Investigation of the reactions between oxygen-containing iron and SiO 2 substrate by X-ray sessile-drop technique
- PDF / 256,342 Bytes
- 6 Pages / 606.24 x 786 pts Page_size
- 31 Downloads / 147 Views
9/11/03
12:04 PM
Page 647
Investigation of the Reactions between Oxygen-Containing Iron and SiO2 Substrate by X-Ray Sessile-Drop Technique E. KAPILASHRAMI, A.K. LAHIRI, A.W. CRAMB, and S. SEETHARAMAN The X-ray sessile-drop method was employed in the present investigation to measure the contact angle between liquid iron and a silica substrate under argon as well as CO-CO2-Ar atmospheres in the temperature range of 1823 to 1833 K. In the latter case, the measurements were carried out in the dynamic mode, and the contact-angle changes were followed as a function of time as oxygen in the gas dissolved in the metal. The static measurements in argon showed that the contact angles in the experimental temperature range are of the order of 135 deg, similar to those observed in the case of the alumina substrate. In the dynamic mode, oxygen partial pressures varying between 9.9104 and 1.5102 Pa were imposed on the system. In these experiments, the contact angle decreased in two stages, with an intermediate steady-state region. Fayalite slag, formed due to the reaction between the metallic phase and the substrate, was found to accumulate around the drop. The results are of relevance in understanding the mechanism of corrosion of silica-containing refractories by molten iron.
I. INTRODUCTION
IN view of the economic implications of the refractory erosion by steel as well as slag melts, the present work was initiated with an aim at understanding the reactions between silica and liquid iron containing well-defined amounts of oxygen. The present studies are also of relevance to clean-steel production, as the erosion products can be sources of nonmetallic inclusions in the steel. In the ingot processing of steel, the molten metal flows through refractory runners. Erosion of these runner refractories would lead to an accumulation of the oxide inclusions in steel. The runner refractories consist of Al2O3 and SiO2 as major components. The reaction between pure, dense alumina and oxygen-containing liquid iron has been investigated in an earlier investigation in the present laboratory.[1] The present work deals with the reactions between pure dense SiO2 and liquid iron containing oxygen. The X-ray sessile-drop method was the primary experimental technique adopted in the present work in order to monitor the wetting characteristics of liquid iron on a silica substrate. The measurements were carried out in purified argon as well as under predetermined oxygen partial pressures generated by suitable mixtures of CO, CO2, and Ar. The contact angles were followed both in the static as well as dynamic modes, the latter providing a kinetic picture of the reactions. The measurements were carried out at 1823 and 1833 K.
contents in liquid iron, the angle decreasing with increasing oxygen content. On the other hand, to the knowledge of the present authors, no systematic work on the wetting characteristics of liquid iron on silica has been reported so far. This could be due to the fact that the difference in the melting points between iron a
Data Loading...
