bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interkristalline Korrosionsrisse an einem Wellenkompensator aus nichtrostendem Stahl X6CrNiTi1810 bei Korrosionsbelastung durch Heißdampf/Dampfkondensat
Authors: Herbsleb G. , Renner M. , Schwaab P. 
Published: May 2005

AbstractRißbildung in einem Einlagen‐Wellenkompensator aus titanstabilisiertem Stahl Werkstoff Nr. 1.4541 (X6CrNiTi1810) wird auf Schwingungsrißkorrosion zurückgeführt. Der Rißverlauf war am Rißbeginn interkristallin, der transkristalline Restbruch zeigt Schwingungsstreifen. Ähnliche Schadensbilder, die unter Schwing‐belastung an austenitischen CrNi‐Stählen in Magnesiumchlorid‐Lösung erhalten wurden, werden im Schrifttum beschrieben. Es gibt jedoch Schadensfälle durch interkristalline Rißbildung in nichtsensibilisierten Gefügen titanstabilisierter ferritischer Chrom‐ und austenitischer Chrom‐Nickel‐Stähle in Hochtemperaturwasser, deren Ursachen bisher nicht aufgeklärt wurden.
Korrosion von glasfaserverstärkten Kunststoffen (GFK) in alkalischen Medien
Authors: Schmiemann A. , Ehrenstein G. W. 
Published: May 2005

AbstractBei der Korrosion von mechanisch belastetem GFK in sauren Medien kann es schnell zur gefährlichen Spannungsrißkorrosion kommen. Dies ist bekannt. Aufgrund mangelnder Anwendungsfälle fehlen jedoch grundlegende Untersuchungen in basischen Medien. In diesem Zusammenhang interessiert sowohl das Verhalten von einzelnen Glasfasern verschiedener Zusammensetzung als auch von damit hergestellten unidirektional verstärkten Rundprofilen mit duroplastischer Matrix. Als Standardmedium wird bei den Versuchen verdünnte Natronlauge (1 N = 4%) eingesetzt. Die Verbunde werden einer Biegebelastung im Medium ausgesetzt.Es stellt sich heraus, daß es sich bei der Alkalikorrosion von Einzelfasern wie auch von GFK um einen diffusionskontrollierten Abbau handelt. Dieser flächige, gleichmäßige Abbau, dem im Fall der Verbunde auch die Matrix unterliegt, kann als weniger kritisch eingestuft werden als die Spannungsrißkorrosion in Säuren. Die Eigenschaften bleiben auch nach bestimmten Schädigungsfortschritten kalkulierbar. Geeignete Gegenmaßnahmen werden diskutiert.
Electrochemical methods of determining the susceptibility to localized corrosion in hardfacing materials exposed to decontaminating solutions for a liquid metal fast breeder reactor
Authors: Eremiaš B. , Stefec R. 
Published: May 2005

AbstractAgents commonly used as decontaminating solutions for liquid metal cooled fast breeder reactors include nitric acid and potassium permanganate (solution No 1) in combinatino with oxalic acid (solution No 2). Overlayed or sprayed hardfacing alloys used for the valves and accessoires of fast breeder reactors are less resistant to localized corrosino in these solutions and are generally inferior to AISI 316L stainless steel which is the substrate for the hardfacing. The corrosion mechanism acting on these alloys when exposed to the No 1 and No 2 decontaiminating solutions makes it possible to apply electrochemical techniques to ascertain the susceptibility to localized attack and to rapidly screen the degree of resistance in these environments.
Electrochemical investigation of the inhibiting properties of 2‐propyn‐1‐ol on carbon steel in hydrochloric acid
Authors: Kristóf T. , Salamon T. 
Published: May 2005

AbstractThe effect of propargyl alcohol (2‐propyn‐1‐ol) on the corrosion of carbon steel was studied in hydrochloric acid solutions of various concentrations (1, 2, 5%) at 40°C and 60°C. The rate of corrosion was measured electrochemically using a polarisation technique. The results obtained showed that the rate of dissolution of carbon steel is considerably decreased by propargyl alcohol in aqueous hydrochloric acid solutions at 40°C and 60°C. Capacitance measurements indicated that the inhibitor species are adsorbed to the steel‐solution interface to a greater extent in the range of negative polarisations. On the basis of impedance spectroscopy measurements the characteristics of the adsorption were separated from those of the electron transfer process. It was established that the chemical processes play an important role in the protecting effect of the inhibitor.
A comparison of the Corrosion behaviour of FeCrAlloy and MA 956 in simulated coal gasification atmospheres
Authors: Santorelli R. L. , Norton J. F. , Bregani F. 
Published: May 2005

AbstractThe corrosion behaviour of two advanced Fe‐based alloys, FeCrAlloy and MA 956, in both as‐received and preoxidized conditions, has been compared during exposure to H2‐CO‐H2O‐H2S gas mixtures. The tests have been performed at 600°C in three H2S‐containing atmospheres for exposure periods up to 1000 h. Weight gain measurements, metallography, X‐ray diffraction and SEM‐EDS analysis of the scales were carried out on the corroded specimens. The results show that the alloys developed mainly Cr‐based oxide scales in the lower H2S‐containing gas mixture whilst in the higher H2S‐containing gaseous environments, both the alloys suffered sulphidation attack. The presence of yttrium in the two alloys, either as a metallic element (in FeCrAlloy) or as an oxide dispersion (in MA 956), was found to influence the character of the Al2O3 scales developed during pre‐oxidation treatments resulting in an improved resistance to sulphidation attack in all the environments investigated. The study has highlighted some differences between the corrosion resistance of FeCrAlloy and MA 956 in the preoxidized form, resulting from changes in the physical properties of the Al2O3 layers.
Corrosion behaviour of Ni3Al alloys in SO2‐containing combustion gases
Authors: Forsén O. , Kaskiala M. , Tikkanen M. H. , Tavi M. 
Published: May 2005

AbstractThe high temperature corrosion behaviour of some nickel aluminides alloyed with zirconium or hafnium is presented. The corrosion tests were carried out in the temperature range 920 to 1010°C, both in air and in atmospheres containing sulphur dioxide, using a thermobalance. The results obtained in air show that all the nickel aluminides display sufficient corrosion resistance up to 920°C. Nickel aluminide alloyed with hafnium is more resistant than the aluminide alloyed with zirconium. The oxide layer on the specimens tested in air is always very thin, exhibits low porosity and consists mainly of Al2O3. Without controlled preoxidation these materials are rather susceptible to corrosion in atmospheres containing sulphur dioxide. The preoxidation in gas mixture containing water vapor and hydrogen markedly improves the corrosion resistance of these alloys. The corrosion implies the selective oxidation of nickel aluminides. The protective layer consists mainly of aluminium oxide and protects the base material also in atmospheres containing sulphur dioxide.
The pitting potential of aluminium in halide solutions
Authors: Baumgärtner Marianne , Kaesche H. 
Published: May 2005

AbstractThe pitting potential Up is an important characteristic of every pitting system. It separates the region of passivity where the metal is practically immune from the region of heavy localized corrosion attack. On the basis of our own experimental results on pitting corrosion in the aluminum/halide‐system, the present paper rediscusses fundamental questions concerning the pitting potential and the pitting process in general.At or above Up, pitting of pure aluminum in chloride solutions is the result of the combined action of single, short‐life tunnelling events, which themselves propagate discontinuously. The same type of attack, to a minor extent, also occurs down to potential values 300 mV below Up. Therefore, the pitting potential is neither a lower limit for pit nucleation nor for pit growth, but appears to be the threshold value where the inactivation of tunnels is just balanced by tunnel nucleation. Taking the direct halogenation of the aluminum surface as the decisive step involved in tunnel nucleation, the pitting potential is given by the sum of the equilibrium potential of the aluminum/aluminum halide‐electrode and the overpotential necessary for an appropriate nucleation rate to gurantee stable pitting. This pitting overvoltage has been evaluated, using the nucleation concept by Volmer, to calculate tunnel nucleation rate and experimental results on the life time of single tunnels. Values of the pitting potential calculated on this basis agree well with experimental results in chloride‐, bromide‐and iodide solutions. Only the case of fluoride pitting is different.
Elektrochemische Untersuchungen zur Korrosion von Nickelüberzügen
Authors: Gugau M. , Speckhardt H. 
Published: May 2005

AbstractDas Korrosionsverhalten von galvanisch abgeschiedenen Nickelüberzügen und von außenstromlos erzeugten Nickel‐Phosphor‐Legierungsüberzügen in wäßrigen Elektrolytlösungen mit für die Offsetdrucktechnik relevanten Anionen wird beschrieben. Als Standard‐Nickelwerkstoff wird für Grundlagenuntersuchungen Walznickel hoher Reinheit herangezogen, als Standard‐Elektrolytlösung dient 0,1 N Schwefelsäure.
Corrosion mechanisms of an AISI type 316L sintered stainless steel in sodium chloride solution
Authors: Fedrizzi L. , Crousier J. , Bonora P.‐L. , Crousier J.‐P. 
Published: May 2005

AbstractThe electrochemical behaviour of a sintered stainless steel and of a wrought AISI type stainless steel of the same composition were compared. The electrochemical measurements used were the evolution of the corrosion potential vs time, the anodic and cathodic polarizations and the current‐time transients. Comparisons were also performed for the sintered alloy before and after stabilization of the corrosion potential. The low corrosion resistance of the sintered stainless steel is due to the formation of a galvanic couple between the free surface and the inside of the interconnected pores. Hence the free surface is cathodically protected by the pores, but reciprocally the corrosion increases inside the pores where the reactive area is very large.
Erosion und Korrosion of metallischer Werkstoffe in feststoffhaltigen Wässern
Authors: Föuhl J. , Weißenberg T. 
Published: May 2005

AbstractDas Zusammenwirken bzw. die gegenseitige Beeinflussung von Erosion und Korrosion wurde an metallischen Werkstoffen in feststoffhaltigen Strömungsmedien untersucht. Prüfwerkstoffe waren Kohlenstoffstahl in unterschiedlichen Härtestufen, ferritischer Chromstahl, Austenit sowie eine Messinglegierung.Als Korrosionsmedium diente Deionat, saure (pH 4,5) und alkalische (pH 10) Lösung sowie salzhaltiges Wasser (3% NaCl). Quarzpartikel wurden als Abraivstoff verwendet, wobei Menge, Korngröße und Strömungsgeschwindigkeit variiert wurden. Zum Vergleich wurden Versuche in feststoffreiem Medium sowie bei Stillstandskorrosion durchgeführt.Je nach Werkstoff und Prüfbedingungen ergeben sich Beanspruchungsbereiche, in denen die mechanische oder korrosive Komponente dominiert, in einigen Fällen entsteht eine synergistische Wechselwirkung beider Mechanismen, die zu deutlich erhöhten Abtragsraten führt.
Intergranular corrosion and stress corrosion cracking of an aged AlCu alloy in 1 N NaCl solution
Authors: Wenzel G. , Knöurnschild G. , Kaesche H. 
Published: May 2005

AbstractThe susceptibility of an aged pure AlCu alloy with 4 wt% Cu to intergranular corrosion (IGC) and to stress corrosion cracking (SCC) has been studied in 1 N NaCl solution. For this purpose the time to failure of thin flat tensile samples under constant load has been determined in dependence of the electrode potential and compared with the electrochemical behaviour of unstressed samples.Below the pitting potential of pure aluminum in 1 N NaCl solution the tensile specimens never failed. Above this potential, failure did occur, and time to failure decreased with increasing electrode potential. Unstressed samples showed intergranular attack at potentials at least 40 mV higher than the pitting potential of pure aluminum.Metallographic examinations showed that mechanical stress accelerates the intergranular attack by a factor 10 to 100. Current densities calculated from the velocity of penetration under stress are in good agreement with values known from the pitting of pure aluminum.From the results obtained in this work the conclusion is that SCC of the aged AlCu alloy can be regarded as stress accelerated IGC.
Elektrochemische Aspekte der Erosionskorrosion in partikelhaltigen Strömungen
Authors: Ehmann I. , Heitz E. , Schnitzler A. 
Published: May 2005

AbstractStrömende, partikelhaltige Flüssigkeiten wirken je nach ihrer Korrosivität in unterschiedlicher Weise auf Metalloberflächen ein. Mit Hilfe elektrochemischer Messungen wird gezeigt, wie sich die Parameter der Erosionskorrosion auswirken. Als Korrosionssystseme dienen acht Eisenwerkstoffe, die in einer feststoffhaltigen Quencher‐Lösung einer Rauchgasentschwefelungsanlage exponiert werden.
Korrosion nichtrostender austenitischer Stähle in (kondensierender) chloridhaltiger Salpetersäure
Authors: Horn Elmar‐Manfred , Schoeller Klaus 
Published: May 2005

AbstractDie Parameter der Korrosion nichtrostender austenitischer Stähle und Nickelbasis‐Legierungen in chloridhaltigen Salpetersäuren werden beschrieben.Untersucht wurde das Korrosionsverhalten des nichtrostenden austenitischen Stahls W.‐Nr. 1.4306 als Salpetersäure‐Qualität in ESU‐Güte bei Beaufschlagung mit schwach chloridhaltigen Salpetersäure‐Kondensaten. Die Kondensate bildeten sich aus siedenden 6 bis 10 M Salpetersäuren mit 15 bis 45 mg Chlorid/1.Die errechneten Abtragungsraten sind mit < 1 μm/a zwar gering, jedoch ist ‐ vornehmlich bei nur geringer Kondensat‐Bespülung der Wärmetauscherflächen ‐ mit örtlichen Aufrauhungen und mit Lochkorrosion, meist unter rostfarbenen, chloridhaltigen Belägen, zu rechnen. Die Lochkorrosionsintensität nimmt mit steigendem Chloridgehalt der zu verdampfenden Salpetersäure‐Lösungen zu.An den aus W.‐Nr. 1.4306 und PTFE gebildeten Dichtflächen trat keine Spaltkorrosion auf.W.‐Nr. 1.4306 (in Salpetersäure‐Qualität und ESU‐Güte) ist bei den hier beschriebenen Anwendungen überfordert; es wird vorgeschlagen, nichtrostende Stähle mit verbesserter Chlorid‐Beständigkeit bei gleichzeitig hoher Salpetersäure‐Beständigkeit zu verwenden, wobei an die Stahlsorten X 1 CrNi 25 21 (W.‐Nr. 1.4335), X 2 CrNiMoN 25 22 2 (W.‐Nr. 1.4466) und/oder X 1 NiCrMoCuN 31 27 4 (W.‐Nr. 1.4563) gedacht wird.
Effect of halide ions on passivation and pitting Corrosion of copper in alkaline solutions
Authors: Allah A. G. Gad , Abou‐Romia M. M. , Badawy W. A. , Rehan H. H. 
Published: May 2005

AbstractThe passivity of copper in NaOH and borate buffer solutions containing chloride, bromide and fluoride ions was studied by using cyclic voltammetry and potentiostatic current transient measurements. At scan rates ≥ 20 mVs−1, the addition of halide ions does not nearly affect the cyclic voltammograms in the absence of pitting. But they differ considerably in presence of pitting. The pitting potential was found to depend on the solution pH and decreased linearly with increase of logarithm of halide ion concentration. The current transients in the passivity as well as in the pitting potential regions were analyzed. Before the pitting, i‐time curves were rather similar to those obtained in the plain solutions. At times > 20 seconds, the current varies linearly with the reciprocal of the square root of time indicating diffusional characteristics of the metal corrosion through the passive layer. In presence of pitting, the pitting current versus time relations fit the Engell‐Stolica equation.
Reduction in area and appearance of hydrogen‐assisted fracture surfaces of cathodically charged differnt Low‐alloy sulphur containing steels
Authors: Pyun Su‐Il 
Published: May 2005

AbstractThe present work is concerned with the role of sulphidic inclusions in hydrogen‐assisted cracking of low‐alloy steels with different sulphur contents. The steels were previously cathodically charged in sulphuric acid solution. Evaluating the susceptibility to hydrogen‐assisted cracking in terms of the reduction in area values, the high sulphur steel is less susceptible than the low sulphur steel. The fracture surface of the low sulphur steel appears rather brittle, with local quasi‐cleavage fractures around large intergranular fracture facets. In contrast, the fracture surface of the high sulphur steel is characterized predominantly by the microvoid coalescence mode, with a great number of manganese sulphide inclusions. The difference between the two sulphur steels is based upon the concept that the interfaces between sulphidic inclusions and matrix act as trapping sites for hydrogen and thus hydrogen is uniformly distributed over the sulphidic inclusions.
30 Jahre anodischer Korrosionsschutz
Authors: Gräfen H. , Kuron D. , Paulekat F. 
Published: May 2005

AbstractDie technische Anwendung des anodischen Korrosionsschutzes geht in das 4. Jahrzehnt. Eine zusammenfassende Darstellung der Entwicklung in den letzten 30 Jahren soll die Effizienz dieser Schutzmethode belegen.Durch den Einsatz des anodischen Korrosionsschutzes in Alkalilaugen sind an un‐ und niedriglegierten Stählen Schäden durch interkristalline Spannungsrißkorrosion, insbesondere in Anlagen der Aluminium‐produzierenden Industrie, nicht mehr aufgetreten.Mit der Einführung des anodischen Korrosionsschutzes können preiswerte passivierbare Werkstoffe (z. B. nichtrostende austenitische Stähle ‐ 1.4301, 1.4401) in Säureanlagen, insbesondere Schwefelsäureanlagen, auch bei hohen korrosiven Betriebsbeanspruchungen ohne Schäden durch abtragende Korrosion eingesetzt werden.Der anodische Korrosionsschutz ist ein Verfahren, das ein sicheres und wirtschaftliches Betreiben von Anlagen ermöglicht.
Verbesserter Schutz gegen Korrosion und Reibkorrosion für Luftfahrtwerkstoffe durch PVD‐Beschichtungen
Authors: Heine B. , Holbein R. 
Published: May 2005

AbstractZur Substitution des ökologisch bedenklichen Kadmiums als Korrosions‐ und Reibkorrosionsschutzbeschichtung für Luftfahrtwerkstoffe wurden PVD‐Beschichtungen auf Aluminiumbasis getestet. Neben Rein‐Al wurden Mg‐ und Li‐legierte Al‐Beschichtungen, in einigen Fällen zusätzlich überdeckt mit einer tribologisch aktiven Deckschicht, mit dem IBAD‐ und Are‐Verfahren auf dem niedriglegierten Stahl 1.7734, dem martensitischen Chromstahl 1.4548 und der Titanlegierung 3.7164 abgeschieden. Im Kondenswasser‐ und Salzsprühtest war der Korrosionsschutz für den 1.7734 durch Al‐, Al/AlMg3‐ und AlLi‐IBAD‐Beschichtungen infolge der relativ hohen Porosität dieser Beschichtungen und einer inhomogenen Mg‐ oder Li‐Verteilung in den Al/AlMg3‐IBAD‐ und AlLi‐IBAD‐Beschichtungen nicht zufriedenstellend. Durch die homogeneren Arc‐Beschichtungen AlMg3 und AlLi konnte ein langzeitiger Korrosionsschutz erzielt werden. Im Vergleich zu Cd‐beschichtetem 1.7734 konnte die Reibkorrosionsbeständigkeit durch eine AlLi/AlN‐Arc‐Beschichtung geringügig verbessert werden. Die Korrosionsbeständigkeit der elektrochemisch edlen Werkstoffe 1.4548 und 3.7164 im Kondenswasser‐ und Salzsprühtest wurde durch die Beschichtungen nicht beeinträchtigt. Die Reibkorrosionsbeständigkeit wurde im Vergleich zu einer Cd‐Beschichtung durch eine TlC/i‐C‐Beschichtung verbessert.
Prevention of transpassive dissolution of austenitic stainless steel counter electrodes in nickel based electrolytic coloring solutions for anodized aluminum
Authors: Çakir Ali Fuat 
Published: May 2005

AbstractIn low nickel ion containing, weak acidic, electrolytic coloring solutions for anodized aluminium, austenitic stainless steel counter electrodes dissolve transpassively. The role of nickel and cobalt ions in preventing the transpassive dissolution of AISI Type 304 and 316 austenitic stainless steel counter electrodes was investigated. Potantiodynamic polarization method was used. The test solutions were a buffer (29.66 g/lt boric acid), a buffered supporting electrolyte (32.6 g/lt boric acid + 26.18 g/lt magnesium sulphate heptahydrate + 14,95 g/lt ammonium sulfate) and the coloring solutions (supporting electrolyte with different nickel (27.6–101 g/lt as heptahydrated sulfate) and cobalt (33–166 ppm) content). The oxidation of bivalent nickel ions starts 200 mV lower than the transpassive dissolution of stainless steel. However, even a small amount of cobaltous ions (165 ppm) in the solution produces a much steeper oxidation peak on the top of the nickel oxidation current. In order to transpassively dissolve a stainless steel electrode in cobalt containing nickel solutions, anodic current must be greater than the combined oxidation peak of nickel and cobalt ions, otherwise the working potential of the stainless steel electrode is always kept at the passive region hence the transpassive dissolution is prevented.
Study of the chemical passivation of iron by phosphonates
Authors: Veres A. , Reinhard G. , Kálmán E. 
Published: May 2005

AbstractThe effect of some phosphonic acids (HMEP, NTMP, HEDP) on the chemical passivation of iron by dissolved oxygen in neutral aqueous solutions has been investigated. It has been shown that in the presence of phosphonic acids chemical passivation cannot be attained. This effect is due to the formation of soluble complexes as could be shown by the stability constants determined.
Breakdown of cadmium passivity in alkaline solution
Authors: El‐Rehim S. S. Abd , El‐Wafa O. Abou , El‐Wahab S. M. Abd , Rashwan S. M. 
Published: May 2005

AbstractThe electrochemical behaviour of a Cd anode was investigated in 0.05–2 M NaOH solutions by the potentiodynamic technique. The polarization curves exhibit active to passive transition prior to oxygen evolution. The threshold potential of the active dissolution is very close to the reversible potential of the system Cd/Cd(OH)2. X‐Ray diffraction and XPS measurements reveal that the passive layer is composed of both Cd(OH)2 and CdO. The influence of increasing amounts of Cl−, Br− or I− ions on the anodic behaviour of Cd in NaOH solution has been investigated. The halides stimulate the anodic dissolution in the active region and tend to break‐down the passive layer in the passive region, leading to pitting attack. The pitting potential shifts to more negative values with increasing halide ion concentration but to the reverse direction with increasing alkali concentration.
The austenitic manganese‐chromium steels resistant to stress corrosion cracking
Authors: Číhal Ing. V. , Přibil Ing. E. 
Published: May 2005

AbstractThe basic type of MnCr steels (composition 0.05Mn19Cr13) was found to be highly resistant to chlorides. Additions of titanium, niobium and vanadium did not impair resistance to stress corrosion cracking, but addition of nickel in excess of 0.5% appreciably impaired the resistance. The chemical composition of the stabilized steels was selected in such a way as to make the ferrite content as low as possible. The two stabilized steel grades ability to passivate was limited, also because of the presence of manganese; this makes these grades suitable only for less aggressive environments.The ferrite content can be controlled, or the chromium content increased for better corrosion resistance, only by adding another strong austenite‐former. Considering the adverse effect of nickel on the resistance to stress corrosion cracking, attention was given to manganese‐chromium grade modified with nitrogen and molybdenum.
Corrosion‐resistant special steels for flue gas desulphurisation plants
Authors: Roth P. 
Published: May 2005

AbstractA Flue Gas Desulphurisation system is a chemical plant‐using materials which have proven their reliability in the chemical industry. Stainless steels with high alloy contents are a good choice, offering advantages such as corrosion resistance, thermal stability, weldability and easy access for inspection.Of importance are the alloying elements molybdenum and nitrogen. A number of steel grades have been developed or modified specially for FGD systems, depending on the corrosive environment.A new high alloyed steel is described, along with recommendations for welding.