Oxidation performance of cold spray Ti-Al barrier coated γ-TiAl intermetallic substrates

Four blends of Al powder containing different amounts of Ti were deposited onto Ti-46A1-7Nb substrates as oxidation protection layers using low-pressure cold spray. The coating morphology and chemical composition were assessed. Optimized heat treatment in protective atmosphere was carried out in order to induce formation of intermetallic phases within the deposits. The specimens were then subjected to 950 degrees C exposure for 100, 250, and 500 h and their oxidation performance was monitored using the gravimetric method. It was found that the oxidation rate of the coating-protected specimens was substantially reduced (an increase in the weight gain of 1.37 mg.cm(-2) after 500 h of specimen with Al coating) as compared to their uncoated counterparts (1.21 mg.cm(-2) after 50 h at 900 degrees C). The oxidation rates increased with increasing content of Ti in the coatings. Substantial changes of the coating integrity were recorded after the long-term oxidation testing. (C) 2014 Elsevier B.V. All rights reserved.