Investigation of ZrO2 nanoparticles concentration and processing time effect on the localized PEO coatings formed on AZ91 alloy

• 作者: Dongjin Choi Zeeshan Ur Rehman
• 来源期刊: 镁合金学报(英文)
• 学科: 工学
• 关键词: Magnesium alloy PEO coating ZRO2 Corrosion Nanoparticles addition
• 年，卷（期）: 2019,（4）
• 页码范围: 555-565
• 页数: 11页
• 分类号: TG1

摘要

AZ91 Mg alloy was treated through a new localized PEO(Plasma Electrolytic Oxidation)coating approach,using electrolyte solutions with varying ZrO2 nanoparticles concentration(2-8 g/L)and processing times.With increase in the ZrO2 concentration,several microstructural changes were observed including;formation of cluster-type structure,damage to the inner layers(∼30 min)and sealing of defects.Corrosion analysis of the final coatings was carried out using potentiodynamic polarization,electrochemical impedance spectroscopy and post-corrosion analysis.It was explored that highest corrosion resistance(Rp∼81.17 kΩcm^2)of the coatings was obtained for ZrO2∼2 g/L.However,higher concentration of the ZrO2 nanoparticles caused weak crystalline coating structure,due to unstable and lower intensity discharges,thus failed to offer high corrosion resistance performance.