Solid-phase reaction of aluminum with the hexagonal and cubic phases of cobalt in film systems

Abstract

Solid-phase reactions taking place in Al/β-Co/MgO(001) and Al/α-Co/MgO(001) film systems under conditions of self-propagating high-temperature synthesis (SHS) are investigated. In both systems, SHS products exhibit the single CoAl superstructure, which epitaxially grows on the MgO(001) surface in the Al/β-Co/MgO(001) structures and has a fine-dispersed disordered structure in the Al/α-Co/MgO(001) films. It appears that the difference in the reagent structure has an effect on the energy of activation but does not change the SHS initiation temperature and the temperature at which the initial phase involved in the reaction products nucleates. It is shown that the SHS initiation temperature in the Al/β-Co/MgO(001) and Al/α-Co/MgO(001) systems coincides with the temperature of CoAl superstructure ordering.