Melfo W M, Dippenaar R J
Faculty of Engineering, University of Wollongong, Wollongong, NSW 2522, Australia.
J Microsc. 2007 Feb;225(Pt 2):147-55. doi: 10.1111/j.1365-2818.2007.01726.x.
A technique was developed to study in situ the early stages of the reaction between iron and air. Using a high-temperature microscope, we observed at temperatures between 1000 degrees C and 1050 degrees C and within the first 30 s of reaction, the formation of iron-oxide layers on the surface of low-carbon steel. We observed the nucleation and growth of a first layer of iron oxide and the consecutive formation in sequence, of higher iron oxides sweeping over the surface of the former oxide. The grain boundaries of the steel substrate remain visible for quite some time following exposure to an oxidizing atmosphere indicating that diffusion through steel grain boundaries may have a determining influence on the formation of oxides. These findings emphasize the importance of conducting further studies to better understand the kinetics and mechanisms by which iron-oxide layers form in the early stages of oxidation.
开发了一种技术来原位研究铁与空气反应的早期阶段。使用高温显微镜，我们在1000摄氏度至1050摄氏度的温度下以及反应的前30秒内，观察到低碳钢表面形成了氧化铁层。我们观察到第一层氧化铁的形核和生长，以及随后依次形成的高铁氧化物扫过前一层氧化物的表面。暴露于氧化气氛后，钢基体的晶界在相当长的一段时间内仍然可见，这表明通过钢晶界的扩散可能对氧化物的形成具有决定性影响。这些发现强调了进行进一步研究以更好地理解氧化铁层在氧化早期形成的动力学和机制的重要性。
