AbstractThe isothermal and thermal cycling oxidation behaviour of a directionally solidified Ni‐Al‐Cr3C2eutectic alloy at temperatures from 800° to 1200 °C in flowing air have been investigated using several physical techniques. At all temperatures an initial, protective, external layer of α‐Al2O3develops on the alloy surface. However, this breaks down mechanically during thermal cycling, enabling a less protective Cr2O3‐rich scale to form.The time of retention of the α‐Al2O3layer at temperature decreases with increasing temperature, failing after between 30 min and 2 h at 1100° and 1200 °C. However, if platinum metal is introduced into the hot zone at these temperatures, this period is increased to about 48 h.Following formation of the external Cr2O3scale, internal oxide penetration into the alloy can be considerable, involving preferential oxide penetration down the alloy/carbide fibre interfaces. Thermal cycling does not influence markedly the oxidation behaviour, although it does result in formation of a greater quantity of nickel‐rich oxide nodules on the scale surface following crack development in the Cr2O3‐rich scale. This crack development is assisted by differential thermal c
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