Development of Toughened Porous Hydroxyapatite Sintered Body for Artificial Bone

1.以四水硝酸钙和磷酸氢二铵为原料，采用半间歇均相反应法制备了细小的棒状羟基磷灰石（HAP）晶体和球形HAP颗粒。通过向反应体系中加入柠檬酸钠（1 × 10 ~（-6）<-3>mol/l）得到球形粒子。研究了不同条件对琼脂-琼脂凝胶法制备羟基磷灰石（HAP）球晶的影响。结果表明，少量添加剂的存在促进了球形HAP或无定形磷酸钙颗粒的形成。将进行更详细的研究，以获得有关球形颗粒形成机制的信息。研究了HAP在煅烧和（或）烧结过程中向其它磷酸钙化合物的化学变化。当HAP的Ca/P摩尔比接近理论值1.67时，在1000-1200 ℃加热3小时， ...更多信息 卢比在其他情况下（Ca/P摩尔比&lt;1.67），认为加热操作使HAP转化为P-磷酸钙.从沉淀HAP的煅烧过程的研究中获得了关于粒度分布变化的有趣信息。分布宽度随煅烧温度的降低而减小.通过CT扫描仪对HAP的绿色压坯体和烧结体的内部均匀性进行了广泛的研究。烧结体比相应的绿色致密体稍微更不均匀。通过对不同显微结构的颗粒进行压制成型和加热操作，获得了相对密度为49.4-85.5%的HAP烧结体。用SEVNB方法评价了多孔HAP陶瓷体的断裂韧性。该值为0.13-0.76 MPam^&lt;1/2&gt;。相对密度与断裂韧性呈线性关系，断裂韧性随相对密度的增加而增加。少

1. The fine rod-like hydroxyapatite(HAP) crystals and spherical HAP particles were prepared with calcium nitrate tetrahydrate and diammonium hydrogenphosphate by the semibatchwise homogeneous reaction. The spherical particle's were obtained by addition of sodium citrate(1x10^<-3> mol/l) to the reaction system.2. An investigation was undertaken to determine the effect of various conditions on preparation of HAP spherulite in agar-agar gel. It was revealed that the existence of small amounts of additives promote the formation of spherical HAP or amorphous calcium phosphate particles. The more detailed studies will be carried out for obtaining information on the mechanism of the spherical particle formation.3. Chemical changes of HAP to other calcium phosphate compounds by the calcination and(or) the sintering process were investigated. In the case of Ca/P molar ratio of HAP was close to the theoretical value of 1.67, no change was occurred even when it was heated at 1000-1200ﾟC for 3 hou … More rs. In other cases (Ca/P molar ratio<1.67), it was recognized that HAP was changed to P-calcium phosphate by heating operation.4. The interesting information, regarding the change of particle size distribution was obtained from a study of the calcination process of the precipitated HAP. The width of the distribution decreased witb decreasing calcination temperatures.5. Internal homogeneity of the green compact body and the sintered body of HAP was widely studied by a CT-scanner. The sintered body was somewhat more heterogeneous than the corresponding green compact body.6. The HAP sintered bodies having relative density of 49.4-85.5% were obtained by the compression molding and the heating operation of the particles with varying microstructures. Fracture toughness of these porous HAP sinipied bodi-es was evaluated by a SEVNB method. The values were 0.13-0.76 MPam^<1/2>. A linear relation between the relative density and fracture toughness was recognized ; the fracture toughness increased with an increase of the relative density. Less