GOALI: Rapid Sintering to Manufacture Fully Dense and Bioactive Nanoscrystalline Hydroxyapatite

这项研究工作探索了一个短时间的致密化过程-称为场辅助烧结技术（FAST）-制造完全致密的纳米晶羟基磷灰石（HA）陶瓷部件。 首先，将建立纳米晶HA陶瓷的FAST处理的基本因素。将研究工艺参数（电、压力、烧结环境和动力学）与致密HA部件的结构和性能之间的关系。 接下来，将确定作为烧结条件的函数的完全致密HA陶瓷的机械性能和生物相容性。 最后，FAST工艺将用于制造近净形纳米晶HA骨科植入物。将对这些致密部件的机械性能和体内性能进行确认。 我们的工业合作伙伴Angstrom Medica（AM）将提供HA纳米粉末，设计用于净形制造的真实的骨科植入物，并测试致密磷酸钙陶瓷的体外生物相容性。 如果成功，这项研究的结果将用于开发一种技术，以有效地制造具有改善的机械和生物学性能的骨科植入物。拟议的工作将创建一个新的FAST制造实践可能基于的工程基础。FAST烧结工艺可在几分钟内实现HA粉末的致密化，而目前使用的热压工艺需要数小时，从而提高了加工生产率。 该工艺的净成形性将适用于在更短的时间内制造骨科植入物，并减少加工步骤的数量。 在最终的HA材料中保留纳米颗粒结构具有很高的潜力，可以生产具有上级机械和生物学特性的植入物，这些特性可以加速愈合，并减少手术后的疼痛和炎症。 工艺相关微观结构及其与这些最终性能的关系的评价将是制造可靠的HA骨科植入物的一个组成部分。

This research effort explores a short time densification process - termed Field Assisted Sintering Technique (FAST) - to manufacture fully dense nanocrystalline hydroxypaptite (HA) ceramic parts. First, the fundamental factors governing the FAST processing of nanocrystalline HA ceramics will be established. The relationship between processing parameters (electrical, pressure, sintering environment, and kinetic) and the resulting structure and properties of dense HA parts will be investigated. Next, mechanical properties and biocompatibility of fully dense HA ceramics as a function of sintering conditions will be determined. Finally, the FAST process will be used to manufacture near net shape nanocrystalline HA orthopedic implants. The mechanical and in vivo properties of these dense parts will be validated. Our industrial partner, Angstrom Medica (AM) in Woburn (MA), will contribute HA nanopowders, will design the real orthopedic implants for net shape manufacturing, and test the dense calcium phosphate ceramics for in-vitro biocompatibility. If successful, the results of this research will be used to develop a technology to efficiently manufacture orthopedic implants with improved mechanical and biological properties. The proposed work will create the engineering foundations on which a new FAST manufacturing practice may be based. FAST sintering process enables densification of HA powders in minutes, as compared to hours in the currently used hot pressing process, thus enhancing the processing productivity. The net shape formability of this process will be adapted to manufacture orthopedic implants in shorter time and with a reduced number of processing steps. The retention of nanocrystallline structure in the final HA material has a high potential to produce implants with superior mechanical and biological properties that expedite healing, and reduce pain and inflammation upon surgery. The evaluation of process dependent microstructure and its relationship to these final properties will be an integral component of manufacturing reliable HA orthopedic implants.