bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adaptation of Linear Polarization Techniques for In-Situ Corrosion Measurements in Water Cooled Nuclear Reactor Environments
Authors: WILDE B. E. 
Published: February 2013

Abstract
Application of electrochemical polarization techniques to study corrosion of steels in aqueous environments at 289 C (554 F) and 1000 psi is described. A galvanostatic polarization circuit is discussed which permits determination of polarization parameters in-situ which are free of error due to resistance polarization in high purity water. Extended corrosion tests on plain carbon steel and Type 304 steel over 500 hours have shown that 99.6 percent correspondence can be achieved between electrochemical corrosion data and conventional weight-change techniques.
In de-oxygenated conditions, the steady-state corrosion rates of plain carbon steel and Type 304 stainless steel are 0.0015 and 0.0011 mg/cm2hr, respectively in water at 289 C. Cathodic and anodic Tafel constants for these steels under the above conditions have been determined and are shown to be independent of exposure time and corrosion rate.
High Temperature Corrosion and Evaporation of Haynes 25 and Hastelloy X-280
Authors: CHARLOT L. A. , WESTERMAN R. E. 
Published: February 2013

Abstract
The corrosion behavior of Hastelloy X-280 and Haynes 25 at 1120 C (2048 F) in atmospheres of oxygen, carbon monoxide, carbon dioxide, water vapor and methane has been investigated. Evaporation rates of the superalloys in vacuo have been determined to 1200 C (2192 F).
Oxidation rates generally were found to increase with increasing pressure in the range 0.04 to 760 torr. Oxidation rates in other oxidants were less than those in pure oxygen. Thermal cycling reduced the oxidation resistance of Haynes 25.
Both alloys carburize readily at 1120 C in a methane atmosphere. The carburization process can be reversed easily and ductility recovered by exposing material to oxidizing atmosphere at the same temperature.
Evaporation of superalloys in vacuo at 1120 C can result in metal loss approximating that found under oxidizing conditions. Preformed oxide films are shown to be ineffective barriers to evaporation in an inert atmosphere (vacuum) at 1120 C.
Sulfide Stress Corrosion of Some Medium and Low Alloy Steels
Authors: SNAPE E. 
Published: February 2013

Abstract
A study made of factors influencing sulfide-stress corrosion of a number of low alloy and medium alloy steels showed that their delayed failures when exposed simultaneously to stress and the corrosive action of acidified brine-hydrogen sulfide solutions have most of the features of hydrogen induced, delayed brittle failures. Different steels subjected to the same exposure conditions showed varying degrees of embrittlement as measured by ductility loss in bend tests.
Ductility could be restored partially by room temperature storage. Ductility restoration was related to the amount of hydrogen removed after exposure.
Delayed failure under stress occurs when corrosion generated hydrogen is absorbed, and lowers fracture strain until it equals the strain under load.
A minimum applied stress was obtained for each steel below which failure did not occur. This “threshold” stress decreased as strength level increased and depended simultaneously on composition and microstructure.
Nickel had little effect on cracking behavior of a steel whereas carbon appeared to be detrimental. Twinned martensite was more susceptible than untwinned martensite. Steels containing austenite were more resistant than body-centered steels.
Effect of Temperature on Stress-Corrosion Fracture
Authors: SYLWESTROWICZ W. D. 
Published: February 2013

Abstract
Prestrained samples of copper-beryllium alloy (1.8 Be, 0.3 Co) were exposed to an ammonia atmosphere at −20, 30 and 90 C (−4, 86, 194 F). It was found that the effect of temperature is related to the amount of plastic deformation. Above a critical value of plastic prestrain, temperature effect reverses; a longer exposure is needed to fracture a sample at 90 than at 30 C. This temperature dependence is explained by considering the number and distribution of dislocations.
Influence of Alternating Current on Corrosion of Mild Steel: Behavior in 1 N Sulfuric Acid
Authors: YAMUNA A. R. , SUBRAMANYAN N. 
Published: February 2013

Abstract
Corrosion behavior of mild steel in 1 N sulfuric acid subject to alternating currents in the range 250 micro-amp to 100 mA cm−2 at frequencies varying from 30 to 1000 cps is reported. It was found that at low current values, the corrosion rate increases with frequencies up to 200 cps, but diminishes with frequencies above this rate. At relatively high current values, the corrosion rate decreases with increasing frequencies. A qualitative explanation of the observations is suggested.
Techniques for Investigating Hydrogen-Induced Cracking of Steels With High Yield Strength
Authors: KIM C D. , LOGINOW A. W. 
Published: February 2013

Abstract
As part of a Song range study to develop grades of steel with improved resistance to hydrogen-induced cracking, techniques for measuring hydrogen uptake and hydrogen permeability were investigated and these parameters were correlated with resistance to hydrogen-induced cracking at different strength levels. The steel used for these studies was a Ni-Cr-Mo steel heat treated to four yield strength values ranging from 95 ksi to 150 ksi. The environment studied was a hydrogen sulfide saturated aqueous solution of 3% sodium chloride and 0.5% acetic acid. The technique used to measure hydrogen permeability consisted of exposing one side of a steel specimen to the sulfide environment and electrochemically measuring the hydrogen permeating to the opposite side. Hydrogen uptake was measured by the vacuum extraction method with specimens exposed to the environment for various time periods. The results of this comparison Stowed that both the resistance to cracking and the apparent diffusivity of hydrogen decreased as the yield strength was increased. Hydrogen uptake increased with increasing yield strength but the steady state permeation rate was not affected by strength level. A concept of hydrogen trapping is proposed to explain the observed relationships among the parameters studied and the mechanical strength of the steel.
The Role of Interstitial and Substitutional Impurities in Stress Corrosion Cracking of Low Carbon Steel in Nitrate Solution
Authors: FLIS J. , SCULLY J. C 
Published: February 2013

Abstract
The metallurgical aspects of the stress corrosion cracking of Fe-0.025% C in 5N NH4NO3 at 75 C (167 F) have been investigated. Sites of preferential corrosion in the alloy [annealed at 925 C (1697 F) and aged at 250 C (482 F)] were examined by transmission electron microscopy, and the susceptibility of the alloy to stress corrosion cracking after varying heat treatment was examined in constant strain rate tests. From the experimental data and calculated rate of transfer of impurities to and from grain boundaries, it was concluded that the tendency of grain boundaries to preferential corrosion is determined primarily by segregated substitutional constituents, and not by C or N.
The Influence of Hydrogen, Oxygen, and Ammonia on the Corrosion Behavior of Plain Carbon Steel in High Temperature Water
Authors: WILDE B. E. 
Published: February 2013

Abstract
The corrosion behavior of plain carbon steel in high temperature water has been studied using electrochemical polarization techniques. The influence of oxygen, hydrogen, and ammonia on the corrosion behavior has been studied over the range &lt; 0.1–100 ppm. Potentiostatic anodic polarization data indicate that only oxygen has any effect on the anodic dissolution kinetics of carbon steel at 289 C (552 F). Controlled potential corrosion experiments at highly noble potentials in oxygenated water did not produce any form of localized corrosion. Cathodic Tafel polarization data indicate that the primary cathodic partial process during corrosion on ammonia and hydrogenated solutions is the reduction of hydrogen ions. Reduced steady-state corrosion rates observed in ammoniated solutions are due to the severe reduction in the limiting diffusion rate of hydrogen ions because of a simple pH effect. In oxygenated solutions, over the range 0.1–50 ppm O2, the major reduction process is the reduction of H+. At 50–100 ppm O2 levels, however, the reduction process changes to O2 + 2H2O + 4e → 4OH−, with the formation of a protective oxide film and a reduction of the steady-state corrosion rate to 0.2 mdd. Linear polarization studies indicated that the steady-state corrosion rate of carbon steel on hydrogenated solutions is relatively independent of H2 content. The corrosion rate on ammoniated solutions decreased with NH3 content over the range 1–100 ppm NH3. Corrosion rates in oxygenated water over the range &lt; 0.08–100 ppm increase through a maximum at approximately 50 ppm then decreases to a low value at 100 ppm. This behavior is interpreted by the formation of a protective oxide film which is dependent on oxygen content. X-ray diffraction studies indicate the presence of a duplex oxide film in high oxygen solutions consisting of γFe2O3 and Fe3O4. At lower oxygen levels, only αFe2O3 was observed and also in ammoniated solutions. In hydrogenated solutions, with the highers corrosion rates, only αFe2O3 was observed on the surface.
Effect of Impurities on the Defects in Oxides and Their Relationship to Oxidation of Metal
Authors: KOFSTAD PER 
Published: February 2013

Abstract
The defect structure of the oxygen-deficient oxides of Nb2O5, Ta2O5, and ZrO2 are discussed. It is suggested that the oxygen vacancies are probably the important defects, except possibly at the most oxygen deficient part of the homogeneity ranges where interstitial cations may predominate. At high oxygen pressures, (small deviations from stoichiometry) effects of impurities become important and, in reported studies, probably determine the point defect concentration. Oxidation of Nb, Ta, Zr, resulting in growth of compact scales of Nb2O5 Ta2O5, and ZrO2, is discussed on the basis of these considerations. It is shown that effects of impurities may explain apparent deviations from the simple behavior predicted by the Wagner theory. It is emphasized that analysis and control of impurities is essential in interpretation of defect structures of oxides and defect-controlled properties and reactions.
Influence of Silicon and Manganese on Corrosion Behavior of Austenitic Stainless Steels
Authors: WILDE B. E. , ARMIJO J. S. 
Published: February 2013

Abstract
The influence of silicon and manganese on the electrochemical and corrosion behavior of a high purity austenitic 14Cr/14Ni-balance Fe alloy has been studied. Over the composition range 50–41, 500 ppm Si, no effect was observed on the kinetics of the anodic or cathodic partial processes. Addition of manganese over the range 5–26,300 ppm accelerates the anodic dissolution kinetics in the active range of potentials and also the steady-state corrosion rate in 1N̄ H2SO4 due to its influence on the kinetics of the cathodic partial process. The nature of this effect is analyzed according to electrode kinetic concepts from which it is shown that manganese changes the value of the electrode process transmission coefficient. Alloys containing manganese and silicon over large concentration ranges are extremely resistant to stress corrosion cracking in boiling 42 w/o MgCl2.
Effect of Cold Working and Annealing on Oxidation Rates of Copper in Dry Air at Room Temperature
Authors: KRISHNAMOORTHY P. K. , SIRCAR S. C 
Published: February 2013

Abstract
The effect of plastic deformation and further annealing on the kinetics of growth of thin oxide films on copper at 30 C (86 F) has been investigated. Oxidation rate was found to decrease markedly with increasing deformation. Further annealing showed an increase in the rate, the most pronounced changes occurring during the recrystallization stage. Results are interpreted in the light of Cabrera-Mott theory of growth of very thin oxide films on metals. The change in rate has been related to the concentration of cation vacancies in the Cu2O semi-conductor, which is dependent on the lattice distortion and defect concentration of the substrate metal.
Studies of Galvanic Corrosion Couples in Liquid Fluorine
Authors: TOY S. M. , ENGLISH W. D. , CRANE W. E. 
Published: February 2013

Abstract
Galvanic corrosion couples of several metals and alloys were tested in liquid fluorine at −320 F (−196 C), and the corrosion rates of the alloys were determined. A relative galvanic corrosion series, based on the rates, was developed as a guide for selecting materials for missile components exposed to fluorine containing propellants for long term storage. Electrode potentials of Al 1100 and copper versus a platinum reference electrode in liquid fluorine verify the general arrangement of the galvanic series. Evidence of pitting was found on Al 2014-T6 and silver coupons exposed to liquid fluorine.
Observations on the Initiation of Stress Corrosion Cracking in Aluminum Alloy 7039
Authors: HELFRICH W. J. 
Published: February 2013

Abstract
The initiation of short-transverse stress corrosion cracking in aluminum alloy 7039-T64 was studied by optical microscopy. Aluminized-plastic replicas were taken from the transverse surface of smooth specimens prior to and periodically during the stress corrosion test. With this technique, it was possible to trace back in time the initiation and propagation of cracks in any given area of the specimen. Dissolution of stressed specimens began at constituent particles resulting in well-defined separations at the particle-matrix interface; in some instances mechanical rupture of the constituents occurred. Stress corrosion cracking started at these interfaces with crack propagation along grain boundaries adjacent to the constituents. It is suggested that the incubation time required to form an incipient stress corrosion crack must be associated with anodic dissolution at specific interfaces, i. e., adjacent to constituents which are cathodic with respect to the matrix.
Effect of Crystal Orientation on the Anodic Polarization and Passivity of Zinc
Authors: ASHTON RICHARD F. , HEPWORTH MALCOLM T. 
Published: February 2013

Abstract
Potentiostatic polarization measurements on exposed (0001), (1010), and (1120) faces of single crystals and on polycrystalline zinc were made in aqueous solutions of sodium hydroxide. Crystal orientation was observed to have a well defined effect on anodic polarization with overvoltages for active dissolution increasing with increasing density of crystal planar packing. Potentials for passivation were equal for (0001) and (1010) crystal specimens, which were both noble to potentials for (1120) specimens.
Stress Corrosion Cracking of Alpha Titanium Alloys at Room Temperature
Authors: POWELL D. T. , SCULLY J. C. 
Published: February 2013

Abstract
Transgranular stress corrosion cracks are formed in Ti-5Al-2.5Sn alloy immersed in a 3 percent NaCl aqueous solution when tensile specimens are dynamically strained over a narrow range of rates. Metallographic evidence suggests that the critical process during crack propagation is entry of hydrogen into the alloy at the crack tip immediately following creation of fresh metal surface. Fractographic examination reveals that cracks propagate by a discontinuous cleavage mechanism. As each incremental growth is arrested, the embrittlement process resumes. Ductile fracture is observed in specimens strained (a) at high tensile rates because there is insufficient time for embrittlement to occur, and (b) at low tensile strain rates because repassivation occurs more readily and hydrogen entry is substantially reduced. In methanolic solutions containing HCl, an identical cleavage crack propagation process is observed. In addition, a slow intergranular dissolution mechanism is found in alloys susceptible and nonsusceptible to cleavage-type failure. This is initiated in specimens that have regions of high residual stress, e.g., sheared edges and continues until the mechanical strength of the alloy is reduced to a very low value. During this process hydrogen is picked up by the metal. Clevage has been observed in specimens broken in air after exposure. Vacuum annealing substantially reduces but does not eliminate this slower form of attack by removing initiation sites. Anodic polarization at low current densities produces extremely severe intergranular attack. The significance of dislocation arrangements, mechanical properties, and electrochemical reactions at the crack tip are discussed in detail. In particular, it is suggested that cathodic polarization can prevent cracking by forming films which reduce the rate of hydrogen ingress. In 10N HCl solutions, cathodic polarization does not prevent cracking.
Mechanisms of Sensitization and Stablization of Incoloy Nickel-lron-Chromium Alloy 825
Authors: RAYMOND E. L. 
Published: February 2013

Abstract
Incoloy(1) nickel-iron-chromium Alloy 825 can become sensitive to intergranular attack by exposure to temperatures in the 1200–1400 F (649–760 C) range. Sensitivity to intergranular attack (as measured by the Huey test) can be correlated to the presence of a chromium-depleted area adjacent to the grain boundary. This area is caused by the cellular precipitation of chromium-rich M23C6 during sensitizing treatments. The chromium-depleted region is between the M23C6 cells, but because the carbides grow by boundary migration the depletion is not in the plane of the grain boundary. Incoloy Alloy 825 can be stablized against intergranular attack by eliminating the chromium-depleted area. The degree of stabiization is related to the amount of carbon remaining in solution after the stablizing treatment. The titanium content of the alloy helps to effect stabtization. Because it has a greater affinity for carbon than does chromium, the titanium reacts to form stable carbides and thus reduces chromium depletion. Maximum stabtization of Incoloy Alloy 825 cannot be obtained if titanium carbide is used as the sole stablizing mechanism. The principal mechanism of stablization for this alloy is that of precipitating the M23C5 at a temperature where the diffusion of chromium is sufficiently rapid to prevent chromium depletion. This occurs at temperatures in the 1700–1800 F (927–982 C) range.
Absorption of Hydrogen by Cathodically Protected Steel
Authors: HUDSON P. E. , SNAVELY E. S. , PAYNE J. S. , FIEL L. D. , HACKERMAN NORMAN 
Published: February 2013

Abstract
Rates of hydrogen evolution and hydrogen absorption were determined by use of membrane experiments in environments simulating soil conditions. The objective of this work was to determine the amount of hydrogen absorbed by steel under various conditions encountered by cathodically protected pipelines. The conditions investigated included a pH range of 3 to 9, absence of and saturation by oxygen, effects of cathode poisons, and metal-to-soil potentials. For a given pipe-to-soil potential, the rate of hydrogen penetration of steel is decreased by the presence of oxygen and arsenic, and increased by the presence of sulfide.
Some Effects of Nitrogen Content on the Stress Corrosion Susceptibility of AIS1 Type 304 Austenitic Stainless Steel
Authors: ECKEL J. F. , COX T. B. 
Published: February 2013

Abstract
The effects of nitrogen content on the susceptibility of AISI Type 304 stainless steel to stress corrosion cracking have been studied by exposing U-bend specimens of the alloy containing various amounts of nitrogen to boiling magnesium chloride solutions. It was found that nitrogen in solid solution in Type 304 stainless steel reduces the resistance of the alloy to stress corrosion. Increasing amounts of nitrogen cause shorter times to crack initiation and more rapid failures by increasing the rate of propagation. The susceptibility of Type 304 is further increased by thermally aging the stressed U-bend specimens at 154 C before exposing them to the corrosive medium. The observations from this investigation seem to support those past theories which suggested that the increased susceptibility of austenitic stainless steels with higher nitrogen contents was due to the formation of nitrogen-rich areas within the austenitic matrix.
Oxidation of Zinc Single Crystals Under Ionic Bombardment
Authors: DEMARIA R. , SPINEDI P. , SUSI-DEMARIA E. 
Published: February 2013

Abstract
Controlled oxidation processes conducted on surfaces of zone refined zinc single crystals under a beam of different gases (pure oxygen, air, inert gases such as helium or argon, in the presence of small amounts of oxygen) have been studied with an electron emission microscope. Surface phenomena which take place under ionic bombardment appear to be the result of two competitive mechanisms, an activating one (introduction of defects into the surfacial layers) and a de-activating one, which can be observed expecially with inert gases (inclusion of gas atoms in the lattice). It has been ascertained that oxide nucleation is preceded by formation of an absorbed oxygen layer.
Corrosion and Mass Transfer With Chemical Reaction–The Dissolution of Magnesium in Hydrochloric Acid
Authors: MARANGOZIS JOHN 
Published: February 2013

Abstract
The purpose of this paper is to review the theory of mass transfer, with and without chemical reaction, and to show how it can be applied in the prediction of uniform corrosion rates. As an example, experimental data reported for the rate of dissolution of magnesium cylinders in hydrochloric acid solutions were analyzed. A mechanism for the reactions and the transport of ions to or from the metal surface was suggested, and the model was used in the prediction of data with considerable success. Application of this method in other corrosion systems is presently under investigation, in an effort to broaden its usefulness and to determine its limitations.
Dislocation Etch Pitting Studies on Tungsten Single Crystals Under Potentiostatic Conditions
Authors: MALOOF S. R. 
Published: February 2013

Abstract
Dislocation etch pitting of the (100) surface occurs in chloride as well as nitrate and sulfate solutions during anodic polarization in a well-defined potential range (+0.3 to +0.7v vs H2) where the current is relatively insensitive to changes in potential. In chloride solutions, increasing the chloride ion concentration or temperature results in an increase in the rate of pitting. This suggests that the chloride ion participates in the pitting process. A linear current-time law is obtained at constant potential. A pitting rate curve established for the (100) surface in 0.5M NaCl is Gaussian in shape with an apparent maximum at a potential of +0.48v. The potential at which the maximum occurs appears invariant with composition or temperature, suggesting that the same chemical species adsorbs on the surface prior to pitting. The decrease in the pitting rate above this potential is explained by the desorption of the chemical species, considered to be WO2−, as a result of further oxidation at more positive anode potentials to the species WO4=. The inability to etch pit the (110) surface under the same conditions is attributed to the direct formation of the doubly charged monotungstate ion WO4= during anodic dissolution and its subsequent adsorption at all positive anode potentials up to as high at 10v. The specificity of etch pitting solutions is explained in terms of a “critical” potential range for pitting.