Title: Corrosion Behaviour of Inconel 617 Coated with Silicon Oxides in Impure Helium
Abstract:Inconel 617 samples were coated with silicon or silicon oxide SiOX(0<X≤2) films by reactive magnetron sputtering method. The coated samples were corrosion-tested in an impure helium environment at 900...Inconel 617 samples were coated with silicon or silicon oxide SiOX(0<X≤2) films by reactive magnetron sputtering method. The coated samples were corrosion-tested in an impure helium environment at 900 and 1 000°C. The impure helium simulates the coolant gas of a high temperature gas cooled reacter now being developed in Japan. The SiOX(X<2) films reacted with the substrate alloy, Inconel 617 at elevated temperatures. Silicon in the SiOX films diffused into the substrate to form the carbide of (Si, Mo)X CY. Nickel and Chromium in the substrate diffused into the SiOX films to form silicides. The SiOX(X<2) films exfoliated appreciably during the corrosion test and hardly protected the substrate against corrosive attack by the impure helium. Rather, SiOX(X<2) films enhanced a carburization of Inconel 617 in the impure helium.On the other hand, the stoichiometric SiO2 films had an excellelent protective effect in the impure helium at 900 and 1 000°C. However, the protective effect of the SiO2 film degraded a little at 1 000°C. Inconel 617 was carburized and oxidized internally to form aluminum internal oxide-layer at 1 000°C.Read More