Cu-Ni-Fe双相合金在800～900℃的低氧压氧化

Oxidation behavior of two-phase Cu-Ni-Fe alloy under low oxygen pressure at 800～900 ℃

研究了经自发分解产生的Cu 30Ni 2 5Fe(摩尔分数 ,% )双相合金在 80 0～ 90 0℃于低氧分压 (只有Fe可被氧化 )条件下的氧化行为。该合金的氧化动力学遵循抛物线规律 ,相同氧化条件下 ,其氧化速率低于纯Fe和二元Cu 2 5Fe合金。氧化膜包括Fe3O4外层和FeO的内氧化物颗粒 ,并且FeO均匀分布在Cu Ni固溶体上 ,与合金两相的初始分布没有联系 ,而内氧化带前沿合金中出现贫Fe的Cu Ni固溶体单相层。讨论了二元 /三元双相合金与单相合金由互固溶度引起的氧化行为差异 ,认为双相合金中难以发生最活泼组元的单一外氧化是由于组元在基体中的扩散受到双相强烈限制的结果。

The oxidation behavior of a spinodally decomposed Cu 30Ni 25Fe (mole fraction, %) alloy containing two phase has been studied under low oxygen pressure. The oxidation kinetics of Cu Ni Fe alloy is approximately parabolic but much lower than those for pure Fe and Cu 25Fe under the same condition. The scales contain the outer layer of Fe 3O 4 and combine with the internal precipitation of FeO that uniformly disperse within the Cu Ni matrix, which has no direct relationship with the initial distribution of the two phases. Moreover, a single phase solid solution of Cu Ni region depleted in Fe is also observed beneath the internal oxidation front. The differences of the oxidation properties between binary/ternary two phase alloys and solid solution alloys are compared in terms of diffusion and solubility, and the absence of an external oxidation of Fe in spite of its high content is attributed to the strong restriction imposed to its outward diffusion in the metal substrate by the simultaneous presence of two metal phases.