Materials Science Forum, Vol.475-479, 721-724, 2005
Oxidation behavior of Rh-xTi refractory alloys
In this paper we report the oxidation behavior of Rh-xTi (x = 15 I 20 atomic percent) alloys isothermally exposed in air between 1000 and 1300 degrees C up to a period of 312 hours. The weight gain of arc-melted Rh-15Ti and Rh-20Ti alloys as a function of time was monitored. Results indicate that the oxidation resistance of Rh-15Ti and Rh-20Ti alloys at 1000 and 1100 degrees C is similar to that of advanced nickel-base superalloys. However, these alloys show excellent oxidation resistance beyond the operational limit for nickel-base superalloys. Optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), and X-ray diffraction (XRD) techniques were used to study the microstructure and morphology of the oxides. These alloys oxidize by forming TiO2 and Rh2O3 complex oxides. The Rh-20Ti alloys displayed lower oxidation resistance than Rh-15Ti alloys.
Keywords:refractory alloys;isothermal oxidation;weight gain measurements;optical microscopy;SEM;X-ray diffraction;EDS analysis