well as the corrosion rate. The results show that the dynamics of the corrosion in printing machines is directly influenced by the type of the paper used for printing. This investigation gave an insight into dynamics and mechanisms of corrosion under conditions close to those in printing production, thus facilitating better understanding of the entire process.

  9. Durability ofAsphalt in Different Corrosion Solution

    Institute of Scientific and Technical Information of China (English)

    CHEN Shuanfa; GUAN Bowen; XIONG Rui; SHENG Yanping; HE Rui

    2011-01-01

    The corrosion to asphalt mixture under different kinds of corrosion solution,such as pH=2 solution,pH=12 solution,pH =12 solution and 10% Na2SO4 solution,was studied.The performance attenuation of asphalt mixture was analyzed under the normal environment and the freeze-thaw environment,and the analysis was given on the sensitivity of the test results to the evaluation index.The experimental results show that the performance of asphalt mixture is attenuated faster under the acidic solution,alkaline solution and sulfate solution.Corrosion factor Kc,freeze-thaw corrosion factor Kf,and freeze-thaw effect factor Kfc are proposed to evaluate asphalt mixture resistance to corrosion in different kinds of corrosion solution.The values of Kc and Kfc decrease with the increasing of corrosion time.The change rule of Kf show that the rate of corrosion is decreased by the action of freeze-thaw in acidic solution and in alkaline solution,but is increased by the action of freeze-thaw in sulfate solution.The microscopic analysis indicates that acid solution reacts with aggregate of asphalt mixture,alkaline solution reacts with asphalt cement of asphalt mixture,the surface tension of sulfate solution and crystallization of sulfate are the main reasons which weak the performance of asphalt mixture.

  10. General corrosion of metallic materials in boric acid environments; La corrosion generalisee des materiaux metalliques en milieu acide borique

    Energy Technology Data Exchange (ETDEWEB)

    Gras, J.M.

    1994-05-01

    Certain low-alloy steel components in PWR primary circuit were corroded by leaking water containing boric acid. A number of studies have been performed by manufacturers in the USA and by EDF in France to determine the rate of general corrosion for low-alloy steels in media containing varying concentrations of boric acid. The first part of this paper summarizes the studies performed and indicates how far work has advanced to date in establishing the resistance of stainless steels to general corrosion in concentrated boric acid solutions. The second part of the paper discusses the mechanism of corrosion and proposes a model. Carbon steels and low-alloy steels - carbon steels and low-alloy steels in deaerated diluted boric acid solutions (pH > 4) corrode very slowly (<20{mu}m/year). The corrosion rate is approximately 1 {mu}m/year in the nominal primary water in static conditions; - in non-deaerated solutions, the corrosion rate is determined by the solubility of iron. Important factors are the pH, the temperature and the operating conditions, which determine the iron solubility in the medium: the rate of renewal of the medium or the S/V ratio of the metal surface exposed to the volume of solution. The steel composition is not a determinant factor. Stainless steels. General corrosion of stainless steels in concentrated boric acid solutions depends primarily on their chromium content. Steels containing less than 15% chromium offer excellent resistance to corrosion regardless of their structure or nickel content. The corrosion rate is less than 10 {mu}m/year at 250 deg C and approximately 40 {mu}m/year at 300 deg C. Steels containing 13% chromium corrode in hot concentrated media. The apparent activation energy of general corrosion is approximately 25 kJ.mol{sup -1}. (author). 31 refs., 12 figs., 13 tabs.

  11. Influence of Direct Current Electric Field on Corrosion Behavior of Tin Under a Thin Electrolyte Layer

    Science.gov (United States)

    Huang, H. L.; Bu, F. R.; Tian, J.; Liu, D.

    2017-08-01

    The influence of a direct current electric field (DCEF) on corrosion behavior of tin under a thin electrolyte layer was investigated based on an array electrode technology by polarization, electrochemical impedance spectroscopy and surface analysis. The experimental results indicate that the corrosion rate of tin near the positive plate of DCEF increases with increased electric field intensity, which could be attributed to the acceleration of the migration of ions, the removal of corrosion products under DCEF and the damage of tin surface oxide film. Furthermore, tin at different positions in a DCEF exhibits different corrosion behavior, which could be ascribed to the difference of the local corrosion environment caused by the DCEF.

  12. STUDY ON THE EROSION-CORROSION BEHAVIOR OF STEELS AND THERMAL SPRAYED COATINGS

    Institute of Scientific and Technical Information of China (English)

    ChenHuahui; ZhaoHuiyou; ShooHesheng; ZhaoShanzhon

    1996-01-01

    16Mn steel, 1Cr18Ni9 stainless steel, thermal sprayed Al2O3-TiO2 ceramic coating and nylonl010-5%Al2O3 coating were tested with an erosion-corrosion tester.The effects of pH values and slurry velocities on the erosion-corrosion behavior of the materials tested were determined. The erosion-corrosion behavior of the materials tested changes with pH values and presents different change tendencies. The erosion-corrosion rates of the materials are increased with slurry velocities. The erosion-corrosion mechanisms for the steels and the coatings are considerably different.

  13. Corrosion of steel reinforced concrete in the tropical coastal atmosphere of Havana City, Cuba

    Directory of Open Access Journals (Sweden)

    Abel Castañeda

    2013-01-01

    Full Text Available The influence of chloride deposition rate on concrete using an atmospheric corrosion approach is rarely studied in the literature. Seven exposure sites were selected in Havana City, Cuba, for exposure of reinforced concrete samples. Two significantly different atmospheric corrosivity levels with respect to corrosion of steel reinforced concrete were observed after two years of exposure depending on atmospheric chloride deposition and w/c ratio of the concrete. Changes in corrosion current are related to changes in chloride penetration and chloride atmospheric deposition. The influence of sulphur compound deposition could also be a parameter to consider in atmospheric corrosion of steel reinforced concrete.

  14. Corrosion-resistant metallic coatings

    OpenAIRE

    F. Presuel-Moreno; M.A. Jakab; N. Tailleart; Goldman, M.; J. R. Scully

    2008-01-01

    We describe recent computational and experimental studies on the corrosion properties of metallic coatings that can be tailored (tuned) to deliver up to three corrosion-inhibiting functions to an underlying substrate. Attributes are tuned by a selection of alloy compositions and nanostructures, ideally in alloy systems that offer flexibility of choice to optimize the corrosion-resisting properties. An amorphous Al-based coating is tuned for corrosion protection by on-demand release of ionic i...

  15. Corrosion-resistant metal surfaces

    Science.gov (United States)

    Sugama, Toshifumi [Wading River, NY

    2009-03-24

    The present invention relates to metal surfaces having thereon an ultrathin (e.g., less than ten nanometer thickness) corrosion-resistant film, thereby rendering the metal surfaces corrosion-resistant. The corrosion-resistant film includes an at least partially crosslinked amido-functionalized silanol component in combination with rare-earth metal oxide nanoparticles. The invention also relates to methods for producing such corrosion-resistant films.

  16. Characterization of the Corrosion Behavior of Alloy 22 Regarding its Lifetime Performance as a Potential Nuclear Waste Container Material

    Energy Technology Data Exchange (ETDEWEB)

    Rebak, R B; McCright, D

    2002-06-04

    Alloy 22 (UNS N06022) was proposed for the corrosion resistant outer barrier of a two-layer waste package container for nuclear waste at the potential repository site at Yucca Mountain in Nevada (USA). A testing program is underway to characterize and quantify three main modes of corrosion that may occur at the site. Current results show that the containers would perform well under general corrosion, localized corrosion and environmentally assisted cracking (EAC). For example, the general corrosion rate is expected to be below 100 nm/year and the container is predicted to be outside the range of potential for localized corrosion and environmentally assisted cracking.

  17. Effect of silty sand in formation water on CO{sub 2} corrosion behavior of carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wei, E-mail: weiliu@ustb.edu.cn; Dou, Juanjuan; Lu, Songle; Zhang, Peng; Zhao, Qinghe

    2016-03-30

    Graphical abstract: Silty sand (SiO{sub 2}) promoted the rapid heterogeneous nucleation of corrosion product (FeCO{sub 3}) and simultaneously decreased its grains growth. Silty sand mixed with corrosion product to form the outer layer of corrosion scale with high compactness, blocking the transport of ferrous ions and leading to the formation of the inner layer of corrosion scale without silty sand. The corrosion rate of carbon steel was obviously reduced due to the existence of silty sand in the outer layer by inhibiting anodic and cathodic currents. - Highlights: • CO{sub 2} corrosion rate of carbon steel was obviously reduced due to the existence of silty sand. • The corrosion scale containing silty sand inhibited anodic and cathodic currents, contributing to low corrosion rate. • A development mechanism of corrosion scale in silty sand containing CO{sub 2} environment was proposed. - Abstract: Corrosion behavior of carbon steel in CO{sub 2} aqueous environment containing silty sand was investigated using corrosion mass loss method, scanning electron microscopy (SEM), energy diffraction spectrum (EDS), and various electrochemical measurements. The results show that the corrosion rate of carbon steel was obviously reduced due to the existence of silty sand. Silty sand promoted the rapid heterogeneous nucleation of corrosion product FeCO{sub 3} and simultaneously decreased its grains growth. Silty sand mixed with corrosion product to form the outer layer of corrosion scale with high compactness, blocking the transport of ferrous ions and leading to the formation of the inner layer of corrosion scale without silty sand. The existence of silty sand in the outer layer of corrosion scale inhibited anodic and cathodic currents.

  18. Plastics for corrosion inhibition

    CERN Document Server

    Goldade, Victor A; Makarevich, Anna V; Kestelman, Vladimir N

    2005-01-01

    The development of polymer composites containing inhibitors of metal corrosion is an important endeavour in modern materials science and technology. Corrosion inhibitors can be located in a polymer matrix in the solid, liquid or gaseous phase. This book details the thermodynamic principles for selecting these components, their compatibility and their effectiveness. The various mechanisms of metal protection – barrier, inhibiting and electromechanical – are considered, as are the conflicting requirements placed on the structure of the combined material. Two main classes of inhibited materials (structural and films/coatings) are described in detail. Examples are given of structural plastics used in friction units subjected to mechano-chemical wear and of polymer films/coatings for protecting metal objects against corrosion.

  19. Solving A Corrosion Problem

    Science.gov (United States)

    1979-01-01

    The corrosion problem, it turned out, stemmed from the process called electrolysis. When two different metals are in contact, an electrical potential is set up between them; when the metals are surrounded by an electrolyte, or a conducting medium, the resulting reaction causes corrosion, often very rapid corrosion. In this case the different metals were the copper grounding system and the ferry's aluminum hull; the dockside salt water in which the hull was resting served as the electrolyte. After identifying the source of the trouble, the Ames engineer provided a solution: a new wire-and-rod grounding system made of aluminum like the ferry's hull so there would no longer be dissimilar metals in contact. Ames research on the matter disclosed that the problem was not unique to the Golden Gate ferries. It is being experienced by many pleasure boat operators who are probably as puzzled about it as was the Golden Gate Transit Authority.

  20. Thin film corrosion. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Raut, M.K.

    1980-06-01

    Corrosion of chromium/gold (Cr/Au) thin films during photolithography, prebond etching, and cleaning was evaluated. Vapors of chromium etchant, tantalum nitride etchant, and especially gold etchant were found to corrosively attack chromium/gold films. A palladium metal barrier between the gold and chromium layers was found to reduce the corrosion from gold etchant.

  1. Corrosion resistant PEM fuel cell

    Science.gov (United States)

    Fronk, Matthew Howard; Borup, Rodney Lynn; Hulett, Jay S.; Brady, Brian K.; Cunningham, Kevin M.

    2002-01-01

    A PEM fuel cell having electrical contact elements comprising a corrosion-susceptible substrate metal coated with an electrically conductive, corrosion-resistant polymer containing a plurality of electrically conductive, corrosion-resistant filler particles. The substrate may have an oxidizable metal first layer (e.g., stainless steel) underlying the polymer coating.

  2. Evaluation of alternatives for upgrading double shell tank corrosion monitoring at Hanford

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, J.L.

    1996-02-23

    Recent discovery of low hydroxide conditions in Double Shell Tanks have demonstrated that the current corrosion control system of waste sampling and analysis is inadequate to monitor and maintain specified chemistries for dilute and low volume waste tanks. Moreover, waste sampling alone cannot provide adequate information to resolve the questions raised regarding tank corrosion. This report evaluates available technologies which could be used to improve on the existing corrosion control system. The evaluation concludes that a multi-technique corrosion monitoring system is necessary, utilizing ultrasonic and visual examinations for direct evaluation of tank liner condition, probes for rapid detection (alarm) of corrosive conditions, and waste sampling and analysis for determination of corrective action. The probes would incorporate electrochemical noise and linear polarization resistance techniques. When removed from the waste tank, the probe electrodes would be physically examined as corrosion coupons. The probes would be used in addition to a modified regimen of waste sampling and the existing schedule for ultrasonic examination of the tank liners. Supporting information would be obtained by examination of in-tank equipment as it is removed.

  3. Mathematical modeling of microbially induced crown corrosion in wastewater collection systems and laboratory investigation and modeling of sulfuric acid corrosion of concrete

    Science.gov (United States)

    Jahani, Fereidoun

    In the model for microbially induced crown corrosion, the diffusion of sulfide inside the concrete pores, its biological conversion to sulfuric acid, and the corrosion of calcium carbonate aggregates are represented. The corrosion front is modeled as a moving boundary. The location of the interface between the corrosion layer and the concrete is determined as part of the solution to the model equations. This model consisted of a system of one dimensional reaction-diffusion equations coupled to an equation describing the movement of the corrosion front. The equations were solved numerically using finite element Galerkin approximation. The concentration profiles of sulfide in the air and the liquid phases, the pH as a function of concrete depth, and the position of the corrosion front. A new equation for the corrosion rate was also derived. A more specific model for the degradation of a concrete specimen exposed to a sulfuric acid solution was also studied. In this model, diffusion of hydrogen ions and their reaction with alkaline components of concrete were expressed using Fick's Law of diffusion. The model equations described the moving boundary, the dissolution rate of alkaline components in the concrete, volume increase of sulfuric acid solution over the concrete specimen, and the boundary conditions on the surface of the concrete. An apparatus was designed and experiments were performed to measure pH changes on the surface of concrete. The data were used to calculate the dissolution rate of the concrete and, with the model, to determine the diffusion rate of sulfuric acid in the corrosion layer and corrosion layer thickness. Electrochemical Impedance Spectroscopy (EIS) was used to study the corrosion rate of iron pins embedded in the concrete sample. The open circuit potential (OCP) determined the onset of corrosion on the surface of the pins. Visual observation of the corrosion layer thickness was in good agreement with the simulation results.

  4. Study of surface interactions of ionic liquids with aluminium alloys in corrosion and erosion corrosion processes

    Science.gov (United States)

    Bermúdez, María-Dolores; Jiménez, Ana-Eva; Martínez-Nicolás, Ginés

    2007-06-01

    Surface interactions of alkylimidazolium ionic liquids (ILs) with aluminium alloy Al 2011 have been studied by immersion tests in seven neat ILs [1- n-alkyl-3-methylimidazolium X - (X = BF 4; n = 2 (IL1), 6 (IL2), 8 (IL3). X = CF 3SO 3; n = 2 (IL4). X = (4-CH 3C 6H 4SO 3); n = 2 (IL5). X = PF 6; n = 6 (IL6)] and 1-butyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide (IL7)]. Immersion tests for Al 2011 have also been carried out in 1 wt.% and 5 wt.% solutions of 1-ethyl,3-methylimidazolium tetrafluoroborate (IL1) in water. No corrosion of Al 2011 by neat ILs is observed. The highest corrosion rate for Al 2011 in water is observed in the presence of a 5 wt.% IL1 due to hydrolysis of the anion with hydrogen evolution and formation of aluminium fluoride. Erosion-corrosion processes have been studied for three aluminium alloys (Al 2011, Al 6061 and Al 7075) in a 90 wt.% IL1 solution in water in the presence of α-alumina particles. The erosion-corrosion rates are around 0.2 mm/year or lower, and increase with increasing copper content to give a corrosion resistance order of Al 6061 > Al 7075 > Al 2011. Results are discussed on the basis of scanning electron microscopy (SEM) observations, energy dispersive spectroscopy (EDS) analysis, X-ray diffraction (XRD) patterns and X-ray photoelectron spectroscopy (XPS) determinations.

  5. Effect of Cl– on the corrosive wear of AISI 321 stainless steel in H2SO4 solution

    Indian Academy of Sciences (India)

    Yanliang Huang; Xiaoxia Jiang; Sizuo Li

    2003-06-01

    The effect of Cl– on the corrosive wear behaviour of AISI 321 stainless steel in H2SO4 solution was studied via the corrosive wear rate, the load bearing capacity of passive film and the relationship between pitting and corrosive wear. There is a critical load at natural potential, below which the corrosive wear rate is slightly lowered by Cl–, while above which is increased. At natural potential there are more pits at low load than that at a higher one in the wear tracks and the pits are also deeper. The load bearing capacity is lowered by Cl– at passive region and then the corrosive wear rate increased.

  6. Effect of chloride content of molten nitrate salt on corrosion of A516 carbon steel.

    Energy Technology Data Exchange (ETDEWEB)

    Bradshaw, Robert W.; Clift, W. Miles

    2010-11-01

    The corrosion behavior of A516 carbon steel was evaluated to determine the effect of the dissolved chloride content in molten binary Solar Salt. Corrosion tests were conducted in a molten salt consisting of a 60-40 weight ratio of NaNO{sub 3} and KNO{sub 3} at 400{sup o}C and 450{sup o}C for up to 800 hours. Chloride concentrations of 0, 0.5 and 1.0 wt.% were investigated to determine the effect on corrosion of this impurity, which can be present in comparable amounts in commercial grades of the constituent salts. Corrosion rates were determined by descaled weight losses, corrosion morphology was examined by metallographic sectioning, and the types of corrosion products were determined by x-ray diffraction. Corrosion proceeded by uniform surface scaling and no pitting or intergranular corrosion was observed. Corrosion rates increased significantly as the concentration of dissolved chloride in the molten salt increased. The adherence of surface scales, and thus their protective properties, was degraded by dissolved chloride, fostering more rapid corrosion. Magnetite was the only corrosion product formed on the carbon steel specimens, regardless of chloride content or temperature.

  7. Application of electrochemical frequency modulation for monitoring corrosion and corrosion inhibition of iron by some indole derivatives in molar hydrochloric acid

    Energy Technology Data Exchange (ETDEWEB)

    Khaled, K.F. [Electrochemistry Research Laboratory, Chemistry Department, Faculty of Education, Ain Shams University, Roxy, Cairo (Egypt)], E-mail: khaled@asunet.shams.edu.eg

    2008-11-15

    The corrosion inhibition effect of four indole derivatives, namely indole (IND), benzotriazole (BTA), benzothiazole (BSA) and benzoimidazole (BIA), have been used as possible corrosion inhibitors for pure iron in 1 M HCl. In this study, electrochemical frequency modulation, EFM was used as an effective method for corrosion rate determination in corrosion inhibition studies. By using EFM measurements, corrosion current density was determined without prior knowledge of Tafel slopes. Corrosion rates obtained using EFM, were compared to that obtained from other chemical and electrochemical techniques. The results obtained from EFM, EIS, Tafel and weight loss measurements were in good agreement. Tafel polarization measurements show that indole derivatives are cathodic-type inhibitors. Molecular simulation studies were applied to optimize the adsorption structures of indole derivatives. The inhibitor/iron/solvent interfaces were simulated and the adsorption energies of these inhibitors were calculated. Quantum chemical calculations have been performed and several quantum chemical indices were calculated and correlated with the corresponding inhibition efficiencies.

  8. TREATMENT TANK CORROSION STUDIES FOR THE ENHANCED CHEMICAL CLEANING PROCESS

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, B.

    2011-08-24

    Radioactive waste is stored in high level waste tanks on the Savannah River Site (SRS). Savannah River Remediation (SRR) is aggressively seeking to close the non-compliant Type I and II waste tanks. The removal of sludge (i.e., metal oxide) heels from the tank is the final stage in the waste removal process. The Enhanced Chemical Cleaning (ECC) process is being developed and investigated by SRR to aid in Savannah River Site (SRS) High-Level Waste (HLW) as an option for sludge heel removal. Corrosion rate data for carbon steel exposed to the ECC treatment tank environment was obtained to evaluate the degree of corrosion that occurs. These tests were also designed to determine the effect of various environmental variables such as temperature, agitation and sludge slurry type on the corrosion behavior of carbon steel. Coupon tests were performed to estimate the corrosion rate during the ECC process, as well as determine any susceptibility to localized corrosion. Electrochemical studies were performed to develop a better understanding of the corrosion mechanism. The tests were performed in 1 wt.% and 2.5 wt.% oxalic acid with HM and PUREX sludge simulants. The following results and conclusions were made based on this testing: (1) In 1 wt.% oxalic acid with a sludge simulant, carbon steel corroded at a rate of less than 25 mpy within the temperature and agitation levels of the test. No susceptibility to localized corrosion was observed. (2) In 2.5 wt.% oxalic acid with a sludge simulant, the carbon steel corrosion rates ranged between 15 and 88 mpy. The most severe corrosion was observed at 75 C in the HM/2.5 wt.% oxalic acid simulant. Pitting and general corrosion increased with the agitation level at this condition. No pitting and lower general corrosion rates were observed with the PUREX/2.5 wt.% oxalic acid simulant. The electrochemical and coupon tests both indicated that carbon steel is more susceptible to localized corrosion in the HM/oxalic acid environment than

  9. Influence of chloride and carbon dioxide on general and crevice corrosion of steam turbine materials for geothermal power plants

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, HaiFeng; Niu, Libin; Oishi, Shuji; Takaku, Hiroshi [Shinshu Univ. (Japan). Faculty of Engineering; Shiokawa, Kunio; Yamashita, Mitsuo [Fuji Electric Advanced Technology Co. Ltd. (Japan); Sakai, Yoshihiro [Fuji Electric Systems Co. Ltd. (Japan)

    2006-09-15

    The influence of chloride and CO{sub 2} on general and crevice corrosion of steam turbine materials for geothermal power plants was investigated in two simulated geothermal waters. The general corrosion rates of the rotor steels with a lower Cr content were accelerated due to the CO{sub 2} in the water, while the corrosion rates of the blade steels with a higher Cr content were controlled mainly by the chloride concentration in the waters. Concerning the crevice corrosion behavior, the galvanic corrosion effects in each of the waters were confirmed for the rotor steels with lower corrosion potentials than those of the blade materials, and almost no difference in corrosion behavior was observed between the two waters tested. Regarding general and crevice corrosion in the two simulated geothermal waters, it was determined that a newly developed rotor material and also an improved heat-treated blade material are promising for actual usage in geothermal power plants. (orig.)

  10. High Temperature Corrosion of Fe-C-S Cast Irons in Oxidizing and Sulfidizing Atmospheres

    Institute of Scientific and Technical Information of China (English)

    Thuan-Dinh NGUYEN; Dong-Bok LEE

    2008-01-01

    The corrosion behavior of spheroidal graphite and flake graphite cast irons was studied in oxidizing and sulfidizing atmospheres between 600 and 800℃ for 50 h. The corrosion rate in the sulfidizing atmosphere was faster than that in air above 700℃, due to the formation of the Feo.975S sulfide. The corrosion rate of the spheroidal graphite cast iron was similar to that of the flake graphite cast iron.

  11. Effects of Temperature on the Slow Strain Rate Tension Stress Corrosion Cracking of Super 13Cr Tubing Steel%温度对超级13Cr油管钢慢拉伸应力腐蚀开裂的影响

    Institute of Scientific and Technical Information of China (English)

    姚小飞; 谢发勤; 吴向清; 王毅飞

    2012-01-01

    Effects of temperature on the stress corrosion cracking of super 13Cr tubing steel were investigated in 3. 5% NaCl,that tensile strength and elongation and cracking time and stress corrosion cracking susceptibility index kscc and fracture morphology were analyzed by slow strain rate tensile stress corrosion cracking (SSRT) experiment method and σ-ε curve and SEM. The results shows that the degree of stress corrosion were lesser at below 60℃ and were severe at higher 80 ℃. With the rise of temperature, the super 13Cr tubing steel tensile strength decreased,e-longation rate decreased, contraction ratio decreases, breaking time was reduced, stress corrosion cracking tendency of increase, the stress corrosion cracking susceptibility index kσ and kε are increasing, and the increased trend of kε were obviously than kσ, effects of temperature on the plastic deformation of super 13Cr tubing steel were greater than the tensile strength.%采用慢应变速率拉伸(SSRT)应力腐蚀开裂试验方法,通过σ-ε曲线和SEM等分析了超级13Cr油管钢抗拉强度、延伸率、断裂时间、应力腐蚀开裂敏感性指数(kSCC)和断口形貌;研究了温度对其在3.5% NaCl溶液中应力腐蚀开裂(SCC)的影响.结果表明:当温度<60℃时应力腐蚀的程度较轻;当温度>80℃时应力腐蚀的程度严重;随温度的升高,超级13Cr油管钢的抗拉强度降低,延伸率减小,断面收缩率减小,断裂时间减小,应力腐蚀开裂的倾向性增大,应力腐蚀开裂敏感性指数kσ和kε均呈现增大的趋势,且kε比kσ增大的趋势更显著;温度对超级13Cr油管钢的塑性变形性的影响比对抗拉强度的影响更大.

  12. Probe Storage

    NARCIS (Netherlands)

    Gemelli, Marcellino; Abelmann, Leon; Engelen, Johan B.C.; Khatib, Mohammed G.; Koelmans, Wabe W.; Zaboronski, Olog; Campardo, Giovanni; Tiziani, Federico; Laculo, Massimo

    2011-01-01

    This chapter gives an overview of probe-based data storage research over the last three decades, encompassing all aspects of a probe recording system. Following the division found in all mechanically addressed storage systems, the different subsystems (media, read/write heads, positioning, data chan

  13. Cultural probes

    DEFF Research Database (Denmark)

    Madsen, Jacob Østergaard

    2016-01-01

    The aim of this study was thus to explore cultural probes (Gaver, Boucher et al. 2004), as a possible methodical approach, supporting knowledge production on situated and contextual aspects of occupation.......The aim of this study was thus to explore cultural probes (Gaver, Boucher et al. 2004), as a possible methodical approach, supporting knowledge production on situated and contextual aspects of occupation....

  14. Slag Corrosion Resistance of β-Sialon-Al2O3 Composites-Part Ⅱ.Kinetics

    Institute of Scientific and Technical Information of China (English)

    LIYoufen; HONGYanruo; 等

    2001-01-01

    The kinetic process of slag corrosion for β-Sialon and β-Sialon-Al2O3 composites has been studied by means of dip method (static and self-rotating),The corrosion model is buitl and the formula of corrosion rate is deduced,which are in accordance with experimental results.

  15. Influence of chemical and materials in the rate of erosion corrosion. Modelling the cycle chemistry and materials characterization measurements on CN Cofrentes; Influencia de la quimica y materiales en la tasa de erosion corrosion. Modelizacion de la quimica del ciclo y medidas de caracterizacion de materiales en C. N. Cofrentes

    Energy Technology Data Exchange (ETDEWEB)

    Paule Ramos, A.; Sanchez-Zapata, J. D.

    2012-07-01

    The chemical cycle and the type of material are some of the factors that have great influence on the phenomenon of erosion-corrosion. The paper present the modeling of chemistry through the software cycle strategies COMSY and materials characterization measures undertaken in order to more effectively control this phenomenon in CN Cofrentes.

  16. Microstructural Modeling of Pitting Corrosion in Steels Using an Arbitrary Lagrangian-Eulerian Method

    Science.gov (United States)

    Yu, Qifeng; Pan, Tongyan

    2017-05-01

    Two microscale numerical models are developed in this work using a moving-mesh approach to investigate the growth process of pitting in different iron phases and the corrosion prevention capability of polyaniline (PANi) on steels. The distributions of corrosion potential and current in the electrolyte-coating-steel system are computed to evaluate the anti-corrosion ability of PANi. The arbitrary Lagrangian-Eulerian approach was used to accomplish the continuous remesh process as was needed to simulate the dynamic growing forefront of the modeled pitting domain. Experimental validation of the numerical models was conducted using the technique of scanning kelvin probe force microscopy (SKPFM). The SKPFM-scanned surface topography and Volta potential difference exhibit comparable results to and thereby prove the numerical results. The potential distribution in the electrolyte phase of the validated models shows that the corrosion pit grows faster in the epoxy-only-coated steel than that in the PANi-primer-coated steel over the simulation time; also, the corrosion pit grows faster in the ferrite phase than in the cementite phase. The simulation results indicate that the epoxy-only coating lost its anti-corrosion capability as the coating was penetrated by electrolyte, while the PANi-based coating can still protect the steel from corrosion after the electrolyte penetration. The models developed in this work can be used to study the mechanisms of pitting corrosion as well as develop more effective corrosion prevention strategies for general metallic materials.

  17. Microstructural Modeling of Pitting Corrosion in Steels Using an Arbitrary Lagrangian-Eulerian Method

    Science.gov (United States)

    Yu, Qifeng; Pan, Tongyan

    2017-03-01

    Abstracts Two microscale numerical models are developed in this work using a moving-mesh approach to investigate the growth process of pitting in different iron phases and the corrosion prevention capability of polyaniline (PANi) on steels. The distributions of corrosion potential and current in the electrolyte-coating-steel system are computed to evaluate the anti-corrosion ability of PANi. The arbitrary Lagrangian-Eulerian approach was used to accomplish the continuous remesh process as was needed to simulate the dynamic growing forefront of the modeled pitting domain. Experimental validation of the numerical models was conducted using the technique of scanning kelvin probe force microscopy (SKPFM). The SKPFM-scanned surface topography and Volta potential difference exhibit comparable results to and thereby prove the numerical results. The potential distribution in the electrolyte phase of the validated models shows that the corrosion pit grows faster in the epoxy-only-coated steel than that in the PANi-primer-coated steel over the simulation time; also, the corrosion pit grows faster in the ferrite phase than in the cementite phase. The simulation results indicate that the epoxy-only coating lost its anti-corrosion capability as the coating was penetrated by electrolyte, while the PANi-based coating can still protect the steel from corrosion after the electrolyte penetration. The models developed in this work can be used to study the mechanisms of pitting corrosion as well as develop more effective corrosion prevention strategies for general metallic materials.

  18. The Growth of Small Corrosion Fatigue Cracks in Alloy 7075

    Science.gov (United States)

    Piascik, Robert S.

    2015-01-01

    The corrosion fatigue crack growth characteristics of small (greater than 35 micrometers) surface and corner cracks in aluminum alloy 7075 is established. The early stage of crack growth is studied by performing in situ long focal length microscope (500×) crack length measurements in laboratory air and 1% sodium chloride (NaCl) environments. To quantify the "small crack effect" in the corrosive environment, the corrosion fatigue crack propagation behavior of small cracks is compared to long through-the-thickness cracks grown under identical experimental conditions. In salt water, long crack constant K(sub max) growth rates are similar to small crack da/dN.

  19. Corrosion of Cast Iron Mill Plates in Wet Grinding

    Directory of Open Access Journals (Sweden)

    Anthony ANDREWS

    2010-12-01

    Full Text Available Corrosion studies were carried out on two different maize grinding plates. Maize was soaked in water for three days and the water decanted and used as electrolyte. Mass loss and pH measurements were carried out every 3 days for 15-day period. Results show that, for each plate, mass loss and pH increased with exposure time. Corrosion rates determined from mass loss data was found to be strongly dependent on pH. The observed behaviour may be explained in terms of the chemical composition and/or microstructures of the plates. Results are briefly discussed in terms of the contribution of corrosion to wear.

  20. Grey interrelation analysis of alloy elements and steel corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Jinglei; Hou Baorong; Huang Yanliang; Guo Gongyu [Chinese Academy of Sciences, Qingdao (China). Dept. of Oceanology

    2000-07-01

    Mathematical grey interrelation analysis method was used to study the correlation of alloy elements and low steel corrosion in the splash zone. Eighteen kinds of low alloy steels were selected for 350-day experiments in a large marine corrosion environment simulating apparatus. The analysis results showed that the correlation of alloy elements and alloy corrosion rate is in the order: Mn>Si>P>V>Cu>Al>Cr>Mo. The correlation degree was 0.92, 0.89, 0.86, 0.83, 0.82, 0.82, 0.81, 0.77. (orig.)

  1. Corrosion and failure processes in high-level waste tanks

    Energy Technology Data Exchange (ETDEWEB)

    Mahidhara, R.K.; Elleman, T.S.; Murty, K.L. [North Carolina State Univ., Raleigh, NC (United States)

    1992-11-01

    A large amount of radioactive waste has been stored safely at the Savannah River and Hanford sites over the past 46 years. The aim of this report is to review the experimental corrosion studies at Savannah River and Hanford with the intention of identifying the types and rates of corrosion encountered and indicate how these data contribute to tank failure predictions. The compositions of the High-Level Wastes, mild steels used in the construction of the waste tanks and degradation-modes particularly stress corrosion cracking and pitting are discussed. Current concerns at the Hanford Site are highlighted.

  2. Corrosion protection by anaerobiosis.

    Science.gov (United States)

    Volkland, H P; Harms, H; Wanner; Zehnder, A J

    2001-01-01

    Biofilm-forming bacteria can protect mild (unalloyed) steel from corrosion. Mild steel coupons incubated with Rhodoccocus sp. strain C125 and Pseudomonas putida mt2 in an aerobic phosphate-buffered medium containing benzoate as carbon and energy source, underwent a surface reaction leading to the formation of a corrosion-inhibiting vivianite layer [Fe3(PO4)2]. Electrochemical potential (E) measurements allowed us to follow the buildup of the vivianite cover. The presence of sufficient metabolically active bacteria at the steel surface resulted in an E decrease to -510 mV, the potential of free iron, and a continuous release of ferrous iron. Part of the dissolved iron precipitated as vivianite in a compact layer of two to three microns in thickness. This layer prevented corrosion of mild steel for over two weeks, even in a highly corrosive medium. A concentration of 20 mM phosphate in the medium was found to be a prerequisite for the formation of the vivianite layer.

  3. Study of corrosion behaviour in saturated bentonite barrier Corroben; Estudio de los productos de corrosion de la capsula y su interaccion con la berrar arcillosa de bentonita Corroben

    Energy Technology Data Exchange (ETDEWEB)

    Azkarate, I.; Insausti, M.; Medina, V.

    2004-07-01

    The corrosion behavior in saturated bentonite of various candidate metallic materials, to be used in the fabrication of containers of high level radioactive waste granite repositories, has been studied in this project. Due to the multi-barrier concept in which the canisters are surrounded by a clay barrier of compacted bentonite blocks, special attention has been paid to the characterization of corrosion products and the interaction between these and the repository sealing bentonite. The following metallic materials have been studied: S355 carbon steel, AISI 316L stainless steel, Cu-ETP electrolytic copper and Cu30Ni alloy. Samples of the alloys have been embedded in saturated bentonite to a water content of 25%, and compacted. The obtained pastilles have been introduced in autoclaves and tested at different temperatures and times ranging from one to 18 months. Once tests have concluded, several parameters have been evaluated: corrosion morphology, general corrosion rates calculated by gravimetric methods, nature and composition of the corrosion products and penetration of the corrosion products into the bentonite. Experimental data obtained are used to developed models of the corrosion behavior of canisters under disposal conditions. Results show that S355 carbon steel has suffered the highest general corrosion attack, with average corrosion rates of 10 per year and maximum penetration of 100 measured in specimens tested at 75C during 18 months. The most common analyzed corrosion product has been siderite, FeCO3. Formation of siderite, in the test conditions, effectively passivated the steel because of its stable and adherent feature. In test carried out at 25 and 5 C, sulfur rich corrosion products are observed, thus indicating a microbiologically corrosion phenomena due to the metabolic activity of bacteria present in the bentonite. No appreciable general corrosion rates, nor sensitivity to localized corrosion, has been observed in the AISI 316L stainless steel

  4. Smart Coatings for Corrosion Protection

    Science.gov (United States)

    Calle, Luz Marina; Li, Wendy; Buhrow, Jerry W.; Johnsey, Marissa N.

    2016-01-01

    Nearly all metals and their alloys are subject to corrosion that causes them to lose their structural integrity or other critical functionality. It is essential to detect corrosion when it occurs, and preferably at its early stage, so that action can be taken to avoid structural damage or loss of function. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional, smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to indicate it and control it.

  5. Effect of biologically relevant ions on the corrosion products formed on alloy AZ31B: an improved understanding of magnesium corrosion.

    Science.gov (United States)

    Jang, Yongseok; Collins, Boyce; Sankar, Jagannathan; Yun, Yeoheung

    2013-11-01

    Simulated physiological solutions mimicking human plasma have been utilized to study the in vitro corrosion of biodegradable metals. However, corrosion and corrosion product formation are different for different solutions with varied responses and, hence, the prediction of in vivo degradation behavior is not feasible based on these studies alone. This paper reports the role of physiologically relevant salts and their concentrations on the corrosion behavior of a magnesium alloy (AZ31B) and subsequent corrosion production formation. Immersion tests were performed for three different concentrations of Ca(2+), HPO4(2-), HCO3(-) to identify the effect of each ion on the corrosion of AZ31B assessed at 1, 3 and 10 days. Time-lapse morphological characterization of the samples was performed using X-ray computed tomography and scanning electron microscopy. The chemical composition of the surface corrosion products was determined by electron dispersive X-ray spectroscopy and X-ray diffraction. The results show that: (1) calcium is not present in the corrosion product layer when only Cl(-) and OH(-) anions are available; (2) the presence of phosphate induces formation of a densely packed amorphous magnesium phosphate corrosion product layer when HPO4(2-) and Cl(-) are present in solution; (3) octacalcium phosphate and hydroxyapatite (HAp) are deposited on the surface of the magnesium alloy when HPO4(2-) and Ca(2+) are present together in NaCl solution (this coating limits localized corrosion and increases general corrosion resistance); (4) addition of HCO3(-) accelerates the overall corrosion rate, which increases with increasing bicarbonate concentration; (5) the corrosion rate decreases due to the formation of insoluble HAp on the surface when HCO3(-), Ca(2+), and HPO4(2-) are present together.

  6. Effect of CO2 on Atmospheric Corrosion of UNS G10190 Steel under Thin Electrolyte Film

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The atmospheric corrosion of UNS G10190 steel under a thin electrolyte film in the atmosphere polluted by CO2 has been studied in the lab using an atmospheric corrosion monitor(ACM) in combination with XRD and SEM observations of the surface of steel. The ACM study indicated that the corrosion rate of the steel increased with increasing carbon dioxide concentration. The XRD and SEM observations showed that no carbonate was found in the corrosion product on the steel surface. The corrosion product consisted of two layers, i. e., inner and outer layer. From the experimental results, it was concluded that CO2 played an enhancing role in the atmospheric corrosion of UNS G10190 steel. The film of the corrosion product showed slight protection.

  7. Corrosion Behavior and Durability of Low-Alloy Steel Rebars in Marine Environment

    Science.gov (United States)

    Liu, Ming; Cheng, Xuequn; Li, Xiaogang; Yue, Pan; Li, Jun

    2016-10-01

    The corrosion resistance of Cr-modified low-alloy steels and HRB400 carbon steel was estimated using the open-circuit potential, potentiodynamic polarization, electrochemical impedance spectroscopic, and weight loss methods in simulated concrete pore solution. Results show that Cr-modified steels exhibit a higher corrosion resistance with a higher critical chloride level (CTL), lower corrosion current density, and higher impedance than carbon steel. The CTL of the steels significantly reduces with increasing temperature. Weight loss measurement shows that the Cr-modified steels exhibit low corrosion rates and small corrosion pitting. The primary constituents of the corrosion scales are Fe2O3, Fe3O4, β-FeOOH, γ-FeOOH, and α-FeOOH. A large amount of α-FeOOH could be detected in the Cr-modified steel corrosion products. Moreover, the Cr-modified steels demonstrate a higher durability than HRB400 carbon steel.

  8. Improvement of carbon corrosion resistance through heat-treatment in polymer electrolyte membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Y.J.; Oh, H.S.; Kim, H. [Yonsei Univ., Seoul (Korea, Republic of). Dept. of Chemical and Biomolecular Engineering

    2010-07-01

    Electrochemical corrosion of carbon in the catalyst layer of polymer electrolyte membrane fuel cells (PEMFCs) is a critical factor in limiting their durability. The corrosion rate increases during the iterative abnormal operating conditions known as reverse current phenomenon. The corrosion causes a decrease of the active surface of the platinum (Pt) catalyst. The graphitization of carbon increases corrosion resistance, and the hydrophobicity of the carbon surface can also play an important role in decreasing carbon corrosion. This study investigated the effect of heat-treating carbon nanofibers (CNFs) for use in PEMFC applications. The aim of the study was to determine if heat treatments modified the carbon surface by eliminating the oxygen functional group and increasing hydrophobicity. The electrochemical carbon corrosion of CNFs were compared after heat treatments at various temperatures. Mass spectrometry was used to measure electrochemical carbon corrosion by monitoring the amounts of carbon dioxide (CO{sub 2}) produced during the electrochemical oxidation process. 2 refs.

  9. Corrosion detector apparatus for universal assessment of pollution in data centers

    Energy Technology Data Exchange (ETDEWEB)

    Hamann, Hendrik F.; Klein, Levente I.

    2015-08-18

    A compact corrosion measurement apparatus and system includes an air fan, a corrosion sensor, a temperature sensor, a humidity sensor, a heater element, and an air flow sensor all under control to monitor and maintain constant air parameters in an environment and minimize environmental fluctuations around the corrosion sensor to overcome the variation commonly encountered in corrosion rate measurement. The corrosion measurement apparatus includes a structure providing an enclosure within which are located the sensors. Constant air flow and temperature is maintained within the enclosure where the corrosion sensor is located by integrating a variable speed air fan and a heater with the corresponding feedback loop control. Temperature and air flow control loops ensure that corrosivity is measured under similar conditions in different facilities offering a general reference point that allow a one to one comparison between facilities with similar or different pollution levels.

  10. Corrosion detector apparatus for universal assessment of pollution in data centers

    Science.gov (United States)

    Hamann, Hendrik F.; Klein, Levente I.

    2015-08-18

    A compact corrosion measurement apparatus and system includes an air fan, a corrosion sensor, a temperature sensor, a humidity sensor, a heater element, and an air flow sensor all under control to monitor and maintain constant air parameters in an environment and minimize environmental fluctuations around the corrosion sensor to overcome the variation commonly encountered in corrosion rate measurement. The corrosion measurement apparatus includes a structure providing an enclosure within which are located the sensors. Constant air flow and temperature is maintained within the enclosure where the corrosion sensor is located by integrating a variable speed air fan and a heater with the corresponding feedback loop control. Temperature and air flow control loops ensure that corrosivity is measured under similar conditions in different facilities offering a general reference point that allow a one to one comparison between facilities with similar or different pollution levels.

  11. Corrosion potential analysis system

    Science.gov (United States)

    Kiefer, Karl F.

    1998-03-01

    Many cities in the northeastern U.S. transport electrical power from place to place via underground cables, which utilize voltages from 68 kv to 348 kv. These cables are placed in seamless steel pipe to protect the conductors. These buried pipe-type-cables (PTCs) are carefully designed and constantly pressurized with transformer oil to prevent any possible contamination. A protective coating placed on the outside diameter of the pipe during manufacture protects the steel pipe from the soil environment. Notwithstanding the protection mechanisms available, the pipes remain vulnerable to electrochemical corrosion processes. If undetected, corrosion can cause the pipes to leak transformer oil into the environment. These leaks can assume serious proportions due to the constant pressure on the inside of the pipe. A need exists for a detection system that can dynamically monitor the corrosive potential on the length of the pipe and dynamically adjust cathodic protection to counter local and global changes in the cathodic environment surrounding the pipes. The northeastern United States contains approximately 1000 miles of this pipe. This milage is critical to the transportation and distribution of power. So critical, that each of the pipe runs has a redundant double running parallel to it. Invocon, Inc. proposed and tested a technically unique and cost effective solution to detect critical corrosion potential and to communicate that information to a central data collection and analysis location. Invocon's solution utilizes the steel of the casing pipe as a communication medium. Each data gathering station on the pipe can act as a relay for information gathered elsewhere on the pipe. These stations must have 'smart' network configuration algorithms that constantly test various communication paths and determine the best and most power efficient route through which information should flow. Each network station also performs data acquisition and analysis tasks that ultimately

  12. TREATMENT TANK CORROSION STUDIES FOR THE ENHANCED CHEMICAL CLEANING PROCESS

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, B.

    2011-08-24

    Radioactive waste is stored in high level waste tanks on the Savannah River Site (SRS). Savannah River Remediation (SRR) is aggressively seeking to close the non-compliant Type I and II waste tanks. The removal of sludge (i.e., metal oxide) heels from the tank is the final stage in the waste removal process. The Enhanced Chemical Cleaning (ECC) process is being developed and investigated by SRR to aid in Savannah River Site (SRS) High-Level Waste (HLW) as an option for sludge heel removal. Corrosion rate data for carbon steel exposed to the ECC treatment tank environment was obtained to evaluate the degree of corrosion that occurs. These tests were also designed to determine the effect of various environmental variables such as temperature, agitation and sludge slurry type on the corrosion behavior of carbon steel. Coupon tests were performed to estimate the corrosion rate during the ECC process, as well as determine any susceptibility to localized corrosion. Electrochemical studies were performed to develop a better understanding of the corrosion mechanism. The tests were performed in 1 wt.% and 2.5 wt.% oxalic acid with HM and PUREX sludge simulants. The following results and conclusions were made based on this testing: (1) In 1 wt.% oxalic acid with a sludge simulant, carbon steel corroded at a rate of less than 25 mpy within the temperature and agitation levels of the test. No susceptibility to localized corrosion was observed. (2) In 2.5 wt.% oxalic acid with a sludge simulant, the carbon steel corrosion rates ranged between 15 and 88 mpy. The most severe corrosion was observed at 75 C in the HM/2.5 wt.% oxalic acid simulant. Pitting and general corrosion increased with the agitation level at this condition. No pitting and lower general corrosion rates were observed with the PUREX/2.5 wt.% oxalic acid simulant. The electrochemical and coupon tests both indicated that carbon steel is more susceptible to localized corrosion in the HM/oxalic acid environment than

  13. [Corrosion of stainless steel 201, 304 and 316L in the simulated sewage pipes reactor].

    Science.gov (United States)

    Bao, Guo-Dong; Zuo, Jian-E; Wang, Ya-Jiao; Gan, Li-Li

    2014-08-01

    The corrosion behavior of stainless steel 201, 304 and 316L which would be used as sewer in-situ rehabilitation materials was studied in the simulated sewage pipes reactor. The corrosion potential and corrosion rate of these three materials were studied by potentiodynamic method on the 7th, 14th, 21st, 56th day under two different conditions which were full immersion condition or batch immersion condition with a 2-day cycle. The electrode process was studied by Electrochemical Impedance Spectroscopy (EIS) on the 56th day. The microstructure and composition of the corrosion pitting were analyzed by Scanning Electron Microscope (SEM) and Energy Dispersive Spectrometer (EDS) on the 56th day. The results showed that 304 and 316L had much better corrosion resistance than 201 under both conditions. 304 and 316L had much smaller corrosion rate than 201 under both conditions. The corrosion resistance of all three kinds of stainless steel under the batch immersion condition was much better than those under the full immersion condition. The corrosion rate of all three kinds of stainless steel under the batch immersion condition was much smaller than those under the full immersion condition. Point pitting corrosion was formed on the surfaces of 304 and 316L. In comparison, a large area of corrosion was formed in the surface of 201.

  14. Aqueous corrosion behavior of uranium-molybdenum alloys

    Science.gov (United States)

    Gardner, Levi D.

    Nuclear fuel characterization requires understanding of the various conditions to which materials are exposed in-reactor. One of these important conditions is corrosion, particularly that of fuel constituents. Therefore, corrosion behavior is of special interest and an essential part of nuclear materials characterization efforts. In support of the Office of Material Management and Minimization's Reactor Conversion Program, monolithic uranium-10 wt% molybdenum alloy (U-Mo) is being investigated as a low enriched uranium alternative to highly enriched uranium dispersion fuel currently used in domestic high performance research reactors. The aqueous corrosion behavior of U-Mo is being examined at Pacific Northwest National Laboratory (PNNL) as part of U-Mo fuel fabrication capability activity. No prior study adequately represents this behavior given the current state of alloy composition and thermomechanical processing methods, and research reactor water chemistry. Two main measurement techniques were employed to evaluate U-Mo corrosion behavior. Low-temperature corrosion rate values were determined by means of U-Mo immersion testing and subsequent mass-loss measurements. The electrochemical behavior of each processing condition was also qualitatively examined using the techniques of corrosion potential and anodic potentiodynamic polarization. Scanning electron microscopy (SEM) and optical metallography (OM) imagery and hardness measurements provided supplemental corrosion analysis in an effort to relate material corrosion behavior to processing. The processing effects investigated as part of this were those of homogenization heat treatment (employed to mitigate the effects of coring in castings) and sub-eutectoid heat treatment, meant to represent additional steps in fabrication (such as hot isostatic pressing) performed at similar temperatures. Immersion mass loss measurements and electrochemical results both showed very little appreciable difference between

  15. Real time corrosion monitoring in atmosphere using automated battery driven corrosion loggers

    DEFF Research Database (Denmark)

    Prosek, T.; Kouril, M.; Hilbert, Lisbeth Rischel

    2008-01-01

    A logger enabling continuous measurement of corrosion rate of selected metals in indoor and outdoor atmospheres has been developed. Principle of the measurement method is based on the increasing electrical resistance of a measuring element made of the material concerned as its cross-sectional are...

  16. Atomistic Modeling of Corrosion Events at the Interface between a Metal and Its Environment

    Directory of Open Access Journals (Sweden)

    Christopher D. Taylor

    2012-01-01

    Full Text Available Atomistic simulation is a powerful tool for probing the structure and properties of materials and the nature of chemical reactions. Corrosion is a complex process that involves chemical reactions occurring at the interface between a material and its environment and is, therefore, highly suited to study by atomistic modeling techniques. In this paper, the complex nature of corrosion processes and mechanisms is briefly reviewed. Various atomistic methods for exploring corrosion mechanisms are then described, and recent applications in the literature surveyed. Several instances of the application of atomistic modeling to corrosion science are then reviewed in detail, including studies of the metal-water interface, the reaction of water on electrified metallic interfaces, the dissolution of metal atoms from metallic surfaces, and the role of competitive adsorption in controlling the chemical nature and structure of a metallic surface. Some perspectives are then given concerning the future of atomistic modeling in the field of corrosion science.

  17. In-situ monitoring of undercoating corrosion damage by Direct Optical Interrogation (DOI)

    Science.gov (United States)

    Lopez-Garrity, Meng

    An approach referred to as "Direct Optical Interrogation" (DOI) has been developed as an extension of the thin film pitting approach developed and used by Frankel and others. Samples were prepared by depositing Al and Al-Cu alloy metallizations about 800 nm thick on glass substrates. These metallizations were then coated with various coatings and coating systems. Samples were introduced to aggressive environments and the progression of corrosion of the metallization under the coating was monitored in situ using low power videography. Because metallizations were thin, corrosion quickly penetrated through the metal layer to the glass substrate and then spread laterally. Measurement of the lateral spread of corrosion enabled non-electrochemical assessment of the corrosion kinetics. In Al-Cu thin films, both aged and as-deposited, corrosion sites are irregularly shaped because there is not enough cathodic current to propagate the entire corrosion site margin at equal rates. In a number of cases, corrosion propagates with a filamentary morphology resembling filiform corrosion. Cu played a strong role in determining under coating corrosion morphology and growth kinetics in experiments with Al-Cu thin films substrates. As-deposited Al-Cu metallizations were more corrosion resistant than aged metallization and both were more corrosion resistant than pure Al. Cu-rich dendrites were formed on the corrosion front. Corrosion rate (current density) was calculated using Faraday's law by collecting corrosion site perimeter and bottom area. Systematic exploration of the effects of a chromate and chromate-free conversion coatings, chromate and chromate-free primer coatings and the presence or absence of a polyurethane topcoat confirmed the extraordinary corrosion protection by chromates. A commercial praseodymium-pigmented primer coating was not particularly effective in retarding undercoating corrosion site growth unless paired with a chromate conversion coating. The presence of a

  18. Relativity between corrosion-induced stress and stress corrosion cracking of brass in an ammonia solution

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The susceptibility to stress corrosion cracking (SCC) of brass in an ammonia solution with various pH values or under various applied potentials was measured at slow strain rate tests. The additive stress in the same solution was measured using two methods. The results indicate that the variation of the susceptibility to SCC with pH value or with potential is in an excellent agreement with the corrosion (passive film or dezincification layer)-induced stress. When pH ? 7, the corrosion-induced tensile stress and the susceptibility to SCC have maximum values and hardly change with increasing the pH value. However, when pH < 7, both the corrosion-induced tensile stress and the susceptibility to SCC reduce rapidly with decreasing the pH value. Both the corrosion-induced tensile stress and the susceptibility to SCC have maximum values at the open-circuit potential, decrease slightly under the anodic polarization, and reduce gradually to zero under the cathodic polarization.

  19. Characterization of Encapsulated Corrosion Inhibitors Containing Microparticles for Environmentally Friendly Smart Coatings

    Science.gov (United States)

    Pearman, Benjamin Pieter; Calle, Luz M.

    2015-01-01

    This poster presents the results obtained from experiments designed to evaluate the release properties, as well as the corrosion inhibition effectiveness, of several encapsulated corrosion inhibitors. Microencapsulation has been used in the development of environmentally friendly multifunctional smart coatings. This technique enables the incorporation of autonomous corrosion detection, inhibition and self-healing functionalities into many commercially available coating systems. Select environmentally friendly corrosion inhibitors were encapsulated in organic and inorganic pH-sensitive microparticles and their release in basic solutions was studied. The release rate results showed that the encapsulation can be tailored from fast, for immediate corrosion protection, to slow, which will provide continued long-term corrosion protection. The incorporation of several corrosion inhibitor release profiles into a coating provides effective corrosion protection properties. To investigate the corrosion inhibition efficiency of the encapsulated inhibitors, electrochemical techniques were used to obtain corrosion potential, polarization curve and polarization resistance data. These measurements were performed using the free as well as the encapsulated inhibitors singly or in combinations. Results from these electrochemical tests will be compared to those obtained from weight loss and other accelerated corrosion experiments.

  20. Electrochemical study of corrosion inhibition of stainless steel in phosphoric medium

    Energy Technology Data Exchange (ETDEWEB)

    Hnini, K.; Chtaini, A. [Laboratoire d' Electrochimie et de Bio Corrosion, Faculte des Sciences et Techniques, Beni-Mellal (Morocco); Khouili, M.; Elbouadili, A. [Laboratoire de Chimie Organique et Analytique, Faculte des Sciences et Techniques, Beni-Mellal (Morocco)

    2004-07-01

    The corrosion of metals represents a terrible waste of both natural resources and money, the failure of some stainless steel resulting from pitting corrosion is some times considered a technological problem, consequently, much effort has been expended in attempting to understand and overcome the corrosion therefore, many stainless steel/ environment combinations have been studied. The use of heterocyclic compounds as inhibitors is one of the most practical methods for protection against corrosion in acidic media. In continuation of our work on development of macrocyclic compounds as corrosion inhibitors we report in our study the corrosion inhibiting behaviour of organic compound Methoxy-2-Allyl-4 Phenol (MAP) containing coordinating and conjugation groups, at three forms (natural, polymerized and chemically treated) on the corrosion of stainless steel in phosphoric acid. This study focused on the comparison for corrosion inhibition proprieties of these different applications using potentiodynamic polarization, electrochemical impedance spectroscopy and SEM. The specimen was evaluated to determine change in his corrosion potential and resistance polarization; These MAP products have exhibited corrosion inhibition by maintaining a high resistance polarization (low corrosion rate) in each application. These results reveal that this compound is efficient inhibitor in all forms; the most inhibition efficiency is obtained with polymerized form. To further evaluate the test data, the steel surfaces were analyzed using scanning electron microscopy, SEM observations of surface treated concrete confirmed presence of inhibitor on the steel surfaces. (authors)