Cathodic micro-arc electrodeposition of yttrium stabilized zirconia (YSZ) coatings on FeCrAl alloy

摘要

The formation of ceramic coatings on metal substrate by cathodic electrolytic deposition (CELD) has received more attention in recent years. But only thin films can be prepared via CELD. Yttrium stabilized zirconia (YSZ) ceramic coatings were deposited on FeCrAl alloy by a novel technique-cathodic micro-arc electrodeposition (CMED). The result shows that, when a high pulse electric field is applied to the cathode which was pre-deposited with a thin YSZ film, dielectric breakdown occurs and micro-arc discharges appear. Coatings with reasonably thickness of ～300 μm and crystalline structure can be deposited on the cathode by utilizing the energy of the micro-arc. The thickness of the as-deposited coating is dominated by the voltage and the frequency. Y_2O_3 is co-deposited with ZrO_2 when Y(NO_3)_3 was added to the electrolyte, which stabilize t-phase, t'-phase and c-phase of ZrO_2 at room temperature. The amount of the m-ZrO_2 in the coating is diminished by increasing the concentration of Y(NO_3)_3 in the electrolyte. This report describes the processing of CMED and studies the microstructure of the deposited YSZ coatings.