The Study of MgO-MgCO3/Al(OH)3 and MgO-MgCO3/HA Double Layer Coatings on Pure Magnesium by Electrolysis for Increasing Corrosion Resistance

• Main Authors: Yun-Chung Tu, 杜允中
• Other Authors: Shiow-Kang Yen
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/17879817439043129872

碩士 === 國立中興大學 === 材料科學與工程學系所 === 103 === In this study, we try to prepare MgO-MgCO3/ Al(OH)3 and MgO-MgCO3/HA double layer coatings on pure magnesium using electrochemical deposition in order to increase corrosion resistance and provide functional surface for biomaterials. The coatings were characterized by XRD, SEM, FIB, XPS and dynamic polarization after annealing treatment. It was found that the first layer is MgCO3 / Mg(OH)2 composite coating and a thin layer of MgO on the top of it. The main structure of Al(OH)3 coating was Gibbsite. The Ca/P ratio of HA coating was 1.31 similar to Octacalcium Phosphate (OCP). Although the Al(OH)3 coating is relatively loose, it exhibits the best corrosion resistance due to its good chemical inertness. The MgCO3-MgO layer has good uniformity with only 0.2~0.5μm thickness but its corrosion resistance is better than that of the porous HA layer with 6μm thickness. However, dynamic polarization results show that both single layer MgO-MgCO3 or double layer MgO-MgCO3/Al(OH)3 or MgO-MgCO3/HA coating can increase the corrosion resistance of pure magnesium.