Effect of Rare Earth La on High Temperature Oxidation of Cobalt-based Superalloy GH5188 at 1100℃
The isothermal oxidation behavior of GH5188 superalloy at 1100℃ was studied by means of intermittent weighting,SEM and XRD.The results show that the main components of the formed oxide scale are Cr2O3 and MnCr2O4.The oxidation behavior can be approximated by parabolic law.The addition of La can help the alloy to form a continuous,compact and stable oxide scale of Cr2O3,improve the adhe-sion between the oxide scale and the alloy matrix,therewith enhance the high temperature oxidation re-sistance of GH5188 superalloy.However,with the increase of La content,the high temperature oxidation resistance of the alloy will decrease,the high temperature oxidation resistance of GH5188 alloy can be improved effectively only by adding proper amount of La(0.029％-0.060％).
cobalt base alloyGH5188high temperature oxidationrare earth element
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