Showing papers on "Corrosion published in 1983"
TL;DR: In this paper, the authors studied stress corrosion in vitreous silica exposed to water and several nonaqueous environments; environments which enhance stress-corrosion crack growth in silica contain active groups with electron donor sites on one end and proton donor sites at the other.
Abstract: The mechanical strength of most glasses and ceramics decreases with time under static loading in an ambient environment. This strength loss is associated with slow growth of preexisting surface flaws due to stress corrosion by water from the surrounding environment. We studied stress corrosion in vitreous silica exposed to water and several nonaqueous environments; environments which enhance stress-corrosion crack growth in silica contain active groups with electron donor sites on one end and proton donor sites at the other. These results suggest a detailed chemical model for the interaction of the environment with mechanically strained bonds in the solid at the tip of a crack. The proposed model for stress-corrosion crack growth also has implications for the long-term strength behavior of a wide variety of brittle materials.
495 citations
TL;DR: In this article, a reaction path for evolution and corrosion on Ru and anodes is proposed, where the surface of anodes prepared by thermal decomposition of contains some, which is stable during anodic polarization.
Abstract: Anodic oxidation of Ru and electrodes in has been investigated using x‐ray photoelectron spectroscopy. During evolution on Ru a highly defective hydrated oxide film is formed as a result of corrosion. At a temperature of 310°C in vacuum this film decomposes to metallic ruthenium. The surface of anodes prepared by thermal decomposition of contains some , which is stable during anodic polarization. A reaction path for evolution and corrosion on Ru and anodes is proposed.
325 citations
TL;DR: In this article, the a.c. impedance of thin polymer films on aluminum alloys, steel, and phosphated steel has been determined over a wide frequency range, resulting in a general model for the electrochemical impedance across the coated surfaces.
243 citations
TL;DR: In this paper, the electrochemical behavior of a carbon steel in 3% solution has been investigated using a rotating disk electrode, and it was found that at the corrosion potential the oxygen reduction reaction is under either diffusional or mixed (activation + diffusion) control depending on both the electrode rotation speed and on the hold time at the free corrosion potential.
Abstract: The electrochemical behavior of a carbon steel in 3% solution has been investigated using a rotating disk electrode. Both steady‐state (diffusional current vs. the disk angular velocity plots) and transient (frequency analysis of the electrohydrodynamical impedance) measurements which specifically sample mass transport phenomena, have been carried out. It is shown that oxygen transport takes place not only in the liquid phase but also through a porous layer of corrosion products. From electrochemical impedance measurements, it was found that at the corrosion potential the oxygen reduction reaction is under either diffusional or mixed (activation + diffusion) control depending on both the electrode rotation speed and on the hold time at the free corrosion potential. In addition, it was shown that the oxygen consumption occurs not only by electrochemical reduction but also by chemical oxidation of ferrous to ferric ions. Finally, because of the possible occurrence of mixed corrosion control, it is emphasized that the use of the polarization resistance in order to evaluate corrosion rates is not always valid.
188 citations
TL;DR: In this article, a review of available published literature has indicated that a lack of quantitative information exists, relative to corrosion of collector surfaces, and available information (mostly qualitative) on durability aspects and corrosion of solar receiver surfaces is described.
Abstract: Commencally or potentially available selective and non-selective absorber surfaces for solar heat collectors are reviewed and the state-of-the-art of solar collector corrosion processes is outlined. The review of available published literature has indicated that a lack of quantitative information exists, relative to corrosion of collector surfaces. Available information (mostly qualitative) on durability aspects and corrosion of solar receiver surfaces is described to indicate potential corrosion problem areas and corrosion prevention possibilities. An outline of appropriate durability tests is presented.
187 citations
TL;DR: In this article, the kinetics of repassivation of Type 304L austenitic stainless steel in 10 M KOH solution have been studied as a function of applied potential, and the technique used involves analysis of the current transients that result from rapid mechanical removal of the pre-existing oxide film while the metal is held at constant potential.
155 citations
TL;DR: In this paper, the authors reviewed the characteristics of existing specimens and then described the development of a new design, and both the practical, including monitoring, and mechanistic significance of electrochemical measurements in flowing environments are discussed.
137 citations
TL;DR: In this article, the growth of porous magnetite on carbon steel in high temperature chloride solution has been studied using the a.c. impedance technique, and the frequency dispersion of the impedance of the growing film has been successfully accounted for by a finite transmission line model.
135 citations
TL;DR: In this paper, the effect of phase on the corrosion behavior of metal matrix composites has been studied in, both in the presence and absence of dissolved oxygen, and the results show that pitting susceptibility is about the same for the composites and their corresponding alloys, except for Al 2024.
Abstract: The effect of the phase on the corrosion behavior of metal matrix composites has been studied in , both in the presence and absence of dissolved oxygen. Anodic polarization behavior has been determined, and pitting potentials have been measured for three composite systems: 2024, 6061, and 5456. General corrosion behavior and the effects of anodizing on the corrosion resistance of the composites have been studied by a‐c impedance techniques. The results show that pitting susceptibility is about the same for the composites and their corresponding alloys, except for Al 2024. In this system, the composite is less resistant to pit initiation than the corresponding wrought aluminum alloy. General corrosion is more significantly affected by the presence of oxygen than by the phase. In the absence of oxygen, corrosion resistance is improved for both the alloys and composites. In addition, the corrosion resistance of the composites can be improved by anodizing.
125 citations
TL;DR: In this paper, a cast Co-Cr-Mo alloy was heat treated to determine whether a significant improvement in the alloy's mechanical properties could be obtained without loss of corrosion resistance.
Abstract: Cast Co-Cr-Mo was heat treated to determine whether a significant improvement in the alloy's mechanical properties could be obtained without loss of corrosion resistance. Tensile, corrosion fatigue, and corrosion tests were carried out using individually cast test pieces. The effect on the tensile properties of solution treatment at 1240° C and of ageing at 720° C was determined for a large range of heat treatment times. In addition the effect of other heat treatments described in the literature was determined. Partial solution treatment gave the greatest improvement in corrosion fatigue behaviour. None of the heat treatments significantly affected the corrosion resistance. In spite of the improvements obtained, it was concluded that for orthopaedic implant applications requiring high corrosion fatigue strength, cast Co-Cr-Mo was less suitable than other currently available products.
TL;DR: In this article, it was shown that the adhesive and cavitation-erosion wear characteristics of these alloys are determined by the composition of the matrix alloy and are influenced to a large extent by a strain-induce fee → hep allotropie transformation in the matrix Alloy.
Abstract: Cobalt-base alloys have enjoyed extensive use in wear-related engineering applications for well over 50 years because of their inherent high-strength, corrosion resistance, and ability to retain hardness at elevated temperatures. Microstructurally, wear-resistant cobalt-base alloys consist of hard particles (Cr7C3) dispersed in cobalt-rich (Co > 50%) solid solution matrix alloys (generally Co-Cr-W/Mo). Recent investigations in the Cabot Corporation Technology Laboratories have shown that the adhesive and cavitation-erosion wear characteristics of these alloys are determined by the composition of the matrix alloy and are influenced to a large extent by a strain-induce fee → hep allotropie transformation in the matrix alloy. Further, it has been shown that the cobalt content in the matrix alloy can be decreased to approximately 30% without significantly degrading relevant wear or corrosion properties. Toughness and abrasive wear resistance, on the other hand, are determined primarily by carbide volume fraction and morphology. Large, hypereutectic carbides are generally preferred for good abrasive wear resistance but are detrimental to toughness considerations. The tribological measurements and microstructural correlations associated with these Cabot investigations are summarized and discussed in this paper.
TL;DR: In this paper, the authors reviewed the literature and the characteristics exhibited by filiform corrosion on different metals and performed calculations to select corrosion mechanisms that were compatible with these characteristics, and the preferred mechanism, compatible with all the primary characteristics, is that oxygen and water reach the corrosion site by diffusing through the porous filiform tail.
Abstract: Filiform corrosion occurs on painted metals and cannot be prevented by conventional corrosion inhibitors. In order to better understand the corrosion phenomena, the literature was reviewed and the characteristics exhibited by filiform corrosion on different metals were cataloged. Calculations were performed to select corrosion mechanisms that were compatible with these characteristics. The preferred mechanism, compatible with all the primary characteristics, is that oxygen and water reach the corrosion site by diffusing through the porous filiform tail. Experiments were conducted which confirmed this mechanism. The mass transfer occurring inside the active corrosion cell, and unresolved questions concerning the speed and width of filiform growth are also discussed.
TL;DR: In this paper, the authors examined the corrosion fatigue of the aluminium-zinc-magnesium alloy 7017-T651 in seawater at frequencies from 0.1 to 70 Hz and found that the changes in fracture mode observed at certain critical crack velocities, and their dependence upon the square root of the reciprocal of the frequency of loading, are consistent with an environment-enhanced crack growth rate involving diffusion of hydrogen ahead of the crack tip during each fatigue cycle.
TL;DR: The SEM examination of the pre- and post-polarized alloy surfaces provided evidence which was consistent with the electrochemical measurements, in that the first three alloys exhibited no appreciable corrosion damage whereas pitting corrosion was observed on Nitinol.
Abstract: Potentiodynamic cyclic polarization of four orthodontic alloys (wires), namely Permachrome, Elgiloy, a beta-titanium alloy and Nitinol in a 1% NaCl solution within -500 mV and +300 mV (SCE) indicated the first three alloys to be passive whereas breakdown of passivity was observed on Nitinol. The SEM examination of the pre- and post-polarized alloy surfaces provided evidence which was consistent with the electrochemical measurements, in that the first three alloys exhibited no appreciable corrosion damage whereas pitting corrosion was observed on Nitinol. The results obtained from X-ray analysis of the pitted surface indicated that this pitting could be due to selective dissolution of nickel from Nitinol.
TL;DR: In this paper, anodic corrosion and O2-evolution on Ru and Ir electrodes in 0.5 M H2SO4 was investigated using X-ray photoelectron spectroscopy.
TL;DR: In this paper, the characteristics of the surface of various stainless steels are reviewed and the properties of these alloys that make them stainless is the formation of Cr2O3 on the surface.
Abstract: The characteristics of the surface of various stainless steels are reviewed. The property of these alloys that makes them stainless is the formation of Cr2O3 on the surface. It has been found that this protective layer can be modified relatively easily by heating, abrading, chemical treatment, or ion bombardment. Modification can be changes in the chemical composition of the surface layer or the formation of a layer of segregated material on the surface. These changes may alter the protective nature of the surface films. The outgassing characteristics of stainless steel surfaces also vary depending upon the treatment these surfaces receive.
TL;DR: In this article, a review is given of research whose objective is to understand the principles governing corrosion beneath organic coatings, including electrical properties of coatings and the nature of the metal substrate in determining coating performance.
Abstract: A review is given of research whose objective is to understand the principles governing corrosion beneath organic coatings. Eight subject areas of special interest are discussed: electrical properties of coatings, the nature of the metal substrate in determining coating performance, electrochemical processes which take place on the metal substrate under the coating, diffusion of reactants through the coating, studies of the metal/coating interface, aggregation of water at the metal/coating interface, inhibitors in coatings, and a specific type of deterioration known as cathodic delamination.
TL;DR: In this paper, the corrosion behavior of copper-nickel alloys in unpolluted and sulphide-polluted seawater has been investigated and it was demonstrated that the co-presence of sulphide and oxygen in seawater results in corrosion rates much higher than those measured when the alloy is exposed alternately to sulphides and oxygen.
Journal Article•
TL;DR: The corrosion behavior of synthetic monazite and borosilicate glass in distilled water has been investigated by means of leachate conductivity measurements, ion-implanted marker techniques, solution analyses, and Rutherford backscattering depth profile analyses.
TL;DR: In this article, the authors describe the cracks that arise during the application of a coating and during service due to diffusion, aging and chemical reactions with atmosphere, e.g. the formation of oxides.
Patent•
19 Oct 1983
TL;DR: Coating compositions, coatings, coated parts and methods of use of chromate/phosphate type compositions are of a type which contains small spheroidal aluminum particles having a defined size as mentioned in this paper.
Abstract: Coating compositions, coatings, coated parts and methods of use of chromate/phosphate type compositions. The coating compositions are of a type which contains small spheroidal aluminum particles having a defined size. The coated materials of the invention having improved corrosion and erosion resistance and improved low profile.
TL;DR: From predicted behavior of galvanic couples made of any two of the materials, potentially useful couples that are not expected to show significantly increased corrosion rates were identified.
Abstract: The objective of this study was to produce corrosion behavior data for each of the commonly used metallic alloys in surgical implants. In addition, by applying the known electrochemical corrosion theory, the study aims to predict the behavior of galvanic couples made of any two of the materials. From this predicted behavior, potentially useful couples that are not expected to show significantly increased corrosion rates were identified.
TL;DR: In this paper, a pH meter has been built which enables pH measurements under pressures from 0.1 up to 100 MPa, and the usual physical chemistry of calcocarbonic equilibria is also presented in a new form which better emphasizes the influence of the partial pressure of CO2 as the controlling variable in the system.
Abstract: In order to determine the acidity of corrosive media prevailing in oil and gas wells where CO2 corrosion is encountered, a pH meter has been built which enables pH measurements under pressures from 0.1 up to 100 MPa. The usual physical chemistry of calcocarbonic equilibria is also presented in a new form which better emphasizes the influence of the partial pressure of CO2 as the controlling variable in the system. According to both theoretical and experimental results, the pH of a production water depends as much upon its alkalinity as upon the level of the CO2 partial pressure. The effect of calcareous saturation or supersaturation is also emphasized. It is then shown through a survey of production waters that their acidity under well conditions is much weaker than is commonly assumed. This stands for both CO2 corrosion and sulfide stress cracking.
TL;DR: In this paper, the authors demonstrate the discontinuous nature of transgranular stress-corrosion cracking (TGSCC) in brass and to account for it in terms of the dynamics of competing plastic deformation and brittle crack growth.
01 Jan 1983
TL;DR: In this paper, the authors provide an overview of recent experimental and theoretical research related to the structure, mechanical properties, and fracture behavior of metal-matrix composites, including thermal degradation and the tensile properties of unidirectionally reinforced FP-Al2O3/EZ33 magnesium composites.
Abstract: The papers presented in this volume provide an overview of recent experimental and theoretical research related to the structure, mechanical properties, and fracture behavior of metal-matrix composites. Topics discussed include: thermal degradation and the tensile properties of unidirectionally reinforced FP-Al2O3/EZ33 magnesium composites the interface structure of heat-treated aluminum-graphite fiber composites and micromechanisms of crack growth in a fiber-reinforced, titanium-matrix composite. The discussion also covers the effects of hot rolling on the mechanical properties of SiC-reinforced 6061 aluminum marine corrosion of graphite-aluminum composites and the oxidation and hot corrosion of directionally solidified molybdenum-strengthened eutectic alloys.
TL;DR: In this paper, the authors evaluate the problem of the corrosion of reinforcing steel in concrete, its economics, and the types of structures affected by this type of corrosion, as well as factors affecting corrosion rate and methods of measurement.
Abstract: The report evaluates the problem of the corrosion of reinforcing steel in concrete, its economics, and the types of structures affected. The mechanisms and specific aspects of this type of corrosion are also discussed, as well as factors affecting corrosion rate and methods of measurement. The subject is discussed in the following chapters: 1 - introduction and background; 2 - magnitude of the problem; 3 - fundamental mechanisms; 4 - factors influencing the rate of corrosion of steel in concrete; 5 - measurement of deterioration; 6 - fatigue of reinforced concrete and influence of environment; 7 - protection methods; 8 - standards; and, 9 - current and needed research. (TRRL)
TL;DR: In this article, the role played by the H2 gas in the formation of nodular corrosion in Zircaloys has been clarified, and the second phase particles of the ZrO2-Zircaloy have been identified.