MECHANISM OF STRUCTURE FORMATION IN SELF-PROPAGATING THERMITE REACTIONS - THE CASE OF ALUMINA AS DILUENT

The mechanism of structure formation of the global reaction Fe2O3 + 2A l --> 2Fe + Al2O3 under self-propagating high-temperature synthesis (S HS) conditions in the presence of alumina as diluent is investigated. The reactants in powder form are converted into products by passing th rough four transformation zones with different structure and compositi on. Some of the early stages of this reaction are explained on the bas is of the mechanism proposed by Korchagin and Podergin (1979). Final p roducts seem to be then formed as a consequence of a crystallization p rocess from a melt. These findings may contribute to improve the manuf acturing of wear and corrosion resistant SHS coatings.