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摘要
The oxidation behavior of TP439 stainless steel in water vapor was studied by means of intermittent weighing method, field emission scanning electron microscope (FE-SEM) and X-ray diffractometer. In the initial oxidation stage, the formed oxide scale of TP439 stainless steel is very thin, the oxidation rate is fast, the oxidation kinetics conforms to the linear oxidation law with a linear rate constant kl of 5.214×10-2, the oxidation process is controlled by the interface reaction; with the increase of oxidation time, the oxide scale gradually thickens, which hinders the inward diffusion of oxygen ions and the out-ward diffusion of metal ions, the control step of the oxidation process is changed from interface reaction control to diffusion control; the oxidation kinetics in the second stage follows a parabolic law with a parabolic rate constant kp of 1.54×10-3, the oxidation control step is diffusion control. The main components of TP439 stainless steel oxidation products are (Cr, Fe)2 O3 and a small amount of Cr2 O3, Fe2 O3, FeCr2 O4 spi-nel oxides. In the early stage of oxidation, there are more oxide particles distributed along the grain boundary on the surface of the steel. This is because the grain boundary is the fast diffusion channel of elements, therefore, network-like oxides along the grain boundary emerges on the steel surface.
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