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Investigation on the oxidation behaviour of gamma titanium aluminides coated with thermal barrier coatings

“…Scanning electron micrograph (a) and EDS analysis (b) of a cross-section of an alloy 98G sample pre-oxidised in air and coated with TBC which was exposed to air at 850 8C for 1100 cycles sample oxidised at 900 8C in air [35]. With increase in the partial pressure of oxygen, TiN was oxidised to titanium oxide, thus limiting the presence of the nitride layer to a narrow zone adjacent to the substrate [36]. The niobium-rich intermetallic phase was oxidised above the nitride layer, probably resulting in a porous initial mixture of Al-, Ti-and Nb-oxides.…”

Microstructure of Oxide Scales Formed on Ti--48Al--8Cr--2Ag Alloy in Air at 900--1000�C

“…Cheng et al 19 and Dettenwanger et al 20 also observed a new cubic phase with a lattice parameter of a = 0.692 nm and named it the X-phase. In fact, the Z-phase and the X-phase are the same phase, which can suppresses the formation of the α 2 -Ti 3 A1 phase and stabilize the Al 2 O 3 scale.…”

Interdiffusion at TiO2/Ti, TiO2/Ti3Al and TiO2/TiAl interfaces studied in bilayer structures

“…The samples were heated from room temperature to different final temperatures between 350°C and 700°C at a linear heating rate of 40°C min 1 . After reaching the final temperature the samples were cooled down quickly to room temperature, with an estimated cooling rate of 200°C min 1 . It is worth noting that no interdiffusion reaction heat was observed, even at the lower heating rate of 10°C min 1 , due to the relatively large mass of the silicon substrate.…”