bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hot corrosion behaviour of Nimonic‐105 in NaCl and Na2SO4
Authors: Kameswari S. 
Published: May 2005

AbstractThe hot corrosion behaviour of Nimonic‐105 alloy was investigated in the presence of NaCl and Na2SO4 by employing the crucible test. The experiments were carried out in the temperature range 700°–800°C for periods of 2 to 20 hours. The end reaction products were characterised by the XRD, XRF, SEM, EPMA and chemical analysis techniques. Weight loss plots obtained in pure salts followed a linear rate law. However, the weight loss results obtained in salt mixtures indicated two zones of severe corrosion. The first zone occured in the presence of low concentrations of NaCl (1–5%) when the salt mixture was maintained in the solid + liquid (S + L) state and the other in the molten state, containing higher concentrations of NaCl (15–30%). Blisters and cracks were observed on the immersed surface of the corroded sample in the first zone and on the exposed top surface in the second zone. Both zones were occurred in the temperature range 700°–800°C, i.e., above the eutectic temperature (635°C) of the corrodent mixture and around the m.p. of NaCl (800°C). The heavy corrosion in the second zone was associated predominantly with voluminous formation of nickel coated Ni3S2 globules, and Na2MoO4. Denudation of alloying elements was observed due to preferential removal by the corrodents. The degradation of the alloy in the presence of corrodents is discussed.
High‐temperature alloys for long‐term service in chemical process industry applications
Authors: Rothman M. F. , Helm P. 
Published: May 2005

AbstractHAYNES® alloys No. 230 und No. 556 are new high‐temperature alloys for the chemical industry. 230TM alloy is used in nitric acid production, while 556TM is employed in waste incineration and complex aggressive process environments. Performance properties are discussed.
Corrosion and stress corrosion cracking of amorphous FeNiMoxB alloys in several neutral and acidic media
Authors: Angelini Emma , Zucchi F. , Antonione C. 
Published: May 2005

AbstractCorrosion and stress corrosion cracking behaviour of a series of amorphous iron alloys FeNiMoxB (x = 0, 2, 4, 8.5) has been investigated in several neutral and acidic media.In particular in aqueous solutions of ferric chloride, potassium tetrathionate and sulphuric acid containing chlorides stress corrosion cracking (SCC) has been studied by means of constant strain tests and corrosion rates have been evaluated by means of weight loss measurements. In several cases polarization curves have been recorded in order to clarify the electrochemical behaviour of the amorphous alloys. SEM observations of the fracture surfaces have been performed.It has been observed that the glassy alloys under investigation are susceptible to SCC at free corrosion potential in all the environments. SCC has been observed on specimens cathodically and anodically polarized in sulphuric acid containing chlorides. Hydrogen embrittlement can reasonably be considered responsible of the SCC phenomenon, except in sulphuric acid solution on specimens anodically polarized and in iron chloride solution.A deleterious effect of molybdenum has been noted on the corrosion rates of unstressed specimens and on the time to failures of stressed samples.
Experiences with a high‐alloyed stainless steel under highly corrosive conditions
Authors: Olsson Jan , Grützner Horst 
Published: May 2005

AbstractThe paper emphasizes experiences from the chemical industry with a highly alloyed stainless steel, Avesta 254 SMO.A number of installations are reported where this 6 Mo austenitic stainless steel has been selected since conventional stainless steels have shown inadequate corrosion resistance. These installations are at the production of
– aluminium fluoride
– chlorate, sodium and potassium
– diamines
– synthetic fibres
– soda and at the recovery of
– solvents, viz. chlorinated hydrocarbons
– sulphur dioxide

Further the paper summarizes some experiences from the fabrication point of view.
Ambiguous Effect of cathodic polarization on crack growth as the general regularity of stress‐corrosion cracking of structural materials
Authors: Marichev V. A. 
Published: May 2005

AbstractThe present study is concerned with the possibility of using the ambiguous effect of cathodic polarization (AECP) on crack growth as a diagnostic tool for determining the role of local anodic dissolution and hydrogen embrittlement in the mechanism of stress‐corrosion cracking (SCC) of different structural materials, irrespective of their base, microstructure and strength. It is shown that AECP is the general regularity of SCC and that the unambiguous effect of polarization (either the acceleration or retardation of crack growth irrespective of loading conditions) may be viewed as a particular case of this general regularity.
Anomalous isotope effects during hydrogen embrittlement of structural materials in electrolytes
Authors: Marichev V. A. 
Published: May 2005

AbstractThe critical stress intensity factors (KHE) in the case of hydrogen embrittlement of high‐strength steels, titanium and aluminium alloys in electrolyte solutions in ordinary and deuterium water and in their mixtures have been determined. Two anomalous isotope effects have been discovered: I ‐ the susceptibility of titanium and aluminium alloys to hydrogen embrittlement is higher in deuterium water than in ordinary water; II ‐ the KHE values for steels in mixtures of ordinary and deuterium water are higher than in ordinary water if the potential is increased. The possible reasons for these effects are discussed.
Contribution of the electrochemical impedance measurement technique to zinc corrosion inhibition studies in acid media
Authors: Troquet M. , Pagetti J. 
Published: May 2005

AbstractElectrochemical impedance measurements have been applied to zinc corrosion inhibition by phosphonium salts in acid media. The results described in this work point out that this method is not always suitable to provide valid information about the corrosion rate: zinc corrosion in acid medium which appears to be too fast a system.
Behaviour of Cu‐Ni alloys in natural sea water and NaCl solution
Authors: Crousier J. , Beccaria A.‐M. 
Published: May 2005

AbstractA series of Cu‐Ni alloys, ranging from 30 to 90% copper was studied by electrochemical methods in 3.5% sodium chloride solution and in sea water.The composition of the corrosion layer and of the solution after various immersion times was determined by chemical methods and X‐ray diffraction.The results are consistent with a corrosion process involving dissolution of copper and nickel enrichment at the surface. The corrosion resistance of all the alloys is better in NaCl solution than in sea water.
Electrochemical studies of Na2CrO4‐Na2So4 melts at 1200 K
Authors: Shi D. Z. , Rapp R. A. 
Published: May 2005

AbstractThe electrochemical response of Na2SO4‐Na2CrO4 solutions at a Pt working electrode was established by cyclic voltammetry and chrono‐potentiometry measurements at 1200 K. Experiments were made under conditions of controlled and electrochemically measured values of melt basicity for basic, neutral, and acidic melts. Despite the thermodynamic stability of chromite ions under reducing conditions, a direct conversion of chromate to chromite upon cathodic polarization was not observed. Rather, the cathodic reduction of chromate ions proceeds by a reversible one‐electron charge transfer to an electroactive intermediate species formed through an equilibrium between CrO and oxide ions in the solution.An irreversible chemical reaction reduces the chromium solute species further to precipitate a solid. As a solute in a corrosive fused salt film, a chromate to chromite transition would not be expected to stabilize the oxidation state and basicity. However, chromate ions to provide a reduction reaction more favorable than sulfate reduction to sulfide; chromate reduction leads to the precipitation of solid NaCrO2 or Cr2O3 in basic or neutral solutions, respectively. A large shift in melt basicity can only occur for mildly acidic solutions with high chromate solute.
KODABA – Ein Informationssystem für Korrosionsdaten
Authors: Schönfeld R. , Leicht R. , Luthardt G. , Wingender H. J. 
Published: May 2005

AbstractKorrosion und korrosionsbedingte Schäden verursachen erhebliche Sicherheitsrisiken und hohe Kosten. Zur Vermeidung bzw. Begrenzung benötigen Anlagenplaner und ‐betreiber Informationen über Art und Auftreten von Korrosionserscheinungen. Der Zugriff auf solche Informationen muß einfach und schnell erfolgen können. Das Informationssystem für Korrosionsdaten KODABA (abgeleitet von KOrrosions‐DAten‐BAank) ist ein leicht an die individuellen Belange eines Anwenders anpaßbares, benutzerfreundliches Informationssystem in Form einer Programm‐Shell zur Erfassung, Sammlung, Dokumentation und Archivierung von Korrosionsdaten verschiedenster Bereiche. Es ermöglicht einen leichten und schnellen Zugriff auf die archivierten Daten und verfügt über komfortable Recherchieroptionen sowie Benutzeroberflächen in drei Sprachen – Deutsch, Englisch, Französisch. Darüberhinaus stehen dem Benutzer eine Reihe von Optionen zur Aufbereitung, Interpretation und Dokumentation der Ergebnisse einer Recherche zur Verfügung. KODABA ist in den Sprachen FORTRAN, CLIPPER und C geschrieben und für den Einsatz auf IBM–kompatiblen Personalcomputern unter dem Betriebssystem MS‐DOS konzipiert. KODABA ist somit ein hilfreiches Instrument für alle, die sich mit Korrosionsproblemen befassen müssen.
Der Einfluß des Ga‐Gehaltes auf die Korrosionsbeständigkeit von NiCr20Mo 10Ga‐Dentallegierungen
Authors: Geis‐Gerstorfer J. , Sauer K.‐H. 
Published: May 2005

AbstractAn fünf experimentellen NiCr20Mo 10Ga Legierungen mit Ga‐Gehalten von 0, 5, 7, 10 und 15 Massen‐% wurde der Einfluß von Ga auf das Korrosionsverhalten in einer Lösung aus 0,1 M Milchsäure, 0,1 M Natriumchlorid und 0,005 M Kaliumthiocyanat untersucht. Als Untersuchungsmethoden dienten elektrochemische Messungen zur Bestimmung von ECORR, EP, iCORR, RP und analytische Messungen zur Bestimmung der Ionenabgabe. Die Ergebnisse zeigten übereinstimmend, daß die Korrosionsbeständigkeit von NiCr20Mo 10Ga erst ab Ga‐Gehalten von über 10 Massen‐% verschlechtert wird.
High temperature oxidation of rapidly solidified alloys
Authors: Schmutzler H. J. , Grabke H. J. , Emmerich K. , Frölich K. 
Published: May 2005

AbstractDuctile and microcrystalline thin Fe‐Cr‐Al foils with an elevated aluminium content up to 12 wt.‐% were produced by a rapid soldification process. Alloys with different compositions were tested in isothermal oxidation experiments (He‐O2, p(O2) = 133 mbar, T = 1273 K) and in cyclic oxidation experiments (dry air). The rapidly solidified alloys show a better oxidation resistance compared to conventionally rolled material. Cerium addition to the alloy leads to an improved oxide adhesion onto the substrate. The oxidation resistance is further improved by increasing the aluminium and decreasing the chromium content of the alloy.
Hot corrosion of α silicon carbide and β silicon nitride
Authors: Hancock P. , Chubb J. P. , Colenbie B. , Finnigan J. W. 
Published: May 2005

AbstractThe effect of hot salt corrosion on the room temperature fracture strength of reaction sintered α silicon carbide and β silicon nitride is investigated. Exposure is carried out using both spray and immersion tests in the temperature range 900–1100°C. The results show a significant reduction in fracture strength following exposure to sodium sulphate and sodium sulphate/chloride environments. Statistical analysis of the results using both cumulative probability and Weibull statistics gives improved data presentation to bar charts and student t tests.Fractographic examination of silicon nitride samples after exposure to sodium sulphate show the preferential attack of the binder phase between the lenticular grains. The mechanism of molten salt attack and methods of data presentation for safe load prediction are discussed. It is suggested that these ceramics be used to replace metals at current operating temperatures in contaminant conditions where they show superior corrosion resistance rather than to use them to increase operating temperatures.
Schutzschichten für Ti3Al gegen Hochtemperaturoxidation
Authors: Grahle P. , Fromm E. , Heine B. 
Published: May 2005

AbstractAls Hochtemperaturoxidationsschutz für das Titan‐Aluminid Ti3Al wurden Beschichtungen aus Aluminium und Aluminiumoxid durch Magnetronsputtern aufgebracht. Zur Prüfung der Übertragbarkeit ihrer Wirksamkeit wurde die effektivste Beschichtung auch auf der Titanlegierung TiAl6V4 abgeschieden. Die Beeinflussung der Oxidationsgeschwindigkeit durch das Aufbringen der Beschichtungen wurde in isothermen Glühungen an Luft bei Temperaturen zwischen 650 °C und 900 °C durch Verfolgung der Gewichtsänderung bestimmt.Ein Beschichten des Ti3Al mit 0,2 μm Aluminium reduzierte die Oxidationsgeschwindigkeit gegenüber der des unbeschichteten Grundwerkstoffs merklich. Sie lag sogar unter der des erheblich höher aluminiumhaltigen, unbeschichteten Titan‐Aluminids TiAl. Durch eine erhöhte Beschichtungsdicke von 0,6 μm konnte der Effekt weiter gesteigert werden. Die geringste Oxidationsrate jedoch wurde nach einem Beschichten mit 0,6 μm Aluminiumoxid verzeichnet. Eine Schichterhöhung auf 1,0 μm brachte hier keine weitere Verbesserung. Die Wirksamkeit der Beschichtung mit Aluminiumoxid ließ sich für kurze Prüfzeiten auch auf TiAl6V4 übertragen: Ein Beschichten mit 0,6 μm Aluminiumoxid senkte die Oxidationsrate bei 700 °C für 30 h auf einen Wert ab, der dem für unbeschichtetes Ti3Al nahe kam.
Ein Beitrag zum Korrosionsverhalten von austenitischem 17‐12‐2 CrNiMoTi‐Stahl in siedenden Essigsäurelösungen ‐ Betriebserfahrungen und Laborversuche
Authors: Duchardt J. , Grötsch G. , Schubert O. 
Published: May 2005

AbstractWie die Erfahrung essigsäureverarbeitender Betriebe mit Apparaten aus X 6 CrNiMoTi 17‐12‐2 (Werkstoff‐Nr. 1.4571) zeigt, ist der Werkstoff nur dann ausreichend beständig in siedender, konzentrierter Essigsäure, wenn das Medium gelösten Sauerstoff und geringe Mengen Wasser enthält und außerdem weitgehend chloridfrei ist.Auslagerungsversuche bei 118°C in konzentrierter Essigsäure mit unterschiedlichen Verunreinigungsgraden zeigten, daß der Werkstoff X 6 CrNiMoTi 17‐12‐2 dann passiv ist, wenn die Essigsäure Sauerstoff, weniger als 1 ppm Chlorid und einige Zehntelprozent Wasser enthält, wobei der Wassergehalt sich nach der Menge an Ameisensäure richtet, die in Spuren immer in Essigsäure enthalten ist. In wasserfreier Essigsäure ist der Stahl aktiv, und Sauerstoff erhöht seine Abtragungsgeschwindigkeit. Ab einer Chloridkonzentration von 1 ppm erfährt der Versuchswerkstoff bei Bedingungen, unter denen er sonst passiv ist, lokalisierte Korrosion, wobei überwiegend kristallographisch orientierter Angriff auftritt. In luftgespülten, siedenden Gemischen aus Essigsäure und Essigsäureanhydrid wird der Stahl bis zu einem Anhydridanteil von 70% stark korrodiert, darüber geht die Korrosion schnell zurück und verschwindet bei 97% Anhydrid nahezu vollständig.
Dithio‐oxamide as inhibitor of Copper corrosion in chloride solutions at various ph values
Authors: Monticelli C. , Brunoro G. , Frignani A. 
Published: May 2005

AbstractThis paper investigates the inhibiting properties of dithiooxamide (DTOA) towards copper corrosion in chloride media at different pH values. The aggressive solutions were prepared by dissolving 0.1 M sodium chloride in a Britton Robinson buffer, adjusted at the pH values of 3, 5, 7 and 9. The inhibitor was tested at the concentration of 10−3 M.The inhibiting efficiency of DTOA was evaluated after 20 days of immersion in the solutions at the temperature of 30°C. Both dc (polarization curves and voltammetric tests) and ac (electrochemical impedance spectroscopy, EIS) electrochemical tests were performed to elucidate the inhibition process.The results indicate that DTOA affords its best inhibiting efficiency at pH 5 and 7, but even at pH 3 it can retard the corrosion process. On the contrary, at pH 9 it stimulates the corrosion process. Between pH 3 and 7, the additive is reputed to form a protective film of Cu(II)DTOA salt, which is formed through a two step oxidative process, probably involving Cu(I)DTOA as an intermediate. The EIS analysis indicates that in chloride solutions copper fits a model of a partially blocked electrode. This analysis suggests that at pH 3 and 7 the film produced on copper by DTOA has a lower porosity than that of the oxide or cuprous chloride films formed in non inhibited solutions, thus hindering the mass transport through the layer.
Reactivity of the surface of zirconium during pickling in nitric‐hydrofluoric acid
Authors: Hlawka F. , Sutter E. M. M. 
Published: May 2005

AbstractThe behaviour of zirconium in hydrofluoric‐nitric acid pickling solutions has been studied using electrochemical methods, X‐ray diffraction and Raman spectrometry. During a pickling experiment the depletion of the solutions could be correlated with the consumption of hydrofluoric acid to form metal oxo‐ or oxofluorocomplexes. The role of nitric acid added to the hydrofluoric acid for pickling has been discussed after replacing it by other strong acids or by hydrogen peroxide. It appears that the zirconium dissolution rate only depends on the hydrofluoric acid concentration, but that the properties of the oxide film are determined by the nature of the strong acid added to HF; it can be assumed that metal dissolution occurs through the oxide film and that ionic diffusion through the film is a rate determining step.
Determination of upper Boundary pitting resistance potential values for austenitic stainless steels under corrosion fatigue
Authors: Eskelinen P. , Forsén O. , Spähn H. , Yläsaari S. 
Published: May 2005

AbstractIn this study Mode IV‐corrosion fatigue (CF) characterized by additional superposition of pitting corrosion was investigated. Corrosion fatigue and polarization experiments were carried out on three austenitic (17Cr–13Ni–5Mo–0.15N, 25Ni–20Cr–5Mo–1.5Cu and 18Cr–10Ni–2Mo–0.5Ti) stainless steels in 0.05 M sulphuric acid to which 20000 ppm Cl− was added. The CF strength decreased drastically when Mode IV‐conditions apply. The damaging effect of pitting corrosion in Mode IV was very pronounced. The relation between pitting, repassivation of the pits and Mode IV‐CF was investigated and it was found that for rotaing beam CF the measured repassivation potential represents a conservative upper boundary value below which mode II‐CF (i.e. CF under stable passivity) replaces Mode IV‐CF, when operating below stress ranges of 75% of the fatigue strength measured in air.
Korrosionsbeständigkeit von plasmagespritzten Aluminiumoxid‐ und Chromoxidüberzügen. Wirkung von NiCr und NiAl als Haftgrund
Authors: Kunkel J. , Stefan T. , Haskó F. 
Published: May 2005

AbstractDie Korrosionsbeständigkeit von plasmagespritzten Al2O3‐ und Cr2O3‐Schichten wurde in 3,5% NaCl und 10% NaOH geprüft, wobei auch die Wirkung von Haftgründen (NiCr und NiAl) auf die Schutzwirkung der Keramiken ermittelt wurde. Die Korrosionsgeschwindigkeit wurde mit mehreren Methoden bestimmt (Massenverlust, Korrosionspotential‐ und Polarisationswiderstandsmessung). Die beiden keramischen Schichten beiten danach wirksamen Schutz. Als Haftgrund ist in der alkalischen Lösung NiCr, in der NaCl‐Lösung NiAl besser.
The corrosion of iron and of three commercial steels in H2H2S and in H2H2S‐CO2 gas mixtures at 400–700 °C
Authors: Gesmundo F. , Viani F. , Znamirowski W. , Godlewski K. , Bregani F. 
Published: May 2005

AbstractThe corrosion behavior of three commercial steels including a carbon, a low‐chromium (2.25Cr‐1Mo) and a medium‐chromium (9Cr‐1Mo) steel in H2H2S and in H2H2S‐CO2 mixtures has been investigated at 400–700 C under two sulfur pressures at each temperature. The ternary mixtures had the same sulfur pressure as the binary gases, but also a small partial pressure of oxygen. The corrosion of pure iron in the same H2H2S mixtures was also studied for comparison. The scales formed on the steels were always composed of sulfides only: they showed a typical duplex structure as well as a strong tendency to crack and spall off during cooling. The corrosion kinetics of the steels were generally irregular, presenting an initial period of decreasing rate and a second approximately linear stage. On the other hand, the scales formed on iron were compact and well adherent to the metal, while the corrosion kinetics appeared to be generally controlled by a surface reaction step, leading to a transition from linear to parabolic behavior. The kinetics and mechanisms of scale growth for both iron and the steels are examined and discussed.
Tarnishing of AuAgCu alloys. Effect of the composition
Authors: Randin J. P. , Ramoni P. , Renaud J. P. 
Published: May 2005

AbstractThe tarnishing resistance of two AuAg binary, one AuCu binary, three AuAgCu ternary and one AuAgCuZn quaternary alloys was investigated using two accelerated tarnish testing procedures. The flower of sulphur test carried out in the gaseous phase and the Tuccillo‐Nielsen method performed in an aqueous liquid solution were used. The tarnished layers were characterized by colorimetric and coulometric measurements. For most of the alloys, the colour turned both reddish and yellowish after tarnishing. A linear trend was found between the colour change and the cathodic charge, indicating that the thickness of the tarnished layer is small enough to be in the range where the reflectivity is linearly related to film thickness. For the high‐silver alloys, the tarnished layer was thick enough to give rise to interference effects and therefore the tarnish is best characterized by the cathodic charge. It was found that the silver content is the dominant parameter influencing the tarnish resistance, but the copper content also plays a role. The tarnishing of AuAg binary alloys was interpreted as a quadratic function of silver content, while that of the ternary and quaternary alloys was found to be a simple additive effect of the silver and copper contributions.
Lining installation and performance in FGD systems
Authors: Goy Walter , Kaempffer Max 
Published: May 2005

AbstractAvailability and reliability of pollution control equipment have become important issues in recent years. Critical components such as scrubbers, ductwork, tanks, and stacks must be protected to withstand the corrosive environments that are characteristic for pollution control systems. Monolithic linings have been applied successfully in many flue gas desulfurization (FGD) systems. More than 4 million m2 of installed linings protect critical steel structures in pollution control to ensure high percentages of plant operation availability.Flake lining systems represent the most extensively used class of materials for materials for FGD linings for ducts, scrubbers, and stacks. Experiences with this type of material, which can be applied either by trowel or spraygun, date back to 1967 in the United States and 1978 in Europe.
Recent initiatives in the use of modern electrochemical instrumentation for FGD corrosion investigation and surveillance
Authors: Illsson T. , Eley C. , Mok W. Y. , Cox W. M. , Meadowcroft D. B. 
Published: May 2005

AbstractThe paper reviews the development of modern continuous corrosion surveillance technology during the past twelve years. Although originally developed to investigate corrosion behaviour in dry flue gas systems, the approach has found increasing use in other fields. Several recent applications in American flue gas desulphurisation (FGD) systems have confirmed its usefulness for the power generation industry.The paper presents a description of the instrumentation and reviews laboratory and in‐plant applications experience. The potential for future use to control corrosion and mitigate its effects in power generation and airpollution control systems is also discussed.