耐火粉-SiO_2-Al-合成雲母-コロイダルシリカ-粘結剤系酸化防止剤の酸化防止機構

概要

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Antioxidation mechanism of a newly developed oxidation inhibitor composed of a refractory powder-SiO_2-aluminum-synthetic mica-colloidal silica-coking bond has been investigated. During heating, the metallic silicon is formed after the reduction by the metallic aluminum of both mullite (3Al_2O_3・2SiO_2) containing in refractory powder and SiO_2. This is oxidized again so as to change gradually to protective amorphous SiO_2 layer which acts as an excellent diffusion barrier to oxigen from atmosphere. Aluminum, in turn, is oxidized to form the protective films composed of α-Al_2O_3 and FeO・Al_2O_3. In addition, a spinel (FeO・Al_2O_3) prevents effectively the formation of low melting fayalite (2FeO・SiO_2), and consequently the protective films remain stable even after prolonged heating at high temperatures. On the other hand, a lot of pores are formed by the volume reduction due to the melting of aluminum, the oxidation of aluminum and the reduction of SiO_2, by which the diffusion of Fe^<2+> and O^<2-> is effectively inhibited.
社団法人日本鉄鋼協会の論文
1984-05-01