The Cross-Sectional Investigation of Oxide Scale FeCr Alloys and Commercial Ferritic Steel Implanted with Lanthanum and Titanium Dopants after Oxidation Test at 900°C

Abstract

The cross-sectional examinations of oxide scales formed by oxidation on the surface of FeCr alloys and Ferritic Steel that implanted with lanthanum and titanium dopants were observed and investigated. Scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS) has been used to study the cross-sectional oxides produced by specimens after oxidation process. X-ray diffraction (XRD) analysis was used to strengthen the analysis of the oxide scale morphology, oxide phases and oxidation products. Cross-sectional observations show the effectiveness of La implantation for improving thinner and stronger scale/substrate interface during oxidation process. The result shows that the thickness of oxide scales formed on the surface of La implanted FeCr alloy and ferritic steel was found less than 3 µm and 300 μm, respectively. The oxide scale formed on the surface of La implanted specimens consisted roughly of Cr2O3 with a small amount of FeO mixture. The oxidation resistance of FeCr alloy that implanted with Lanthanum showed better quality than that of commercial alloy. The beneficial effect of La implanted sample on the oxidation resistance was clearly visible to improve the adherence of oxide scale. Cross-sectional observations revealed the effectiveness of La implantation for improving thinner and stronger scale/substrate interface during oxidation process which presents the homogenous structure with good adherence and a uniform inter-diffusion layer between substrate and oxide layer.