Some Words on Corrosion Mechanism

Aluminium can react with oxides on the surface of the refractory and in the pores. If Al reacts on the surface, the liquid product of reaction (silicon) will dissolve in Al and will be taken away. It should not be calculated as a product in a calculation of 

The volume effect of reactions on the surface is negative the reactimi products occupy less space than reactants do, meaning there will be no continuous film, and A1 will continue to penetrate inside the refractory. The silicon that appears in the pores (especially in dead-end pores) will crystallize, and the volume effect of some reactions is positive, which means that the products of reactions might incline the pores, causing spalling and cracking [15,16] (Table 3.5). 

The porous film of the aluminium oxide that appears is not a barrier for the reactions of A1 with constituents of the refractory. Molten aluminium and magnesium will continue to penetrate inside the refractory through pores (which will not 

3 Refractories and Heat Insulation Materials for the Cast House 

Sodium on the surface of molten aluminium may also add its input in the corrosion of refractories. Reactions (3.13) and (3.14) proceed with a negative volume effect, which also doesn t promote the formation of continuous alumina film  

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