Autowave oxidation of Dy-Co films

The kinetics of the initial oxidation stage for Co sub x Dy sub 1-x (x < 0.7) films is considered. A substantial difference was revealed between explosive heating and osothermic oxidation. Autowave oxidation did not proceed deep into the film, as in the isothermic case, but originated from an oxide nucleus penetrating onto the whole film surface in a self-maintaining way. The front temperature was estimated to be roughly in excess of both metal and oxide melting points. The temperature dependences of oxide-layer depth and delay time, as well as pressure on critical temperature, were investigated. After covering the whole film surface by the oxide wave, further oxidation penetrated deep into the film.