摘要
Al<sub>2sub>O<sub>3sub>/ZrO<sub>2sub> composite coating was prepared on 2A70 aluminum alloy by microarc oxidation (MAO) in a phosphate electrolyte containing K<sub>2sub>ZrF<sub>6sub>. The effects of K<sub>2sub>ZrF<sub>6sub> in the electrolyte on the coating thickness, surface morphology, elemental composition and abrasive resistance were investigated. The results indicated that the MAO coating thickness increase due to the addition of K<sub>2sub>ZrF<sub>6sub> in the electrolyte. In the electrolyte containing 6.0 g/L K<sub>2sub>ZrF<sub>6sub>, the coating was the most uniform and compact. The MAO coating formed in the electrolyte without K<sub>2sub>ZrF<sub>6sub> was mainly composed of 纬-Al<sub>2sub>O<sub>3sub> and a little 伪-Al<sub>2sub>O<sub>3sub>. Zirconium in the form of t-ZrO<sub>2sub> was detected in the MAO coatings formed in the electrolyte containing K<sub>2sub>ZrF<sub>6sub>, and the Zr content increases with increasing concentration of K<sub>2sub>ZrF<sub>6sub>. A 纬-Al<sub>2sub>O<sub>3sub> and t-ZrO<sub>2sub> nanocomposite coating was formed in the electrolyte containing 6.0 g/L K<sub>2sub>ZrF<sub>6sub>, and which exhibited the highest abrasive resistance.