Correlation of microstructure and mechanical properties of Al₂O₃‐C bodies containing Nano‐Al₂O₃ and Nano‐TiO₂ additives

Abstract

Al 2 O 3 -C foam filters have been successfully used for steel and aluminum melts filtration. Improving the high-temperature mechanical properties enhances the capability and application of these filters for the filtration of large steel casting parts along with ingot casting or continuous casting of steel for long periods of time. In this study, adding nano-Al 2 O 3 and/or nano-TiO 2 to the composition of Al 2 O 3 -C filters was investigated. Uniaxially pressed Al 2 O 3 -C samples containing additives in the range from 0 to 1.0 wt% of nano-oxides were prepared. The physical and mechanical properties, as well as microstructural analysis, were measured after sintering at 1600°C for 5 hours under a petroleum coke bed. The results showed that the presence of nano-Al 2 O 3 particles in the composition led to an increase in the cold crushing strength (CCS) due to the formation of the Al 3 CON phase which acts as a chemical bonding between Al 2 O 3 particles and the carbonaceous matrix. On the other hand, the addition of 1.0 wt% of nano-TiO 2 in the composition caused an increase of 50% in the hot modulus of rupture (HMOR), attributed to the formation of columnar Al 2 O 3 grains in the microstructure.

Nanoscale toughening of low carbon Al2O3‐C refractories by means of SiCnw/Al2O3 composite reinforcement

“…Therefore, these limitations eventually undermine the performance of new products. In contrast, the direct addition of low‐dimensional additives into the refractory matrix is a common method with controllable components and high industrial feasibility 30–34 . However, commercial low‐dimensional additives have high costs and are difficult to be dispersed, or even suitable commercial products are missing 2 .…”

“…In contrast, the direct addition of low-dimensional additives into the refractory matrix is a common method with controllable components and high industrial feasibility. [30][31][32][33][34] However, commercial lowdimensional additives have high costs and are difficult to be dispersed, or even suitable commercial products are missing. 2 Pre-synthesized composite powders containing low-dimensional components as reinforcement can effectively overcome the above disadvantages.…”