摘要:

AbstractDie Wasserstoffentwicklung an Titanhydriden erfolgt nach einem gekoppelten Entladung‐Rekombination‐Mechanismus, wobei zu berücksichtigen ist, daß ein Teil des sich entwickelnden Wasserstoffs in das Metall diffundieren kann. Die Geschwindigkeit der in mehreren Stufen ablaufenden Hydridbildung und Diffusion ist abhängig vom Bedeckungsgrad, der Rekombination der Wasserstoffatome und vom Wasserstofftransport in das Metall, der geschwindigkeitsbestimmend wird, wenn das System sich vom Gleichgewicht entfernt. Für die Untersuchungen (quasistationär und kinetisch) wurde auf dem Metall eine einheitliche Hydridschicht erzeugt, und zwar durch Beizen in konz. Salzsäure oder durch kathodische Polarisation. Die identifizierten Hydride ‐ TiH2, TiH und TiH1,96zeigen unterschiedliche Überspannung, die auch von der Gasbespülung be

ISSN:0947-5117    

DOI:10.1002/maco.19740250702

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY

摘要:

AbstractDespite the fact that combustion atmospheres in gas turbines are normally strongly oxidizing, microexamination of corroded alloys often not only reveals an anticipated external oxide scale and a degree of internal oxidation, but also a significant amount of sulphide phase(s), particularly after turbine operation in marine situations. Thus a degree of selective sulphidation as well as oxidation occurs. While the exact method of the further propagation of the corrosion product(s) is subject to doubt, it is possible that subsequent oxidation of these sulphide particles may be a factor. It is clear, however, that a necessary prerequisite for the reduction of this complex form of attack is the elimination of or control oh the sulphidation which occurs concurrently with oxidation. The theory underlying the possible development of sulphidation resistant alloys via. selective sulphidation of specific alloying element additions is reviewed. On this basis a number of alloying elements, which can form so‐called refractory sulphides of high melting point, and which hitherto have been largely ignored, are put forward in discussion as being potentially useful as additions to Ni‐based alloys for the inhibition of attack in sulphur/oxygen environments. In this assessment thermodynamic data for these refractory sulphides have been calculated and are quo

ISSN:0947-5117    

DOI:10.1002/maco.19740250703

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY

摘要:

AbstractDie Lochfraßkorrosion von Nickel wurde in Abhängigkeit von Zeit, pH, Potential und Konzentration in verschiedenen Salzlösungen gemessen. Dabei zeigt sich, daß die Lochzahl zeitlich von der Konzentration der Salze abhängt, wobei die Zeitabhängigkeit linear oder parabolisch sein kann. Die Potentialabhängigkeit der Lochzahl folgt wieder einem Expotentialgesetz. Von den untersuchten Salzen wirken vor allem die Chloride lochfraßerzeugend;. ihre Wirkung wird durch Nitrate teil‐ weise stark stimuliert. Auch Sulfate beeinflussen die Wirkung der Chloride, jedoch in verschiedenen Konzentrationsbereichen unterschiedlich. Aufgrund der Ergebnisse werden mögliche Mechanismen der Lochbildung und des Lochwachstum

ISSN:0947-5117    

DOI:10.1002/maco.19740250704

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY

摘要:

AbstractTaking into account the phase composition and morphology of the scales three groups of alloys may be distinguished. The first of them contains alloys forming monophase scales which constitute solid solutions of sulphides of both alloy components (AgCu type). The mte of corrosion of these alloys is a monotonous function of their composition, and the mechanism of scale formation depends on the geometrical configuration of the reaction system. The second group includes alloys the components of which form sulphides of limited mutual solubility or sulphides having spinel structures (FeCr type); the scale may then be a mono‐ or double phase one and the exact structure is a function of the concentration of the alloying element. The metals belonging to the third group form mutually immiscible sulphides (CuZn type). The scales form double layers, the external layer being made up by sulphides of the base metal, while the internal layer is a heterophase mixture of the sulphides of both alloy components. The kinetics and the mechanism of the corrosion of these alloys is largely independent from the atmosphere (elemental sulphur or H2H2S mixtu

ISSN:0947-5117    

DOI:10.1002/maco.19740250705

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY

摘要:

AbstractThe corrosion of Ni base alloys under molten ash deposits containing considerable quantities of alkali sulphates can take place as a sulphidation or oxidation. The former is very dangerous with respect to gas turbine operation since it gives rise to a decrease in strength of the materials; this type of corrosion is also predominant under thick layers of molten deposits at higher oxygen pressures, the effect being then increased by the poorer transport properties of the melt respect to oxygen diffusion. When cobalt sulphate is found in the ash the accelerated oxidation of Ni base alloys is due to the stable redox system Co+2/Co+2in the melt Increasing the acidity of the flue gases (increasing SO3content) enhances the corrosion rate and the solubility of corrosion products in the melt.

ISSN:0947-5117    

DOI:10.1002/maco.19740250706

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY

摘要:

AbstractThe carbamate turns out to be a good inhibitor of the corrosion of brass (80/20 and 59/41) in 0.5 N sodium chloride, 1.0 n sodium hydroxide and buffer solutions (NaOH and citric acid, pH 4.4‐6.0). The inhibiting effect depends on inhibitor concentration, so that in some cases corrosion may even be stimulated. The inhibitor effect is attributed to the formation of insoluble complexes with the two alloy component

ISSN:0947-5117    

DOI:10.1002/maco.19740250707

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY

ISSN:0947-5117    

DOI:10.1002/maco.19740250708

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY

ISSN:0947-5117    

DOI:10.1002/maco.19740250709

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY

ISSN:0947-5117    

DOI:10.1002/maco.19740250710

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY

ISSN:0947-5117    

DOI:10.1002/maco.19740250711

出版商:WILEY‐VCH Verlag GmbH    

年代:1974

数据来源: WILEY