Role of nitrogen on the oxidative stability of Ti5Si3 based alloys at elevated temperature

摘要: Abstract Ti 5 Si 3 has been extensively studied as a candidate material for high temperature application due to its melting point (2130 °C), low density (∼4.3 g/cm ) and excellent oxidation resistance in oxygen above 1000 °C. However, stoichiometric alloy experiences accelerated during exposure air It was proposed that nitrogen responsible the increased air. In present study, isothermal reaction kinetics of at 1000 °C investigated. Compared slow parabolic rate oxygen, faster linear observed when is exposed nitrogen. Further studies on behavior changing nitrogen/oxygen atmospheres showed stable up 400 h gas contained 50% N 2 . Breakaway occurs after short exposures least 75% , concentration increased. Furthermore, time breakaway decreases with increasing partial pressure. Extensive analysis products SEM XRD revealed formation fast growth nitride-containing subscale interferes establishment continuous protective silica scale contributes oxidation.