Atomic transport mechanisms in thin oxide films grown on zirconium by thermal oxidation, As-derived from18O-tracer experiments
Atomic transport mechanisms in thin oxide films grown on zirconium by thermal oxidation, As-derived from18O-tracer experiments
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DOI：
10.1016/j.actamat.2011.08.035
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发表时间：
2011-12
期刊：
影响因子：
9.4
通讯作者：
G. Bakradze;L. Jeurgens;T. Acatürk;U. Starke;E. Mittemeijer
中科院分区：
文献类型：
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作者：
G. Bakradze;L. Jeurgens;T. Acatürk;U. Starke;E. Mittemeijer
利用16 O和18 O同位素进行了纯Zr在450 K下干热氧化的两阶段氧化实验，揭示了氧化膜（厚度<10 nm）的原子输运机制。为此，在超高真空条件下，通过交替离子溅射和真空退火步骤的循环处理，制备了裸（即没有自然氧化物）Zr（0001）和Zr（101 <$0）单晶表面。接下来，在450 K和pO 2 =1×10−4Pa下，先在16 O2（g）中氧化，然后在18 O2（g）中氧化。利用飞行时间二次离子质谱仪记录了氧化膜中18 O示踪剂的深度分布。得出的结论是，氧化过程的早期阶段是由氧运输到金属/氧化物界面通过晶格和沿着的纳米尺寸的氧化物晶粒的晶界，而在继续氧化，只有氧晶格运输控制的氧化过程。提出了氧化膜生长机理。
Two-stage oxidation experiments using16O and18O isotopes were performed to reveal the governing atomic transport mechanism(s) in thin (thickness <10nm) oxide films grown during the initial stages of dry thermal oxidation of pure Zr at 450K. To this end, bare (i.e. without a native oxide) Zr(0001) and Zr(101¯0) single-crystalline surfaces were prepared under ultra-high vacuum conditions by a cyclic treatment of alternating ion-sputtering and in vacuo annealing steps. Next, the bare Zr surfaces were oxidized at 450K and at pO2=1×10−4Pa, first in16O2(g) and subsequently in18O2(g). The18O-tracer depth distributions in the oxide films were recorded by time-of-flight secondary ion mass spectrometry. It was concluded that the early stage of the oxidation process is governed by oxygen transport to the metal/oxide interface through the lattice and along the grain boundaries of the nanosized oxide grains whereas, on continuing oxidation, only oxygen lattice transport controls the oxidation process. An oxide-film growth mechanism is proposed.