研究了Cu-20Ni-20Cr-2Si合金在900℃,0.1 MPa纯氧中的氧化行为。结果表明:合金由三相组成,氧化动力学偏离抛物线规律,其瞬时抛物线速率常数随时间而降低。与前面研究的三相Cu-20Ni-20Cr合金形成含有所有组元氧化物及它们复合氧化物的复杂氧化膜结构不同,目前研究的Cu-20Ni-20Cr-2Si合金内部形成了连续的Cr2O3层,这是由于向Cu-20Ni-20Cr合金中加入了第四组元Si后,降低了合金表面活泼组元形成氧化物所需的临界浓度,使合金表面易于形成活泼组元氧化物膜。
Oxidation behavior of Cu-20Ni-20Cr-2Si alloy was studied at 900 ℃ in 0.1 MPa pure oxygen. Results show that the alloy is composed of three phases. The oxidation kinetics deviates from the parabolic rate law and its instantaneous parabolic rate decreases continuously with time. The present Cu-20Ni-20Cr-2Si alloy is different from the previous Cu-20Ni-20Cr aUoy that formed complex scales containing various components and their mixed oxides. On the contrary, it formed a continuous Cr203 layer because the adding Si to Cu-20Ni-20Cr alloy decreases the critical concentration of forming reactive component oxides and is able to form the reactive component oxides on the alloy surface easily.