bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intergranular Corrosion of Nonsensitized Austenitic Stainless Steels — 1. Environmental Variables
Authors: ARMIJO J. S. 
Published: February 2013

Abstract
Intergranular corrosion of nonsensitized stainless steels is reviewed, with emphasis on corrosion experienced in nitric-dichrornate solutions. Electrical resistance changes occurring during corrosion of Type 304 stainless ' steel in nitric-dichromate solutions are used to measure the rate of intergranular attack. Effects of HN03 concentration, Cr+6 concentration, temperature and stress on the intergranular corrosion reaction have been studied. The over-all corrosion reaction is found to consist of an incubation period, followed by a penetration period in which the rate of intergranular dissolution is linear. Measured activation energies for incubation and penetration periods are identical.
The effect of applied stress is to increase both incubation and penetration rates. Low stress levels have greatest effect on the incubation rate, while high stress levels have greatest effect on the penetration rate.
Appreciable grain boundary hardening is observed in nonsensitized Type 304 stainless steel. The grain boundary hardening is attributed to adsorbed impurities at grain boundaries. This segregation presents another variable which may be important in this type of intergranular attack.
Effect of Oxygen Concentration and pH on Electrode Potential of Stainless Steels and Operation of Microcouples
Authors: KOROVIN YU. M. , ULANOVSKII I B. 
Published: February 2013

Abstract
Using Russian steels of 13 Cr and 18–9 analyses in general experiments are conducted varying pH and oxygen concentrations in sea water to determine the relative effect of these variables on corrosion rates in crevices. Effect of oxygen concentrations in the range 1–9 mg/1 and pH 8.3 to 2.3 are reported.
Changes in pH were found to strongly and changes in oxygen concentration weakly influence the corrosion rate. Authors postulate that anodic passivity is effected after application of tenths of a milliampere per square centimeter whereas when the pH in the anodic space is lowered, critical current density required for passivation increases 40–50 fold.
Heat treatment of the steel does not influence electrode potentials when solution pH is lowered.
An Improved Exfoliation Test for Aluminum Alloys
Authors: LIFKA B. W. , SPROWLS D. O. 
Published: February 2013

Abstract
A new rapid test capable of producing exfoliation in susceptible aluminum alloys within a few days has been developed. This test is useful in studies of corrosion control and alloy development. Most significant is the excellent correlation of this laboratory test with exposures to natural marine environments. It is noteworthy also that the test procedure is applicable to all types of wrought aluminum alloys.
Test conditions involve cyclic exposure to acidified sodium chloride solution and to high relative humidity in a cabinet held at 95 F (35 C). This test is preferable to other laboratory procedures not only because of its speed but also because it produces readily visible exfoliation, does not require extensive specimen preparation and is not restrictive as to specimen size.
Effects of Mo, Cu, Si and P on Anodic Behavior of 17 Cr Steels
Authors: LIZLOVS E. A. 
Published: February 2013

Abstract
Effects of additions of 1–3 percent molybdenum alone and in combination with copper, silicon and phosphorus on the anodic behavior of 17 Cr stainless steel were evaluated by potentio-dynamic polarization measurements and film breakdown studies in sulfuric acid. As molybdenum content increased the critical current density for passivity decreased, passivation potential shifted in the active direction and stability of passive film, as revealed by breakdown times, increased. Copper and silicon additions tended to enhance effects of molybdenum, in general, while phosphorus was detrimental. No addition had significant effect on potential at which transpassive behavior occurs. All samples displayed a wide passive region over which anodic protection could be applied in sulfuric acid medium.
Stress Corrosion Cracking off Ti and Zr in HCl-Methanol Solutions
Authors: MORI KENJI , TAKAMURA AKIRA , SHIMOSE TAKAAKI 
Published: February 2013

Abstract
It was discovered by the authors that Ti is easily attacked by stress corrosion cracking in methanol containing HCl. This is a report on a study to assess quantitatively stress corrosion cracking of Ti in alcohol solutions. At the same time stress corrosion cracking of Zr was studied because of its similarity in chemical behavior to Ti.
Stress corrosion cracking of Ti occurs in methanol solutions containing HCl or H2SO4 and that of Zr is observed in methanol containing HCl or H2SO4 or HCOOH and in ethanol containing HCl. In HCl-alcohol solutions it is observed also that the larger the molecular weight of the alcohol, the longer life the metals have.
Addition of water to HCl-methanol solution prevents stress corrosion cracking of Ti and Zr. Critical concentration of water in 0.4 percent HCl-methanol solution is about 1.5 percent for Ti and about 3 percent for Zr. To prevent stress corrosion cracking by stress relief, annealing temperatures should be higher than 500 C (932 F) for Ti and 450 C (842 F) for Zr.
Polarization and Corrosion of Ferrosilicon Alloys for Iron Ore Beneficiation Media
Authors: ROBINSON F. P. A. , DuPLESSIS D. J. 
Published: February 2013

Abstract
Ferrosilicon alloys containing from 7.5 to 15 percent silicon and alloying additions of Cr, Ni, Cu, C, U and Mo were subjected to weight loss and polarization tests in NaCl/Na2SO4, HCl and H2SO4 electrolytes. Corrosion resistance was found, in accordance with existing knowledge, to increase with silicon content. Chromium was found to be particularly beneficial as regards corrosion resistance, whereas generally speaking, the other elements had little effect. By the judicious addition of the above-mentioned elements, a 12.5 percent silicon alloy was produced with satisfactory resistance and the high specific gravity necessary for heavy medium separation.
Oxidation Characteristics of the Lanthanide Metals
Authors: GREENE N. D. , HODGE F. G. 
Published: February 2013

Abstract
Oxidation rates and rate equations off La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Lu„ Y were determined in dry and moist air in the temperature range 100–800 C (212–1472 F) by precision weight gain measurements Oxide structures were examined by both metallographie and x-ray analyses.
Observed oxidation characteristics are related to oxide structures and the physico-chemical properties of the rare earth metals.
Polarization of Strained AISI 4340 Steel in Oxygenated NaCl Solutions
Authors: TOY S. M. 
Published: February 2013

Abstract
Electrode reactions involved in the stress corrosion of AISI 4340 steel in sodium chloride solutions were studied by pulse galvanostatic and potentiostatic experiments. The redox cell system involves two principal cathodic reactions and one anodic reaction. These electrochemical reactions are affected by the application of stress, by change in pH, by oxygen content and the heat-treated condition of the materials. The effect of stress is to shift the cathodic polarization curve in an electropositive direction with increasing tensile load. It is equivalent to cathodic control for the conditions investigated and is described by the electrochemical interpretation, based on the coupling of the redox branches which produce the largest corrosion current.
Embrittlement of High Strength AISI 4340 Steel in Boiling NaCl Solution
Authors: LOGAN HUGH L. , WEHRUNG JOHN M. 
Published: February 2013

Abstract
The resistance of high strength AISI 4340 steel tubing, quenched in oil and tempered at 425 F (218 C), to corrosive media has been investigated. The exterior surface of the specimen was exposed to boiling NaCl, the interior cavity was evacuated and the specimen was subjected to a tensile stress. Specimens failed, with little evidence that cracking was developing, after several hours' exposure and after hydrogen had penetrated through the specimen wall. Appearance of the initial fracture and its mode of development indicate it originated within the specimen wall. The data indicate that failure resulted from hydrogen embrittlement.
Use of Ammonia to Supress Oxygen Production and Corrosion in Boiling-Water Reactors
Authors: LESURF L. E. , BRYANT P. E. C. , TANNER M. G. 
Published: February 2013

Abstract
Radiolysis of the coolant in nuclear reactors cooled by boiling water results in oxygen in the steam and recirculated water phases. This has dictated the use of stainless steels as the major circuit materials for these reactors. It is shown that ammonia additions to the coolant eliminate oxygen production, permitting the use of mild steel for circuit construction with consequent savings in capital cost Corrosion data are presented for various out-reactor materials (carbon steel, low alloy steels, stainless steels, Monel alloy 400, Inconel alloy 600) exposed out-of-flux to the coolant of two phase in-reactor loops when operated neutral and with ammonia addition. Activation of corrosion products from different origins is discussed. Intergranular attack is related to the presence of oxygen or oxidizing radiolytic species in the water.
Hot Corrosion of Gas Turbine Alloys
Authors: BERGMAN P. A. 
Published: February 2013

Abstract
Types of hot corrosion encountered in aircraft gas turbines operating in marine environments were reproduced in laboratory tests. Nickel and cobalt-base alloys were tested in the products of combustion of JP-5 and 0, 2 and 200 ppm sea salt between 1600 F (871 C) and 2000 F (1093 C). Higher chromium alloys were generally (but not always) more resistant to hot corrosion. Attack was caused by sodium sulfate, corrosion occurring only in the temperature range in which sodium sulfate was deposited in a molten state. (About 1600 F (871 C) to 1875 F (1024 C)/ 2000 F (1093 C). Effects of another alkali metal and two alkaline-earth metals, sulfur and chlorine also were evaluated.
Microstructural changes were studied by metallographic techniques and chemical compositional changes and sulfides were identified by electron microprobe analyses. The nature of attack is discussed and some concepts of the hot corrosion mechanism postulated. Apparently, depletion of chromium in surface zones through the formation of oxides and sulfides reduces the corrosion resistance of depleted zones, thereby promoting severe hot corrosion.
Effect of Halide Additions on Anodic Behavior of Nickel in Sulfuric Acid Solutions
Authors: POSTLETHWAITE JOHN , FREESE LEONARD B. 
Published: February 2013

Abstract
A potentiokinetic study, dE/dt = 950 mV/hr, has been made of the effects of sodium chloride, bromide and iodide additions, in the range 0.001 to 0.1 M, on the anodic behavior of pure nickel in deaerated N/10 sulfuric acid. Each experiment comprised a forward and reverse sweep in the potential range (relative to the standard hydrogen electrode) −0.5 to +1.2 V. Halide additions affected the anodic behavior of the nickel in both active and passive regions. All halides studied lowered the corrosion potential, raised the primary passivation potential and increased the critical passivation current density. Additions of 0.01 M and greater resulted in elimination of the normal passive region.
Reactivation was much greater on reverse sweeps with chloride additions than in either plain acid or with other halides. Negative slope marking the active-passive transition on forward sweep sometimes was eliminated but was evident always on the reverse sweep showing that even when attacks in active and passive regions merge there is a change of electrode process at the normal active passive transition.
Anodic Corrosion Characteristics of Aluminum 7075 and 7178
Authors: ROEBUCK A. H. , LUHAN J. V. 
Published: February 2013

Abstract
High-strength alloys 7075 and 7178 are widely used now in the −T6 tempers by the aerospace industry. Several more corrosion-resistant tempers have been developed recently: 7075–T73 (stress corrosion resistant) and 7075–T76 and 7178–T76 (exfoliation resistant).
Electrochemical characteristics as determined by “dynamic” (current versus potential) and “static” (current versus time) tests were found to correlate well with their performance in accelerated corrosion and natural environment marine tests. Attack on the −T6 temper was found to be localized in nature, while that on the resistant tempers (−T76 and −T73) was general, showing crystallographic form. The −T6 tempers polarized more rapidly and were less active than the −T76 or −T73 tempers. Anodic control of the corrosion process is postulated to be more important in 7075 than in the more highly alloyed 7178; the latter showing mixed anodic-cathodic control.
Identification of the Initial Oxide Films on 18-8 Stainless Steel in High Temperature Water
Authors: NAKAYAMA T. , OSHIDA Y. 
Published: February 2013

Abstract
Initial oxide film formed on 18–8 stainless steel in high temperature water at 300 C (572 F) for 1 hour was identical with corundum type crystals like (Cr, Fe)2O3 alone or its coexistence with α-Fe2O3. On the contrary, the oxide film produced by prolonged oxidation (24 hours) consisted mainly of the spinel type crystals containing nickel.
Stress Corrosion of Titanium Alloys In Aqueous Magnesium Chloride Solution at 154 C
Authors: SANDERSON G. , SCULLY J. C. 
Published: February 2013

Abstract
Titanium alloys have been found susceptible to slow intergranular stress corrosion cracking in MgCl2 solutions boiling at 154 C (309 F). Titanium metal suffers from pitting but not from cracking in the same solution. Experiments on Ti-Al alloys have shown that as aluminium is added there is a transition from pits linked by wide fissures to narrow cracking. The effect of chemical polishing of specimens, which creates a surface layer of hydride phase, is to change the mode of cracking in the richer alloys from predominantly intergranular to predominantly trans-granular. This is explained by the formation of reactive dislocations in these alloys particularly at the hydride/matrix interfaces where corrosion attack is initiated. Formation of a hydride phase at the bases of pits during corrosion also will create reactive interfaces. Intergranular cracking arises from segregation to the grain boundaries of solute and possibly impurity atoms.
Optical Microscopy Studies of Anodic Dissolution of Iron In Sulfuric and Hydrochloric Acid Solutions
Authors: FELLONI L , CAMMAROTA G. P. 
Published: February 2013

Abstract
Microscopical observation was made during and after intensiostatic polarization of Armco iron electrodes. A correlation between etching degree and grain orientation was evident in sulfuric acid solutions. In hydrochloric acid solutions a smoothing at the inside of the grains, independently of their orientation and preferential corrosion at the boundaries occurred. It is suggested that in sulfuric acid the dissolution mechanism involving anion participation may be effective, while in hydrochloric solutions a competitive adsorption very probably takes place between Cl− and OH− or water molecules.
Microelectrodes for Corrosion Studies
Authors: CLEARY H. J. 
Published: February 2013

Abstract
Microelectrode technology is currently being developed by medical and biological workers for use in microanalytic and intracellular studies. The possibilities of applying this new technology to investigations of corrosion phenomena are examined in the paper. Oxygen cathode, pH and potential-measuring microelectrodes with working tips ranging from 10 to 100 microns in diameter are being developed for the study of corrosion mechanisms. Techniques for the construction, storage, calibration and use of stable electrodes are described. Probe dimensions and very high impedance characteristics lead to positioning and electrical measurement difficulties which are also discussed.
Influence of Prepolarization on the Electrochemical Behavior of Iron-Carbon Alloys
Authors: WOOD G. C , SOLTZ G. C. 
Published: February 2013

Abstract
The influence of anodic and cathodic prepolarization of electrodes, containing respectively 0.03, 0.48, and 1.3 percent carbon, in de-aerated N and 0.1 N sulfuric acid at 25 C (77 F) on the subsequent open circuit potential-time curves has been determined. Anodic pretreatment always lowers and cathodic pretreatment raises the initial potential on these curves. Magnitude of the potential shift and time required to resume the rest potential are larger the higher the prepolarizing time. The influence of carbon content and acid concentration is complex. Special experiments have indicated the importance of specimen, and especially solution history, and have permitted an interpretation in terms of polarization diagrams. The most likely explanation is the influence of sulfide or noble metal or metalloid ions derived from the alloy or possibly the solution in altering the number of active anodic sites. This is achieved by an increase in the degree of hydrogen poisoning or by accumulation or plating out of metals or metalloids.
Stress Corrosion Cracking and Corrosion Behavior of Ti and Ti-Al Alloys in Methanol Iodine Solutions
Authors: SEDRIKS A. J. , GREEN J.A.S. , SLATTERY P.W. 
Published: February 2013

Abstract
Studies have been made of the corrosion characteristics and susceptibility to stress-corrosion cracking of pure titanium and Ti-Al binary alloys in methanol-iodine solutions. The results indicate that two distinct stress-corrosion mechanisms may be operative, depending on the composition of the solid. In pure titanium and a Ti-2.09 w/o Al alloy failures were found to be intergranular, while in the higher alloys (&gt;5 w/o Al) only the initial part of the crack was intergranular, the part adjacent to the final ductile fracture being largely transgranular. In all the materials examined, the intergranular stress-corrosion process could be inhibited by cathodic polarization or the introduction of water in the methanol-iodine solution. On the basis of these and other observations, it is suggested that this process represents stress-accelerated intergranular corrosion involving dissolution of metal at a crack tip. The transgranular crack propagation stage observed in the higher alloys has the characteristics of mechanical failure, and its occurrence appears to be related to a reduced propensity for cross-slip.
Polarization Behavior of Iron-Cobalt Alloys in Sulfuric Acid Solutions
Authors: MOTTERN M. M. , MYERS J. R. 
Published: February 2013

Abstract
Anodic polarization behavior of iron, cobalt and seven iron-cobalt alloys in H2-saturated 1, 5 and 10 N sulfuric acid solutions was investigated at 22 C using a potentiostatic technique. Cobalt and the 95 w/o cobalt alloy did not passivate in any acid studied. In 10 N acid, specimens containing 60 w/o or more cobalt failed to exhibit a normal active-to-passive transition. Specimens containing 75 and 80 w/o cobalt were passivated only marginally in 5 N acid. Specimens which did not have a normal passive region exhibited “secondary” passivation at potentials just prior to visible oxygen evolution. Tafel slopes for anodic dissolution and oxygen evolution varied from 0.040 to 0.065 and 0.065 to 0.095 volt, respectively and appeared to be composition and pH independent. Corrosion potentials were linear functions of pH over the pH range +1.87 to −1.08; dEcorr/dpH varied from −0.035 to −0.045, independent of composition. Ecorr decreased linearly with composition from a value of −0.360 volt vs SCE for pure cobalt to −0.505 volt for pure iron. Critical current density increased slightly with increasing cobalt content and obeyed the expression: logicr = logicro + kpH. The passive current density increased with both increasing cobalt content and increasing acid concentration. Values of io, H2, icorr and βc” for iron and cobalt in H2-saturated, 1, 5 and 10 N acid were determined from cathodic polarization curves. Hydrogen overvoltage at 1 ma/cm2 for iron and cobalt appeared to increase linearly with pH; dη/dpH ≅ −0.045. Effect of time on the cathodic polarization parameters for iron in H2-saturated 1 N acid was determined.
The Role of Surface Stress on Hydrogen Absorption by 4340 Steel
Authors: PHALEN D. I. , VAUGHAN D. A. 
Published: February 2013

Abstract
The reaction kinetics of stressed, high strength steel with cathodically generated hydrogen are shown to follow the first-order rate equation, with rate constant k = −5 × 105 exp [−9700/RT] in which the activation energy is equivalent to that for diffusion of hydrogen in iron. The pre-exponential constant, however, is several orders of magnitude greater than that obtained for diffusion and is discussed in terms of the number of reactive sites. While the number of incipient sites is believed to be comparable to the number of subgrain (domain) boundaries in martensity (1012 cm−2), a stress of 85 ksi activates approximately 107 sites/cm2. These sites are not activated by a surface tensile stress of less than 40 to 50 ksi. When these sites are activated, however, hydrogen diffuses to the area of higher tensile stress. In the case of ferritic structure, the hydrogen reaction rate does not increase with the magnitude of the tensile stress.
The Effect of Silicon on the Stress Corrosion Resistance of Low Alloy High Strength Steels
Authors: CARTER C. S. 
Published: February 2013

Abstract
The effect of five levels of silicon, within the range 0.09% to 2.15%, on the stress corrosion resistance of 4340 steel was established in 3.5% sodium chloride solution for two tensile strength ranges (280 to 300 ksi and 230 to 240 ksi). At the higher strength range, the threshold stress intensity KISCC was independent of silicon content, but the stress corrosion crack velocity was significantly retarded when the silicon content exceeded 1.5%. At the 230 to 240 ksi strength range, steels containing less than 1.5% silicon exhibited a higher KIscc threshold than steels of higher silicon content. Strength level had a significant effect on crack velocity characteristics.
Discussion: Surface Stress on Hydrogen Absorption by 4340 Steel
Authors: HUDGINS C M. 
Published: February 2013

Abstract
This brief note is a discussion of the paper “The Role of Surface Stress on Hydrogen Absorption by 4340 Steel” by D. I. Phalen and D.A. Vaughan, “Corrosion,” 24, 243–246 (1968) August.
Sulfidation of a Complex Nickel Base Alloy-Inconel 713C
Authors: CHANDER J. , McQUEEN H. J. 
Published: February 2013

Abstract
The reaction between a complex high-temperature nickel-base alloy Inconel 713 C and hydrogen sulphide diluted with air was investigated in the temperature range of 705 C to 927 C under atmospheric pressure. The sulphidation in an atmosphere of 10% hydrogen sulphide between 816 C-885 C has been found to follow a parabolic-rate law with an activation energy of about 55 kcals/mole. Metallographic studies have shown that the scale is composed of two distinct layers. X-ray and electron microprobe analyses demonstrated that the outer layer is composed mainly of Ni3S2 and that the inner layer is a mixture of unidentified sulphides with chromium and aluminum as major components. The reduced rate of corrosion appears to be the result of the formation of the inner layer of scale.
Mechanism of Corrosion Tunnelling With Special Reference to Cu3Au
Authors: SWANN P. R. 
Published: February 2013

Abstract
A flat corrosion interface is unstable on alloys undergoing preferential dissolution of one component. This instability results from the uneven accumulation of the less soluble component which enables pits to develop and grow into corrosion tunnels. Electron microscope observations of CU3AU exposed to a ferric chloride solution suggest that surface diffusion or ionization and re-deposition of gold occurs on the walls of corrosion tunnels and that this accounts for the discrepancy between observed and calculated tunnel diameters. No evidence was found to support the volume diffusion theory of tunnel formation.