新型Co-Al-W合金高温氧化行为研究

Research on Oxidation Behavior of Novel Co-Al-W Alloy at High Temperature

摘要:

研究了γ′-Co3(Al,W)相沉淀强化的新型钴基高温合金，Co-Al-W抗高温氧化性能。利用SEM、EPMA、XRD等方法研究了新型Co-Al-W合金在800 ℃和900 ℃空气中静态氧化增重动力学和抗高温氧化机理，并与镍基高温合金Manaurite900相比较。研究发现，在800 ℃氧化时，9.8W合金抗氧化能力最强，但在900 ℃时，9.8W和7.5W合金的增重最大，Manaurite900和10.7W的抗氧化能力最好。合金在2种温度下氧化后，表面氧化膜主要由三层构成，即Co氧化物Co3O4组成的氧化膜最外层，Co、Al、W复杂氧化物组成的中间过渡层及Al和Co氧化物组成的氧化膜最内层。

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.