Twinning, Phase Transformations, and Film Formation of Zirconia-based Ceramics

9628694 Heuer建议的研究包括三个主题：i)利用显微硬度压痕研究未掺杂的单斜氧化锆单晶和多晶中的形变孪生随载荷、取向和温度的变化。在1100℃以下，m-ZrO2为稳定相。将研究压痕诱导滑移和孪生之间的竞争；ii)将这些晶体加热到四方(T)相场中，将允许在t-ZrO2中进行类似的研究；这里，重点将放在滑移系统，滑移和铁弹性变形之间的竞争，以及压痕损伤在冷却时形核马氏体t到m相变中所起的作用；iii)已经发现了一种生物启发的化学方法来形成纯的和Y203掺杂的ZrO2薄膜。将对优化成膜所需的水化学进行系统研究。在半导体级硅基和镍基合金上沉积氧化锆基薄膜分别对氧传感器和热障涂层具有重要意义。这项拟议的研究将检验氧化锆基陶瓷的基本力学行为。氧化锆已被用作研究其他韧性陶瓷增韧的模型系统。这一建议包括三个研究主题：1)单斜相和2)四方相氧化锆形变孪晶的显微硬度压痕研究，以及3)优化氧化锆基陶瓷自组装薄膜沉积的化学研究。了解这些自组装薄膜有可能使材料研究人员在任何衬底上沉积任何材料的薄膜。

9628694 Heuer The proposed research contains three topics: i) Deformation twinning in undoped monoclinic zirconia (m-ZrO2 ) single crystals and polycrystals as a function of load, orientation and temperature will be studied using microhardness indentation. At temperatures up to 1100C, m-ZrO2 is the stable phase. The competition between indent-induced slip and twinning will be studied; ii) Heating these crystals into the tetragonal (t) phase field will allow similar studies in t-ZrO2; here, the emphasis will be on slip systems, the competition between slip and ferroelastic deformation, and the role the indentation damage plays in nucleating the martensitic t to m transformation on cooling; iii) A bio-inspired chemical route to thin film formation of pure and Y203-doped ZrO2 has been discovered. The aqueous chemistry needed to optimize film formation will be systematically studied.. Deposition of ZrO2-based films on semiconductor grade Si and Ni-base alloys have implications for oxygen sensors and thermal barrier coatings, respectively. The proposed research will examine the fundamental mechanical behavior of zirconia-based ceramics. Zirconia has been used as a model system for understanding toughening in a number of other tough ceramics. This proposal includes three research topics: deformation twinning in 1) monoclinic and 2) tetragonal zirconia studied by microhardness indentation, and 3) a study of the chemistry to optimize the deposition of self-assembling thin films of zirconia-based ceramics. Understanding these self- assembling films has the potential to enable materials researchers to deposit a film of any material on any substrate.