High temperature oxidation behavior of Mo-Zr alloys in pure oxygen condition

In the current study, alloys of Mo-95Zr, Mo-80Zr, Mo-50Zr, Mo-35Zr, Mo-20Zr and Mo-3Zr (at. %) were prepared to investigate the microstructure and oxidation behaviors of the whole composition range of Mo-Zr as-cast alloys. Laves, (Zr) and/or (Mo) intermetallic phases were presented in the primary dendrite, eutectic or peritectic structures in the prepared alloys. The isothermal oxidation process was accompanied by the formation of multilayer, consisting of the porous and loose ZrO2 and MoO3, which was individually changed from the (Zr), Laves and (Mo). The specimens were examined using a combination of gravimetry and several surface-analytical techniques, including X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscope and electron microprobe. Phases composition on the microstructure and oxidation behavior, and the sources of internal stress and defects formation in oxide layer on these alloys during oxidation have been discussed.