bluuebunny/crossref_metadata_2025_split huggingface dataset:
Segregation studies of oxidized Y and Zr doped NiAl
Authors: Schumann E. , Yang J. C. , Rühle M. , Graham M. J. 
Published: May 2005

AbstractConventional electron microscopy, analytical electron microscopy, high resolution electron microscopy and high resolution SIMS have been used to investigate the effect of the reactive elements, Yand Zr, on the oxide scale formation on NiAl. Polycrystalline NiAl samples, doped with either 0. 1 wt% Yor 0.2 wt% Zr, were oxidized in air at 1200°C. 18O tracer experiments in conjunction with high resolution SIMS suggest that the reactive elements reduce the outward diffusion of cations. Energy dispersive X‐ray spectroscopy on a dedicated STEM showed that the reactive elements segregate to the grain boundaries in the oxide scale and to the metal/oxide interface. The amount at the oxide scale grain boundaries was calculated to be 0.2 monolayers for both Zr and Y doped NiAl. The amounts of segregation were calculated to be 0.15 monolayers (Zr‐doped) and 0.07 monolayers (Y‐doped) at the metal/oxide interface. The presence of sulfur was detected in Y‐rich particles in the NiAl close to the interface.
A combined approach: Isotopic exposure/SIMS analysis/SEM to Study the Early Stages of oxidation of β‐NiAl at 1473 K
Authors: Jedliński J. , Bernasik A. , Graham M. J. , Mitchell D. F. , Sproule G. I. , Borchardt G. 
Published: May 2005

AbstractThe early oxidation stages of unmodified and yttrium‐implanted β‐NiAl have been studied at 1473 K using sequential isotopic exposure (so‐called two‐stage oxidation) combined with low and high resolution SIMS analysis and SEM characterization.The scales growing on unmodified material comprised typically a cracked morphology with oxide ridges growing outward from the cracks. Some ridges were formed at the reaction temperature during the first oxidation stage and continued growing during the second stage. This resulted in a network of ridges on the outer surface of the scale.Two regions: non‐cracked areas and cracked round patches were observed in the scale on yttrium‐implanted β‐NiAl. No ridges but thin lace‐like oxide was formed in cracks and round particles extruded from some crack centres. No network was formed by the lace‐like oxide. Inward oxygen transport contributed significantly to the overall matter transport in the patches, while its contribution in the remaining scale was much less pronounced. The very thin outermost layer of most patches was enriched in Cr, which was present at a level of ca. 90 ppm only in the starting material. This finding is discussed in terms of the effect of Cr on the phase transformation of unstable aluminas into the stable β‐Al2O3.The results showed that the scales were inhomogeneous regarding both composition and microstructure. Therefore, only analytical methods having respectable sensitivity and resolution might be used to give reliable information regarding the growth mechanisms of scales. This applies to SIMS as well as to the electron microscopy methods.
Environmental cracking behaviour of the Precipitation hardened stainless steel, 17‐4 PH, under applied potential
Authors: Prasad Rao K. , Raja K. S. 
Published: May 2005

AbstractThe main aim of the work was to study the effect of applied potentials (both cathodic and anodic) on the environmental cracking behaviour of 17‐4 PH stainless steel material. For this a 1.5 mm thick 17‐4 PH sheet was taken and subjected to 1. solutionising (1050 °C, 45 min, air cooled) and 2. solutionising followed by aging treatments. Aging was carried out at 480 °C for 1 hr, 510 °C for 4 hrs and over aging at 550 °C for 2 hrs and 600 °C for 4 hrs. U‐bend samples were made according to ASTM standard G30‐79 for environmental cracking studies. Samples were tested in 3.5%, NaCl solution (pH = 2.0) under various applied potentials and the failure time at each potential was noted. Fractography was done using scanning electron microscope.Under the open circuit potentials both the solution treated samples and the over aged samples were found to be highly resistant to environmental cracking while the peak aged samples were found to be inferior. Under highly cathodic potentials, the over aged samples exhibited relatively better resistance than the other samples. At relatively less cathodic potentials, the solution treated samples, too, had better resistance. The peak aged samples failed very quickly by the application of cathodic potentials whether highly cathodic or not. Under the anodic potentials, the solution treated samples exhibited better resistance to cracking. Active path dissolution was found to be operative under anodic potentials while hydrogen absorption under cathodic potentials.
Neue Wege bei der zerstörungsfreien Korrosionsüberwachung von Rohrleitungen
Authors: Morgner W. 
Published: May 2005

AbstractDie einwandfreie Funktion von Rohrleitungen und Behältern ist eine wesentliche Voraussetzung für die Verfügbarkeit, Leistung und Sicherheit von Anlagen in der Chemie und Energieversorgung. Das Qualitätsmanagement dieser Rohrleitungssysteme umfaßt eine gründliche Iststandsanalyse einschließlich zerstörungsfreier Prüfung und des rechnerischen Festigkeitsnachweises mittels FEM, eine Lebensdauerprognose und daraus abgeleitete gezielte Instandhaltung. Moderne CAD‐Software ermöglicht es, die Ergebnisse der visuellen Kontrolle, der ZfP und der rechnerischen Absicherung direkt in der Isometric abzuspeichern und aus ihr wieder abzufordern. Es wird ein Ultraschall‐PC beschrieben, der als Notebook realisiert wurde und die beschriebenen Manipulationen vor Ort ermöglicht. Es wird auf Entwicklungen des corrosion monitoring unter Zuhilfenahme elektrischer Messungen. Polarisationswiderstandsmessungen, akustischen und elektrochemischen Rauschens hingewiesen.
Ein neuer Verfahrensansatz zur Früherkennung wasserstoffinduzierter Spannungsrißkorrosion
Authors: Lang M. A. , Altpeter I. , Dobmann G. 
Published: May 2005

AbstractDie durchgeführten Untersuchungen haben gezeigt. daß die Eindiffusion von Wasserstoff zu Veränderungen der mikromagnetischen Prüfgrößen führt. Dies läßt rich durch die Wechselwirkung magnetischen Struktur mit sich verändernden lokalen Eigenspannungsfeldern erklären. Damit ist prinzipiell eine frühzeitige Erkennung wasserstoffinduzierter Spannungsrißkorrosion vor der Rißentstehung möglich.
Einsatz des Wirbelstromprüfverfahrens zur zerstörungsfreien Bestimmung der Angriffstiefe von Korrosionsschäden an Flugzeug Tragflächenbeplankungen
Authors: Thomas H.‐M. , Casperson R. 
Published: May 2005

AbstractVorgesellt wind ein Prüfsystem zur zerstörungsfreien Bestimmung der Angriffstiefe von Korrosionsschäden vom Typ Muldenkorrosion und Lochfraß. Grundlage hierfür ist die Wirbelstromprüfung, wobei Meßsignale einer speziellen Tastsonde zu bildhaften Informationen zusammengetragen werden, die anschließend an einem PC‐Bildschirm quantitativ ausgewertet werden können. Das beschriebene Prüfsystem wurde für den Bereich der Betriebsüberwachung von Flugzeugen entwickelt. Als erster praktischer Einsatz wurde das System in Zusammenarbeit mit Daimler‐Benz Aerospace an Flugzeugen des Typs Tornado eingesetzt. Allgemein lassen rich die erreichten Ergebnisse auf andere Prüfsituationen mit vergleichbaren Schädigungsmechanismen übertragen. Aufgrund des Skin‐Effekts der Wirbelströme muß jedoch die Aussage auf den oberflächennahen Bereich beschränkt bleiben. Liegt das Prüfteil in Form von Blechen (auch geschichtet) vor, so ist eine Aussage für die zur Prüfsonde abgewandten, verdeckten Oberfläche(n) möglich.
Corrosion of bronze by acetic and formic acid vapours, sulphur dioxide and sodium chloride particles
Authors: Bastidas J. M. , Chico B. , Alonso M. P. , Mora E. M. 
Published: May 2005

AbstractThis paper studies the corrosion of patinated and unpatinated bronze by acetic and formic acid vapours, sulphur dioxide and sodium chloride salt particles, at 100% relative humidity. Weight loss, X‐ray diffraction, infrared and scanning electron microscopy were the techniques used. Acetic and formic acid vapours, sulphur dioxide and sodium chloride produce a high corrosion rate on bronze. In general, no protective effect was found by the patina on bronze. The principal compounds identified were Cu2O, Cu2S, Cu5(SO4)2(OH)6· 5H2O, Cu(CH3CO2)2· XH2O and Cu(HCO2)2.
Spannungsrißkorrosion an CuZn‐Legierungen in sulfathaltigem Leitungswasser
Authors: Allertshammer W. 
Published: May 2005

AbstractIm Zuge der Untersuchung eines Schadensfalles an einem α‐Sondermessing wird die Auslösung von Spannungsrißkorrosion durch Sulfate nachgewiesen. Zur Klärung der Zusammenhänge wurden Auslagerungsversuche in 10%iger Na2SO4‐Lösung und Leitungswasser durchgeführt und mit Literaturergebnissen verglichen.
Material performance in a solvent extraction Liquefaction plant in Japan
Authors: Fujikawa H. , Shida Y. , Miyuki H. , Maruyama N. 
Published: May 2005

AbstractCorrosion behaviour of various steels and alloys in the solvent extraction coal liquefaction process in Japan has been studied by the inplant testing in a 1 ton/ day plant and by the laboratory tests related to it. The severest corrosion was observed in the high pressure separator, corrosion thickness loss and pitting depth being the greatest and stress corrosion cracking being observed for 18–8 series austenitic stainless steels. The cause may be the occurrence of water condensate containing high Cl− and H2S. Otherwise corrosion was relatively mild. No obvious symptom of notorious organic‐chloride corrosion reported in the U.S. has been observed.
Effect of heat treatments on 8090 AlLi alloy pitting susceptibility in sea water
Authors: Beccaria A. M. , Traverso P. 
Published: May 2005

AbstractThe pitting susceptibility of 8090 Al‐Li alloy in sea water, after different heat treatments, was investigated.Free corrosion and electrochemical tests were carried out at 25°C, in quiescent sea water at pH = 8.2 and dissolved oxygen = 6.5 ppm.The microstructure was examined by metallographic microscopy and by X‐Ray microdiffractometry, while the corrosion layer was characterized by chemical methods and by Infrared and X‐Ray photoelectron spectroscopies.The following was observed:
aging treatments lead to a non homogeneous microstructure which increases the average corrosion rate as well as pitting susceptibility;
heat treatments do not affect the average passive film composition;
in all examined states, Al‐Li alloy 8090 is subject to localized corrosion which takes place preferentially at the grain boundaries.
A comparative study of benzotriazole and 2‐amino‐5‐mercapto‐1,3,4‐thiadiazole as Copper corrosion inhibitors in acid media
Authors: Bastidas J. M. , Otero E. 
Published: May 2005

AbstractIn this paper the corrosion behaviour of copper in 5% (by weight) citric, sulphuric and hydrochloric acids is studied. The efficiency of 2‐amino‐5‐mercapto‐1,3,4‐thiadiazole (AMT) as a corrosion inhibitor is compared with the use of benzotriazole (BTA). The experimental techniques were weight loss, polarization curves, polarization resistance and electrochemical impedance spectroscopy. AMT showed greater inhibition efficiency than BTA in sulphuric and hydrochloric acids. In citric acid AMT and BTA show a similar behaviour.
Systematic investigation on the corrosion of iron under conditions relevant to Storage of nuclear waste
Authors: Trefz J. , Schweinsberg M. , Reier T. , Schultze J. W. 
Published: May 2005

AbstractCorrosion tests were performed on steel samples in q‐brine (pH 4.9), and for comparison in phthalate buffer (pH 4.9) and borate buffer (pH 8.4) at 170°C for 30 h in an autoclave. The samples were subsequently investigated by a wide variety of electrochemical, optical and UHV methods. A systematical combination of both non‐modifying and modifying methods was employed to allow for all measurements to be performed on a small number of samples.In borate buffer (pH 8.4), a thick (200 nm), homogeneous passivating oxide layer is found to build up on iron under test conditions (170°C, 30 h), resembling the anodic oxide layer (+ 1 V, 25°C) with respect to its optical and n‐semiconducting properties. No evidence for a barrier‐type layer is found for samples treated in phthalate buffer (pH 4.9) at 170°C for 30 h. The iron surface is covered by a precipitate layer in this case. In the chloridic q‐brine, a precipitate layer of Mg‐Fe‐oxichlorides is formed and large‐scale active corrosion is observed.
Environmental effects on materials Effect of SO2 on the corrosion of unalloyed steel and weathering steel – an attempt to simulate Atmospheric Corrosion
Authors: Oesch S. 
Published: May 2005

AbstractLaboratory exposures of unalloyed steel and weathering steel have been performed in humid atmospheres and atmospheres containing sulphur dioxide in order to simulate atmospheric corrosion. No significant difference in the corrosion mechanism of the two steels was observed. At high sulphur dioxide concentrations (10 ppm) a large amount of iron sulphates was formed resulting in an unrealistic corrosion behaviour compared to atmospheric corrosion, while at lower concentrations (0.5 ppm) a more realistic behaviour was observed. The microstructures of the corroded surfaces were investigated by scanning electron microscopy (SEM/EDX). Corrosion products were analysed using X‐ray diffraction (XRD) and ion chromatography (IC). Results from gravimetric evaluation are also reported.
State of Intermetallics Development
Authors: Sauthoff G. 
Published: May 2005

AbstractA brief overview is given on the state of development of intermetallic alloys for high‐temperature applications with discussion of problems and prospects. In particular alloys on the basis of the titanium aluminides Ti3Al and TiAl, the nickel aluminides Ni3Al and NiAl, the iron aluminides Fe3Al and FeAl, chromides and silicides are regarded.
Oxidation of intermetallics – Japanese activity
Authors: Taniguchi S. 
Published: May 2005

AbstractOxidation studies on intermetallic compounds carried out in Japan in the last ten years have been summarized and critically reviewed. The major effort was expended to improve the oxidation resistance of TiAl‐base materials. The methods tried include alloying additions, surface treatments and combinations of the both. Alloying additions to TiAl were more closely reviewed here. An excellent oxidation resistance was obtained owing to the formation of Al2O3 scales by alloying additions of 0.2Zr, 0.2Hf or 500 ppm Cl, and by Nb‐ion implantation. Preoxidation under reduced oxygen pressures also resulted in the formation of protective Al2O3 scales. Ceramic coatings and MCrAlY type coatings showed some improvement in the oxidation resistance. Studies on other aluminides of current interest arc relatively few. On the other hand, studies on suicides arc becoming more active than before, though still few in comparison with TiAl‐base materials. In the concluding remarks directions for future studies are shown.
Hot Salt Corrosion of titanium aluminides
Authors: Nicholls J. R. , Leggett J. , Andrews P. 
Published: May 2005

AbstractThere is considerable interest in the use of γ‐TiAl within advanced gas turbines where they offer greater high temperature capability over conventional titanium at reduced weight. These factors would enable engines with greater thrust to weight ratio to be developed. Thus γ‐TiAl offers the potential of replacing nickel based alloys within the high pressure compressor and potentially the fourth stage turbine.Service in both of these locations would require that the γ‐TiAl be resistant, not only to oxidation, but hot salt corrosion. This paper presents a study of the hot salt corrosion resistance of γ‐TiAl over the temperature range 500–700°C.At 700°C, laboratory tests have shown that corrosion rates in a salt ladened environment are some 20X that of equivalent oxidation for exposures out to 100 h. The morphology of attack is consistent with a corrosion mechanism involving the vapour phase transport of aluminium from within the alloy and formation of a non protective oxide scale. A model for the corrosion mechanisms is presented, involving intermediate chloride phases. The mechanism is believed to be self sustaining, requires little chloride present, and leads to the observed accelerated oxidation rates.
Adsorption studies of water on copper, nickel, and iron using the quartz‐crystal microbalance technique: Assessment of BET and FHH models of adsorption
Authors: Lee S. , Staehle R. W. 
Published: May 2005

AbstractIn the atmospheric corrosion of copper, nickel, and iron, the adsorption of water affects the corrosion rates. Knowledge of water adsorption and metal oxyhydroxide formation is important in understanding the atmospheric corrosion process. The purposes of the present research were (1) to measure the adsorption of water on metal surfaces as a function of temperature and relative humidity (RH) and (2) to assess Brunauer‐Emmett‐Teller (BET) model and Frenkel‐Halsey‐Hill (FHH) model for water adsorption. In the present research, the quartz‐crystal microbalance (QCM) technique was used to measure the mass changes of copper, nickel, and iron at 0 to 100% RH and 7–90°C under nitrogen environments. Less water was adsorbed on copper, nickel, and iron which formed oxides than on gold. BET and FHH models could not fit the data points with single functional relationships. ΔH values were calculated using modified BET method and they decreased with temperature.
Corrosion resistance of TiN and MoN coated grey cast iron in acid solutions
Authors: Lunarska E. 
Published: May 2005

AbstractGrey cast iron containing 3.39% C, 2.76% Si, 0.37% Mn, 0.05 %, P and 0.005 % S, with different shape of graphite was covered with Mo and Ti nitrides by cathodic are plasma deposition method at 400°C. Incorporation of C from the substrate caused the formation of molybdenum carbide. Formation of diffused interphase layer due to incorporation of Mo into the substrate caused increase in the coating adhesion.Electrochemical measurements showed that H3PO4 and H2SO4 solutions penetrated to substrate through flaws in coatings, mainly occurred at the graphite particles. The local corrosion degradation of material was accompanied by hydrogen evolution and formation of microcracks. In the case of coated vermicular cast iron merging of microcracks led to falling off the pieces of coated material. The Mo containing coatings exhibited lower susceptibility to crack formation but higher susceptibility to environmental degradation than the Ti containing coatings. The highest protection in acid solutions provided the complex (Mo,Ti)N coating.
Untersuchungen zur Prüfung geschweißter NiCrMo‐Legierungen für Rauchgasentschwefelungsanlagen auf selektive Korrosion
Authors: Riedel G. , Kirchheiner R. , Heubner U. 
Published: May 2005

AbstractNiCrMo‐Legierungen finden dort Anwendung, wo eine sehr hohe Korrosionsbeständigkeit gefordert wird, sowohl in oxidierenden als auch in sogenannten reduzierenden Medien. Alle Standardtests für die Prüfung auf interkristalline Korrosion geben jedoch nur stark oxidierende Bedingungen vor. Es ist deshalb die Aufgabe gestellt, Testmethoden für die Prüfung auf selektive Korrosion in weniger stark oxidierenden Medien zu finden, wie sie in den bei der Rauchgasentschwefelung fossil befeuerter Kraftwerke auftretenden wässrigen Medien überwiegend gegeben sind. Mit diesem Ziel wurde das anodische Polarisationsverhalten der NiCrMo‐Legierungen C‐276, C‐4 und 59 in schwefelsauren Lösungen mit Zusatz strukturspezifisch wirkender Anionen wie SCN− and Cl− untersucht, wobei sowohl die lösungsgeglühten und sensibilisierten Knetwerkstoffe als auch mit artgleichem Zusatz und unterschiedlichem Wärmeeinbringen hergestellten Schweißverbindungen geprüft wurden. Es ergibt rich, daß im Aktiv‐Passiv‐Übergangsbereich der Werkstoffe zwischen dem Verhalten unterschiedlicher Wärmebehandlungszustände der NiCrMo‐Legierungen in Hinblick auf selektive und interkristalline Korrosion tatsächlich differenziert werden kann, allerdings nur unter exakt einzuhaltenden, werkstoffabhängigen Prüfbedingungen. Diese Prüfbedingungen entsprechen zwar dem weniger stark oxidierenden Charakter, wie er in den wässrigen Medien der Rauchgasentschwefelung vorliegt, Sind aber gegenüber einer praktischen Belastung wesentlich verschärft. Die rich erweisende unterschiedliche Anfälligkeit der verschiedenen Werkstofftypen und ‐zustände gegenüber selektiver Korrosion entspricht jedoch der praktischen Erfahrung. Im Fall eines über 8 kJ/cm hinausgehenden Wärmeeintrags beim Schweißen wird eine Tendenz zu verstärkter selektiver Korrosion der Schweißverbindungen am deutlichsten für die Legierung C‐276, gefolgt von der Legierung C‐4. Im Fall der Legierung 59 wird ein Einfluß des Wärmeeintrags beim Schweißen erst dann erkennbar, wenn die Streckenenergien bei so extremen Werten wie 6,2 kJ/cm einerseits oder 15,1 kJ/cm andererseits liegen. Die Legierung 59 erweist sich auch in dieser Hinsicht als die am wenigsten empfindliche NiCrMo‐Legierung.Obwohl die bisher erprobten Testbedingungen eine erste Annäherung an ein Prüfverfahren darstellen, welches den realen Bedingungen in Rauchgasentschwefelungsanlagen entspricht, erlauben ihre Ergebnisse keine Vorhersage des Korrosionsverhaltens der Werkstoffe unter solchen Betriebsbedingungen. Eine Bewertung im Sinn einer Rangfolge dürfte jedoch möglich sein.
The influence of various major and minor alloying elements on the corrosion of an Fe‐40 %Cr Superferritic stainless steel in sulphuric acid
Authors: Potgieter J. H. , Varga K. 
Published: May 2005

AbstractThe corrosion resistance of an Fe‐40%Cr superferritic alloy containing various major and minor alloying additions, e. g. nickel, molybdenum, aluminium, zirconium, nitrogen, niobium, titanium and ruthenium, as well as various combinations of them, was investigated in dilute sulphuric acid. Although small nickel and molybdenum additions alone cannot cause spontaneous passivation of the Fe‐40%Cr alloy to which they are added, a combination of these two alloying elements result in an Fc‐40%‐Cr superferritic stainless steel which can passivated spontaneously in dilute sulphuric acid. Further additions of minor alloying elements like Ti, Nb, Ru and N have an influence on the time required to achieve spontaneous passivation and the final open‐circuit potential eventually reached. Further additions of Al and Zr to the Fe‐40%Cr‐2%Ni‐2%Mo alloy did not have much of an effect on the final open‐circuit potential reached, and only affected the time required before this potential was reached in each case.
Korrosion von Bauelementen in der Mikroelektronik
Authors: Brand U. J. , Fröhlich Th. , Kohler St. , Bühler H.‐E. 
Published: May 2005

AbstractKorrosionserscheinungen an Bauteilen der Mikroelektronik treten aus unterschiedlichen Gründen auf und sind in der Literatur beschrieben. Sie werden nicht nur durch die Betriebsumstände hervorgerufen, sondern werden nicht selten auch durch die Fertigung begünstigt. Untersuchungen zum Ausfall mehrerer Platten, die in der Steuerungselektronik einer Fettaufbereitungsanlage für Großküchenabwässer zum Einsatz gekommen sind, wurden durchgeführt. Bei der licht‐ und elektronenmikroskopischen Betrachtung der ausgefallenen Platine wurden verschiedene Korrosionserscheinungen gefunden, die hauptsächlich an dem eingesetzten Lötwerkstoff auftraten. Aus diesem Grund sind an der als Lötstoff eingesetzten Zinn‐Blei‐Legierung unter Laborbedingungen potentiostatische Halteversuche und Versuche hei freier Korrosion mit Medien durchgeführt warden, welche die Schadstoffe der Umgebungsluft der Anlage in erhöhten Mengen beinhalten, um damit ein Aufkonzentrieren an den Oberflächen der Platine zu simulieren. Anhand der ermittelten Stromdichte‐Werte für verschiedene Potentiale und der Korrosionserscheinungen an den Proben werden Rückschlüsse auf den vorliegenden Schadensfall gezogen. Bei den unter Laborbedingungen durchgeführten Versuchen werden ähnliche Korrosionserscheinungen beobachtet, wie sie an den Bauelementen der ausgefallenen Platinen gefunden wurden. Es wird aufgrund der vorliegenden Ergebnisse Vermutet daß Lochfraß und selektive Korrosion der Sn‐Pb‐Legierung ursächlich für den Ausfall der untersuchten Platinen der Steuerungselektronik ist.