Kinetics of high temperature oxidation of (Nb,Co,Cr)7Si6 and (Nb,Co,Cr)8Si7 silicide compounds

F. Zamoum; T. Benlaharche; N. David; R. Podor; M. Vilasi

doi:10.1016/j.intermet.2007.12.009

Kinetics of high temperature oxidation of (Nb,Co,Cr)₇Si₆ and (Nb,Co,Cr)₈Si₇ silicide compounds

F. Zamoum, T. Benlaharche, N. David, R. Podor, M. Vilasi

Univ.́ Henri Poincaré

Research output: Contribution to journal › Article › peer-review

Abstract

Nb₃Co₃CrSi₆ (isostructural to Nb₃Fe₃CrSi₆) and Nb₄Co₄Si₇ (isostructural to Zr₄Co₄Ge₇) intermetallic compounds have been studied from the oxidation point of view. Isothermal oxidation results at 1300 °C are discussed. The volatilisation of the external chromia layer formed by oxidation on Nb₃Co₃CrSi₆ was quantified by analysing the thermogravimetric curves on the basis of the differential equation that describes the oxidation kinetics. Nb₄Co₄Si₇ is a typical SiO₂-forming compound with a parabolic oxidation constant k_p′ = 6 × 10^-13 g²/cm⁴ s. Nb₃Co₃CrSi₆ oxidises by formation of a duplex SiO₂-Cr₂O₃ layer but is mainly a Cr₂O₃-forming compound with k_p′ = 1.8 × 10^-11 g²/cm⁴ s and the linear volatilisation constant k_l′ = 1.85 × 10^-9 g/cm² s. Transformation of Nb₃Co₃CrSi₆ into Nb₄Co₄Si₇ slows down the diffusion of Cr towards the surface leading to an overall decreasing of the Cr₂O₃ formation rate.

Original language	English
Pages (from-to)	498-507
Number of pages	10
Journal	Intermetallics
Volume	16
Issue number	4
DOIs	https://doi.org/10.1016/j.intermet.2007.12.009
Publication status	Published - 1 Apr 2008
Externally published	Yes

Keywords

A. Silicides, various
B. Oxidation
C. Coatings, intermetallic and otherwise
G. Aerospace constructional uses

Access to Document

10.1016/j.intermet.2007.12.009

Cite this

@article{e56975064bdf4bd6822775b8d73f021d,

title = "Kinetics of high temperature oxidation of (Nb,Co,Cr)7Si6 and (Nb,Co,Cr)8Si7 silicide compounds",

abstract = "Nb3Co3CrSi6 (isostructural to Nb3Fe3CrSi6) and Nb4Co4Si7 (isostructural to Zr4Co4Ge7) intermetallic compounds have been studied from the oxidation point of view. Isothermal oxidation results at 1300 °C are discussed. The volatilisation of the external chromia layer formed by oxidation on Nb3Co3CrSi6 was quantified by analysing the thermogravimetric curves on the basis of the differential equation that describes the oxidation kinetics. Nb4Co4Si7 is a typical SiO2-forming compound with a parabolic oxidation constant kp′ = 6 × 10-13 g2/cm4 s. Nb3Co3CrSi6 oxidises by formation of a duplex SiO2-Cr2O3 layer but is mainly a Cr2O3-forming compound with kp′ = 1.8 × 10-11 g2/cm4 s and the linear volatilisation constant kl′ = 1.85 × 10-9 g/cm2 s. Transformation of Nb3Co3CrSi6 into Nb4Co4Si7 slows down the diffusion of Cr towards the surface leading to an overall decreasing of the Cr2O3 formation rate.",

keywords = "A. Silicides, various, B. Oxidation, C. Coatings, intermetallic and otherwise, G. Aerospace constructional uses",

author = "F. Zamoum and T. Benlaharche and N. David and R. Podor and M. Vilasi",

year = "2008",

month = apr,

day = "1",

doi = "10.1016/j.intermet.2007.12.009",

language = "English",

volume = "16",

pages = "498--507",

journal = "Intermetallics",

issn = "0966-9795",

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TY - JOUR

T1 - Kinetics of high temperature oxidation of (Nb,Co,Cr)7Si6 and (Nb,Co,Cr)8Si7 silicide compounds

AU - Zamoum, F.

AU - Benlaharche, T.

AU - David, N.

AU - Podor, R.

AU - Vilasi, M.

PY - 2008/4/1

Y1 - 2008/4/1

N2 - Nb3Co3CrSi6 (isostructural to Nb3Fe3CrSi6) and Nb4Co4Si7 (isostructural to Zr4Co4Ge7) intermetallic compounds have been studied from the oxidation point of view. Isothermal oxidation results at 1300 °C are discussed. The volatilisation of the external chromia layer formed by oxidation on Nb3Co3CrSi6 was quantified by analysing the thermogravimetric curves on the basis of the differential equation that describes the oxidation kinetics. Nb4Co4Si7 is a typical SiO2-forming compound with a parabolic oxidation constant kp′ = 6 × 10-13 g2/cm4 s. Nb3Co3CrSi6 oxidises by formation of a duplex SiO2-Cr2O3 layer but is mainly a Cr2O3-forming compound with kp′ = 1.8 × 10-11 g2/cm4 s and the linear volatilisation constant kl′ = 1.85 × 10-9 g/cm2 s. Transformation of Nb3Co3CrSi6 into Nb4Co4Si7 slows down the diffusion of Cr towards the surface leading to an overall decreasing of the Cr2O3 formation rate.

AB - Nb3Co3CrSi6 (isostructural to Nb3Fe3CrSi6) and Nb4Co4Si7 (isostructural to Zr4Co4Ge7) intermetallic compounds have been studied from the oxidation point of view. Isothermal oxidation results at 1300 °C are discussed. The volatilisation of the external chromia layer formed by oxidation on Nb3Co3CrSi6 was quantified by analysing the thermogravimetric curves on the basis of the differential equation that describes the oxidation kinetics. Nb4Co4Si7 is a typical SiO2-forming compound with a parabolic oxidation constant kp′ = 6 × 10-13 g2/cm4 s. Nb3Co3CrSi6 oxidises by formation of a duplex SiO2-Cr2O3 layer but is mainly a Cr2O3-forming compound with kp′ = 1.8 × 10-11 g2/cm4 s and the linear volatilisation constant kl′ = 1.85 × 10-9 g/cm2 s. Transformation of Nb3Co3CrSi6 into Nb4Co4Si7 slows down the diffusion of Cr towards the surface leading to an overall decreasing of the Cr2O3 formation rate.

KW - A. Silicides, various

KW - B. Oxidation

KW - C. Coatings, intermetallic and otherwise

KW - G. Aerospace constructional uses

U2 - 10.1016/j.intermet.2007.12.009

DO - 10.1016/j.intermet.2007.12.009

M3 - Article

AN - SCOPUS:40849095748

SN - 0966-9795

VL - 16

SP - 498

EP - 507

JO - Intermetallics

JF - Intermetallics

IS - 4