Oxidation studies of Nb-17Al-xMo alloys

The oxidation of Nb-25Al, Nb-17Al and Nb-17Al-xMo (x=20,30,40at%) alloys in static air at temperatures up to 1773K was studied using differential scanning calorimetry and thermogravimetric analysis, The binary and ternary alloys (x=20,30)exhibited increased rates of weight gain in two temperature regimes, 1123K - 1623K and 1623K - 1773K with Nb-17Al-20Mo showing reduced weight gain rates as compared to Nb-17Al. In Nb-17Al-40Mo the start of weight gain was shifted to 973K and was followed by a decrease in weight in the temperature range 1273K to 1623K. No protective scale was formed on any of the alloys studied.