Degradation of Aluminide Coatings in Fe-AI-Cr Alloy on the Isothermal Oxidation


Fe base superalloy has a good mechanical strength to be used as component operating at high temperaturewith oxidative environment. Although, the oxidation rate can not be tolerated as it will be oxidized and form oxide scaleof un-protective FeD. Coating is a proper solution that this alloy can be used at high temperature. In this research, packaluminizing on sample was conducted with temperatures of 900°C, 1000°C and I 100°C for 10 hours in inert (argon)environment and then an oxidation test was carried out at temperature of 650°C by an isothermal method for 10 hours inair environment. It was carried out an analysis for characteristics of coating and oxide scale formed in Fe-AI-Cr superalloy resulted from pack aluminizing. From this experiment, it was indicated by XRD analysis that the coating formedon substrate was a layer of FeAlz compound, other than coating it was found a diffused zone, where in this area itoccurred movement of Fe and Cr atoms from substrate toward coating, while Al atoms moved from coating to substrate.The increase of temperature of pack aluminizing process will affect settling rate of Al and coating growth.Keywords: Superalloy, pack aluminizing, isothermal oxidation.L. Juwital, D. H. Prajitno2, J. W. Soedarsono3, A. Manat1Materials Science Department, Indonesia University, JI. Salemba Raya 4, Jakarta /043, Indonesia.2Metallurgy Laboratory, PTNBR-BATAN, JI.Taman Sari 71, Bandung, Indonesia3Metallurgy Engineering Department, Indonesia University, Kampus UI Depok, Jawa Barat 16424, Indonesia4Materials Science Department, Indonesia University, JI. Salemba Raya 4, Jakarta 10430, Indonesia