Use of phase diagrams in studies of refractories corrosion

Typical applications of phase diagrams to specific problems of refractories corrosion are highlighted. Saturation solubilities of refractories compone nts in molten slags can be estimated using existing phase diagrams. These c an then be used to predict the corrosion behaviour, and qualitatively compa re the corrosion resistance, of a refractory in different slags or differen t refractories in the same slag. If the slag is not saturated with refracto ries components, using relevant phase diagrams, the conditions under which solid reaction product phases form at refractories/slag interfaces can be p redicted, which assists understanding of direct and indirect dissolution. B y checking the compatibility between impurities or additives and refractori es components at high temperatures, their influence on corrosion resistance can be predicted, aiding their selection. Phase diagrams also reveal that atmosphere affects refractories corrosion resistance by altering the valenc e of some components (in particular, iron oxide) in the refractories and/or slags. The compatibility between refractories and slags indicates the corr osion resistance of different refractories, assisting refractories selectio n for specific applications. Finally, phase diagrams can be used to assist design of refractories composition. Repeated experimental corrosion test re sults show good agreement with phase diagram predictions. Therefore, use of the information which is available in existing phase diagrams can reduce t he need for expensive and time consuming experiments to evaluate high tempe rature corrosion of refractories (and other ceramics). (C) IoM Communicatio ns Ltd and ASM International.