Formation, breakage, and reinforcement of thin oxide films on Fe-base alloys at High Temperature

本工作的目的是明确铁基合金薄膜在高温氧化过程中积累的应力是导致薄膜断裂和加速氧化动力学的原因。在O^2-20%H_2O-N_2气氛中，Fe-16Cr工业合金在1273K下氧化3.6K。在氧化过程中记录了氧化引起的质量变化。将声发射传感器与合金带材结合在一起，在带材背面安装氢探测器，并在高温氧化试验中同时记录这两种现象。在加速氧化动力学之前，观察到了大量的声发射事件，表明氧化膜已经破裂，但在此阶段可以自我固化。在声发射事件发生后，在合金带材的背面检测到氢。这可能在氧化膜/金属衬底界面上演化，因为作为氧化剂的水蒸气的消耗穿透了破碎的氧化膜中的缺陷。

The objective of the work is to make clear that stresses accumulated in the thin oxide films on Fe-base alloys on high temperature oxidation is responsible for the breakage of films and the accelerated oxidation kinetics. The Fe-16Cr commercial alloy was oxidized at 1273 K for 3.6 ks in O^2-20% H_2O-N_2 atmosphere. Mass change due to oxidation was recorded during oxidation. An acoustic emission sensor was combined with alloy strip and a hydrogen detector was installed on the backside of the strip, and the both phenomena were recorded simultaneously during high temperature oxidation tests. A lot of acoustic emission events were observed before an accelerated oxidation kinetics indicating that the oxide films were broken but they could cure themselves at the stage. Hydrogen was detected at the backside of the alloy strip after the initiation of the acoustic emission event. This might evolve at the oxide film/metal substrate interface due to consumption of water vapor as an oxidant that penetrate imperfection in broken oxide films.