Comparison of Isothermal Oxidation Behavior of Co-10Cr-xSi (x = 0,5,10) Alloys at 1073 K

TP374.2; The oxidation behavior of Co-10Cr-xSi (x = 0, 5, 10, nominal composition, at％ ) alloys in 0. 1 MPa pure O2 at 1073 K was investigated. Co-10Cr presents the worst oxidation resistance with the mass gain of about 7. 531 mg/ cm2 after 24 h oxidation, while Co-10Cr-10Si presents the best oxi-dation resistance with the much lower mass gain of about 0. 078 mg/ cm2 . Co-10Cr-10Si is about two magnitudes lower than that of Co-10Cr. The oxidation behavior of Co-10Cr-5Si is intermediate be-tween that of Co-10Cr and Co-10Cr-10Si. The nodular oxides have occupied most of the alloy sur-face, and their microstructure is similar to Co-10Cr, to some extent. On the contrary, only a fraction of the surface is covered by the Cr2O3 layer, whose microstructure is similar to that of Co-10Cr-10Si.