ALUMINA-COATED TI-25AL-10NB-3V-1MO FOR IMPROVED OXIDATION RESISTANCE

The potential use of plasma sprayed Al2O3 as an oxidation barrier for Ti-25Al-10Nb-3V-1Mo at high temperatures was investigated. The effecti veness of the coating was tested under conditions of cyclic oxidation. One cycle of the oxidation process involved exposing the sample at 1, 000 degrees C for one hour followed by cooling to room temperature. Al 2O3 was found to be very effective in preventing oxidation of the Ti-2 5Al-10Nb-3V-1Mo substrate. No significant elemental diffusion occurred between the coating and the substrate during cyclic oxidation. Cracks were observed to form in the Al2O3 layer in the vicinity of the inter face, on completion of the thermal cycling experiments. Young's modulu s and damping measurements were performed on the ascoated samples and samples cycled from 1,000 degrees C.