Abstract
The isothermal oxidation resistance in air at 1273, 1323, and 1373 K of Fe-20Cr alloys with 1 wt pct dispersoid of Y203, La2O3, A12O3, TiO2, SiO2, Cr2O3 and without dispersoid prepared by a conventional sintering and rolling procedures was examined. It was found that SiO2 dispersoid reduced, while A12O3 dispersoid slightly increased the oxidation resistance. The dispersoids of TiO2 and Cr2O3 showed no beneficial effect on the oxidation resistance except for the oxidation after 10 h at 1373 K. The oxidation behavior after 10 h at 1373 K was rather complex including accelerated oxidation. The beneficial effect of La2O3 and Y2O3 dispersoids was excellent at all temperatures. The oxidation rates during the early stage of oxidation for the alloys with dispersoid were apparently dependent on the type of the dispersoid. There was no evidence that dispersoid accumulated at the scale-alloy interface. Comparison of results obtained for the oxidation of the alloys prepared by a powder metallurgical procedure with results for the alloys by arc-melting procedure indicated that the grain size of the alloy is an important factor for reduction of oxidation rate but does not seem to be critical, because the grain size of the alloys with dispersoid was not dependent on the type of the dispersoid. Ion Microanalyses of the Cr2O3 scale formed after 1 h oxidation at 1373 K showed an interesting feature in that all the dispersed elements were incorporated in the scale and the iron content of the scale was lower on the alloys which exhibited better oxidation resistance.
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Nagai, H., Takebayashi, Y. & Mitani, H. Effect of dispersed oxides of rare earths and other reactive elements on the high temperature oxidation resistance of Fe-20Cr alloy. Metall Trans A 12, 435–442 (1981). https://doi.org/10.1007/BF02648540
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DOI: https://doi.org/10.1007/BF02648540