Effect of surface roughness of MgO substrate on size distribution of inclusions

Experiments were carried out to investigate the effect of surface roughness of MgO substrate on the formation and size distribution of inclusion particles employing new experimental methodology. The reaction of MgO refractory with Al deoxidised liquid Fe can take place, which results in forming both MgO and spinel type of inclusions. The number density of inclusions increases with increasing surface roughness of the substrate, which could be explained by Gibbs-Thompson effect. Activated interfacial reactions between the substrate and liquid Fe are believed to be more dominant than the effect of increased surface roughness of the substrate on the number density of inclusions. It is recommended to use Al 2 O 3 based nozzle than MgO based one of similar surface roughness from a viewpoint of the generation of lower number density of inclusions.