Preparation Al2O3/ZrO2 composite coating in an alkaline phosphate electrolyte containing K2ZrF6 on aluminum alloy by microarc oxidation

► The effects of K2ZrF6 in the electrolyte on characteristics of the MAO coatings were investigated. ► More uniform and compact MAO coating was obtained due to the addition of K2ZrF6. ► γ-Al2O3/t-ZrO2 nanocomposite MAO coating was prepared in the electrolyte with 6.0 g/L K2ZrF6. ► Abrasive resistance of the MAO coatings was improved due to the addition of K2ZrF6.