【作者】 孟晔；

【导师】 强文江； 贾成厂；

【作者基本信息】 北京科技大学 ， 材料科学与工程， 2019， 博士

【摘要】 本文采用放电等离子烧结(SPS)方法制备了HAP陶瓷、HAP/CNTs复相陶瓷、xCNTs-HAP/yCNTs-HAP层状复合陶瓷以及HAP/45S5生物玻璃层状复合陶瓷。系统研究了烧结工艺及CNTs含量对HAP陶瓷及HAP/CNTs复相陶瓷的显微组织结构、物相变化及力学性能的影响规律,并在此基础上创造性地提出了不同CNTs含量的HAP/CNTs层状复合陶瓷的制备思路,配合正交实验探讨了影响xCNTs-HAP/yCNTs-HAP层状复合陶瓷力学性能的各因素的显著性,分析计算出最佳组合方案并进行了验证。为了在提高HAP力学性能的同时兼顾改善其生物降解性能,提出了HAP/45S5生物玻璃层状复合陶瓷的制备思路并在不同温度下进行了烧结,对烧结体的显微结构、物理性能和力学性能进行了研究,探讨了这一制备思路的工艺可行性及应用前景。研究发现,烧结温度达到950℃时,HAP陶瓷中出现HAP晶粒由球形长大成柱状。1000℃烧结时,HAP开始出现部分的分解。烧结温度在900℃时烧结体的各项性能最优。采用SPS技术成功制备致密的HAP/CNTs复相陶瓷。探讨了CNTs含量和烧结温度对烧结体性能的影响。研究发现HAP/CNTs复相陶瓷在900℃进行SPS烧结即可达到致密化,此时HAP已开始出现分解现象,CNTs的存在使化学平衡发生了移动,导致HAP更易分解。讨论了碳纳米管强化机制。HAP/1 wt.%CNTs复合陶瓷在900℃进行SPS烧结的综合性能较好。抗弯强度、断裂韧性和断裂功分别比SPS烧结HAP陶瓷提高了 166%、169%和184%。用预制层叠法配合SPS烧结制备了xCNTs-HAP/yCNTs-HAP层状复合陶瓷,并考察了层数、CNTs含量组合及层厚比对性能的影响。研究表明,层状复合材料在力学性能及应力应变曲线上均显示出了各向异性。采取了正交试验方法对层状结构设计中各因素进行了考查。根据试验结果选出最优工艺参数并进行了验证。该工艺下试样的抗弯强度和断裂功相比HAP/1 wt.%CNTs复合陶瓷分别提高了64.4%和744%,已达到密质骨的力学性能。提出了 HAP/45S5生物玻璃层状复合陶瓷的制作思路,考察了烧结温度对HAP/45S5层状复合材料的物理性能和力学性能的影响,并分析了不同温度下界面的结合及原子迁移和扩散情况。45S5的存在起到了阻碍HAP晶粒长大的作用。烧结体的抗弯强度和断裂功均在950℃时最高,分别比纯HAP烧结体提高了82.2%和500%,已达到支架材料的力学性能要求。45S5生物玻璃的存在,可以调节最终系统的降解以增强其生物反应,显示出更大的向宿主骨结合生长的趋势,同时保持其机械完整性。因此HAP/45S5生物玻璃层状复合材料在作为支架材料的方向上有较好前景。更多还原

【Abstract】 In this paper,HAP ceramics,HAP/CNTs composite ceramics,xCNTs-HAP/yCNTs-HAP laminated composite ceramics and HAP/45S5 biological glass laminated composite ceramics were prepared by spark plasma sintering(SPS).The effects of sintering process and CNTs content on the microstructures,phase transformation and mechanical properties of HAP ceramics and HAP/CNTs multiphase ceramics were systematically studied.On this basis,the preparation ideas of HAP/CNTs layered composite ceramics with different CNTs content were creatively put forward.With orthogonal experiments,the significant factors affecting the mechanical properties of xCNTs-HAP/yCNTs-HAP layered composite ceramics were discussed.The optimum combination scheme is calculated and verified.In order to improve the mechanical properties of HAP as well as its biodegradability,the preparation method of HAP/45S5 Bioglass laminated composite ceramics was put forward and sintered at different temperatures.The microstructure,physical properties and mechanical properties of the sintered body were studied,and the feasibility and application prospect of the preparation method were discussed.It is found that when sintering temperature reaches 950℃,HAP grains grow from spherical to columnar in HAP ceramics.When sintered at 1000 ℃,HAP began to decompose partially.The properties of sintered body are the best when the sintering temperature is 900℃.Dense HAP/CNTs composite ceramics can be successfully prepared by SPS technology.The effects of CNTs content and sintering temperature on the properties of sintered bodies were discussed.It was found that the densification of HAP/CNTs composite ceramics could be achieved by SPS sintering at 900℃.At this temperature,HAP began to decompose.The presence of CNTs shifted the chemical equilibrium and made HAP decompose more easily.The strengthening mechanism of carbon nanotubes was discussed.HAP/1 wt.%CNTs composite ceramics sintered by SPS at 900℃ have better comprehensive properties.Compared with SPS sintered HAP ceramics,its flexural strength,fracture toughness and fracture work are increased by 166%,1 69%and 184%,respectively.xCNTs-HAP/yCNTs-HAP laminated composite ceramics were prepared by precast lamination method and SPS sintering.The effects of the number of layers,the combination of CNTs content and the thickness ratio of layers on the properties were investigated.The results show that the laminated composites exhibit anisotropy in mechanical properties and stress-strain curves.The orthogonal test method was adopted to examine the factors in the design of layered structures.According to the test results,the optimal process parameters were selected and verified.Compared with HAP/lwt.%CNTs composite ceramics,the bending strength and fracture work of the samples under this process were increased by 64.4%and 744%respectively,and the mechanical properties of the compact bone were achieved.The idea of fabricating HAP/45S5 Bioglass laminated composite ceramics was put forward.The effects of sintering temperature on the physical and mechanical properties of HAP/45S5 laminated composite were investigated.The interfacial bonding,atomic migration and diffusion at different temperatures were analyzed.The existence of 45S5 hinders the growth of HAP grain.The bending strength and fracture work of the sintered body are the highest at 950℃,which are 82.2%and 500%higher than that of pure HAP sintered body,respectively.The mechanical properties of the sintered body meet the requirements of the scaffold material.The presence of 45S5 Bioglass can regulate the degradation of the final system to enhance its biological response,showing a greater trend of binding growth to host bone while maintaining its mechanical integrity.Therefore,HAP/45S5 Bioglass laminated composites have good prospects as scaffold materials.更多还原