Abstract
Nb-20Mo-15Si-5B-20Cr alloy has been oxidized in air in a range of temperatures from 700 to 1,300°C. A 24 hour exposure to air shows a minimum in weight gain per unit area at 900 and 1,000°C. Below and above this temperature the alloy has an oxide scale composed of oxide-metal interface which has been characterized by x-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, and x-ray mapping. Formation of CrNbO4 appears to be beneficial for the oxidation resistance while another Cr oxide, Cr2O3, may form mainly at temperatures below 1,000°C. SiO2 formation has been restricted to temperatures above 1,000°C. Long term oxidation consisting of seven successive 24 hour cycles of heating shows better oxidation resistance at 1,300°C for times longer than 96 hours but below that usual lower weight gain per unit area at lower temperature has been observed.
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Ventura, J., Varma, S.K. The oxidation resistance of Nb-20Mo-15Si-5B-20Cr up to 1,300°C. JOM 61, 72–75 (2009). https://doi.org/10.1007/s11837-009-0108-5
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DOI: https://doi.org/10.1007/s11837-009-0108-5