Abstract:The high-temperature oxidation resistance of Co-Al-W alloy, strengthened by a ternary compound γ′-Co3(Al, W) phase, was investigated. The kinetic data of mass gain and the cyclic oxidation behavior of the Co-Al-W alloys, including Co-9Al-7.5W (7.5W), Co-9Al-9.8W (9.8W) and Co-9.2Al-10.7W (10.7W), were studied at 800 and 900 oC by XRD, SEM and EPMA technologies, and they were compared with a nickel-base Manaurite900 (MAN900) alloy. The results show that the anti-oxidative ability of 9.8W alloy is the best at 800 oC among these alloys. But at 900 oC the square of mass gain of 7.5W and 9.8W alloys are much greater, while the anti-oxidant property of MAN900 and 10.7W alloys are superior to other alloys. The oxide scales at 800 and 900 oC exhibit a multi-layered structure, including an outer layer of Co3O4, an intermediate layer composed of complex oxides of Co, Al and W elements layer, and an internal attacked layer with oxides of Co and Al.