Showing papers on "Corrosion published in 1982"
Book•
01 Jan 1982TL;DR: In this article, the authors present a research work that aims at mapping out the various mechanisms which control the process of steel corrosion in concrete, and illustrate how steel corrosion is illustrated.
Abstract: The research work that is presented in this thesis aims at mapping out the various mechanisms which control the process of steel corrosion in concrete._x000D_ The process of corrosion is illustrate ...
1,321 citations
Journal Article•
TL;DR: In this paper, the authors examined the reactions of various concretes on steel reinforcement and concluded that the most significant influences on the corrosion of prestressing wire in concrete are: the presence of chloride, presence of nitrates, the composition of concrete, the degree of carbonation of the concrete; concrete compaction and chlorides and sulphates should be used as far as possible when steel is embedded.
Abstract: The author details the reactions of various concretes on steel reinforcement. Although portland cements, slag cements and high alumina cements are all hydraulic binders, each possess special properties which are examined. The discussion of causes and methods of preventing the corrosion of steel reinforcement covers such aspects as galvanised steel reinforcement, effects of concrete composition, corrosion of steel reinforcments in concrete and prestressed reinforcement. It is concluded that the most significant influences on the corrosion of prestressing wire in concrete are: the presence of chloride; the presence of nitrates; the composition of the concrete; the degree of carbonation of the concrete; concrete compaction and, chlorides and sulphates should be used as far as possible when steel is embedded. (TRRL)
621 citations
TL;DR: In this article, a detailed chemical model for the interaction of the environment with mechanically strained bonds in the solid at the tip of a crack was proposed, which has implications for the long-term strength behavior of a wide variety of brittle materials.
Abstract: The mechanical strength of many glasses and ceramic materials decreases with time under static loading and ambient environments. This strength loss is associated with slow growth of pre-existing surface flaws due to a stress-corrosion process. To make long-term strength predictions for ceramic components, it is important to understand the stress-corrosion mechanism. We have studied stress corrosion in vitreous silica exposed to water and several non-aqueous environments and report here that environments which enhance stress corrosion are composed of molecular 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 also has implications for the long-term strength behaviour of a wide variety of brittle materials.
421 citations
01 Jan 1982
TL;DR: In this article, the authors present over 40 selections of ZIRCONIUM-Barrier Cladding Attributes and Recent Studies of Crack Initiation During Stress Corrosion Cracking of Zirconium Alloys, Oxidation of Zircaloy-4 in Steam at 1300 to 2400/sup 0/C.
Abstract: This book contains over 40 selections. Some of the titles are: Zirconium-Barrier Cladding Attributes; Recent Studies of Crack Initiation During Stress Corrosion Cracking of Zirconium Alloys; Oxidation of Zircaloy-4 in Steam at 1300 to 2400/sup 0/C; and Residual Stresses in Textured Zirconium Alloys.
313 citations
TL;DR: In this paper, a prefabricated FRP (fibreglass-reinforced-plastic) casing is used initially as the form to cast plain concrete, and thereafter to confine the concrete, act as tensile reinforcement and provide corrosion protection.
Abstract: Synopsis Plastics reinforced with continuous glass fibres have outstanding tensile strength in the fibre direction and excellent corrosion resistance, but are characterized by low modulus and low compressive strength. It is proposed to develop composite members in which a prefabricated FRP (fibreglass-reinforced-plastic) casing is used initially as the form to cast plain concrete, and thereafter to confine the concrete, act as tensile reinforcement and provide corrosion protection. Significant cost savings are possible with the proposed combination of materials, especially in exposed structures, such as bridges. An experimental investigation of FRP-encased concrete cylinders in axial compression and of rectangular FRP-encased beams in bending is presented. The results demonstrate the excellent strength and ductility characteristics of FRP-encased members. The behaviour of circular FRP-encased concrete beam-columns is described also, in terms of analytically obtained moment-axial-load and ductility-axial-l...
302 citations
TL;DR: In this article, a fracture mechanism map for quartz is presented which was constructed using a combination of theoretical insights and experimental data, with particular emphasis on the influence of chemical effects on fracture controlled by preexisting cracks (stress corrosion).
268 citations
TL;DR: The corrosion rates of chromium and nickel showed a slight increase, while cobalt and copper dissolved to a very much greater extent in the presence of protein, however, with molybdenum the corrosion was inhibited by protein.
Abstract: The corrosion of the pure metals aluminium, cobalt, copper, chromium, molybdenum, nickel, and titanium and of a cobalt-chromium molybdenum casting alloy has been studied in buffered saline with and without the presence of the proteins serum albumin and fibrinogen. The corrosion of aluminium and titanium was unaffected by the protein. The corrosion rates of chromium and nickel showed a slight increase, while cobalt and copper dissolved to a very much greater extent in the presence of protein. However, with molybdenum the corrosion was inhibited by protein.
238 citations
Patent•
23 Apr 1982TL;DR: An electrochemical storage cell or battery with an anode space for an alkali metal as the anolyte and a cathode space with a sulfur-containing catholyte substance, which are separated from each other by an alkaline-ion-conducting solid electrolyte and are confined by a cell wall of metal, particularly of a light metal or steel, is provided by a protective layer by applying to at least that part of the metal cell wall in contact with the acid-resistant material 001 to 2 mm thick by means of a conductive adhesive which retains its
Abstract: An electrochemical storage cell or battery with an anode space for an alkali metal as the anolyte and with a cathode space for a sulfur-containing catholyte substance, which are separated from each other by an alkali-ion-conducting solid electrolyte and are confined by a cell wall of metal, particularly of a light metal or steel Long-life corrosion protection of the metal cell wall is provided by a protective layer by applying to at least that part of the metal cell wall in contact with the catholyte substance, a foil of corrosion-resistant material 001 to 02 mm thick by means of a conductive adhesive which retains its adhesive properties at operating temperatures
177 citations
TL;DR: Amplitude spectra of low frequency electrochemical noise are presented in this article, which indicate the possibility of a non-perturbative electrochemical corrosion monitoring technique capable of detection of pitting and crevice attack.
171 citations
TL;DR: In this paper, the variation with time of the corrosion rates of galvanized steel and bare steel rebars has been studied as a function of the relative ambient humidity, mortar carbonation and the presence or absence of chloride ions.
Abstract: The variation with time of the corrosion rates of galvanized steel and bare steel rebars has been studied as a function of the relative ambient humidity, mortar carbonation and the presence or absence of chloride ions. Corrosion rates are estimated from Rp measurements with electronic compensation for the ohmic drop between the working imd reference electrodes.It is shown that a normal galvanized coating with a continuous layer of practically pure zinc in contact with mortar gives effective protection to the steel reinforcing bars against the aggressive action of carbonation and chlorides. The protective effect of this galvanized coating is much greater under partial immersion conditions of the mortar than in very humid atmospheres, although in the latter case the corrosion rate decreases with time.
130 citations
TL;DR: The findings suggested that the presence of voids, together with poor oral hygiene, led to crevice corrosion of the Type 304 stainless steel and formation of colored corrosion products which can result in enamel stains.
TL;DR: A detailed kinetic study of corrosion reactions of iron in HCl, H2SO4, and H3PO4 is made by a modified version of the gasometric technique as discussed by the authors.
Abstract: A detailed kinetic study of corrosion reactions of iron in HCl, H2SO4, and H3PO4 is made by a modified version of the gasometric technique. Reaction rates are measured at different tempera...
TL;DR: In this article, seven types of corrosion and precorrosion of painted metals are reviewed: blistering, early rust, flash rusting, anodic undermining, filiform corrosion, cathodic delamination, and wet a...
Abstract: Seven types of corrosion and precorrosion of painted metals are reviewed: blistering, early rusting, flash rusting, anodic undermining, filiform corrosion, cathodic delamination, and wet a...
TL;DR: In this paper, the sintering process of aluminium nitride was described and the main mechanical properties (hardness, strength, toughness, thermal shock resistance...) were measured and the effects of porosity and temperature were compared with the mechanical properties of other structural ceramics.
TL;DR: In this article, the technique of bonding steel reinforcement externally to hardened concrete is described, and the results show that significant improvements in performance could be achieved in terms of ultimate load, crack control, and stiffness.
TL;DR: In this article, the role of silicon in scale formation and scale maintenance on refractory metals and high temperature alloys is discussed and various coating concepts are discussed ranging from brittle silicide coatings to modified MCrAl-Y overlayers and composite structures with dispersed silicide reservoirs in ductile matrices.
TL;DR: In this article, surface enhanced Raman scattering (SERS) was used to detect photoaltered layers of the benzotriazole complex during anodic anodization.
Abstract: New aspects of molecular interactions in corrosion inhibition are reported in this first investigation of benzotriazole on copper using surface enhanced Raman scattering (SERS). The observation of hysteresis in the Raman intensity of concentrated solutions as a function of applied voltage is attributed to a conformation or bonding rearrangement in the protective layer. Also, a photoalteration of the benzotriazole complex, which occurs during anodization, produces improved corrosion resistance and increases the Raman activity. The ability of SERS to detect these photoaltered layers provides a new probe for corrosion studies. 18 refs.
TL;DR: Slow strain rate stress corrosion tests on notched or pre-cracked specimens of pre-stressing steel immersed in Ca(OH)2 solutions, to which HCl was added where the pH needed to be reduced, have shown that enhanced cracking results at potentials below about − 900 mV, irrespective of pH, with an intermediate region in which cracking is absent or less severe than at other potentials.
TL;DR: A relationship between mass transfer conditions for condenser tubes in service and electrochemical rotating disc electrode experiments based on mass transfer coefficients analogies is proposed in this article, where a reaction order of one has been found for the reduction of oxygen on copper base alloys, and the elementary anodic dissolution processes under flow conditions has been studied.
TL;DR: In this article, the role of corrosion deposits in influencing the near-threshold fatigue crack propagation behavior of 2XXX and 7XXX series aluminum alloys is examined in detail with the aid of X-ray photoelectron spectroscopy, scanning Auger spectrograms, and secondary ion mass spectroscopic analyses.
Abstract: The role of corrosion deposits in influencing the near-threshold fatigue crack propagation behavior of 2XXX and 7XXX series aluminum alloys is examined in detail. The composition, thickness, and distribution of fracture surface oxide films are characterized with the aid of X-ray photoelectron spectroscopy, scanning Auger spectroscopy, and secondary ion mass spectroscopy analyses. It is found that the extent of crack closure due to corrosion debris in aluminum alloys is strongly dependent on the composition and aging treatment. The results suggest that environmentally-influenced near-threshold crack propagation in some aluminum alloys is controlled by twoconcurrent andmutually-compctitive mechanistic processes: a dominant role of crack closure due to corrosion deposits (which tends toarrest completely the near-threshold crack) and a strong embrittling effect (which considerablyincreases near-threshold crack growth rates) concomitantly with the crack tip oxidation phenomenon in the moist medium. The near-threshold corrosion fatigue characteristics of aluminum alloys are contrasted with those in a wide range of steels in order to gain an insight into the various
TL;DR: In this article, the authors demonstrate the effects of shallow corrosion pits up to 250μm deep on the initiation offatigue cracking in both plain and notched specimens of a low-alloy steel.
Abstract: The initiation of fatigue cracks at corrosion pits has been responsible for the failure of a wide range of engineering components The present work demonstrates the effects ofcorrosion pits up to 250μm deep on the initiation offatigue cracking in both plain and notched specimens of a low-alloy steel Fatigue strength can be reduced by as much as 70% due to the presence of such corrosion pits The concepts of linear elastic fracture mechanics are used in an attempt to describe the development and growth of fatigue cracks from shallow corrosion pits
TL;DR: In this article, it is shown that the true corrosion current density can only be determined if the non-linearity of the system is avoided, which is not possible from analysis of a.c. impedance results without model assumptions.
TL;DR: In this paper, the performance of laser-glazed zirconia (containing 8 wt.% Y 2 O 3 ) thermal barrier coatings was evaluated in cyclic oxidation and cyclic corrosion tests.
TL;DR: In this article, the corrosion behavior of aluminum alloys containing lithium was investigated as a function of composition and aging and correlated with the microstructure, and the results showed that aging to peak hardness had little effect on the corrosion resistance.
TL;DR: In this paper, a mechanism of low-temperature hot corrosion is proposed based on rapid dissolution of the more noble metal or metal oxide in liquid salts. But it is not shown that the dissolution of cobalt oxides can prevent the formation of a protective Cr2O3 or A12O3 film.
Abstract: This paper presents a mechanism of low-temperature hot corrosion that is based on rapid dissolution of the more noble metal or metal oxide in liquid salts. It is proposed that the rapid degradation of cobalt-base alloys results from dissolution of cobalt or cobalt oxides on the surface, which prevents the formation of a protective Cr2O3 or A12O3 film. The reaction occurs in two stages: (a) an initial stage, during which an Na2SO4-CoSO4 liquid forms on the surface, and (b) a propagation stage, during which SO3 migrates inward and cobalt outward through the molten salt. At longer times, cobalt dissolves at the scale/salt interface and forms Co3O4 and/or CoSO4(s) in different regions of the reaction product. The mechanisms of transport of various reactants and products through the liquid salt and the effects of their relative transport rates on the reaction product morphology have been considered.
TL;DR: In this paper, the composition of the rust on the surface of steel panels was determined after atmospheric exposure times of 2 weeks, 2 months and 6 months, and it was shown that the dominant anion in these atmospheric corrosion experiments is sulfate.
Patent•
15 Apr 1982
TL;DR: In this article, a composite graphite and silicon carbide barrier was constructed to resist thermal shock and thermal expansion, and a new composition was formed by infiltrating aluminum phosphate into the graphite to form a single body of graphite.
Abstract: The invention provides a composite carbon or graphite having desirable properties such as corrosion and wear resistance. The invention combines a graphite substrate with a protective porous zone of silicon carbide. The whole body of graphite plus silicon carbide then is infiltrated with aluminum phosphate. An adhered barrier of silicon carbide, ranging in thickness between 0.015 and 0.050 inch thick is integrated with a graphite stratum to form a very hard surface, resistant to mechanical and chemical wear. The silicon carbide barrier is closely compatible to the graphite substrate, in resistance to thermal shock and in qualities of thermal expansion. In order to improve oxidation resistance further, a new composition was formed by infiltrating aluminum phosphate through the silicon carbide into the graphite to form a single body of composite graphite.
TL;DR: In this article, the authors determined quantitatively the corrosion fatigue life for three different types of corrosion behavior: passive corrosion, active corrosion and pitting corrosion based on corrosion kinetics and fracture mechanics.
Abstract: Based on corrosion kinetics and fracture mechanics, it has been possible to determine quantitatively the corrosion fatigue life for three different types of corrosion behavior. Under general, active corrosion, corrosion fatigue life is controlled by the corrosion rate and the applied alternating stress range. If pitting corrosion occurs, corrosion fatigue life depends on the incubation time for nucleating a pit, the pit growth kinetics, and a critical pit depth, which is a function of the applied stress range. It has been assumed that under passive corrosion conditions, the passive layer has to be penetrated by slip steps, to form corrosion fatigue cracks. The corrosion fatigue crack initiation in this case is controlled by the repassivation kinetics of the material and also by a critical notch depth, depending on the applied stress range. It has been found that a critical current density exists, below which no corrosion fatigue cracks can initiate. Comparison of the theoretically calculated life times with experimental results showed a quite good correlation.
TL;DR: In this article, the authors studied the stress corrosion cracking of a sensitized Type 304 stainless steel at room temperature using controlled potentials and two concentrations of sodium thiosulfate.
Abstract: The stress corrosion cracking of a sensitized Type 304 stainless steel has been studied at room temperature using controlled potentials and two concentrations of sodium thiosulfate. In both constant extension rate and constant load tests, the crack velocities attain extremely high values, up to 8 μm s-1. Scratching electrode experiments conducted at various pH values on simulated grain boundary material show that both the crack initiation frequency and crack velocity are closely related to the repassivation rate of the grain boundary material as expected on a dissolution-controlled mechanism; however, the maximum crack velocity at any potential is consistently about two orders of magnitude higher than that predicted from the electrochemical data. Frequent grain boundary separation ahead of the crack tip is thought to occur, but retarded repassivation of the grain boundary material is a necessary feature of the cracking. Effects of strain-generated martensite are discussed.