Volume 1, Issue 3 (March 2004)
Investigation of Burning Iron in Oxygen-Enriched Atmospheres through Microanalysis Techniques
Promoted-ignition testing of 3.2-mm diameter iron rods was performed in high purity oxygen at 0.69 and 6.9 MPa, with the samples subjected to a comprehensive visual and compositional microanalysis. Scanning electron microscopy and electron probe microanalysis, utilizing both energy and wavelength dispersive spectroscopy, were performed to clarify the burning process and aid in the development of a qualitative model of the burning iron rod system. The detached drops and rods of both self-extinguished and quenched samples were examined revealing that a drop, on detachment, is comprised of a significant proportion of unreacted metal. A high concentration of oxygen was detected within the unburned (melted and resolidifed) metal, enhancing the combustion process within the detached slag. The analysis also revealed a detached sphere of melted and resolidified (but unreacted) iron within the attached molten oxide drop on a quenched rod.