Various carbon contents in the MgO-C refractory were studied with respect to the oxidation resistance and the wetting behavior with slag. The bulk density, apparent porosity, cold crushing strength, oxidation rate, and mass loss rate of the fired MgO-C refractories with various carbon contents were measured and compared. The wetting and penetration behavior of the cured MgO-C refractory with the molten slag were observed in-situ. The contact angle and the shape parameters of molten slag, including the apparent radius, height, and volume were compared. The results showed that the regenerated MgO effectively restrained the carbon oxidation in the MgO-C refractory, which was more evident at the low carbon content refractory. The contact angle between the MgO-C refractory and the molten slag increased as the carbon content increased. The increased contact angle decreased the penetration of the molten slag.

A novel and aqueous gel-casting process has been successfully developed to fabricate porous MgAl₂O₄ ceramics by using hydratable alumina and MgO powders as raw materials and deionized water as hydration agent. The effects of different amounts of deionized water on the hydration properties, apparent porosity, bulk density, microstructure, pore size distribution and compressive strength of the samples were investigated. The results indicated that the porosity and the microstructure of porous MgAl₂O₄ ceramics were governed by the amounts of deionized water added. The porous structure was formed by the liberation of physisorbed water and the decomposition of hydration products such as bayerite, brucite and boehmite. After determining the addition amounts of deionized water, the fabricated porous MgAl₂O₄ ceramics had a high apparent porosity (52.5–65.8%), a small average pore size structure (around 1–3 μm) and a relatively high compressive strength (12–28 MPa). The novel aqueous gel-casting process with easy access is expected to be a promising candidate for the preparation of Al₂O₃-based porous ceramics.

In this work, magnesium borate (Mg₂B₂O₅) and aluminum borate (Al₁₈B₄O₃₃) whiskers with a high aspect ratio were successfully synthesized using a molten salt method. The phase transformation and morphology involution of the whiskers were studied by XRD, IR-FT, TG-DSC, and SEM-EDS with different boron/metal ratios and reaction temperatures. The results show a rich boron environment and appropriate reaction temperature to be the crucial factors with respect to the composition and morphology of the borate whiskers. Mg₂B₂O₅ whiskers with a diameter of several hundred nanometers and a 10–60 length–diameter ratio were obtained when the B/Mg ratio was 1.5:1 and the reaction temperature was 800°C. For Al₁₈B₄O₃₃ whiskers, a synthesis temperature of 1000°C and a B/Al ratio of 3:9 were found to be optimal with respect to the whisker morphology. A liquid-solid (LS) mechanism is proposed as the growth mechanism of the whiskers on the basis of the experimental phenomena.

Nano-Y₂O₃ powder was added to the composition of MgO-C refractory to improve its mechanical properties and oxidation resistance. The changes in bulk density (BD), flexural strength (FS), cold crushing strength (CCS), and oxidation rate were studied with the phase and microstructural developments. The BD, FS and CCS of the MgO-C refractories were increased by adding the nano-Y₂O₃ powder, which contributed to the dispersion of the nano-Y₂O₃ in the gaps between differently sized MgO particles. Meanwhile, the oxidation rate of the MgO-C refractory added with the nano-Y₂O₃ was decreased owing to a dense oxidised layer was formed. The dense layer hindered the inward diffusion of oxygen and protected the refractory from oxidation.