【作者】 童昀；

【导师】 周振君；

【作者基本信息】 长安大学 ， 材料学， 2008， 硕士

【摘要】 羟基磷灰石（HA）陶瓷具有与天然骨相似的化学组成,临床实验已经证明了它是生物医学应用领域的候选移植材料。具有多孔结构的生物陶瓷,在组织内生长和控制生物降解率上均有明显的优点。然而,传统方法制备的多孔陶瓷的气孔尺寸及其分布决定于成孔剂的颗粒尺寸及分布,这将导致多孔陶瓷具有较差的力学性能。凝胶注模法在控制气孔形貌、结构均匀性和减少缺陷和减小缺陷尺寸上有明显优势,因此该方法已经被认为是制备均匀显微结构陶瓷的主要方法。本文首先介绍了羟基磷灰石的性质和结构,并阐述了多孔羟基磷灰石生物陶瓷材料的国内外研究现状。然后,采用低温自燃烧法制备超细羟基磷灰石粉体,并以该粉体为原料,用凝胶注模成型法制备了多孔羟基磷灰石陶瓷。通过X射线衍射（XRD）、透射电子显微镜（TEM）、扫描电子显微镜（SEM）等现代分析测试技术对粉体和多孔陶瓷的组成与形貌进行了检测。研究结果表明:低温自燃烧法制备羟基磷灰石粉体工艺可以得到分散良好的粒径为20nm～80nm的HA粉体。在1200℃下,通过控制保温时间可以成功地控制多孔陶瓷的气孔尺寸和气孔率,且其强度随着气孔尺寸和气孔率的增大而减小。单体浓度15wt%的试样在1200℃下烧结的抗折强度为0.0626MPa,抗压强度为83.62 MPa,其开气孔率为39.59vol%。最后,研究了各个工艺参数对粉体尺寸、料浆流变性和多孔陶瓷显微结构的影响,进而得到制粉时最佳络合剂乙二醇/Ca²⁺物质的量比为1/1, n（H₂O）/ n(Ca²⁺)为30,pH值为2～3,煅烧温度为800℃;制浆时最佳水/粉料质量比为1.5/1,球磨时间为5h,分散剂浓度为2wt%,pH值为10;坯体须经过从90%湿度25℃温度到低湿度80℃温度的一系列干燥制度。更多还原

【Abstract】 Hydroxyapatite （HA） ceramics has chemical compositions closely resembling that of mineral phase of natural bone. Many in-vivo experiments have confirmed the HA as a potential implant material for biomedical applications. To fabricate a bioceramic with porous configuration, the evidence of tissues ingrowth and biological responses provide obvious advantages in tissue-implant fixation and controlled biodegradation rate. The pore size or pore size distribution is directly related to the particle size or particle size distribution of introduced polymeric powders by traditional methods. This leads to the poor mechanical properties for the porous ceramics. Several advantages can usually be obtained for gel-casting route such as controlled pore geometry, structural uniformity, and minimum defects/defect size, etc, and which methodology has long been considered as a major processing for production of ceramics with a more uniform microstructure.First, the properties and the crystal structure of hydroxyapatite were introduced, and the domestic and foreign situations of the research about hydroxyapatite ceramics were reviewed. Then, the ultrafine hydroxyapatite powder was prepared by low-temperature combustion synthesis （LCS）. Using the powder, the hydroxyapatite porous ceramics was prepared by gel-casting route. Characters of the powders and porous ceramics were studied by XRD, TEM, and SEM. The results show that the diameters of hydroxyapatite powders prepared by LCS are 20～80 nm. The porous ceramic sintered at 1200℃with a successful control of pore size and porosity characters can be obtain by controlling holding time. The strength of the porous hydroxyapatite ceramic decreased with increased pore size and porosity. The flexural and compression strength of specimen sintered at 1200℃for 2h showed a value of 0.0626MPa and 83.62 MPa, with a porosity of 39.59vol%.Finally, the effect of technological parameters on the size of powders, fluidity of the ceramic slips and microstructure of the porous ceramic were investigated, and many optimum parameters were obtained, which is that the optimum n（glycol）/Ca²⁺ is 1/1, the n（H2O）/n(Ca²⁺) is 30,the value of pH is 2～3, the temperature to calcine is 800℃at the phase of the powder was created; the optimum m（H₂O）/m（powder） is 1.5/1, the time of milling is 5h, the concentration of dispersant is 2wt%, the value of pH is 10 when the slurry was cranked out. The waterish ceramicembryoes must be dried under a series of system from the humidity of 90% and the temperature of 25℃to the low humidity and the temperature of 80℃.更多还原