本研究主要分為「奈米級氧化鋯粉末之合成與燒結性質研究」和「鈉鈣磷酸鹽玻璃/氧化鋯複合體之結構特性」兩個部份。第一個部份主要細分為奈米級氧化鋯粉末之合成參數、相變動力學、晶粒成長機制與燒結性質之研究。第二個部份則為鈉鈣磷酸鹽玻璃的添加對氧化鋯複合體結構特性之影響。
粉末製備係以ZrOCl2•8H2O和Y(NO3)3•6H2O為原料，利用化學共沉法合成奈米級氧化鋯粉末。研究結果指出，當改變合成參數為：低的初始溶液濃度、高的pH值與反應溫度，則可合成粒徑小且比表面積大之奈米粉末，並以3 wt%的PEG當分散劑之分散效果較佳。
經由非恆溫結晶動力學之探討，可發現3Y-PSZ奈米粉末的相形成溫度約為700 K，其結晶活化能為401.89 kJ/mol，由結晶成長形態指數與反應機制指數判斷，為三維的體成核機制。利用XRD分析發現，當煆燒溫度為773 - 1073 K時，單斜相氧化鋯的晶粒成長指數由2.37增至2.89，顯示晶粒成長之形狀接近圓球狀，亦由SEM與TEM顯微結構觀察得知，3Y-PSZ之晶粒大小約為10 - 20 nm，而結晶團簇的大小約為50 nm。
然而，奈米級氧化鋯的晶粒成長活化能會隨Y2O3穩定劑的添加量增加而增加，且奈米級氧化鋯的晶粒成長為「晶粒旋轉驅動晶粒成長」的機制，藉由熱驅使晶粒旋轉，使兩晶粒的結晶取向具有一致性，結合後造成晶粒變大。此外，4YSZ在1673 K燒結2小時便可燒結緻密，相對密度>98%，抗彎強度為722±30 MPa。
另外，將鈉鈣磷酸鹽玻璃粉末與商用氧化鋯粉末混合燒結，當鈉鈣磷酸鹽的添加量由0至5 wt%，在1673 K燒結2小時後，氧化鋯複合體的結構由100%的正方相，部份轉變成立方相和單斜相；當添加量由5增至20 wt%時，氧化鋯的主要結構由正方相轉變為單斜相，並於燒結過程中產生少量的HA、Ca(PO3)2、Ca2P2O7和TCP。此外，隨鈉鈣磷酸鹽的添加量增加，其氧化鋯複合體之密度與機械性質下降，然而，未添加鈉鈣磷酸鹽玻璃之氧化鋯燒結體在1673 K燒結2小時後，其密度、硬度和破裂韌性分別為6.03 g/cm3，15.09 GPa和6.12±0.10 MPa•m1/2。

The objective of this study is mainly divided into “preparation and sintering properties of zirconia nanopowders” and “structural properties of sodium-calcium phosphate and zirconia composites”. In the first section, we investigate on the synthesis and colloidal processing of zirconia nanopowder, phase transformation kinetics, crystal growth mechanism and sintering properties. In the second section, the effect of sodium-calcium phosphate addition on the structure of zirconia composites is investigated.
A crystalline nanopowder of 3Y-PSZ has been synthesized using ZrOCl2•8H2O and Y(NO3)3•6H2O as raw materials by a co-precipitation process. Results shown that the surface area increased with reducing crystalline size, low initial solution concentration, high pH and reaction temperature, increase surface area increasing and crystallite size decreasing. In addition, the amount of 3 wt% PEG had better dispersive in this study.
It is noted that the crystallization temperature and formation activation energy of the 3Y-PSZ nanopowders estimated by DTA/TG are about 700 K and 401.89 kJ/mol, respectively. The results of XRD patterns show that the isothermal crystal growth morphology parameter (n) of m-ZrO2 increased from 2.37 to 2.89, when the 3Y-PSZ are calcined at 773 - 1073 K for 2 h, corresponds to the spherical growth from a constant number of nuclei. A nanocrystallite size distribution between 10 and 20 nm and nanocrystallite clusters appearance of around 50 nm are obtained in SEM and TEM observations.
The growth activation energy of the nanocrystallites increased with increasing amount of Y2O3 addition. It can be seen that the crystalline orientation of the zirconia grains was the same by the rotation of particles during heat treatment, resulting in the occurrence of larger crystallites. It seems to note that the nanocrystalline zirconia has been in control of the mechanism of the driving force of grain rotation. Moreover, the bending strength of high dense 4YSZ sintered at 1673 K for 2 h is 722±30 MPa.
Besides, commercial zirconia nanopowders mixed with various amounts of sodium-calcium phosphate were prepared and sintered at different temperatures for 2 h in air. The results show that the main formation of t-ZrO2 transformed into parts of c-ZrO2 and m-ZrO2. When the composites with 0 to 5 wt% sodium-calcium phosphate sintered at 1673 K for 2 h; where as the composites with 5 to 10 wt% sodium-calcium phosphate consist of m-ZrO2 as predominant phase and a lesser amounts of HA, Ca(PO3)2, Ca2P2O7 and TCP as minor phases. The mechanical properties of the composites decreased with an increase in amount of sodium-calcium phosphate. The density, hardness and toughness of the zirconia sinter without sodium-calcium phosphate addtion fired at 1673 K for 2 h, are 6.03 g/cm3, 15.09 GPa and 6.12±0.10 MPa•m1/2, repectively.

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