Showing papers on "Corrosion published in 1978"
TL;DR: In this article, the polarization resistance method is applied to bars embedded in hardened mortar and immersed in Ca(OH)2-saturated solution, and an acceptable agreement between the gravimetric and the electrochemical weight loss data is found.
Abstract: Up to this time all the methods to measure the corrosion rate of reinforcing steels embedded in hardened concrete have been of the destructive type, which requires much time and materials and makes the full scale study of the phenomenon difficult. The authors have applied the polarization resistance method to bars embedded in hardened mortar and immersed in Ca(OH)2-saturated solution, and have found an acceptable agreement between the gravimetric and the electrochemical weight loss data.
469 citations
TL;DR: A mathematical model of the initiation stage of crevice corrosion has been developed, based on the generally accepted mechanism of oxygen depletion within the crevice, followed by a pH fall and eve... as discussed by the authors.
Abstract: A mathematical model of the initiation stage of crevice corrosion has been developed, based on the generally accepted mechanism of oxygen depletion within the crevice, followed by a pH fall and eve...
243 citations
TL;DR: In this article, the composition and structure of passive films formed on a series of iron-chromium alloys in de-aerated 1M H 2 SO 4 were quantitatively studied.
235 citations
Book•
01 Dec 1978
TL;DR: In this article, the authors present practices, techniques, materials, and equipment used for basic corrosion and cathodic protection of pipelines and present formulas, practices, and recommendations based on study of large and small pipeline systems.
Abstract: This book presents practices, techniques, materials, and equipment used for basic corrosion and cathodic protection of pipelines. Written by an electrical engineer and a leading authority on control of pipeline corrosion in the United States and overseas. Presents formulas, practices, and recommendations based on study of large and small pipeline systems. Includes survey methods and techniques, groundbed design, instrumentation, construction practices, maintenance procedures, and economics. Evaluates cathodic protection with rectifiers, galvanic anodes, and other current sources.
198 citations
TL;DR: Experimental studies have been carried out using crevices of Type 316 stainless steel freely exposed in chloride solutions, and the characteristic behaviour of corrosion potential with time, together w....
Abstract: Experimental studies have been carried out using crevices of Type 316 stainless steel freely exposed in chloride solutions. The characteristic behaviour of corrosion potential with time, together w...
168 citations
TL;DR: In this paper, it was inferred that a well reproducible critical potential for crevice corrosion nucleation exists, which depends on the type of steel and is more negative than the critical potential of pit nucleation.
147 citations
TL;DR: In this article, the carburization of NiCr 32 20 and NiCrSi 60 16 has been studied in CH4-H2 mixtures in the temperature range 900-1100°C.
Abstract: The carburization of NiCr 32 20 and NiCrSi 60 16 has been studied in CH4-H2 mixtures in the temperature range 900–1100°C. The methods included thermogravimetric measurements and studies on reacted specimens by X-ray diffraction, metallographic, and chemical analysis. Upon carburization internal carbides M7C3 and M23C6 are formed (M=mainly Cr); the rate of carburization is determined by carbon diffusion in the Fe-Ni matrix with carbide precipitations. The effect of the alloying elements Ni and Si on the carburization resistance of austenitic alloys is explained. By the same methods the oxidation and carburization in CO-H2O-H2 mixtures have been studied. The important role of a stable chromium oxide layer for the carburization resistance was confirmed. Creep tests at 1000°C in a CO-H2O-H2 atmosphere where Cr2O3 is stable showed carburization occurring through cracks in the oxide layer. At high strain rates premature failure occurs by carburization, which is followed by internal oxidation and formation of cracks, voids, and holes.
146 citations
TL;DR: In this article, the effect of chromium and molybdenum on the formation of the passive film of stainless steels and its corrosion resistance to the chloride ion was investigated.
Abstract: This investigation is concerned with the effect of chromium and molybdenum on the formation of the passive film of stainless steels, and its corrosion resistance to the chloride ion. The corrosion resistance to the chloride ion was estimated by the potential decay method and the measurement of the anodic polarization curve. The composition analysis of the passive film was performed by Auger Electron Spectroscopic Analysis. The following conclusions were obtained from the test results: (1) The passive film was more resistant in the environment containing chloride ions as the chromium content in the passive film increased, and (2) molybdenum was observed on AES analysis to have an effect on the increment of the chromium content in the passive film and to promote the passive film formation of stainless steels, probably adsorbing on the active metal surface in the form of molybdate.
125 citations
TL;DR: In this article, the authors studied the oxidation of NC 132 hot-pressed silicon nitride in dry oxygen at 1521 to 1731 K. The rate of O2 uptake and N2 release, as a function of time, was measured volumetrically.
Abstract: The oxidation of NC 132 hot-pressed silicon nitride in dry oxygen was studied at 1521 to 1731K. The rate of O2 uptake and N2 release, as a function of time, was measured volumetrically. The ratio of N2 released to O2 consumed was smaller than expected from the stoichiometry of the oxidation reaction for Si3N4. The low value was attributed to impurities in the material. The oxidation rate followed the parabolic law with an activation energy of 440 kJ/mol. The corrosion scales (examined by microsurface techniques) were porous due to bubbles of released N2. The scales consisted of a mixture of unoxidized silicon nitride grains, crystalline oxides (SiO2 and MgSiO3containing other elements), and a glass phase. Reoxidation showed that the oxide scale was not protective. The magnesium profile in the subsurface layers indicated that the diffusion of magnesium in the unoxidized material was the rate-limiting step in the oxidation.
118 citations
110 citations
TL;DR: In this paper, the corrosion and electrochemical properties of amorphous iron-chromium alloys containing different sets of glass-forming metalloidal elements, boron, carbon, silicon and phosphorus, have been investigated.
Abstract: Corrosion and electrochemical behaviours of amorphous iron-chromium alloys containing different sets of glass-forming metalloidal elements, boron, carbon, silicon and phosphorus, have been investigated. The corrosion resistance in 0.1N H2SO4 increases in the order of alloys containing silicon, boron, carbon and phosphorus, and the corrosion resistance in 3% NaCl increases in the order of alloys containing boron, silicon or carbon, and phosphorus. Difference in the corrosion resistance of amorphous alloys containing various metalloids has been interpreted in terms of the difference in the formation rate of the chromium-enriched protective film on the surface of alloys.
TL;DR: In this article, a scanning laser beam was used to melt and normalize the surface layer of sensitized 304 stainless steel and Strauss tests indicated a complete resistance to intergranular corrosion.
Abstract: A scanning laser beam was used to melt and normalize the surface layer of sensitized 304 stainless steel. Subsequent Strauss tests indicated a complete resistance to intergranular corrosion. Mechanical testing at strains less than 15% also showed laser surface melting to indefinitely extend specimen life in a stress corrosion environment. At strains greater than 15%, the laser‐scanned protective layer was breached by cracks. A maximum critical laser‐scanning velocity compatible with normalization of the surface layer is calculated. Similarly, a minimum critical laser‐scanning velocity required to avoid resensitization is determined. The stress distribution in a 304 stainless‐steel specimen with a laser‐melted and self‐quenched surface layer is estimated and shown to be compatible with the observed appearance of martensite in the melted surface layer.
TL;DR: In this paper, anodic polarization curves of amorphous and crystalline Cu 50 Ti 50 and Cu 50 Zr 50 alloys have been examined in various acidic, neutral and alkaline solutions.
Abstract: Corrosion rates and anodic polarization curves of amorphous and crystallinecu 50 Ti 50 and Cu 50 Zr 50 alloys have been examined in various acidic, neutral and alkaline solutions. The amorphous alloys are very stable in acidic and alkaline solutions, but unstable in agressive chloride solutions. The corrosion resistance of these amorphous alloys is higher than that of the crystallized alloys. The high corrosion resistance of amorphous alloys is attributable to the high chemical homogeneity of amorphous alloys without localized crystalline defects such as precipitates, segregates, grain boundaries, etc. Metalloid elements play an important role in the corrosion behavior of amorphous alloys; the addition of phosphorus to amorphous CuTi alloy greatly increases the corrosion resistance, even in 1N HCl.
TL;DR: In this paper, the corrosion behavior of carbon steel in wet elemental sulphur under both aerobic and anaerobic conditions was studied as a function of the initial pH of the system and the particle size of sulphur.
TL;DR: In this paper, the morphology of horse shoe corrosion of copper and copper alloys in sea water cooled condensers in power stations is discussed, and the mechanism of nucleation and of development of this type of corrosion is discussed.
Abstract: The morphology of horse shoe corrosion of copper and copper alloys in sea water cooled condensers in power stations is presented, and the mechanism of nucleation and of development of this type of corrosion is discussed. Horse shoe corrosion is the result of the formation of an active-passive cell: the pH of the sea water is the determining factor, and development of the corrosion is strongly influenced by the local hydrodynamic conditions. The results allow the requirements for a reliable cathodic protection of the condenser tubes to be defined.
TL;DR: Pitting corrosion of a cold-worked 18Cr 10Ni 2Mo stainless steel in an 0.1M NaC1 solution was studied using a potentiostatic technique, and statistical measurements of the pit dimensions and distribution were made using a metallographic image analyzer as discussed by the authors.
TL;DR: In this paper, the corrosion of 90:10 and 70:30 Cu:Ni alloys in flowing seawater (1.62 m/s) has been studied as a function of oxygen concentration using the linear polarization, ac impedance, and potential step methods for measuring the polarization resistance.
Abstract: The corrosion of 90:10 Cu:Ni and 70:30 Cu:Ni alloys in flowing seawater (1.62 m/s) has been studied as a function of oxygen concentration using the linear polarization, ac impedance, and potential step methods for measuring the polarization resistance. The high nickel alloy is found to be more corrosion resistant than the 90:10 Cu:Ni alloy under the conditions employed, provided that [O2] ≤6.60 mg/L. In oxygen saturated seawater, the superior behavior of the 70:30 Cu:Ni alloy is no longer observed. The loss in corrosion resistance of the 70:30 Cu:Ni alloy is correlated with a shift in the corrosion potential, to a value more noble than the “break-away potential” (defined here as the potential at which a sudden increase in anodic current occurs on sweeping the potential in the active to noble directions).
Journal Article•
TL;DR: In this paper, the authors reviewed the evidence arising from exposure tests on reinforced concrete members relating to the influence of cracking on corrosion and concluded that there is no relationship exists between crack width and corrosion, and that the exposure test data currently available are mostly derived from tests of situations that experience shows do not pose any significant corrosion risk.
Abstract: This paper reviews the evidence arising from exposure tests on reinforced concrete members relating to the influence of cracking on corrosion. This evidence gives no reason to conclude that any relationship exists between crack width and corrosion. This result is confirmed by considerations of the chemistry of corrosion of steel in concrete and the physical nature of cracks. However, it is pointed out that the exposure test data currently available are mostly derived from tests of situations that experience shows do not pose any significant corrosion risk. Suggestions are made as to the direction which the search for a more logical approach to design against corrosion might take.(a) /TRRL/
TL;DR: In this paper, the corrosion properties of amorphous FeCr, Fe�xMo and FeW alloys were examined in 1 N HCl.
Abstract: The corrosion rates and electrochemical behaviors of amorphous FexMo13P7C and FexW13P7C alloys have been examined in 1 N HCl, in comparison with corrosion behaviors of amorphous FexCr13P7C alloys. The chromium, molybdenum and tungsten increase significantly the corrosion resistance of amorphous FePC alloys. Amorphous FeCr, FeMo and FeW alloys are immune to pitting corrosion in 1 N HCl. The corrosion resistance of amorphous iron alloys containing Cr, Mo or W of 5 at% or more increases in the order of FeW, FeMo and FeCr alloys.
TL;DR: In this paper, the electrochemical methods for the measurement of the critical pitting potential have been analyzed in terms of their applicability to aluminium and its alloys and the difficulties associated with different methods are reviewed.
TL;DR: In this paper, the presence of metal ions (Cd 2+, Mn 2+, Zn 2+ ), more electronegative than the cathodic potential for the hydrogen evolution reaction on iron in a 0.25M H 2 SO 4 solution, inhibits the hydrogen reaction and corrosion of iron.
01 Jan 1978
TL;DR: In this paper, the authors consider the problem of determining the stresses at all points of a component for the loads and forces to which the component will be subjected during its working life.
Abstract: One of the important considerations in the design of an engineering component or structure is that it shall not deform excessively or break under the loads or forces to which it will be subjected during its working life, that is to say, its mechanical strength shall be sufficient. For any particular design, the stresses at all points can be determined, by calculation or some experimental method of stress analysis, for the loads and forces to which that component will be subjected. The stresses must obviously not exceed the permissible stress for the material chosen and the factors governing the choice may vary. In some cases, limitations of space or weight may dictate the size and hence the stresses, the material being chosen accordingly; or the material may be chosen with some other factor in mind, such as cost or corrosion resistance, and the size of the component made to fit.
01 Jan 1978
TL;DR: In this paper, the National Bureau of Standards (NBS) performed a comprehensive analysis of the United States economy in terms of the cost of metallic corrosion, and the analysis required in this study was placed under contract to the Battelle Columbus Laboratories (BCL).
Abstract: Metallic corrosion is the degradation that results from interaction of metals with various environments, such as air, water, chemical products, and pollutants. This process has a significant effect on many sectors of the American economy, since corrosion and its prevention results in the utilization of materials, energy, labor, and technical expertise which would otherwise be available for alternative uses. As a result of corrosion, users of metal products incur a wide range of costs, including painting and other methods of corrosion control, more expensive, corrosion-resistant materials, premature replacement of capital goods, larger spare parts inventories, and increased maintenance. Some of these expenses (the avoidable costs) could be reduced through the economical best practice application of available corrosion control technology, but lessening the remaining costs (the presently unavoidable costs) would require advances in technology. In response to a Congressional directive, this study of the cost of metallic corrosion to the United States was undertaken by the National Bureau of Standards (NBS). The analysis required in this study was placed under contract to the Battelle Columbus Laboratories (BCL). The overall study was conducted jointly by BCL and NBS. Four aspects of the US economy received especially detailed analysis for corrosion costs. Thesemore » were the Federal Government, personally owned automobiles, electric power industry, and loss to the nation of energy and materials due to corrosion. 22 refs., 12 tabs.« less