Microstructural and Mechanical Characterization of Alumina Coating on 07X16H6M Substrate

Abstract:

Alumina coating is given to a 07Х16Н6M stainless steel substrate, to withstand high frictional loads at elevated temperatures. Properties like high hardness, good adhesion and low thermal mismatch are essential for the coating. An 80%Ni-20%Cr bond coat is given for better adhesion of the alumina coating to the substrate. Air plasma spray technique was used for bond coat as well as the alumina coating.The substrate, bond coat and the alumina coating were characterized using optical microscopy, scanning electron microscopy (SEM) and nanoindentation. Hardness was evaluated using nanoindentation in all the three regions at loads varying from 2 mN in the bond coat to 50 mN in the alumina coating. Alumina coating showed the highest hardness of 11.5 GPa, followed by the bond coat – substrate interface having a hardness of 7.4 GPa. Substrate exhibited the least hardness of 6.3 GPa.

• Periodical: Materials Science Forum (Volumes 830-831)
• Pages: 667-670
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.830-831.667
• Online since: September 2015
• Authors: J. Srinath*, G. Sudarshan Rao, Deepak Dinesh, P. Ramesh Narayanan, S.C. Sharma, Koshy M. George
• Keywords: Alumina, Bond-Coat, Coating, Hardness, Nanoindentation

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