Oxidation of Four NiAl-Ag Alloys at 900°C in 1 Atm O2


Article Preview

Small amounts of silver have been added to the intermetallic compound β-NiAl for the purpose of improving its mechanical properties. Four ternary NiAl-Ag alloys NiAl-0.5Ag, NiAl-1Ag, NiAl-5Ag and NiAl-10Ag (at.%), and an Ag-free β-NiAl have been oxidized at 900oC for 24 h in 1 atm O2 to study the effect of the presence of silver on the oxidation of β-NiAl. The kinetics of all the alloys were generally composed of two main parabolic stages with slightly larger parabolic rate constants for the second stage, except for NiAl-10Ag, which has an instantaneous parabolic rate constant decreasing with time. A continuous external layer of Al2O3 formed on all the alloys. In particular, the scales formed on NiAl-5Ag and NiAl-10Ag contained a thin and discontinuous layer of silver at the alloy/Al2O3 interface. Furthermore, NiAl-10Ag formed also isolated Ag particles or even a discontinuous Ag layer occasionally surmounting the Al2O3 scale. The addition of minor amounts of silver does not affect significantly the oxidation of β-NiAl, because silver is essentially present as a second phase due to its very small solubility in this intermetallic compound.



Materials Science Forum (Volumes 475-479)

Main Theme:

Edited by:

Z.Y. Zhong, H. Saka, T.H. Kim, E.A. Holm, Y.F. Han and X.S. Xie




X.J. Zhang and Y. Niu, "Oxidation of Four NiAl-Ag Alloys at 900°C in 1 Atm O2", Materials Science Forum, Vols. 475-479, pp. 775-778, 2005

Online since:

January 2005





[1] R. D. Noebe, R. R. Bowman and M.V. Nathal: Int. Mater. Rev. 38 (1993), p.193.

[2] D. B. Miracle: Acta. Metall. Mater. 41 (1993), p.649.

[3] J. L. Smialek: Metall. Trans. A9 (1978), p.309.

[4] M. W. Brumm and H. J. Grabke: Corros. Sci. 33 (1992), p.1677.

[5] M. W. Brumm and H. J. Grabke: Corros. Sci. 34 (1993), p.547.

[6] M. W. Brumm, H. J. Grabke and B. Wagemann: Corros. Sci. 36 (1994), p.37.

[7] H. J. Grabke and G. H. Meier: Oxid. Met. 44 (1995), p.147.

[8] S.L. Yang, F.H. Wang, Y. Niu and W.T. Wu: Mater. Sci Forum 369-372 (2001), p.361.

[9] J. Zhou and J. T. Guo: Mater. Sci. Eng. A 339 (2003), p.166.

[10] X. Zhang and Y. Niu: J. Mater. Sci and Technol., to be submitted.

[11] F. S. Pettit: Trans. Met. Soc. AIME 239 (1967), p.1296.

[12] G.C. Wood and F.H. Stott: Brit. Corros. J. 6 (1971), p.247.

[13] J. D. Kuenzly and D.L. Douglass: Oxid. Met. 8 (1974), p.139.

[14] F.H. Stott and G.C. Wood: Corros. Sci. 17 (1977), p.647.

[15] H.M. Hindam and W.W. Smeltzer: J. Electrochem. Soc. 127 (1980), p.1622.

[16] F. Gesmundo and Y. Niu: Oxid. Met. 50 (1998), p.1.

[17] F. Gesmundo and Y. Niu: Oxid. Met., submitted for publication.

[18] F. Gesmundo, Y. Niu and W. Wang: Oxid. Met. 56 (2001), 537.

[19] Y. Niu and F. Gesmundo: Oxid. Met. 60 (2003), p.371.

[20] Y. Niu, Z. L. Zhao and F. Gesmundo, M. Al-Omary: Corros. Sci. 43 (2001), p.1541.

[21] Z.L. Zhao, Y. Niu, F. Gesmundo, C.L. Wang, Oxid. Met. 54 (2000), p.559.

[22] Y. Niu, F. Gesmundo, F. Viani and W. T. Wu: Oxid. Met. 47 (1997), p.21.