Synthesis and oxidation of Zr3Al3C5 powders

Abstract

Abstract Predominantly single phase Zr3Al3C5 powders were synthesized in an Ar atmosphere using Zr – Al intermetallics and graphite as starting materials. The reaction path of Zr3Al3C5 synthesis was discussed based on differential scanning calorimetry and X-ray diffraction results. Lattice parameters of Zr3Al3C5 determined using the Rietveld method are a = 3.347 Å and c = 27.642 Å. In addition, the oxidation of Zr3Al3C5 powders was tested by using thermogravimetry – differential scanning calorimetry. The starting and complete oxidation temperatures are 400 °C and 1200 °C, respectively. These temperatures are much higher than those for ZrC, suggesting that Zr3Al3C5 has better oxidation resistance than ZrC. On the other hand, the oxidation degree of Zr3Al3C5, defined for the complete carbide – oxide transformation, overshot 100 % during oxidation. This overshooting is attributed to the formation of amorphous carbon. The phase evolution during the oxidation of Zr3Al3C5 was also investigated.