【作者】 韩颖超；

【导师】 李世普；

【作者基本信息】 武汉理工大学 ， 材料学， 2002， 硕士

【摘要】 仿人长干骨的结构梯度进行材料设计：外层为致密层，内层为多孔松质层。采用HAP粉末为原料，添加一定量的生物玻璃，来制备多孔梯度HAP人工骨。 本研究首次采用自燃烧法合成了纳米级HAP粉末。自燃烧法以溶胶-凝胶法为基础，特别适合于纳米粉体的合成。按照摩尔比n（Ca）／n（P）=1.67及n（Ca离子）／n（柠檬酸）=1将Ca（NO₃）₂·4H₂O、（NH₄）₂HPO₄与柠檬酸混合，在80℃加热蒸发，几小时后凝胶形成。然后在200℃燃烧，最后经750℃煅烧得到纳米HAP粉末。经XRD分析及TEM观察，为纯相的HAP，平均粒径为85nm。通过对自燃烧法制备的纳米级羟基磷灰石（HAP）粉末，进行的DTA、TG和XRD测试，分析纳米HAP的生成历程，并对反应机理进行了初步探讨。对该工艺的影响因素：水量、PH值、温度和柠檬酸的量进行了初步讨论。结果发现，反应机理主要为溶胶凝胶生成阶段的络合物sol-gel法机理和煅烧阶段的氧化还原燃烧机理；HAP的生成主要经历了β-Ca₂P₂O₇、γ-Ca₂P₂O₇、CaH₂P₂O₇、C₂Ca、CaCO₃等相；最佳工艺条件是：[H₂O]／[Ca²⁺]=30～35，PH值在2～3之间，加热温度为80℃左右，柠檬酸与钙离子的比在1～2之间。 本研究采用含生物玻璃前驱体粉末原料，添加柠檬酸造孔剂，模压成型，在1050℃烧结保温3小时，获得了显气孔率为54％、体积密度为1.28S／cm³、抗弯强度为13.25MPa的多孔HAP人工骨材料。 研究发现，加入玻璃粘结剂可以促进材料的烧结，降低烧结温度。随着烧结温度的升高和保温时间的延长，显气孔率和吸水率逐渐减小，体积密度逐渐增加。抗弯强度随着烧结温度的升高和保温时间的延长而增加，多孔烧结体的强度可以主要通过气孔率来判断。 通过1050℃不同保温时间烧结的多孔HAP的形貌观察，可以清楚地看到孔径大小的梯度变化，与人长骨的梯度结构基本一致。致密层存在少量的尺寸为50μm左右的气孔和大量的尺寸为5μm左右的微孔，这是原料中残留有机物烧失以及粉末颗粒烧结不致密形成的；多孔层存在大量的尺寸为500μm左右的大孔，这是柠檬酸造孔剂烧失形成的，在大孔之间存在一些约50μm、100μm的气孔。随着保温时间的延长，梯度界面变得更加致密，宏观气孔孔的边缘钝化，且较大的缺陷被愈合，气孔的形状更加近似球形，气孔的尺寸由500μm左右减小到400μm左右。更多还原

【Abstract】 The structure of artificial bone was designed according to the long bone of people, the outer was compact layer, the inner was porous spongiosa layer.HAP powders were firstly prepared by auto-combustion method in this study. The calcium nitrate, ammonium hydrogen phosphate and citric acid were blended according that the mole ratio of Ca/P and Ca2+/(citric acid) were 1.67 and 1. Then the blender were heating at 80 to form gel after some hours. At last the gel was firing at 200 and calcined at 750 to get the HAP powders. The results showed that the sample was pure-phase HAP and the grain size was about 85 nm. Via TG-DTA and XRD testing on the nanosized hydroxyapatite (HAP) prepared by auto-combustion method, the course of HAP was analyzed, and the mechanism of reaction was discussed. The influence factors of this method such as, the quantity of water, PH value, temperature and the quantity of citric acid were studied. The results show that the mechanism of reaction is complex mechanism in the generating stage of sol-gel and then the oxidation-reduction combustion mechanism; The forming of HAP mostly experienced the phases of B-Ca2P2O7, y- Ca2P2O7, CaH2P2O7, C2Ca, CaCO3 and so on. The optimum technical parameters are that the n(H2O)/ n(Ca2+) is 30-35, the PH value is 2-3, the heating temperature is about 80, and the mole ratio of citric acid to Ca2+ is 1-2.The material was sintered at 1050 for three hours to get the porous artificial bone, that its apparent porosity was54%, its volume density was 1.28 g/cm3, and its bending strength was 13.25Mpa.The results showed that the sintering temperature was reduced by adding bioglass. Along with the rising of sintering temperature and the increasing of heat preservation time, the porosity and water absorption reduced, the density and bending strength increased, the bending strength was mostly estimated by the porosity.Through observing the interface of porosity HAP sintered at 1050, the gradient changing of pore size was observed that was like gradient structure of bone. In the compact layer there were a few about 50 y mpores and many about 5um micropores. In the porous layer there were many about 500um pores.更多还原