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研究了Cr含量相对较高的Cu-Ni-30Cr合金在700℃～800℃,0.1MPa纯氧气中的氧化行为。结果表明:合金氧化动力学较复杂,其瞬时抛物线速率常数随时间而降低,氧化动力学曲线通常不是由单一的抛物线或直线组成而是由几段组成。Cu-Ni-Cr为三相合金,3相的存在增加了合金表面形成Cr2O3氧化膜所需临界浓度,但30at%Cr足以使合金表面形成连续的Cr2O3外氧化膜。氧化膜内层是合金和氧化物相共存的混合区,被氧化的岛状物是由Cr2O3和Cu,Ni组成。这种混合内氧化机制与经典内氧化明显不同。
The oxidation behavior of Cu-Ni-30Cr alloy with relatively high Cr content in pure oxygen at 700 ℃ ~ 800 ℃ and 0.1MPa was studied. The results show that the oxidation kinetics of the alloy is complex and its instantaneous parabolic rate constant decreases with time. The oxidation kinetics curve usually consists of several sections instead of a single parabola or a straight line. Cu-Ni-Cr is a three-phase alloy. The presence of three phases increases the critical concentration required for forming Cr2O3 oxide film on the alloy surface, but 30at% Cr is sufficient to form a continuous Cr2O3 outer oxide film on the alloy surface. The inner layer of the oxide film is a mixed zone where the alloy and the oxide phase coexist. The oxidized island is composed of Cr2O3 and Cu and Ni. This mixed internal oxidation mechanism is obviously different from the classical internal oxidation.