Synthesis of Al₂O₃–Y₂O₃ Ceramic Coatings on the Fe–Cr–Al Wire via Aqueous Cathodic Plasma Electrolysis

The Al 2 O 3 –Y 2 O 3 coating was successfully prepared by cathodic plasma electrolysis on the FeCrAl wire. Influences of the electrolyte composition and the processing parameters on the microstructure and property of the Al 2 O 3 –Y 2 O 3 ceramic coating were systematically investigated. The coating was mainly composed of γ-Al 2 O 3, α-Al 2 O 3, and Y 2 O 3 . Experimental results showed that the thickness of the coating was gradually increased with the increase of working voltage, while the bonding became poor. With an increase in the deposition time, the thickness and the electrical resistance of the Al 2 O 3 –Y 2 O 3 coating were increased in a certain range. When the Al 2 O 3 –Y 2 O 3 coating was deposited at 110 V for 60–90 s, the bonding between the coating and the substrate was superior, and the coating microstructure was dense, continuous, and uniform with the electrical resistance reaching up to ∼40 MΩ. The formation mechanism of the coating was also discussed based on the electrochemical mechanism and the plasma discharge.