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Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 November 2007
DOI: 10.31399/asm.tb.htcma.t52080201
EISBN: 978-1-62708-304-1
.... The third environment, for which less data exists, contains either SO2 or O2-SO2 mixtures. chromium oxide oxygen activity sulfidation sulfur 7.1 Introduction Sulfur is one of the most common corrosive contaminants in high-temperature industrial environments. Sulfur is generally present...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 July 2000
DOI: 10.31399/asm.tb.fec.t65940183
EISBN: 978-1-62708-302-7
... the procedures for a wide range of alloys and environments. The examples also show how factors such as alloy concentration, crystal lattice orientation, temperature, and dissolved oxygen affect corrosion behavior. active-passive metals alloy systems anodic polarization cathodic polarization corrosion...
Image
Published: 01 July 2000
Fig. 7.33 (a) Schematic polarization curve for iron showing passivity (curve A), active corrosion (curve B), and for oxygen reduction (curve C). (b) Effective polarization curve (curve E) when pitting has activated 1% of the surface (Details can be found in text.) More
Series: ASM Technical Books
Publisher: ASM International
Published: 01 January 2000
DOI: 10.31399/asm.tb.cub.t66910021
EISBN: 978-1-62708-250-1
... not occur spontaneously. Active Behavior Another possible behavior is that the metal corrodes. A metal’s behavior is described as active when it corrodes in the solution. When active behavior is observed, the metal dissolves in solution and forms soluble, nonprotective corrosion products. Corrosion...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 August 2005
DOI: 10.31399/asm.tb.pb.t51230221
EISBN: 978-1-62708-351-5
... ]. As might be expected, metals with a higher oxygen affinity (i.e., more “active” in this context) make for superior brazes than more noble metals in this case. Fig. 7.9 Maximum strength of metal/alumina couples plotted as a function of the oxygen affinity of the braze 7.1.2 Chemical Reaction...
Image
Published: 01 November 2007
Fig. 5.21 Carburization rate constants of several Fe-Ni-Cr alloys at 1000 °C (1830 °F) in the test environment with a carbon activity of 0.8 and an oxygen potential such that SiO 2 is not stable as shown in Fig. 5.18 . Source: Ref 35 More
Image
Published: 01 July 2000
Fig. 6.4 Schematic experimental polarization curves (solid curves) assuming active-passive behavior for the individual metal-oxidation curve and Tafel behavior plus limiting diffusion for the individual dissolved-oxygen and hydrogen-ion reduction curves (dashed curves) More
Image
Published: 01 November 2007
Fig. 5.19 Carburization rate constants of several Fe-Ni-Cr alloys at 825 °C (1520 °F) in the test environment with a carbon activity of 0.8 and an oxygen potential such that SiO 2 is stable (but not Cr 2 O 3 ), as shown in Fig. 5.18 . Source: Ref 35 More
Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.tb.ssde.t52310155
EISBN: 978-1-62708-286-0
.... Table 1 shows the factors by which additions of various elements to stainless steel (j) alter the thermodynamic activity of other alloying elements (i). Influence of alloying elements on the thermodynamic activity of carbon, nitrogen, sulfur, and oxygen Table 1 Influence of alloying elements...
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Published: 01 November 2007
Fig. 5.20 Carburization rate constants as a function of silicon content in the alloy for several Fe-Ni-Cr alloys tested at 825 °C (1520 °F) in the test environment with a carbon activity of 0.8 and an oxygen potential such that SiO 2 is stable (but not Cr 2 O 3 ), as shown in Fig. 5.18 More
Image
Published: 01 November 2007
Fig. 5.22 Carburization rate constants as a function of Ni to Cr + Fe ratio [Ni/(Cr + Fe)] for several Fe-Ni-Cr alloys tested at 1000 °C (1830 °F) in the test environment with a carbon activity of 0.8 and an oxygen potential such that SiO 2 is not stable as shown in Fig. 5.18 . Source: Ref More
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.tb.ssde.t52310019
EISBN: 978-1-62708-286-0
... 2 + / Fe is positive, then a net corrosion current i will flow, resulting in iron dissolution and consumption of oxygen gas according to the net reaction, 2Fe (S) + O 2 + 2H 2 O → 2Fe 2+ + 4OH − . The magnitude of this current will determine the rate or iron dissolution according...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 April 2004
DOI: 10.31399/asm.tb.ps.t62440103
EISBN: 978-1-62708-352-2
... that the filler metal wets and spreads over the component surfaces. However, this situation represents the ideal case because oxides and other nonmetallic species are usually present on surfaces that have been exposed to ambient atmospheres and these will interfere with or inhibit wetting and alloying. Any oxygen...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 January 2000
DOI: 10.31399/asm.tb.cub.t66910049
EISBN: 978-1-62708-250-1
... the stable corrosion products that will form. Thermodynamic concepts are referenced throughout this book to explain observed corrosion behavior. For example, copper will not corrode in a strong hydrochloric acid (HCl) solution if oxygen is not present; if oxygen is dissolved in the HCl, however, copper...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 July 2000
DOI: 10.31399/asm.tb.fec.t65940001
EISBN: 978-1-62708-302-7
... and precipitate compounds such as hydroxides, oxides, or sulfides. At sufficiently high temperatures, metals corrode in gases, particularly oxygen to form oxides. Whereas the mechanism in this case appears to be one of direct chemical attack, the mechanism may still be electrochemical in nature, with ions...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2015
DOI: 10.31399/asm.tb.cpi2.t55030025
EISBN: 978-1-62708-282-2
... is shown in Fig. 9 . The sulfidation behavior of alloy 800 at temperatures and oxygen and sulfur potentials representative of coal-gasification processes is illustrated in Fig. 10 to 12 . Additionally, as the oxygen and sulfur activities may vary in service, the tendencies for sulfidation and oxidation...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 August 2018
DOI: 10.31399/asm.tb.msisep.t59220009
EISBN: 978-1-62708-259-4
...) to minimize the effects of the change. Conversely, when the chemical potential or activity of a reactant is increased (by dissolving more oxygen in the steel, for instance) the reactions will change in the direction associated with the consumption of the reactant (to reduce the activity). Thus, basic slags...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 October 2011
DOI: 10.31399/asm.tb.mnm2.t53060369
EISBN: 978-1-62708-261-7
..., which can revert back to hydrated iron oxides (rust) in the presence of oxygen and water ( Fig. 15.1 ). In this example, the metal returns to its more chemically stable state from the reactions it has with the surrounding environment. Fig. 15.1 The corrosion cycle of steel Corrosion...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.tb.ssde.t52310027
EISBN: 978-1-62708-286-0
... steel differ thermodynamically from those in carbon steel because of the presence of high chromium concentrations. This lowers the activity of oxygen and sulfur, making them more soluble, as Table 1 indicates ( Ref 19 ). It also alters the efficiency of deoxidizing elements. Aluminum is a powerful...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 July 2000
DOI: 10.31399/asm.tb.fec.9781627083027
EISBN: 978-1-62708-302-7