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

点击翻译按钮获取中文摘要

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.