PAN Lei, GAO Zhi, FU Weidong, YANG Qin, WANG Zuochuang, MA Beiyue
To improve the thermal shock resistance and reduce the cost of slag line of submerged entry nozzle (SEN) refractories, zirconia-carbon refractories were prepared by partially replacing calcia-stabilized zirconia with zirconia hollow spheres. The effects of different additions of zirconia hollow spheres (0, 5 wt.%, 10 wt.%, and 15 wt.%) on the mechanical properties, thermal shock resistance, and slag corrosion resistance of the materials were investigated. The results show that with the increase of zirconia hollow sphere addition, the apparent porosity of the samples increases, while the bulk density and cold compressive strength decrease significantly. In contrast, the cold modulus of rupture (MOR) remains relatively stable, with a maximum reduction rate of 9.5%. In terms of high-temperature performance, as the addition of zirconia hollow spheres increases, the thermal expansion rate of the samples decreases from 0.71% to 0.61%, and the thermal shock resistance is significantly enhanced. The hot modulus of rupture first increases and then decreases, which is attributed to the fact that excessive addition of zirconia hollow spheres weakens the structural strength of the material. Regarding slag corrosion resistance, both the slag penetration resistance and slag corrosion resistance of the samples gradually decrease with the increase of zirconia hollow sphere content. When the additions of zirconia hollow spheres are 5 wt.%, 10 wt.%, and 15 wt.%, the corrosion rates increase by 4.5%, 16.6%, and 65.1%, respectively. In conclusion, an appropriate amount of zirconia hollow spheres (0-10 wt.%) partially replacing calcia-stabilized zirconia is beneficial for the high-temperature strength and thermal shock resistance of ZrO2-C refractories, but excessive addition leads to a decline in strength and slag corrosion resistance.
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