Effect of cerium on the wettability between 304 stainless steel and MgO–Al2O3-based lining refractory

Abstract In the current study, the wettability between three types of Al2O3–MgO refractories and the 304 stainless steel with and without cerium was investigated using a sessile drop method under a reducing atmosphere at 1580 °C. The contact angle between the stainless steel without cerium and Al2O3, MgO·Al2O3, MgO refractories was 133.3°, 135.7°, 119.0°, respectively, while it was 121.6°, 137.4°, 115.2° for the stainless steel with cerium, respectively. The solid oxide layer on the surface of drops prevented the molten droplet from spreading and increased the contact angle. The reaction between the steel drop and the refractory at the interface lowered the contact angle. For the Al2O3 refractory, the added cerium in the stainless steel reacted with the refractory and formed a Ce–Al–O interaction layer, resulting in a lower contact angle. The reduction of MgO refractory by hydrogen gas led to the formation of solid Mg–Si–O products on the droplet surface, resulting in an increase of the contact angle. The cerium in the molten steel generated cerium oxides, lowered the formation of Mg–Si–O products, and decreased the contact angle between the magnesia refractory and the steel. The reduction of the lining refractory by hydrogen gas led to the formation of a few MgO·Al2O3 particles on the Ce-free droplet, which slightly increased the contact angle. The cerium generated solid Ce–Al–O products on the lower surface of the droplet and at the steel/refractory interface, leading to a slight increase of the contact angle.