A novel strategy was exploited for the fabrication of AlN-AlON refractories via nitrogen gas pressure sintering of Al 4 O 4 C. The phase transformation and microstructure evolution during the reaction at 1600-1800 • C were thoroughly investigated. The results indicated that the high N 2 pressure was essential for the effective nitridation. The in situ generated AlN-AlON refractories had a homogeneous local chemical composition, and the (101) plane of AlN and the (222) lattice plane of Al 5 O 6 N were bonded at their grain boundary with no amorphous phase. The as-fabricated AlN-AlON refractories treated at 1700 • C by a 20 atmnitrogen pressure exhibited an optimum bending strength of 111.10 MPa, combining an apparent porosity of 20% with a low bulk density of 1.97 g/cm 3 . The diffusion of the generated oxygen led to an increase in the apparent porosity and decrease in the bulk density at 1800 • C. Furthermore, the fabrication mechanism of AlN-AlON refractories under the nitrogen gas-pressure was discussed.
The synergistic effects of Al3BC3–Al antioxidants on optimizing the oxidation resistance of low‐carbon MgO–C refractories were investigated. The results indicated that the oxidation index and rate constant of low‐carbon MgO–C refractories with optimized Al3BC3–Al additions were 13% and 1.10 × 10−4 cm2 min−1 at 1400°C for 3 h, respectively, which is much lower than that of Al or Al3BC3 containing ones. Single Al3BC3 is not a suitable antioxidant for low‐carbon MgO–C refractories; however, if Al3BC3 was initially protected and Al reacted as the antioxidant, enhanced oxidation resistance at high temperature can be achieved. The formation of dense MgO–MgAl2O4–Mg3B2O6 layer contributed to superior oxidation resistance, and the temperature for the generation of this layer was as low as 1100°C due to liquid and vapor phase–assisted reactions with Al3BC3–Al. Furthermore, a self‐repairing function was achieved at 1600°C with the combination of Al3BC3–Al additions in spite of the faster oxidation rate.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.