Electrical characteristics identification of dielectric film breakdown during plasma electrolytic oxidation process

• A pulse test method was used to identify dielectric breakdown of growing oxide film.
• The inter-relationship between externally-imposed electrical conditions and coating behaviors was established.
• The electrical characteristics identification technique can be used to real-time diagnostics and self-adaptive control of PEO process.

To identify the electrical characteristics of dielectric breakdown of growing oxide film during plasma electrolytic oxidation (PEO) process, a real-time identification method based on pulse test technique was presented. The voltage–current characteristic curve and impedance curve of pulse tests were analyzed. A sharp increase in pulse current was observed when applied potential increased to critical breakdown voltage, and the breakdown voltage and absolute impedance value of oxide film increased with processing progress. Therefore, the electrical characteristics identification technique could be used for process diagnostics and self-adaptive control of PEO process.