In service, automotive exhaust manifolds are submitted to rapid thermal cycling up to 700–750 °C. To simulate an increase in exhaust gas temperature, a high-silicon cast iron was tested for rapid thermal cycling up to 800 °C. In addition to the well-known duplex oxide scale, rapid cyclic oxidation promotes the formation of a columnar zone at the substrate/oxide interface that has never been reported. It is evidenced that this columnar zone proceeds from a repetitive process. Based on detailed metallographic analysis using optical observations, in-situ XRD, micro-analyses and Raman spectroscopy, a mechanism explaining the formation of this columnar zone is proposed.

在使用中，汽车排气歧管经受高达 700–750 °C 的快速热循环。为了模拟废气温度的升高，对高硅铸铁进行了高达 800 °C 的快速热循环测试。除了众所周知的双相氧化皮外，快速循环氧化促进了从未报道过的基材/氧化物界面处柱状区的形成。有证据表明，这个柱状区域是从一个重复的过程中产生的。基于使用光学观察、原位 XRD、显微分析和拉曼光谱的详细金相分析，提出了解释该柱状区形成的机制。