Emission of electrons and positive ions upon fracture of oxide films

During tensile deformation of oxide‐coated aluminum, small cracks a few hundredths of a mm in length occur in the oxide film. During and following the appearance or elongation of these cracks, electron emission (EE) and positive ion emission (PIE) are detected in the surrounding vacuum. Crack propagation in the oxide coating can be detected with an acoustic emission (AE) transducer. Correlations between charged particle emission and film fracture can then be determined. A comparison of rates of EE, PIE, and AE, the distribution of the number of electrons or ions per burst, and the time distributions relative to crack propagation of both EE and PIE are presented. The time distributions indicate distinct differences in the rate limiting steps governing EE and PIE.