【作者】 郭军松；

【导师】 张建民；

【作者基本信息】 郑州大学 ， 物理化学， 2003， 硕士

【摘要】 本论文就生物活性陶瓷羟基磷灰石纳米材料的制备以及运用电泳沉积技术沉积羟基磷灰石涂层进行了研究。羟基磷灰石作为常用的生物活性材料，因具备良好的生物活性和生物相容性而广泛运用于临床，但是由于本身的脆性，限制了羟基磷灰石单独作为植骨材料的应用，而必须与其它的传统医用金属材料一起使用，才能满足作为医用材料强度方面的要求，因此，本论文就电泳沉积羟基磷灰石涂层进行了研究。在制备涂层之前，首先利用湿法制备出结晶度在纳米范围的羟基磷灰石颗粒，并利用X射线衍射、傅立叶变换红外光谱等技术对所制得的羟基磷灰石颗粒进行了表征；然后利用电泳沉积技术在钛合金上得到羟基磷灰石生物陶瓷涂层，并依据实验所测得参数和电泳沉积的具体过程，提出了电泳沉积生物陶瓷的电容充电模型；最后就电泳沉积过程的动力学进行了理论推导，得到了不同条件下沉积量与时间之间的关系式，同时利用这些关系式所得的结论和实验数据，拟合出在一定条件下沉积量与时间之间的关系。主要结论如下： （1）通过采用煅烧CaCO₃所制得的CaO悬浮液与稀磷酸反应，只要控制好所加的钙磷物料比为1.67，并通过长时间的陈化，同时保证反应过程在隔绝空气的环境下进行，就能制备出纯度高、结晶度小的羟基磷灰石颗粒。 （2）用上述方法制备的羟基磷灰石颗粒，经X射线衍射（XRD）、傅立叶变换红外光谱（FTIR）等技术的表征，发现颗粒的纯度高、羟基磷灰石的结晶度在纳米尺度范围之内。 （3）用上述方法制备羟基磷灰石，经洗涤、脱水后，容易在乙醇中做带电处理，得到的羟基磷灰石颗粒的zeta电位为30-40毫伏、粒径为1-25μm、最几分布为7μm的悬浮液，这种悬浮液很容易通过电泳技术在钛合金上制得羟基磷灰石涂层。 （4）通过对电泳沉积过程以及实验参数的分析，如果假设在电极上不发生任何化学反应，并且颗粒只受电场力的作用，则电泳沉积过程可用电容的充电过程来模拟。 （5）假设悬浮液中只有羟基磷灰石导电，而分散介质不导电，从理论上推导出不同条件下电泳沉积量与沉积时间之间的关系式。利用这些关系式所得的结纳米生物活性陶瓷材料的制备以及电泳沉积生物陶瓷涂层的研究论和恒流一等浓度条件下所得到的沉积量与时间的数据，拟合出不同电流条件下所对应的经基磷灰石颗粒运行速度之间的关系式。利用此关系式和恒压一等浓度条件下不同时间所对应的电流强度的数据，拟合出恒压一等浓度条件下沉积量与时间之间的关系曲线，此曲线与实验所得的曲线在沉积初期符合的程度比较好。更多还原

【Abstract】 Hydroxyapatite (HAP), formulated as Caio(PO4)e(OH)2, has become a favorable biomaterial for implants since its chemical composition and crystal structure are similar to the calcium phosphate minerals present in biological hard tissue. The clinical use of HAP as a load-bearing implant, however, is limited because of its mechanical brittleness and low tensile strength. Many efforts have been made in recent years in the development of processing methods for depositing HAP on the implant alloy substrate in order to have high strength as well as excellent biocompatibility and bioactivity. Electrophoretic deposition of HAP bioceramic coatings has recently attracted considerable attention because of a variety of advantages of the method of the coating fabrication, such as a low process temperature, ability to deposit on porous or complex shapes of substrate, the simple control of deposit thickness.It has been studied in this thesis that nanometer hydroxyapatite materials were fabricated by a wet method and bioceramic coatings of hydroxyapatite were prepared by the electrophoretic deposition (EPD) technique. The major results and conclusions are summarized as follows:1. Hydroxyapatite for EPD was prepared by wet method using CaCO3 and H3PO4 as the raw materials. The crystal structure and chemical composition of the product were determined by X-ray diffraction (XRD) and Fourier transform infrared(FTIR). The results show that the high pure nanometer hydroxyapatite materials can be prepared while CaO obtained from the decomposition of CaCO3 reacted with H3PO4 for 96 hours in the Ca/P ratio of 1.67.2. HAP coatings on clinical alloys were obtained by electrophoretic deposition that is a combination of two processes: electrophoresis and deposition. Electrophoresis is the motion of charged HAP particles in a suspension under the influence of an electric field, and deposition is the coagulation of HAP particles to a dense mass. The sintered surface of bioceramic coatings deposited by electrophoresis method was detected by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Accordingto the relationship of the deposition time versus the deposit weight and the current density as well as deposit weight versus applied voltage, a model of capacity charging is proposed to explain the process of EPD.3. The kinetics of EPD was studied under the precondition that the charged powder of HAP is the only carrier of electric charge in suspension. The kinetic equations are developed for constant-current and constant-voltage EPD using mass balance conditions. The formula of deposition weight versus time as well as the relationship of velocity versus deposition time could be derived from the experimental data of current versus time, which is obtained under the condition of constant voltage and constant concentration of HAP, and the relationship between observed current and velocity of HAP powders, which results from the theoretical kinetic equation and experimental data measured at the condition of constant current and constant concentration of HAP. The calculated kinetic curve is better fit at the beginning of EPD to the experimental curve plotted under the condition of constant voltage and constant concentration of HAP.更多还原