bluuebunny/crossref_metadata_2025_split huggingface dataset:
Untersuchungen zur Schwingungsrißkorrosion von Stählen in Meerwasser
Authors: Esdohr J. , Bohnenkamp K. 
Published: May 2005

AbstractEs wurden Versuche an CT‐Proben von zwei Stählen mittlerer Festigkeit zur Schwingungsrißkorrosion in synthetischem Meerwasser bei 10, 1 und 0,2 Hz durchgeführt. Die unteren Grenzamplituden der Spannungsintensität ΔK1 für Rißwachstum waren in Meerwasser ohne Polarisation und in gasförmigem Wasserstoff gegenüber Luft erniedrigt. Der Rißfortschritt je Lastwechsel war in der Regel bei der niedrigsten Frequenz am stärksten erhöht. In Meerwasser ergaben sich bei niedrigen Amplituden ΔK1 die relativ stärksten Änderungen. Mit kathodischer Polarisation gilt dies für einen schmalen mittleren Bereich, mit gasförmigem Wasserstoff für höhere ΔK1.
Stress corrosion cracking of weldments of AISI Type 316 stainless steel
Authors: Shaikh H. , Khatak H. S. , Gnanamoorthy J. B. 
Published: May 2005

AbstractThe weldments of AISI Type 316 stainless steel prepared by the tungsten inert gas (TIG) and manual metal arc (MMA) welding processes, were tested in a boiling solution of 5 M NaCl + 0.15 M Na2SO4(pH = 1.3) at an initial stress level of 200 MPa under the open circuit potential (OCP) and the impressed potential (IP) conditions using the constant load technique. Anodic polarisation above the critical cracking potential (CCP) which was determined by the OCP test, accelerated the stress corrosion cracking of both the weldments whereas slight cathodic polarisation below the CCP prevented it. The cracks initiated through pits in both the types of weldments under open circuit as well as impressed potential conditions. The TIG weldments cracked in the heat affected zone whereas the MMA weldments failed in the fusion zone at all potentials. At open circuit potential, the MMA weldments failed by the stress assisted dissolution of delta ferrite, while the TIG weldments failed by the TGSCC of austenite. On anodic polarisation, the MMA weldment failed by the dissolution of delta ferrite and intergranular SCC of austenite, while in the TIG weldments the cracks initiated and propagated in the intergranular mode in the austenite.
Expertensysteme für den Korrosionsschutz
Authors: Fischer Wulf , Mader Werner , Fohmann Lothar 
Published: May 2005

AbstractFür die korrekte Lösung von Korrosionsproblemen benötigt der Ingenieur ein umfangreiches Wissen über die Verknüpfung von Fakten aus den klassischen Gebieten Chemie, Metallurgie und Maschinenbau sowie empirisches und heuristisches Wissen. Experten auf dem Gebiet der Korrosion sind rar, und oft ist ihr Wissen nicht zur rechten Zeit und am rechten Ort verfügbar.Dies sind die Gründe für die jährlichen Verluste von 50 Mrd. DM in der BRD durch Korrosionsschäden, von denen 20% durch den Einsatz des heutigen Stands des Wissens eingespart werden könnten.Expertensysteme stellen ein geeignetes Mittel zur Bewältigung der oben angeführten Probleme dar. Im Jahr 1985 wurde deshalb damit begonnen, im Labor für Korrosionsschutztechnik das Expertensystem CORROS aufzubauen. Die Domäne von CORROS ist das Korrosionsverhalten des Korrosionssystems Wasser/metallische Werkstoffe.
The Oxidation of cobalt‐tantalum base alloys containing carbon
Authors: El‐Dahshan M. E. , Hazzaa M. I. 
Published: May 2005

AbstractThe oxidation of cobalt‐tantalum carbon alloys, containing 10 and 15 wt.% Ta and carbon in the range 0–1 wt%, was carried out in oxygen and air at atmospheric pressure at 900, 1000 and 1100°C. The alloys oxidised according to the parabolic rate law with activation energy of about 38 Kcal/mole. In general, the addition of tantalum decreases the oxidation rates, in comparison with cobalt and with the same mass of chromium added to cobalt. Again, the presence of carbon in the Co‐Ta alloys decreases its oxidation rates in comparison with carbon‐free alloys. The scales formed on Co‐Ta and Co‐Ta‐C alloys consist mainly of an outer layer of cobalt oxide, CoO, and an inner porous layer of mixture of oxides: cobalt oxide; CoO, tantalum oxide; Ta2O5, and solid solution of these two oxides; CoTaO4 at all temperatures in the range of 900°‐1100°C. The binary Co −10% Ta and Co −15% Ta show an internal oxidation along the internal phase, increasing of alloy tantalum content increases the density of the internal phase. The presence of carbon in the ternary Co‐Ta‐C alloys has little effect and there is no apparent preferential penetration along the tantalum carbide network. In contrast to carbide present in Co‐Cr‐C alloys, where these carbides were preferentially attacked, the outer scale was disrupted, due to the formation of carbon gaseous oxides.
Korrosionsbeständigkeit von CrNi‐Stahlguß (Typ 18/9 bzw. 18/13) mit erhöhtem Siliciumgehalt in konzentrierten Salpetersäurelösungen
Authors: Staronka Andrzej , Holtzer Mariusz 
Published: May 2005

AbstractDie Korrosionsgeschwindigkeit von CrNi‐Stahlguß Typ 18/9 und 18/13 mit verschiedenem Kohlenstoff‐(0,035 − 0,12%) und Siliciumgehalt (etwa 4%) wurde in Salpetersäurelösungen mit Konzentrationen von 27‐96% sowie mit Zusatz von Cr6+‐Ionen im Temperaturbereich etwa 25‐100°C untersucht. Dabei wurden auch mechanische Eigenschaften und die Struktur der genannten Stahlgußsorten bestimmt.Es wurde festgestellt, daß im Falle von Salpetersäurelösungen mit einer Konzentration von 80% und höher bzw. niedriger, aber mit Zusatz von Cr6+‐Ionen die Anwendung des CrNi‐Stahlgusses mit etwa 4% Silicium‐ und möglichst niedrigem Kohlenstoffgehalt erforderlich ist. Die Ergebnisse der Laboruntersuchungen wurden in der Industrie bestätigt.
High‐temperature internal sulphur corrosion of H 18 N 9 steel
Authors: Gasior Eugeniusz , Wilczyńnski Andrzej 
Published: May 2005

AbstractThe paper presents some results of investigations into the high‐temperature corrosion of the CrNiSi steel H 18 N 9 S in atmospheres containing sulphur and oxygen. Specimens of the steel H 18 N 9 S were exposed at various temperatures to an atmosphere containing 47% Argon, 50% hydrogen, 3% hydrogen sulphide and about 0.2% oxygen. Corrosion was connected with intense internal sulphidation. This process causes a decrease of the chromium content in the metallic matrix and, consequently, γ→α transformation.In the temperature range between 830–930°C the thickness of the external scale is by 6 to 10 times smaller than that of the internal sulphidation zone.
High temperature corrosion in gases with low oxygen partial pressure
Authors: Meadowcroft D. B. 
Published: May 2005

AbstractThe technological importance of the high temperature corrosion behaviour of metals in gases with a low oxygen potential and containing other oxidants is outlined. This indicates the wide interest in the role of sulphur and also chlorine compounds, their aggressiveness being such in low oxygen potentials that serious corrosion rates can occur even below 400°C. The scientific basis of our understanding of corrosion in such atmospheres is discussed, and applied to the case of corrosion in sub‐stoichiometric combustion products in pulverized coal boilers.
The development of silicon‐containing oxides during the oxidation of iron‐chromium‐base alloys
Authors: Stott F. H. , Gabriel G. J. , Wei F. I. , Wood G. C. 
Published: May 2005

AbstractThe influence of silicon on the oxidation of Fe‐14% Cr and Fe‐28% Cr has been studied at high temperature, with particular emphasis on the development and nature of the healing SiO2 layer. In general, silicon is a less effective addition than aluminium to these alloys in improving oxidation resistance because SiO2 grows at a lower rate than α‐Al2O3. Hence, silicon is a less successful oxygen secondary getter and development of a complete healing layer of SiO2 is less rapid than that of α‐Al2O3 on a corresponding aluminium‐containing alloy. Nonetheless, the addition of only 1% Si to Fe‐28% Cr causes a marked reduction in the overall oxidation rate, particularly by facilitating development of the Cr2O3 scale. Precipitates of SiO2 form at the alloy/scale interface. These grow inwards and laterally until they eventually link up to establish a continuous healing layer at the interface after several hundred hours exposure at 1000°C. Similar features are observed for Fe‐14% Cr‐3% Si but the healing SiO2 layer develops after a much shorter time for Fe‐14% Cr‐10% Si, due to the high silicon availability. In every case, the healing layer has been shown to be amorphous SiO2. Although this phase is very protective during isothermal oxidation, it is a site of weakness during cooling and scale spallation is very extensive from specimens where the SiO2 is continuous, with failure occurring cohesively within that layer.Ion implantation of silicon into Fe‐14% Cr and Fe‐28% Cr gives a reduced oxidation rate due to facilitation of a more rapid establishment of a Cr2O3 scale. Similar implantation of yttrium into the ternary alloys assists in development of the silicon‐containing oxide layer, possibly associated with an influence on the nucleation of the oxide precipitates in the early stages of exposure.
Wasserstoffinduzierte Spannungsrißkorrosion an der Schmelzgrenze zwischen einem niedriglegierten Stahl und hochlegiertem Schweißgut
Authors: Risch K. 
Published: May 2005

AbstractBei der Aufklärung eines Schadens wurde erkannt, daß entlang der Schmelzgrenze zwischen einem hochnickelhaltigen Schweißgut und einem niedriglegierten Stahl ein sehr schmaler Saum mit martensitischem Gefüge und hoher Härte vorliegt. Hier war es unter der gleichzeitigen Wirkung von eindiffundiertem atomarem Wasserstoff und einer mechanischen Beanspruchung zu Trennungen gekommen. Dieselbe Gefahr besteht auch am Übergang von unlegiertem Stahl zu einem Schweißgut auf der Basis austenitischer Stähle. Abhilfe durch eine Wärmebehandlung ist nicht möglich.
Molecular structure and efficiency of triazole derivates and other heterocyclics as Corrosion inhibitors for copper
Authors: Penninger J. , Wippermann K. , Schultze J. W. 
Published: May 2005

AbstractThe inhibition of copper corrosion by various triazole derivates, benzotriazole (BT) and other heterocyclic compounds is investigated to reveal the relation between molecular structure and inhibition efficiency. Measurements of weight loss yield the protection factor S depending on inhibitor concentration c, potential ε, pH and temperature T. Current potential curves i(ε) show that various processes are inhibited, for example the oxygen reduction or the anodic copper oxidation. Capacity measurements and XPS analysis, prove the formation of protective layers, the stability of which determines the applicability of the inhibitor under varying conditions. The influence of molecular structure is explained on the basis of electrochemical and surface analytical measurements. 3‐Amino‐5‐alkyl‐1,2,4‐triazoles (AAT) are the best inhibitors in the whole pH range since they can form molecular compound layers in neutral and alkaline solutions but heteropolar‐compound layer in acid solutions. An intermediate aliphatic chain length gives the best efficiency since it allows sufficient solubility on the one hand and an effective hydrophobicity of the inhibitor layer on the other. The influence of similar heterocyclic compounds is tested but they have much smaller efficiencies. Benzotriazole is comparable in neutral and weak alkaline solutions but it is less effective in acid solutions and fails at high temperatures.
Gegen Benzin, Kerosin und Mineralöle Beständige organische Werkstoffe
Authors: Hauffe Karl 
Published: May 2005

AbstractFür Bauteile, die mit Benzin, Kerosin und Mineralölen in Kontakt kommen, werden in zunehmendem Maße organische Werkstoffe eingesetzt, wie z.B. hochdichtes Polyethylen, Phenolharze, Polyamide, Polyester, Acrylharze, Epoxy‐ und Fluorcarbonharze, allein oder als Verbundwerkstoffe mit Glas‐, Kohlenstoff‐ und Aramidfasern. Im Automobil‐ und Flugzeugbau werden z.B. Benzintanks und Rohrleitungen aus hochdichtem Polyethylen und mit Asbest verstärktem Phenolharz verwendet. Ferner werden glasfaserverstärkte Polyester als Werkstoffe für Verteiler, Zündgehäuse, Getriebeabdeckung und Ventile im Automobilbau empfohlen. Polyvinylidenfluorid‐Hexafluorpropylen, ein Harz mit 65% Fluor, wird für harte Temperatur‐ und Korrosionsbedingungen, kurzzeitig bis 620 K, in Ölen und Treibstoffen im Flugzeug‐ und Raketenbau verwendet. Auch Polyformaldehyd ist ein gegen alkoholhaltige Kraftstoffe besonders beständiger Werkstoff. Neben seiner guten Beständigkeit gegen Kerosin und Motoröle ist teilfluoriertes Polyvinylidenfluorid auch resistent gegen UV‐ und β‐Strahlen und bietet sich daher als Werkstoff in der Raumfahrt an.
Mechanistic features of molten salt corrosion in coal fired boilers
Authors: Flatley T. , Latham E. P. , Morris C. W. 
Published: May 2005

AbstractIn general, the hottest outlet sections of both superheaters and reheaters in modern CEGB boilers are tubed in austenitic stainless steels. Experience over the last 10–15 years has indicated that molten salt fireside corrosion can significantly reduce design lives, corrosion rates being a function of

metal temperature
gas temperature
coal chlorine content
the tube's aerodynamic position
The characteristic visual features of this form of corrosion such as “classical” wastage flats, honeycomb pitting, and localised pitting at tube geometrical features such as weld beads, and lugs is described. Also discussed are some of the metallographic features of molten salt corrosion, including substrate carburization, internal oxidation/sulphidation and corrosion scale morphology.Whilst uncertainty remains in understanding the precise mechanism, the CEGB have adopted a pragmatic approach using new/alternative materials such as shields, coatings and co‐extruded tubes. However, such a policy may not be the most economic: for example, in some circumstances the alloy 50 Cr 50 Ni is required to give a guaranteed degree of protection. What is still required is the quantification of the role of Na, K, Cl etc. in fuel on deposition and corrosion rates, and the source and influence of carburization so that further operational control of this molten salt corrosion is available.
Corrosion behaviour of structural materials in sodium influenced by formation of ternary oxides
Authors: Bhatt N. P. , Borgstedt H. U. 
Published: May 2005

AbstractFast breeder reactors use liquid sodium metal as the coolant in their primary and secondary circuits. Corrosion behaviour and compatibility of structural materials in sodium at the operating temperature of the reactors has been found to be influenced by oxygen impurity in sodium even at parts per million level. The compatibility of structural materials in sodium influenced by oxygen in the liquid metals has been dealt with previously on the basis of formation of binary oxides of the solid metals. Since then many of the structural metals have been found to form ternary oxides in sodium. Several three phase equilibria and free energy of formation data for the ternary oxides of structural metals with sodium are reviewed in this paper. Threshold oxygen levels in sodium for the formation of binary oxides and ternary oxides on structural metals are derived from the relevant thermodynamic data. Many of the structural metals are found to form ternary oxides at much lower oxygen levels in sodium than required for the formation of respective binary oxides. Threshold oxygen levels in sodium for the formation of ternary oxides of major constituents of stainless steel are also presented. Corrosion behaviour of the structural metals and austenitic steels influenced by formation of ternary oxides is discussed.
The nature of crevice corrosion of aluminum in chloride solutions
Authors: Baumgärtner Marianne , Kaesche H. 
Published: May 2005

AbstractTo study crevice corrosion of pure aluminum, polished specimens partly covered with a glass foil were polarized potentiostatically in 1 N NaCl‐solution at potentials negative to the critical potential for stable pitting (pitting potential). For comparison, non‐crevice experiments were performed on polycrystalline and singlecrystalline material in neutral as well as acidified 1 N NaCl‐solution and in AlCl3‐solutions. Corrosion morphology was examined by scanning electron microscopy. In current‐time plots recorded during experiments on crevice corrosion, both an incubation and a propagation stage are discernible. If experiments were interrupted during the induction period, micropits were found inside the crevice. This unstable micropitting is detectable down to 0.30 V below the pitting potential. In contrast, during crevice corrosion propagation, the aluminum surface undergoes general attack. In a range of 0.2 V below the pitting potential, dimpled surfaces are produced. At more negative potentials, metal dissolution occurs crystallographically oriented. An identical behaviour was detected on unshielded samples polarized in the same potential range in both 1 N AlCl3‐ and acidified 1 N NaCl‐solution. Hence, the build‐up of an acidic electrolyte is considered the sufficient requirement for crevice corrosion initiation.
Microtunnelling during selective alloy dissolution and during pitting
Authors: Kaesche H. 
Published: May 2005

AbstractThe kinetics and the morphology of selective dissolution of alloys containing a noble component and of pitting of passive metals are discussed emphasizing common properties of both localized dissolution processes. Dealloying of CuAu(Pd)‐alloys and pitting of aluminum and aluminum alloys are considered as typical cases. Dealloying requires the nucleation of terrace site vacancy clusters, since easily dissolvable kink sites of screw dislocations are blocked by noble metal atoms. Pitting requires the nucleation of pores in the passive oxide film, which inhibits active metal dissolution. In both cases, rapid local crystallographic attack, ranging from etch pitting to very narrow tunnelling, is involved in the nucleation process. The term tunnelling is appropriate for all these events. While the scale of tunnelling events is much larger in the case of pitting compared with the case of dealloying, the calculation of the breakthrough potential of dealloying and of pitting is basically equivalent. Gross pitting, ending in the formation of macroscopic holes, is the result of localized renucleation of tunnelling events due to localized accumulation and hydrolysis of metal halogenide salt solution.
Spannungsrißkorrosion von Rohren aus INCONEL 600: Einfluß von Wärmebehandlung, NaOH‐Konzentration und Temperatur
Authors: Borello A. , Masci Domenica , Mignone A. 
Published: May 2005

AbstractEine Unterschung über den Einfluß der Wärmebehandlung auf das SpRK‐Verhalten von Rohren aus Inconel 600 in NaOH‐Lösungen bei 315 bis 360°C wurde ergänzt durch Untersuchungen über den Einfluß der NaOH‐Anreicherung unter Magnetitschichten; die dabei auftretenden Gefügeänderungen wurden mittels TEM nachgewiesen. Versuche mit C‐Ringen und mit langsamer Dehnung (slow strain rate, SSR) bei 10−6s−1 Dehngeschwindigkeit führten zu den gleichen Ergebnissen; REM‐Untersuchungen wurden zur Beurteilung der Bruchflächen ausgeführt. Dabei zeigte sich, daß Wärmebehandlung die Anfälligkeit für SpRK in Natronlauge bei hohen Temperaturen vermindert; insbesondere scheint die Wärmebehandlung bei 650°C/50h das SpRK‐Verhalten besonders wirkungsvoll zu verbessern.
Comparison of Different boiler tube materials and the corrosion resistance in burning of municipal waste
Authors: Forsén O. , Yläsaari S. 
Published: May 2005

AbstractThe aim of this paper is to investigate the corrosion risks in burning of pretreated municipal waste as additional fuel together with bark in a fluidized‐bed boiler. It was deduced that the burning of bark alone did not cause corrosion in the materials tested. When the waste was burnt the corrosion of steels was insignificant when providing that the surface temperature of material was below 300°C. When the surface temperature was over this temperature, the burning of municipal waste caused corrosion in the conventional boiler steel. The stainless steels were not corroded even in these conditions. The impact of waste combustion on flue gas releases was also studied.
Corrosion during incineration of a sulphur and chlorine bearing mixture of rubbers and plastics
Authors: Knights C. F. , Cavell I. W. , Phillips B. A. 
Published: May 2005

AbstractExposures of materials to conditions arising from the incineration of sulphur and chlorine bearing rubbers and plastics for up to 556 days have shown a clear ranking of resistant materials.At material temperatures of 1000°C, with daily cycling to room temperature, only ceramics, notably alumina and silicon carbide, had adequate resistance. At 900°C, with daily temperature cycling to room temperature, the most resistant alloys were the nickel‐based superalloys containing 16–19% Cr, and 2.9–3.4% of each of aluminium and titanium. These alloys were the most resistant under low and high air flow rates during incineration and to air/HCl mixtures. Somewhat less resistant were the cobalt −26% Cr alloys not containing iron.Sulphur attack was not prominent for these resistant alloys but was very apparent for the less resistant nickel alloys. Particularly aggressive components of the rubbers and plastics were the chloride levels and brass and lead contamination.A wide range of coatings were shown to be ineffective.
Korrosion von ölgefeuerten Zentralheizungskesseln
Authors: Koebel Manfred , Elsener Martin 
Published: May 2005

AbstractDie rauchgasseitige Korrosion von ölgefeuerten Warmwasserkesseln erfolgt je nach rauchgasseitiger Materialtemperatur überwiegend durch Schwefelsäurekorrosion oder durch Sauerstoffkorrosion:
– Bei Materialtemperaturen von 60°C und höher liegt reine Schwefelsäurekorrosion vor, und die Abtragungsgeschwindigkeiten liegen bei 0,1–0,3 mm/Jahr (auf Brennerlaufzeit umgerechnete Werte). Die Korrosionsprodukte bestehen aus löslichen Eisen(II)‐ und Eisen(III)sulfaten. Höhere Abtragungsgeschwindigkeiten können dann auftreten, wenn an den Korrosionsbelägen der Nachschaltheizflächen eine nennenswerte katalytische Schwefeltrioxidbildung stattfindet.
– Bei Materialtemperaturen von 40°C dominiert bereits der Mechanismus der Sauerstoffkorrosion, und die Abtragsgeschwindigkeit beträgt rund das Zehnfache (1,5–3 mm/Jahr, umgerechnet auf Brennerlaufzeit). Durch einen hohen Anteil an Eisenoxidhydraten, insbesondere Goethit (α‐FeOOH), lassen sich die gebildeten Korrosionsschichten nur schwer entfernen.
– Auch für sog. Nieder‐ und Tieftemperaturkessel mit konstruktiven Maßnahmen zur Anhebung der rauchgasseitigen Materialtemperatur werden deutlich reduzierte Standzeiten erwartet. Dies deshalb, weil diese Maßnahmen erst im Stationärbetrieb des Kessels voll wirksam werden.

Ein Teil dieser Ergebnisse wurde aus Messungen des Gewichtsverlusts an Korrosionsproben aus St 35.8 und Grauguß gewonnen, welche den Rauchgasen eines ölgefeuerten Prüfstandkessels ausgesetzt wurden. Wesentliche Erkenntnisse lieferten jedoch auch Feldmessungen des Schwefeltrioxidgehalts an etwa 30 im praktischen Einsatz befindlichen Kesseln.
Effect of preloading on corrosion fatigue of 70/30 brass
Authors: Wu D. 
Published: May 2005

AbstractThe effects of a single tensile overload and precycling load in air on subsequent corrosion fatigue cracking in 70/30 brass exposed to 1 M sodium nitrite solution were studied. A single tensile overload caused a decrease in subsequent corrosion fatigue crack propagation rate. Precycling load also showed retardation effects, depending on the load conditions for precycling and corrosion fatigue. A transsition from a higher mean stress for precycling to a lower mean stress for corrosion fatigue decreased corrosion fatigue crack growth rate, while an opposite transition did not appreciably change the corrosion fatigue crack propagations. The responses of bulk mechanical properties to a presingle overload and precycling load in air were measured, showing hardening which may probably be responsible for the observed retardation.