Showing papers on "Corrosion published in 1970"
TL;DR: In this article, the authors used fracture mechanics techniques to measure the crack velocities in water as a function of applied stress intensity factor and temperature, and apparent activation energies for crack motion were obtained.
Abstract: Stress corrosion cracking of six glasses was studied using fracture mechanics techniques. Crack velocities in water were measured as a function of applied stress intensity factor and temperature, and apparent activation energies for crack motion were obtained. Data were consistent with the universal fatigue curve for static fatigue of glass, which depended on glass composition. Of the glasses tested, silica glass was most resistant to static fatigue, followed by the low-alkali aluminosilicate and borosilicate glasses. Sodium was detrimental to stress corrosion resistance. The crack velocity data could be explained by the Charles and Hillig theory of stress corrosion. It is probable that stress corrosion of glass is normally caused and controlled by a chemical reaction between the glass and water.
920 citations
TL;DR: The electrochemical behavior of reinforcing steel in stagnant alkaline solutions, especially calcium hydroxide, has been investigated in this paper, where it was found that the oxidation processes that take place on steel are determined by the degree of surface oxidation of the sample and by dissolved oxygen, but not by the type of cation present.
Abstract: The electrochemical behaviour of reinforcing steel in stagnant alkaline solutions, especially calcium hydroxide, has been investigated. It was found that the oxidation processes that take place on steel are determined by the degree of surface oxidation of the sample and by dissolved oxygen, but not by the type of cation present.In aerated solution, ferrosoferric oxide (Fe3O4) is the intermediate oxidation product on the steel surface while ferrous hydroxide is the intermediate product in de-aerated solution.In pure alkaline solutions, the critical pH above which stable passivity occurs is 11·5. This value increases when the alkaline solution is contaminated with aggressive ions or when reinforcing steel having mill-scale on its surface is used. A linear relationship holds between the pH of the alkaline solution and the highest concentration of sodium chloride that can be tolerated (CC1-): pH = n logCcc− + K where nand K are constants.Calcium hydroxide solutions prepared fronl water of different lo...
269 citations
TL;DR: In this paper, the anodic behavior of pure Al and some specially prepared Al-Cu alloys has been studied to check the mechanism of intergranular corrosion of aged Al-4%Cu.
251 citations
01 Jul 1970
TL;DR: In this paper, the Na2SO4-induced accelerated oxidation of nickel has been studied at 1000°C and it has been found that low oxygen activities in the Na 2SO4, which are produced by the formation of NiO, cause the sulfur activity of Na 2 SO4 to be increased.
Abstract: The Na2SO4-induced accelerated oxidation of nickel has been studied at 1000°C. It has been found that low oxygen activities in the Na2SO4, which are produced by the formation of NiO, cause the sulfur activity of the Na2SO4 to be increased. Nickel and sulfur from the Na2SO4 combine to form nickel sulfide and the oxide ion activity of the Na2SO4 is increased. The accelerated oxidation of nickel occurs because oxide ions react with NiO to form a nonprotective oxide scale. The accelerated oxidation of nickel is not self-sustaining since oxide ions are not produced when conditions in the Na2SO4 are no longer favorable for the formation of nickel sulfide.
226 citations
TL;DR: In this article, a defect structural model has been proposed which shows why the Cu2O formed on the Cu-Ni is more protective than that formed on Cu, and the defect structural models have been used to show that the Cu 2O films formed on two different types of alloys were quite protective and exerted significant ohnmic polarization on both anodic and cathodic local cell corrosion reactions.
220 citations
TL;DR: In this article, a theory for the pitting of Al, supporting air-formed or barrier-type anodic oxide films, in Cl− solutions is proposed, where the morphology and distribution of attack as pitting proceeds depend upon the changing relative cathode/anode area ratio on the electrode, as well as the degree of polarization of the anodic and cathodic processes.
190 citations
TL;DR: In this article, the role of the chloride ion in iron corrosion is assessed from the viewpoint of developing the concept that would lead to a general explanation, and experimental observations relating to...
Abstract: The role of the chloride ion in iron corrosion is assessed from the viewpoint of developing the concept that would lead to a general explanation. The experimental observations relating to ...
116 citations
TL;DR: Stress corrosion cracking in AISI 4340 steel was studied utilizing an Sb/Sb2O3 Ag/AgCl probe which simultaneously measured the crack tip electropotential and the electrolyte pH of the regi...
Abstract: Stress corrosion cracking in AISI 4340 steel was studied utilizing an Sb/Sb2O3 Ag/AgCl probe which simultaneously measures the crack tip electropotential and the electrolyte pH of the regi...
112 citations
TL;DR: In this paper, anodic inhibitors such as benzoate, chromate, nitrite, phosphate and stearate are added to a corrosive concrete medium to prevent the corrosion of reinforcing steel.
Abstract: Reinforcing steel, whether embedded in Portland concrete or Portland cement-blast furnace slag concrete and mixed with distilled or tap water, becomes passivated. On the other hand, when the concrete is mixed with sea water, the steel corrodes severely, and when Helwan mineral water is used for mixing, a borderline condition is obtained. Portland cement-blast furnace slag concrete had poorer corrosion resistance compared with ordinary Portland cement concrete.Steel passivity is not impaired when Portland cement concrete or Portland cement-blast furnace slag concrete is admixed with up to 8% of sulphates. However, when cement extract is used, the passivity is impaired when as little as 0·2% of sodium sulphate is added.Additions of some anodic inhibitors such as benzoate, chromate, nitrite, phosphate and stearate to a corrosive concrete medium are efficient in preventing the corrosion of reinforcing steel. The critical concentration for inhibition is higher in the case of Portland cement-blast furna...
104 citations
95 citations
TL;DR: The early stages of oxidation of Ni-base alloys in 1 atm O2 at 600°C have been studied by transmission electron diffraction and microscopy as mentioned in this paper, showing that significant amounts of NiO are produced before the steady-state, healing layer of the appropriate less-noble metal oxide is formed at the scale base.
01 Jan 1970
TL;DR: In this article, the authors define corrosion inhibitors as substances that inhibit one or more of the partial processes of the corrosion process as a whole, and define them as substances whose presence is not essential to the occurrence of an electrochemical process, but leads to a retardation of this process by modifying the surface state of the metallic material.
Abstract: In general, any phase constituent whose presence is not essential to the occurrence of an electrochemical process, but leads to a retardation of this process by modifying the surface state of the metallic material, will be called an inhibitor (this applies to electrolytic phases). Such modification of the surface state implies adsorption, the formation of “surface compounds,” or a reaction between the metallic material and the inhibitor with separation of the corrosion products at the contact surface of the metallic material with the electrolytic conductor.1 If we consider that corrosion is the degradation of a metallic material through the passage of its constitutive elements to a state of combination with surrounding materials, making particular reference to corrosion phenomena in electrolytic conductors, we can define corrosion inhibitors as substances that inhibit one or more of the partial processes of the corrosion process as a whole.
TL;DR: In this article, ellipsometric measurements were made during galvanostatic reduction of the passivefilms formed on Fe in a sodium borate buffer solution, and the composition of the film estimated from the results of ellipsometry, coulometry and chemical analysis of Fe2+ reductively dissolved from the film is represented as Fe2O3.
TL;DR: Even though cast vitallium did not exhibit passivity breakdown in the form of a pitting attack, polarization behavior between the behavior for stainless stell and pure titanium was observed and Pure titanium remained passive within the limits employed in this investigation.
Abstract: The corrosion resistance of materials employed for surgical applications was dertermined and compared by means of potentiostatic anodic polarization techniques. In a physiological saline solution the passive breakdown potential of stainless steel materials was dependent upon the oxygen content opf the solution, and the microstructure of the material. The breakdown is passivity was found to be due to a pitting type of corrosion attack. Pure titanium remained passive within the limits employed in this investigation. Even though cast vitallium did not exhibit passivity breakdown in the form of a pitting attack, polarization behavior between the behavior for stainless stell and pure titanium was observed.
Patent•
10 Dec 1970
TL;DR: A coating on a metal substrate of CrO3 and pulverulent metal in aqueous medium and containing particular organic liquid provides a corrosion and alkali resistant coating to the metal.
Abstract: A coating on a metal substrate of CrO3 and pulverulent metal in aqueous medium and containing particular organic liquid provides a corrosion and alkali resistant coating to the metal. The pulverulent metal, of which metal flake is of special interest, the liquids and the CrO3, typically all supplied by chromic acid, are mixed and applied to the metal substrate. The resulting coated substrates have electroconductivity, e.g., for application of electrocoating primer, after the application and baking of the coating composition on a substrate.
TL;DR: In this paper, the existence of a new phase, cubic FeS associated with tetragonal iron sulfide, Fe1 + xS, has been revealed, which has a sphalerite-like structure.
Abstract: Studies of the corrosion products of metallic iron formed in the absence of air oxidation in solutions of hydrogen sulfide have revealed the existence of a new phase, cubic FeS, associated with tetragonal iron sulfide, Fe1 + xS. This new phase is metastable and has a sphalerite-like structure.
TL;DR: In this paper, the acidity and the concentrations of metal ions in the solution within progressing stress-corrosion (s.c.) cracks in some alloy steels were estimated and it was found that the solution is always pH 3·6-3·8 near the crack tip regardless of the particular type of alloy steel.
TL;DR: A specific corrosion inhibitor for copper and copper alloys, called benzotriazole, is used in industry to reduce the corrosion of these alloys under both atmospheric and immersed conditions as discussed by the authors.
Abstract: Benzotriazole is a specific corrosion inhibitor for copper and copper alloys. It is now widely used in industry to reduce the corrosion of these alloys under both atmospheric and immersed conditions. Corrosion of copper may produce a surface stain or tarnish, pitting of surfaces of pipes or promote pitting of other metals, such as aluminium, which are in contact with dissolved copper in the water. Benzotriazole is used to reduce these forms of attack and the methods by which it is applied are discussed in this paper.
TL;DR: In this paper, the authors used precracked double cantilever beam (DCB) specimens to measure the resistance to stress corrosion cracking of 10 high strength aluminum alloys in a variety of heat treatment conditions.
Abstract: Resistance to stress corrosion cracking of 10 high strength aluminum alloys in a variety of heat treatment conditions has been measured using precracked double cantilever beam (DCB) specimens. A new technique is described, and stress corrosion crack growth rates for the alloys tested are presented as a function of the plane-strain stress intensity KI. Crack growth rates for alloys in the T3 and T6 tempers showed both KI-independent and KI-dependent behavior, whereas alloys in the more resistant tempers showed only KI independent behavior over the KI range studied. Double cantilever beam specimen data correlated with established trends from smooth specimens tested by alternate immersion in 3.5% NaCl solution. From the crack growth rate data and the speed and simplicity with which it is obtained, it is concluded that the DCB specimen will be highly useful for (1) comparing and rating alloys, (2) developing new alloys and heat treatments, (3) comparing the effects of environments, (4) achieving or e...
TL;DR: In this paper, the authors presented accelerated life data on several integrated circuit metallization systems including Al, MoAu, Ti-Pt-Au and a new system where the RF sputtered Ti: W layer is a pseudo alloy of 10-20 percent Ti in W. Life tests include total water immersion, high-pressure steam and 85°C/85 percent RH bias on bare and plastic-encapsulated devices.
Abstract: Accelerated life data are presented on several integratedcircuit metallization systems including Al, Mo-Au, Ti-Pt-Au, and a new system Ti: W-Au where the RF sputtered Ti: W layer is a pseudo alloy of 10-20 percent Ti in W. Life tests include total water immersion, high-pressure steam and 85°C/85 percent RH/bias on bare and plastic-encapsulated devices. Heat-age and resistivity-ratio data are presented showing the metallurgical stability of the Ti: W-Au system. The corrosion resistance decreases as Ti-Pt-Au > Ti: W-Au >> Mo-Au ? Al.
TL;DR: In this paper, it is proposed that the various localized forms of corrosion have the common feature of local acidification by hydrolysis and the acidity is viewed as having a responsible role in the self-perpetuating character of these corrosion forms.
Abstract: It is proposed that the various localized forms of corrosion (pitting, stress corrosion cracking, intergranular corrosion, crevice corrosion, filiform corrosion, tuberculation, and exfoliation) have the common feature of local acidification by hydrolysis. The acidity is viewed as having a responsible role in the self-perpetuating character of these corrosion forms. Three possible benefits of this rationale are offered.
TL;DR: Tungsten carbide is the only compound to have shown catalytic activity and sufficient resistance against corrosion in acid media under anodic polarization to act as an anode catalyst in low temperature fuel cells containing an acid electrolyte.
Abstract: NOBLE metals have been found to be the most suitable materials as anode catalysts for hydrogen oxidation in low temperature fuel cells containing an acid electrolyte. The one exception is tungsten carbide1, which is the only compound to have shown catalytic activity and sufficient resistance against corrosion in acid media under anodic polarization to act as an anode catalyst. In addition, tungsten carbide (WC) possesses a good electrical conductivity.
Book•
01 Jan 1970
TL;DR: The ocean environment (Factors affecting the corrosivity of seawater, Forms of corrosion); Corrosion of metals in the marine environment (Carbon steel, Low-alloy steels, Stainless steels), Nickel and nickel-base alloys, Cobalt, Copper and copper-base alloy, Titanium and titanium-base Alloy, Aluminum and aluminum base alloy, Beryllium, Magnesium, Special-Purpose metals, Cathodic protection); Designations and compositions of selected copper and aluminum alloys as mentioned in this paper.
Abstract: The ocean environment (Factors affecting the corrosivity of seawater, Forms of corrosion); Corrosion of metals in the marine environment (Carbon steel, Low-alloy steels, Stainless steels, Nickel and nickel-base alloys, Cobalt, Copper and copper-base alloys, Titanium and titanium-base alloys, Aluminum and aluminum-base alloys, Beryllium, Magnesium, Special-Purpose metals, Cathodic protection); Designations and compositions of selected copper and aluminum alloys.
TL;DR: In this paper, the role of sulphide inclusions in pit nucleation phenomena is discussed and it is shown that these are probably also the main sites for the Pit nucleation In Fe16Cr crystals of high purity.
Abstract: Electron microprobe analysis has shown that the corrosion pits in Fe13Cr and 25Cr20Ni commercial stainless steels nucleate only at the sulphide inclusions. These are probably also the main sites for the Pit nucleation In Fe16Cr crystals of high purity. The role of the sulphide inclusions in pit nucleation phenomena is discussed.
Patent•
28 May 1970TL;DR: In this paper, a method of and apPARATus for SUBSTANTIALLY PREVENTING CORROSION of GLASSWARE DURING WASHING THEREOF with a corrosion producing DETERGENT SOLUTION in a MECHANICAL DISHWASHER of the household type in which an ALKALINE DETERGent SOLUTION CONTACTS the GLASSware for CLEANING THTEREOF WHILE SIMULTANEOUSLY CONTACTing a PIECE OF METAL COMPRISING E
Abstract: A METHOD OF AND APPARATUS FOR SUBSTANTIALLY PREVENTING CORROSION OF GLASSWARE DURING WASHING THEREOF WITH A CORROSION PRODUCING DETERGENT SOLUTION IN A MECHANICAL DISHWASHER OF THE HOUSEHOLD TYPE IN WHICH AN ALKALINE DETERGENT SOLUTION CONTACTS THE GLASSWARE FOR CLEANING THEREOF WHILE SIMULTANEOUSLY CONTACTING A PIECE OF METAL COMPRISING EITHER ZINC OR MAGNESIUM OF A MIXTURE THEREOF.
TL;DR: In this paper, the dissolution rate of porous anodic oxide films formed on Al has been studied in (COOH) 2 solutions of different concentrations and temperatures, and it was demonstrated that the dissolution at the pore-base is enhanced by the applied electrical field across the barrier layer whereas the rate of dissolution from the pores does not change at all even when the current is interrupted.
TL;DR: In this article, the results of a program designed to investigate the above reports and firmly establish whether indeed electrochemical techniques can be used as valid accelerated tests in pitting• corrosion studies.
Abstract: For some years now, many workers have been active in the development of a stainless steel that is resistant to pitting and crevice corrosion in halide media. Electrochemical techniques combined with statistical multiple‐regression analysis have beeen used to derive a relationship between pitting susceptibility and chemical composition. Recent publications in the literature have suggested, however, that the use of electrochemical accelerated tests for pitting corrosion studies leads to erroneous conclusions about the pitting susceptibility of alloys. This paper describes the results of a program designed to investigate the above reports and firmly establish whether indeed electrochemical techniques can be used as valid accelerated tests in pitting‐ corrosion studies.Extensive experimental investigation in 1M sodium chloride on Type 430 stainless steel have shown an excellent correlation between electrochemical and chemical techniques, both in visually observed pitting susceptibility and metal weight loss data. Further, data obtained in 1M sodium chloride containing different dissolved gases have indicated why other authors failed to obtain any correspondence between electrochemical and chemical accelerated pitting tests. Values of the critical breakdown potential were found to vary from −0.035 VSCE to −0.185 VSCE for the same steel in saturated with oxygen and hydrogen, respectively.Controlled potential chemical tests have shown, that although pitting can occur at potentials active to the breakdown potential, the corrosion potential in a given redox system rises to values more noble than this latter potential, as a necessary prerequisite for pit initiation.
TL;DR: In this paper, the relationship between the intercrystalline corrosion and the precipitation of carbides of chromium has been proved by the theory of depletion, and it is indicated that studies of the subject relation are most conveniently made with the aid of extraction replicas or possibly thin metal foils as specimens for microscopy.
TL;DR: In this article, the anodic behavior of mild steel during yielding, at constant potential in various hotnitrate solutions, has been studied, and the influence of solution composition, pH, strain rate and electrode potential has been examined.