Development and Oxidation Resistance of Si-Modifide MCrAlY Coatings on Nb-Base Alloy


Article Preview

Halide-activated pack cementation and Air plasma spraying methods were utilized to deposit Si-modified MCrAlY coatings. Nb-base alloys were coated with MCrAlY by Air plasma spraying and followed by pack siliconizing process at 1100°C for 8h and 10h. The pack powders were consisted of 5 Wt.℅NH4Cl、35 Wt.℅Si、60 Wt.℅Al2O3. Si-modified MCrAlY coatings have three-layer microstructure. The outer layer was composed of NbSi2 and Nb3Ni2.4Cr1.6Si6, while the middle layer comprised the compound of Nb、Ti、Ni、Cr、Si. The inner layer adjacent to the substrate was silicide. Isothermal oxidation resistance of Si-modified MCrAlY coatings was tested at 1250°C in static air. Si-modified MCrAlY coatings had excellent oxidation resistance, because continuous Cr2O3 and SiO2 scales which serve as obstacle of oxygen diffusion were formed after oxidation.



Materials Science Forum (Volumes 546-549)

Edited by:

Yafang Han et al.




X. X. Li and C. G. Zhou, "Development and Oxidation Resistance of Si-Modifide MCrAlY Coatings on Nb-Base Alloy", Materials Science Forum, Vols. 546-549, pp. 1721-1724, 2007

Online since:

May 2007




[1] R.A. Perkins and G.H. Meier, J. Mater., 42 (8) (1990) 17.

[2] P.J. Bania, J. Mater. , 46(7) (1994) 16.

[3] L. Gauer, S. Alperine, P. Steinmetz and A. Vassel, Oxid. Met. , 42(1994) 49.

[4] M. Vilasi, M. Francois, R. Podor and J. Steinmetz, J. Alloys Comp., 264(1998)244-251.

[5] Bewlay BP, Jackson MR, Lipsitt HA. Metall Trans A 1996; 27A: 3801.

[6] Vilasi M, Francois M, Podor R, Steinmetz J. J Alloys Comp 1998; 264: 244.

[7] Mueller A, Wang G, Rapp RA, Courtright EL. J Electrochem Soc. 1992; 139: 1266.

[8] S. Priceman, L. Sama, Electrochem. Tech. 6(9-10) (1968) 315.

[9] A. Mueller, G. Wang, R.A. Rapp and E.L. Courtright, J. Electrochem. Soc., 139 (5) (1992) 1266.

[10] A. Mueller, G. Wang, R.A. Rapp, E.L. Courtright and Thomas A. Kircher, Mater. Sci. Eng., A155 (1992) 199. Fig. 6. (a) Cross-section of MCrAlY/Si-10h coating oxidized at 1250℃ for 100h and magnified (b) Oxide layer.