The Effect of Protective Coatings on the Oxidation Behavior of 6061Al/SiC Composite at High Temperatures

Abstract:

This paper analyses the effect of protective coatings on the oxidation behavior of 6061Al/SiC composite material at temperatures ranging from 500 to 800 K. Aluminum and AlCrN coatings are employed as protective coatings in order to improve the oxidation resistance of the composite. SEM, EDAX, XRD and oxidation measurement techniques are used to study the oxidation behavior and to characterize the composite specimens. Oxidation of the composite material without protective coatings is seen to be very rapid during the initial stages of exposure to the high temperatures but subsequently slowed down due to the formation of a protective surface layer of oxide. The oxidation was especially severe above 600 K. The interface between the matrix and reinforcement particles and the grain boundary regions of intermetallic precipitates in the matrix enhance this oxidation process since they provided sites for oxidation initiation. Aluminum coating on the composite obtained by DC magnetron sputtering technique and AlCrN coating obtained by low voltage electron beam evaporation technique reduce the oxidation rate effectively since the interface regions between the matrix and reinforcement, grain boundary regions of the matrix are unexposed to the atmosphere. Aluminum coating provides better oxidation resistance for 6061 Al/SiC composites.

• Periodical: Advanced Materials Research (Volumes 383-390)
• Pages: 3949-3953
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.383-390.3949
• Online since: November 2011
• Authors: N.K. Udayashankar, S. Rajasekaran, Jagannath Nayak
• Keywords: 6061Al/SiC Composite, AlCrN, Metal Matrix Composite (MMC), Oxidation Measurement

References

[1] Elomari S., Boukhili R., Skibo M.D., J. Mater. Sci. (1995) 30 3037.

[2] Fridlymander J.N., in: Metal Matrix Composites, Chapman and Hall, (1995) Oxford, p.15, Ch. 1.

[3] Elomari S., Boukhili R., Lloyd D.J., Composite Science and Technology (1996) 44 1873.

[4] Bowles R.R., Macini D.L., Toaz M.W., Proceeding of the Second Conference on Advanced Composites, ASTM International, Minnesota, MI, (1990) p.21.

[5] Nieh T.G., Karlak R.F., Scripta Metall Mater (1984) 18 25–28.

[6] Christman T., Suresh S., Acta Metall (1988) 36(7) 1691–1704.

[7] Suresh S., Christman T., Sugimura Y. Scripta Metall Mater (1989) 23 1599–1602.

[8] Chawla K.K., Esmaeili A.H., Datye A.K., Vasudevan A.K., Scripta Metall Mater (1991)25 1315–1319.

[9] Appendino P., Badini C., Marino F., Tomasi A., Materials Science and Engineering A (1991) 135, 275-279.

[10] Sharma S.C., Journal of Materials Engineering and Performance (2000) 9, 3, 344-349.

[11] Pardo A., Merino M. C., Arrabal R., and Feliu Jr S. Oxidation of Metals, (2006) 67, Nos. 1/2, P 67-87.