Quantitative parameters and definition of stages of anodic-cathodic microplasma processes on aluminum alloys

Abstract

Positive (anode) and negative (cathode) voltage-time charts have been registered for half-wave anodic, AC polarization, and AC-C polarization and for negative polarization (C-packets), respectively. During the process, the visual characteristic changes of the microdischarges were also analyzed, namely: the color and dimension of the microdischarges and the character of the movement on the surface. The quantitative parameters for the microplasma process stages were also defined. For different aluminum alloys, it was found that spark voltage and microarc voltage are not dependent on the alloy composition and the current density. It was likewise shown that a negative current has no influence on the process parameters at the initial stages of the AC microplasma processes. The study's hypothesis on the role of a negative current in initiating phase transition was therefore confirmed. © 2005 The Japan Institute of Metals.