Oxidation behavior of Nb-30Si-(10,20) Cr alloys have been evaluated in air from 700 to 1400 degrees C by heating for 24 h and furnace cooling them. The lower weight gain per unit area has been observed for 20Cr alloy at 1200, 1300, and 1400 degrees C. Pesting has been observed at lower temperatures (700, 800, 900 degrees C). Analysis indicates that the powder formation at 900, 100, 1100 degrees C may be associated with beta form of Nb2O5 (base centered monoclinic form). However the m-monoclinic form of Nb2O5 evolves at temperatures above 900 degrees C while o-orthorhombic Nb2O5 forms at below this temperature. The phases in the alloys have been calculated using the Pandat(TM) software program at different temperatures using calculated Nb-Cr-Si phase diagrams.