A combined study of the oxidation mechanism and resistance of AISI D6 steel exposed at high temperature environments

In this work it is thoroughly examined the oxidation performance of D6 tool steel under isochronal and isothermal oxidations. Isochronal oxidation tests, from ambient temperature to 1000 degrees C, revealed the oxidation rate of the coupons at different temperatures. Four different temperatures were selected for the isothermal oxidation test, which correspond to different oxidation rates. The oxidation and the examination of the samples were accomplished by thermogravimetric analysis (TG) in air with which the mass gain of the samples due to oxidation was simultaneously acquired. The samples were, also, examined by scanning electron microscopy (SEM), in order to observe their surface before and after the oxidation tests. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were used for the accurate identification of the as formed oxides. The results revealed that in every case two distinct layers of oxides were formed while their composition was different, depending on the temperature of oxidation. Furthermore, the thickness of the as formed oxides is increased when the oxidation is performed at higher temperatures. (C) 2011 Elsevier B. V. All rights reserved.