- 學位論文
水熱法製備鎂部分取代氫氧基磷灰石粉末及表面塗層於AZ91鎂合金之研究
Preparation of Magnesium-Substituted Hydroxyapatite Powder and Coating on Magnesium Alloy AZ91 Surface by the Hydrothermal Method
摘要
本研究分為兩部分，第一部分以二水磷酸氫鈣(CaHPO4•2H2O, DCPD)與氫氧化鈣( Ca(OH)2 )為反應物，固定鈣磷比1.67在去離子水中混合作為反應改變製程條件尋找粉末製備水熱製程的最佳條件，所有條件HAp粉末為粒徑20~70μm的片狀白色粉末，在沒有鎂摻雜的情況下製程條件175℃、20小時可得到結晶性最佳且無三斜磷鈣石雜相的HAp粉末，IOC分析結果顯示HAp結晶性隨著製程溫度以及製程時間的增加而增加。在反應物中添加1wt%的氫氧化鎂(Mg(OH)2)，利用水熱製程合成鎂部分取代氫氧基磷灰石粉末Mg-HAp，摻雜鎂元素會使得最佳條件HAp粉末結晶性下降並使三斜磷鈣石雜相生成，XPS分析結果顯示晶體鍵結能有下降的情況，代表鎂摻雜有進入HAp晶格。 第二部分利用水熱製程在鎂合金表面製備水熱塗層。鎂合金前處理分為噴砂處理、非晶鎂鋁水滑石以及結晶鎂鋁水滑石用以比較表面效應的影響。水熱製程條件固定為150℃、6小時，塗層厚度50μm，是由氫氧化鎂、碳酸鈣、氫氧化鈣組成的混和塗層。藉由韋伯函數進行分析得知，水熱混合塗層破壞形態皆屬於損耗破壞模式，水滑石前處理會造成結合強度下降，並使得韋伯模數以及可靠度降低。將各條件試片進行模擬體液浸泡實驗，在37.5℃的漢克溶液內長時間浸泡並和氫氧化鎂塗層試片進行比較。在浸泡時間2天到32天，浸泡溶液鈣磷含量隨著浸泡時間明顯下降，試片表面鈣磷含量上升並發現表面析出缺鈣氫氧基磷灰石，明顯改善鎂合金在氯離子溶液中的腐蝕現象，提升生物相容性。
並列摘要
This study is divided into two parts. First, using dicalcium phosphate dehydrate (CaHPO4•2H2O, DCPD) and Calcium Hydroxide (Ca(OH)2) as starting material, mixed with DI water. The Ca/P ratios in the starting slurry was 1.67. This study intends to optimize the synthesis parameters of hydroxyapatite (HAp) powders by hydrothermal method. All conditions of HAp powder prepared by this method is composed of sheet particle with size about 20 to 70μm. The optimized synthesized of HAp powder without magnesium doping at 175℃ for 20 hours has best crystallinity and eliminates DCPA impurity phase. Referring to the IOC% analysis results, the crystallinity increases while increasing process temperatures and process time. Adding 1 wt% Magnesium hydroxide (Mg(OH)2) in starting material to synthesize magnesium-substituted hydroxyapatite powder (Mg-HAp) by hydrothermal method. Doping magnesium reduces the best condition of HAp powder crystallinity and improve the dicalcium phosphate anhydrous (CaHPO4 ,DCPA)impurity phase. The XPS analysis results showrd magnesium doping reduces the HAp crystal binding energy. Second, growth of hydrothermal coating on magnesium alloy AZ91 surface by hydrothermal method. Pre-treatment of Mg alloy sample was sand blast or Mg-Al hydrotalcite process to compare with surface effect. The hydrothermal process conditions are 150℃ for 6 hours. Mixed coating thickness is approximate 50μm. The mixed coating is composed of magnesium hydroxide, calcium carbonate and calcium hydroxide. From the analysis of Weibull distribution function, mixed hydrothermal coating are generally reliable materials with a wear-out failure model. Weibull modulus and reliability are reduced with pre-treatment of Mg-Al hydrotalcite process. Coating samples are immersed in Hank’s solution at 37.5℃ of various durations for 2 days to 32 days. The content of calcium and phosphorus for Hank’s solution are reduced, but for mixed coating surface are increased, with immersed from 2days to 32days. The mixed film is intend to make Calcium-deficient Hydroxyapatite deposition and improve Mg alloy corrosion in solution which contain chloride ion for great biocompatibility.