High-temperature oxidation behaviour of SPS-prepared Mo and Mo–5Ta alloys

ABSTRACT The high-temperature oxidation behaviour of SPS-prepared Mo and Mo–5Ta alloys are investigated under the temperature range 300–700°C for 0–120 min in static air condition. The oxidation weight gains of Mo and Mo–5Ta conform to parabolic law at different oxidation times of 500°C and all remain at low levels. At low temperature (≤ 500°C), the oxidation resistance improves with Ta addition. However, at 600°C and 700°C, the oxidation of Mo–5Ta increases and the weight gain is obvious. Compared with pure Mo, a continuous and dense oxide scale can be formed quickly on the surface of Mo–5Ta alloys during the oxidation process at 500°C, which improves the oxidation resistance of the alloys. The volatile MoO3 and generated Ta2O5 above 500°C cause more voids to form in the matrix, resulting in the deterioration of the oxidation resistance of the alloys.