- 學位論文
水熱法合成析鍍Mg與F離子共同取代之氫氧基磷灰石於Mg-Al-Zn合金之鍍層特性研究
A Study on the Characteristics of Hydrothermally Synthesized Mg/F Co-Doping Hydroxyapatite Coatings on the Mg-Al-Zn Alloy
摘要
氫氧基磷灰石(HAp)具有良好生物相容、生物活性以及引導骨生能力，磷灰石結構可透過其他陽/陰離子的取代，來改善本身物理、化學性質；鎂基合金不但具有高比強度可降低應力遮蔽效應發生，獨特的降解特性能釋放Mg2+刺激骨組織生長。基於此，本實驗利用水熱法直接合成HAp並析鍍於Mg-Al-Zn合金，在飽和水蒸氣氛圍下更能得到缺陷少的HAp結構，此外在水熱合成過程中藉由Mg2+和F─離子的嵌入進行部分取代，以期獲得較佳之HAp鍍層特性。實驗結果顯示水熱法可合成結晶性佳之Mg2+和F─離子部分取代之HAp粉末，然而水熱直接析鍍在鎂合金基材之HAp鍍層結晶性降低並有雜相存在。Mg2+和F─離子的取代，對HAp的晶格體積造成改變，能有助於HAp結晶度提高，塗層與基材間的剪切強度相對來的好，Mg2+和F─離子的取代確實有效改善和提升HAp本身性質。在模擬體液環境下進行抗腐蝕性測試之結果顯示，經表面析鍍HA鍍層之Mg-Al-Zn基材腐蝕阻抗較未析鍍HAp鍍層者顯著提高。
並列摘要
Hydroxyapatite (HAp) has excellent biocompatibility, bioactivity and osteoconductivity. The physical and chemical properties can be modified and improved by the substitution of the cations or anions within the apatite crystal structure. Mg-based alloys represent high specific strength, which can effectively reduce the stress-shielding effect. The release of Mg2+ ions by the degradation of Mg substrate can help to induce the growth of bone structure. Accordingly, the aim of present study is to hydrothermally synthesize HAp and coatings, which have lower structure defects under the saturated steam atmosphere, on the Mg-Al-Zn alloy. In addition, better HAp coating properties can be obtained by the substitution of Mg2+ and F─ ions during the hydrothermal synthesis. Experimental results show that Mg2+ and F─ ions substituted HAp powders with good crystallinity can be synthesized by the hydrothermal method. But the hydrothermally synthesized HAp coatings on the Mg substrate have impurity phases and display lower crystallinity. The substitution of Mg2+ and F─ ions changes the lattice constant of HAp. It helps to increase the crystallinity and the adhesive strength between coating and substrate. Through the examination of corrosion resistance under the simulated body fluid (SBF), the results show that the corrosion resistance of Mg-Al-Zn alloy is significantly increased with the deposition of HAp coatings.