Kinetics Oxidation and Characterization of Cyclically Oxidized Layers at High Temperatures for FeMnSiCrNiCe and FeSiCrNi Alloys

Abstract

Conventional stainless steels are used in cyclic oxidation, but the high amount of Cr and mainly Ni increase the price of these alloys. The objective of the present study was to assess the cyclic oxidation resistance of FeSiCrNi and FeMnSiCrNiCe alloys in comparison to AISI 304 and AISI 310 stainless steels by evaluating the oxidation kinetics and using characterization techniques to determine the oxides formed. The alloys were melted in induction furnaces and cast in sand molds. Cyclic oxidation tests were carried out in an automated oven in cycles of one hour for heating and maintenance at high temperature (850, 950 or 1050 °C) and 10 minutes for cooling. To characterize the oxidized layers, X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDS) analysis were performed. The oxidation kinetics were determined. The results showed that the studied alloys presented better results than AISI 304 at 850 °C, but at 1050 °C, AISI 310 presented the best results. At 950 °C, the FeSiCrNi alloy presented layer detachment and FeMnSiCrNiCe presented a higher rate of mass variation than AISI 310, both without oxide detachment. For both alloys, formation of chromium and manganese oxides with parabolic rate of mass gain occurred.

Keywords

• Cyclic oxidation
• FeSiCrNi alloy
• FeMnSiCrNiCe
• Oxidation kinetics
• Layer characterization