Cyclic regularities of the acoustic emission generation during plasma-electrolytic oxidation of an Al–Mg alloy in the bipolar mode

The paper analyzes the features of acoustic emission (AE) signal generation during plasma-electrolytic oxidation (PEO) AMg6 aluminum alloy in a bipolar (anode-cathode) pulsed mode within each cycle voltage application. authors studied range PEO modes that almost completely covers all standard technological for processing alloys by current densities (6–18 A/dm2) and ratio half-cycles (0.7–1.3), which allowed fixing studying AE accompanying formation oxide layers various purposes. For first time, due to registration, new stage was identified, there no microarc breakdown substrate, but accompanied an increase layer thickness, nature has not yet been determined. According known stages, systematized repetitive forms manifestation cycles exposure identified their five types three subtypes. study shows approach used establish stages “acoustic amplitude” parameter poor accuracy, since it does take into account form signals half-period registration. Therefore, developed tested analyzing frames synchronously with change forming PEO, proposed “acoustic-emission median” parameter, allows identifying main subtypes stages. An experimental carried out identify these confirmed operability, high accuracy sensitivity recorded at cathode “soft sparking”. latter is particular interest, means given resolution equal cycle.