Effects of frequency on growth process of plasma electrolytic oxidation coating

Electrochemical impedance spectroscopy and transient waveform analysis were used in the current paper to study the effects of frequency on the growth process of plasma electrolytic oxidation (PEO) coating, which was prepared on Ti6Al4V using single-pulse power supply. The results showed that the voltage range of the anodic spark stage was not affected by frequency, and the structures of the coatings prepared at the same termination voltage were very similar. The voltage range of the micro arc stage increased with frequency, and the damage of the microdischarges to the coating decreased with frequency. Results also confirm that the PEO process can be monitored via transient waveform analysis.

► Frequency effects on PEO process are studied by EIS and transient waveform analysis.
► The voltage range of anodic spark stage is not affected by frequency.
► Coating structure is close at the same termination voltage in anodic spark stage.
► The voltage range of micro arc stage decreases with frequency.
► PEO process can be monitored by transient waveform method.