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 beta-SiC pore-foaming and gel-casting techniques, and their pore structure and properties were tailored by tuning the content of beta-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.