Ceramic Quasicrystals

非技术描述：准晶体是由规则大小和形状的积木组成的，可以填充空间，但没有可重复的图案。 宏观准晶体自古以来就为数学家和艺术家所知，他们用这种模式制作马赛克。 分子准晶是非常罕见的。 它们只在有限数量的合金和一些陨石中发现。 这种不寻常的结构（平铺）使它们成为非常坚固的材料，因为缺乏周期性可以防止裂纹的传播。 今天建造的绝大多数承重结构都是由陶瓷材料制成的，但陶瓷准晶还不为人所知。 该项目旨在开发从纳米颗粒制备准晶陶瓷的通用方法，使其既简单又多样化。这种陶瓷材料在国防、汽车工业、航空航天、电子工业等方面具有重要的应用价值。 该项目包括对学生进行尖端材料工程和计算机模拟技术的综合多方面培训。 它还包括一个完整的外展和教育计划，集中在早期科学教育和准晶瓷砖，统一科学和美学价值。技术专长：陶瓷和复合准晶制备的关键将是自组织的陶瓷纳米颗粒进入准晶相。 这种方法将使制造商能够避免极高的温度和压力。 该项目选择的纳米颗粒是用聚合物改性的球形SiO2。这种纳米颗粒具有两种相互竞争的长程相互作用，它们抑制了传统相的结晶，有利于准晶。实验（Kotov）和模拟（Glotzer）的协同作用使得在温和条件下通过实验实现SiO2块体陶瓷准晶成为可能。 准晶相最初在计算机上模拟组装在水分散体。 在三维结晶成非周期性结构之后，最初的软材料被退火以制造通过强共价键互连的坚固的大块整料。复合准晶的制备方法有单体渗透法和层层组装法。不同的准晶陶瓷的机械性能和裂纹扩展机制进行了比较研究。他们预计将揭示一系列以前从未见过的任何其他材料的属性。 韧性、透明度和制备简单性的结合可能会导致陶瓷及其应用的变革。

NON-TECHNICAL DESCRIPTION: Quasicrystals are made from building blocks of regular size and shape that can fill up the space but do not have a repeatable pattern. Macroscale quasicrystals have been known since ancient times to mathematicians and artists who made are mosaics with such patterns. Molecular quasicrystals are very rare. They are found only for limited number of alloys and some meteorites. This unusual structure (tiling) makes them promising candidates for exceptionally strong materials because the lack of periodicity prevents the propagation of cracks. Vast majority of load-bearing structures built today are from ceramic materials but ceramic quasicrystals are not known. This project is aimed at developing general methods for preparation of quasicrystalline ceramics from nanoparticles that can make it both simple and diverse. Such ceramics materials may be of value for national defense, automotive industry, aviation, and electronics. The project includes an integrated multifaceted training of students in the cutting edge materials engineering and computer simulation technologies. It also includes an integral Outreach and Education Program, centered on early science education and quasicrystalline tilings which unite scientific and aesthetic values.TECHNICAL DETAILS: The key to the preparation of ceramic and composite quasicrystals will be self-organization of ceramic nanoparticles into quasicrystalline phases. This approach will allow the manufacturers to avoid extremely high temperatures and pressures. The nanoparticles selected for the project are spherical SiO2 modified with a polymer. Such nanoparticles feature two competing long-range interactions that inhibit crystallization in traditional phases in favor of quasicrystals. The synergy of experiment (Kotov) and simulations (Glotzer) make it possible to experimentally realize bulk ceramic quasicrystals from SiO2 under mild conditions. Quasicrystal phases simulated initially on the computer are assembled in aqueous dispersions. Following the three-dimensional crystallization into aperiodic structures, the initially soft materials are annealed to make robust bulk monoliths interconnected by strong covalent bonds. The composite quasicrystals are being made by monomer infiltration or layer-by-layer assembly. Different quasicrystalline ceramics are being comparatively investigated for mechanical properties and crack propagation mechanisms. They are expected to reveal set of properties previously unseen for any other materials. The combination of toughness, transparency and simplicity of preparation may lead to transformative changes in ceramics and their applications.