On wetting of dense alumina substrate by low alloy steel containing oxygen

Abstract

This investigation was carried out to determine the wetting characteristics of low alloy steel grades that contained, among other elements, chromium around 5 wt.% and oxygen up to approximately 400 ppm. The tests were performed from the melting temperature to a temperature of 1,600 °C using a high-temperature observation furnace CLASIC operating under non-oxidizing conditions. The influence of oxygen on the examined steel's wetting behavior, i.e., the temperature dependence of surface tension and wetting angle, was found and verified by statistical analysis using the Kruskal-Wallis test. In addition, the phase transition temperatures, ascertained from DTA measurements, were in strong correlation with those theoretically calculated. To provide better insight into the wetting mechanism, SEM/EDX analyses of the wetted alumina surface and of the vertical cross-section of the steel/alumina interface were made using a scanning electron microscope (SEM) JEOL 6490 LV. Beyond the mentioned techniques, the study was accompanied by calculations performed in FactSage oxide database.