Abstract: Effects of α-Al_2O_3 micro-powder on properties of low carbon MgO-C refractories were investigated with fused magnesia and flake graphite as starting materials, and Novolak phenolic resin as binder. The results show that: (1) with Al_2O_3 micro-powder addition, apparent porosity of MgO-C refractories decreases, both bulk density and MOR increase, and especially oxidation resistance improves noticeably. (2) The reaction of Al_2O_3 micro-powder in the matrix of MgO-C improves the textual integrity of MgO-C refractories and ceramic bonding, due to formation of an continuous in-situ spinel matrix. (3) The inward diffusion velocity of oxygen through the porous decarburized layer is slowed down by the formation of MgO dense layer and continuous in-situ spinel matrix, which results in the improvement of oxidation resistance.

Key words: α-Al_2O_3 micro-powder%MgO-C refractories%in-situ spinel%oxidation resistance