Effect of Na₂SiO₃·5H₂O concentration on microstructure and mechanical properties of plasma electrolytic oxide coatings on AZ31 Mg alloy produced by twin roll casting

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• 作者：Salim Levent Aktuğ^a ; Salih Durdu^a ; ^b ; Işıl Kutbay^a ; ^{kutbay@gtu.edu.tr" class="auth_mail" title="E-mail the corresponding author} ; Metin Usta^a ; ^c
• 关键词：C. Mechanical properties ; Plasma electrolytic oxidation (PEO) ; TRC AZ31 Mg alloy ; Scanning electron microscopy (SEM) ; X-ray diffraction (XRD)
• 刊名：Ceramics International
• 出版年：2016
• 出版时间：January 2016
• 年：2016
• 卷：42
• 期：1
• 页码：1246-1253
• 全文大小：3508 K

文摘

In this study, AZ31 Mg alloys produced by twin roll casting (TRC) were coated by plasma electrolytic oxidation (PEO) in solution of potassium hydroxide (KOH) and different concentration of sodium metasilicate pentahydrate (Na₂SiO₃·5H₂O) electrolytes at 0.140 A/cm² current density for 60 min. The phase structure, morphology, hardness, adhesion strength, surface roughness and wear resistance of the PEO coatings were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), micro-hardness tester, micro-scratch tester, profilometer and tribometer, respectively. The XRD results indicated that Forsterite (Mg₂SiO₄) and Periclase (MgO) phases were formed on the surface of the coated magnesium alloys. The surface of the coatings is very porous and rough due to the presence of micro-discharges through PEO process. It was seen that the wear rate, hardness and surface roughness of the coatings were increased when the concentration of Na₂SiO₃·5H₂O electrolyte was increased.