The influences of microdischarge types and silicate on the morphologies and phase compositions of plasma electrolytic oxidation coatings on Zircaloy-2

► ZrO2 coatings are grown on Zircaloy-2 by plasma electrolytic oxidation. ► Characteristic solidification structures are formed on the coatings. ► This structure has not been found on the PEO coatings of other valve metals. ► Very low thermal conductivity of zirconia helps the formation of the structure.