Showing papers on "Corrosion published in 1972"
TL;DR: In this article, an introduction to corrosion science and engineering is given, with a focus on the control of corrosion and control of control of the environment. But this is not a comprehensive review of the literature.
Abstract: (1972). Corrosion and Corrosion Control: An introduction to corrosion science and engineering. British Corrosion Journal: Vol. 7, No. 3, pp. 98-98.
424 citations
TL;DR: In this article, the authors describe a research on Atmospheric Rusting, which has been in progress for 5 y in the Department of Metallurgy at Cambridge University, and present the connection between the electrochemical mechanism of atmospheric corrosion with that of corrosion under immersed conditions.
298 citations
TL;DR: In this paper, it has been shown that the entity which is most accurately correlated with corrosion rate is the transfer resistance, the limit of the faradaic impedance at infinite frequency, and the measurement of this resistance constitutes nowadays the best electrochemical test for corrosion, and allows thea priori calculation of corrosion rate.
Abstract: The various methods of evaluating corrosion rate and charge transfer resistance have been critically reviewed on the basis of the recent developments on the measurement and interpretation of faradaic impedances. It is demonstrated that the entity which is most accurately correlated with corrosion rate is the transfer resistance, the limit of the faradaic impedance at infinite frequency. In the case of iron, with and without inhibitor (propargylic alcohol), it has been ascertained, under various experimental conditions, that the measurement of this resistance constitutes nowadays the best electrochemical test for corrosion, and allows thea priori calculation of corrosion rate.
250 citations
Journal Article•
01 Jan 1972-Science reports of the Research Institutes, Tohoku University. Ser. A, Physics, chemistry and metallurgy
TL;DR: In this article, the effect of catalytic effect of Cu and P on the oxidation of Fe(II) hydroxo-complexes in aqueous solutions has been investigated and the mechanism of atmospheric rusting deduced from the results obtained in the present investigation has been used to explain the difference in behaviour between ordinary mild steels and low alloy steels during atmospheric exposure.
Abstract: The oxidation processes of Fe(II) hydroxo-complexes to α-, β-, γ-, and δ-FeOOH and Fe3O4, which are important atmospheric products of steels, and the effect of Cu2+, PO43− ion on the oxidation of the Fe(II) hydroxo-complexes in aqueous solutions have been investigated. The mechanism of atmospheric rusting deduced from the results obtained in the present investigation has been used to explain the difference in behaviour between ordinary mild steels and low alloy steels during atmospheric exposure. It is concluded that Fe(II) complexes are transformed to amorphous δ-FeOOH by the catalytic effect of Cu and P present in steels. The amorphous δ-FeOOH forms a compact rust layer that enhances corrosion resistance of the steel.
231 citations
217 citations
TL;DR: In this paper, the authors examined the basis of intergranular corrosion in austenitic stainless steels by relating the grain boundary composition to the corrosion properties and found that the chromium depleted zones exist and that the depletion theory was valid for tests in weakly oxidizing solutions, however, the impurity segregation and not chromium depletion best explains the deterioration of corrosion properties.
Abstract: The basis of intergranular corrosion in austenitic stainless steels is examined by relating the grain boundary composition to the corrosion properties. The technique of Auger electron spectroscopy has been used to obtain the chemistry of intergranular fracture surfaces. It was found that the chromium depleted zones exist and that the depletion theory was valid for tests in weakly oxidizing solutions. In highly oxidizing solutions, however, the impurity segregation and not chromium depletion best explains the deterioration of corrosion properties. Impurity elements such as sulfur, silicon, nitrogen, and phosphorous were observed in the various steels examined. An attempt is made to explain the observed corrosion properties on the basis of chromium depletion and solute segregation theories combined with an electrochemical mechanism.
116 citations
115 citations
TL;DR: In this paper, it was found that during corrosion of stainless steel and mild steels in chloride solutions, the most susceptible sites for pit nucleation were the inclusions of manganese sulfide.
Abstract: It was found by microprobe analysis that during corrosion of stainless steel and mild steels in chloride solutions the most susceptible sites for pit nucleation were the inclusions of manganese sulfide. In the case of stainless steels, the corrosion pits were initiated mainly at mixed manganese and iron sulfide inclusions surrounding the particles of Al and Cr oxides, while in mild steel, the pits were formed mainly on separate manganese particles.
113 citations
TL;DR: In this article, the critical pitting potential is qualitatively related to the resistance of a material to passivity breakdown by pit initiation, and evidence is presented to demonstrate that although the critical pit potential is correlated with resistance to pit initiation by a material, it is not directly related to its resistance to passive resistance.
Abstract: Evidence is presented to demonstrate that although the critical pitting potential is qualitatively related to the resistance of a material to passivity breakdown by pit initiation, it is o...
104 citations
TL;DR: In this paper, the evolution of thought during the last 25 years on the mechanism of pitting corrosion of copper in supply waters is traced and the significance of early observations reconsldered m the light of recent knowledge.
Abstract: The evolution of thought during the last 25 years on the mechanism of pitting corrosion of copper in supply waters is traced and the significance of early observations reconsldered m the light of recent knowledge. A simplified approach to the Membrane Cell Theory, the role of surface films in the initiation mechanism and methods of prevention and protection are included.
TL;DR: In this paper, a quantitative theory for the rate of propagation of stress corrosion cracks in metals is presented and discussed, based on the film rupture mechanism and valid when phenomena at the crack tip control the propagation rate.
Abstract: A quantitative theory for the rate of propagation of stress corrosion cracks in metals is presented and discussed. The theory is based on the film rupture mechanism and is valid when phenomena at the crack tip control the propagation rate. The important parameters in the theory are the strain required to rupture the passive film, the amount of corrosion before repassivation, and the creep rate of material at the crack tip. Plausibility of the theory is demonstrated for stainless steel and for a magnesium alloy.
01 Dec 1972
TL;DR: In this article, the significance of matrix and grain boundary microstructural characteristics on the mechanical properties and stress corrosion susceptibility of 7075 aluminum alloy has been evaluated and the effect of grain boundary precipitate spacing is most significant to the crack propagation stage of stress corrosion.
Abstract: The significance of matrix and grain boundary microstructural characteristics on the mechanical properties and stress corrosion susceptibility of 7075 aluminum alloy has been evaluated. Maximum strength was found to be associated with a Guinier-Preston zone matrix. The precipitate-free-zone adjacent to high angle grain boundaries had only a slight effect on yield and tensile strength but a greater influence on hardness. Stress corrosion susceptibility was studied in an aqueous chloride environment over a 0.7–3.5 pH range. For material of highest strength, grain boundary precipitate spacing was found to be of primary importance to susceptibility. The effect of grain boundary precipitate spacing is most significant to the crack propagation stage of stress corrosion. These results indicate that improved properties for Al-Mg-Zn type alloys could be attained by a desirable combination of matrix and grain boundary structure.
TL;DR: The corrosion of Ti-6Al-4V at 37°C in several simulated body fluids and bovine plasma was studied using the passive current-time technique, indicating a corrosion rate considerably higher for the Type 316 L stainless steel.
Abstract: The corrosion of Ti-6Al-4V at 37°C in several simulated body fluids and bovine plasma was studied using the passive current-time technique. A 0.9% NaCl (bw)-0.1 N NaH2PO4 solution gave results closest to those using bovine plasma as an electrolyte.
All of the samples showed an activation period of 10–15 hr, after which an increase in the corrosion rate was observed. Several possible explanations for this effect are given.
For comparison, a sample of Type 316 L stainless steel was tested using isotonic saline solution as the electrolyte. Both the initial and final current densities were considerably higher than those for Ti-6Al-4V indicating a corrosion rate considerably higher for the Type 316 L stainless steel.
TL;DR: In this article, it is suggested that in those systems of metal and environment where the conditions are between those for general dissolution and complete inactivity, localised corrosion and stress may act conjointly to promote crack extension by selective attack upon compositional or structural features pre-existing in the metal, by the stress exposing relatively small areas of bare, reactive metal or by adsorption of appropriate species at sites where the energy for fracture is thereby lowered.
Abstract: Despite many attempts over the years to rationalise stress corrosion cracking in terms of a single mechanism, it is proposed that the growing body of evidence more readily supports a continuous spectrum of mechanisms. Thus, it is suggested that in those systems of metal and environment where the conditions are between those for general dissolution and complete inactivity, localised corrosion and stress may act conjointly to promote crack extension by selective attack upon compositional or structural features pre-existing in the metal, by the stress exposing relatively small areas of bare, reactive metal or by adsorption of appropriate species at sites where the energy for fracture is thereby lowered. The implication is that a change in the composition or structure of the alloy or in the characteristics of the environment may result in a change in the mechanism of cracking and indeed, in some cases, that crack extension may be the result of more than one mechanism operating.
Book•
01 Jan 1972
TL;DR: In this article, stress corrosion testing with Precracked Specimens was performed on high strength steels and high strength aluminum alloys, including Titanium alloys. And the results showed that they were stable.
Abstract: : Contents: Fundamentals; Stress Corrosion testing with Precracked Specimens; High Strength Steels; High Strength Aluminum alloys; Titanium alloys.
TL;DR: The pitting of pure iron and its alloys with chromium and copper, in neutral chloride solutions, has been studied using microscopy and time-lapse photography, and measurements have been made of local variations of pH value and electrode potential using micro-electrodes as mentioned in this paper.
Abstract: The pitting of pure iron, and its alloys with chromium and copper, in neutral chloride solutions, has been studied using microscopy and time-lapse photography, and measurements have been made of local variations of pH value and electrode potential using micro-electrodes. Primary pitting at a few discrete points is followed by secondary pitting at a large number of points. On pure iron the pits are generally polygonal in shape, while with chromium-iron alloys the shape is less regular and attack is confined to grain boundaries. Facetting of the metal surface within the pits is commonly observed.The initial growth of pits corresponds to a current density of up to 1 A/cm2 but this rapidly decreases and, following accumulation of corrosion product, the corrosion rate settles down to a relatively low figure. The long-term penetration rate is reduced significantly by small alloying additions of copper.pH differences of up to 8 units have been measured between the pitted area (acid) and the surrounding u...
Patent•
11 Jul 1972
TL;DR: In this article, the authors present an approach to the inhibition of the corrosion of metallic parts in contact with aqueous systems by adding to the system of a corrosion inhibiting concentration of a water-soluble organophosphonic acid compound having a carbon to phosphorus bond in combination with a water solubilized orthophosphate.
Abstract: The present disclosure is directed to the inhibition of the corrosion of metallic parts in contact with aqueous systems. This effect is accomplished by the addition to the system of a corrosion inhibiting concentration of a water-soluble organophosphonic acid compound having a carbon to phosphorus bond in combination with a water-soluble orthophosphate. The aqueous system should contain solubilized calcium salts and should possess a basic pH. Under certain conditions it is desirable to utilize water-soluble metal cations as a adjunct to the treatment.
TL;DR: In this article, the adsorption properties of polished iron, zinc, copper and aluminium samples have been compared with those of pre-exposed samples of these metals, showing that almost quantitative adaption of sulfur dioxide has been obtained on preexposed iron samples at r.h.
TL;DR: In this paper, a review of the present knowledge on the thermodynamics and kinetics of electrochemical corrosion in the presence of electrolytes (aqueous solutions, molten salts, etc.) and of gaseous atmospheres is given.
TL;DR: In this article, the corrosion properties in NaCl solutions at room temp. of the various phases present in aluminium bronzes are investigated over periods up to 850 h by combination of electrode kinetic, quantitative analytical, electron microscopic and X-ray methods.
TL;DR: In this article, the pitting susceptibility of 304 stainless steel was evaluated using chemical tests using glycerol-ethanolic AlCl 3 + FeCl 3+ LiCl solutions.
TL;DR: In this paper, a technique called tribo-ellipsometry was developed which simulates film rupture by abrading off the surface oxide during subsequent repassivation of the exposed surface, which allows simultaneous determination of film growth kinetics by ellipsometry and current transients during that time interval following removal of the oxide film.
Abstract: Since the susceptibility of a material to stress corrosion cracking (SCC) may be related to the rupture of a protective film and the repassivation rate of the material thus exposed, a technique, tribo-ellipsometry, has been developed which simulates film rupture by abrading off the surface oxide. During the subsequent repassivation of the exposed surface, this technique allows simultaneous determination of film growth kinetics by ellipsometry and current transients during that time interval following removal of the oxide film. The major advantage of the technique is that the ellipsometric transient allows one to determine which part of the current transient is responsible for repassivation and which part is involved in metal dissolution. The utility of the technique is demonstrated by comparing repassivation rates for a low carbon steel in a sodium nitrate solution in which the metal is susceptible to SCC to those in a sodium nitrite solution, in which it is not. Results obtained using this metho...
01 Nov 1972-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this paper, fatigue tests were carried out on 4140 steel heat treated to various hardness levels and environmental effects were reported in dry and moist air, aerated and deaerated 3 pet NaCl solution, and under conditions of cathodic protection and of passivity.
Abstract: Fatigue tests were carried out on 4140 steel heat treated to various hardness levels. Environmental effects are reported in dry and moist air, aerated and deaerated 3 pet NaCl solution, and under conditions of cathodic protection and of passivity. Critical corrosion rates were measured below which the environment does not affect fatigue life. The results are interpreted in terms of environmentally-induced plastic deformation.
Patent•
27 Mar 1972
TL;DR: In this article, a method of treating a STEEL surface to modify it to improve its hardness or resistance to corrrosion is described. But this method is limited to the case where the surface is subjected to the implantation of selected IONS.
Abstract: A METHOD OF TREATING A STEEL SURFACE TO MODIFY THE SURFACE TO IMPROVE ITS HARDNESS OR RESISTANCE TO CORROSION CHARACTERISED IN THAT THE SURFACE IS SUBJECTED TO THE IMPLANTATION OF SELECTED IONS ADAPTED SO TO MODIFY THE SURFACE STRUCTURE AS TO IMPROVE ITS HARDNESS OR CORROSION RESISTANCE.
TL;DR: In this paper, the effect of temperature over the range 10 to 90 C (50 to 194 F) on the pitting corrosion of a series of molybdenum bearing austenitic stainless steels in an acid chloride medium is demonstrated.
Abstract: The effect of temperature over the range 10 to 90 C (50 to 194 F) on the pitting corrosion of a series of molybdenum bearing austenitic stainless steels in an acid chloride medium is demonstrated. The role of molybdenum in improving the corrosion resistance of these alloys is clearly shown.