Synthesis nano-apatite powders by chemical and physcial methods
Dr. San-Yuan Chen
|摘要:||本論文以合成奈米級的磷灰石為主要目的，因此，將論文分為主要的兩個架構：以化學法溶膠凝膠法合成奈米級的磷酸鹽與以物理法用雷射剝離激發氫氧基磷灰石靶材得奈米級的磷酸鹽粉末。在溶膠凝膠法合成磷灰石方面，選擇了三種不同的鈣與磷當成前驅溶液的來源，分別是第一組Ca(OC2H5)2 + P(OC2H5)3，第二組Ca(NO3)2．4H2O + P(OC2H5)3以及第三組Ca(OH)2+ H3PO4。這三組不同的鈣與磷來源以Ca/P莫耳比計量合成的磷灰石粉末大部分的粒徑大小都屬於奈米級的，第一組合成的是穩定的磷酸鈣相，後兩組合成的是穩定的氫氧基磷灰石相。以準分子雷射剝離製備奈米級磷灰石粉末方面，將雷射頻率控制在1Hz，改變雷射能量及雷射腔體壓力這兩個參數。結果顯示在雷射能量較低與腔體壓力較低的條件下，靶材受激發後所收集到的粉末其粒徑大小分佈較均勻，粒徑大小是屬於奈米級的。|
Nano-apatite powders have been synthesized by chemical and physical methods in this research. The chemical and physical processes used in this study were sol-gel and excimer laser ablation methods, respectively. In sol-gel method, various calcium and phosphate sources with Ca/P ratio of 1.67 were used as the starting precursors to fabricate nano-apatite powders. These calcium and phosphate sources were categorized as Ca(OC2H5)2 + P(OC2H5)3, Ca(NO3)2．4H2O + P(OC2H5)3, and Ca(OH)2 + H3PO4. Although nano-apatite powders can be produced by all these three sources, hydroxyapatite (HAp) as surface-active bioceramics can be only obtained from Ca(NO3)2．4H2O + P(OC2H5)3 and Ca(OH)2 + H3PO4. In contrast, calcium phosphate (TCP) as resorbable bioceramics was fabricated by Ca(OC2H5)2 + P(OC2H5)3. In excimer laser ablation method, the effects of laser energy and chamber pressure on the material properties of final apatite product were investigated. It was observed that the nano-apatite powders derived from low laser energy and chamber pressure would have narrow particle size distribution and good crystallinity.
|Appears in Collections:||Thesis|