High-strength and corrosion-resistant Al₂O₃ ceramics with excellent closed-cell structure

As a lightweight refractory, porous Al₂O₃ ceramics are advocated in the iron and steel smelting industry because of their excellent resource-saving and low heat loss. However, the severely poor slag corrosion resistance and low mechanical strength caused by open pores shorten their service life. To solve this problem, Al₂O₃ ceramics with excellent closed-cell structure were fabricated by combining β-SiC pore-foaming and gel-casting techniques, and their pore structure and properties were tailored by tuning the content of β-SiC and sintering temperature. It is noted that the closed pores introduced in the dense Al₂O₃ matrix play a pivotal role in improving the corrosion resistance and mechanical strength while maintaining the lightweight. And the sample with closed porosity of 20.6% exhibited compressive strength of 640 MPa and flexural strength of 272 MPa. Meanwhile, its corrosion and penetration indices were at a low level, 6.3% and 54.8%, respectively.