Nanophases: Energetics Metastability, and Implications for Processing and Use (SGER Award)

纳米材料（粒径在1-100纳米范围内）作为陶瓷前驱体、催化剂、吸附剂、分子筛、涂层等都很重要。这项工作旨在验证一个假设，即在体中亚稳态的结构实际上是能量稳定的纳米级材料。以gamma氧化铝作为技术上重要的例子，Co-PI与美国铝业公司合作，提出通过高温溶液量热技术确定α - gamma转变的焓作为粒度（表面积）的函数。PI提出通过高温溶液量热技术确定氧化铝中α - γ转变的焓作为粒度的函数。研究结果将有助于理解亚稳相纳米粒子的稳定性。

9500812 Navrotsky Nanophase materials (particle sizes in the 1-100 nm range) are important as ceramic precursors, catalysts, and adsorbents, molecular sieves, coatings, etc. This work seeks to test the hypothesis that structures which are metastable in the bulk are actually energetically stabilized as nanoscale materials. Using gamma alumina as a technologically important example, in collaboration with Alcoa, Co-PI proposed to determine the enthalpy of the alphagamma transition as a function of particle size (surface area) by high temperature solution calorimetric techniques. %%% PI proposed to determine the enthalpy of the alpha-gamma transition in alumina as a function of particle size by high temperature solution calorimetric techniques. The results will be useful in understanding the stability of nanosize particles of metastable phases.