Synergistic Phase Combination for High Strength Ultrafine-Grained Bioceramics

 描述（由申请人提供）：由于在材料微观结构、化学和加工技术的开发和控制方面取得了显著进展，陶瓷在牙科中的应用正在稳步扩大。同时，陶瓷部件在骨科关节置换手术中的使用仍然很普遍。陶瓷表面由于低磨损率而对于关节置换是有吸引力的，但它们固有地易碎。因此，即使成功率通常很高，在骨科和牙科中也确实会发生体内失败。需要一种可靠的、高强度的、具有低磨损性的生物陶瓷，用于矫形外科和牙科。我们的目标是开发具有协同相组合的超细晶氧化锆/尖晶石陶瓷，从而获得高晶界稳定性、高可靠性和断裂韧性。该项目提出了一项重大的技术创新，该创新依赖于1）在双相生物陶瓷中氧化锆（3 Y-TZP）和超细晶粒纳米尖晶石（MgAl 2 O 4）之间的协同微观结构和热性能的结合，以及2）创建受控的超细晶粒表面，抑制水解降解并降低磨损性。这些双相材料将通过确保骨科和牙科应用中更长的寿命性能来推进生物陶瓷领域。在具体目标1中，将合成并表征氧化锆-尖晶石陶瓷（3 Y-TZP/nS）。在具体目标2中，将建立晶粒细化的条件，并测量超细晶粒3 Y-TZP和3 Y-TZP/nS陶瓷的耐低温降解性（LTD）、磨损特性和机械性能。拟议工作的预期成果是开发和生产具有高强度，高可靠性，低磨损性的新型生物陶瓷，同时在需要时提供优异的美学效果，从纳米尖晶石相的存在。通过开发创新的晶粒细化工艺，目前的氧化锆陶瓷和新型氧化锆-纳米尖晶石生物陶瓷的耐磨性预计将显著降低，这是另一个重要的转化成果。拟议工作的影响将来自新材料和技术的发展，并可能远远超出骨科和牙科领域，如果我们预期，这些新的生物陶瓷表现出超塑性，这将大大促进在高温下加工。

 DESCRIPTION (provided by applicant): Applications of ceramics in dentistry are steadily expanding due to outstanding progress in the development and control of materials microstructures, chemistry and processing techniques. Meanwhile, the use of ceramic parts in orthopedic joint replacement procedures remains widespread. Ceramic surfaces are attractive for joint replacement because of low wear rates but they are inherently brittle. As a consequence, even if success rates are generally high, in vivo failures do occur, both in orthopedics and in dentistry. There is a need for reliable, high strength bioceramics with low abrasiveness for use in both orthopedics and dentistry. Our goal is to develop ultrafine-grained zirconia/spinel ceramics with synergistic phase combination leading to high grain boundary stability, high reliability and fracture toughness. This project presents a major technological innovation that relies on 1) the combination of synergistic microstructural and thermal properties between zirconia (3Y-TZP) and ultrafine-grained nanospinel (MgAl2O4) in dual phase bioceramics and 2) the creation of a controlled ultrafine-grained surface inhibiting hydrolytic degradation and reducing abrasiveness. These dual-phase materials will advance the field of bioceramics by ensuring longer life performance in orthopedic and dental applications. In specific Aim 1, zirconia-spinel ceramics (3Y- TZP/nS) will be synthesized and characterized. In specific Aim 2, conditions for grain size refinement will be established and resistance to low temperature degradation (LTD), wear characteristics and mechanical properties of ultrafine-grained 3Y-TZP and 3Y- TZP/nS ceramics will be measured. Expected outcomes of the proposed work are the development and production of novel bioceramics with high strength, high reliability, low abrasiveness while offering excellent esthetics when needed, from the presence of the nanospinel phase. The projected significant reduction in abrasiveness of current zirconia ceramics and novel zirconia-nanospinel bioceramics by developing an innovative grain refinement process constitutes another important translational outcome. The impact of the proposed work will originate from the development of new materials and technology and may extend well beyond orthopedic and dental fields if, as we anticipate, these novel bioceramics exhibit superplasticity, which would greatly facilitate processing at high temperature.