Oxidation behaviors of Nb-Si-B ternary alloys at 1100 °C under ambient atmosphere

Oxidation behaviors of the Nb-based two phase alloys comprising the Nb(Si, B) solid solution and Nb-5(Si, B)(3) phases have been evaluated based on the microstructural characterizations of isothermally oxidized samples at 1100 degrees C under ambient atmosphere. The oxide products were identified as beta-Nb2O5, NbO2 and 3Nb(2)O(5)center dot B2O3, while the existence of Si/B rich crystalline oxide or glassy oxide layers could not be confirmed from the microstructural analysis results. The critical oxidation sequences with respect to the selected alloy compositions are discussed in terms of microstructural evolutions during oxidation exposure. (C) 2011 Elsevier Ltd. All rights reserved.