Supplemental Funding for Women Engineering Research Assist- ants: Aqueous Solution Precipitation of Inorganic Particu- lates with Uniform Distribution of Nonequilibrium Additives

该项目研究了当无机成分从含有特定添加剂成分的溶液中快速沉淀时形成的微尺寸结晶产品的鉴定和表征。在大多数情况下，当两种溶液在流动混合装置（尼尔森快速混合法）中快速混合时，这些沉淀是在均匀成核和大过饱和条件下产生的。为了扩大该技术的应用，一种修改允许通过二次成核机制使用更可溶性的体系。用电子显微镜和x射线法对产物晶体进行表征，以确定结晶度和添加剂分布的均匀性。在设计实验时，可视化和采用的基本模型是连续晶体生长，即晶体表面是扩散的。这项工作的动机是生产适合多种应用的均匀固体混合物，例如耐火材料，催化剂和半导体系统的原材料。这项工作还为从溶液中快速生长晶体所涉及的基本机制提供了见解。

This project investigates the identification and characterization of the micro-sized crystalline products formed when inorganic components are rapidly precipitated from solution containing a specific additive component. These precipitations are derived in most instances by homogeneous nucleation and under conditions of large supersaturations, as two solutions are rapidly mixed in a flow-mixing device (Nielson rapid mixing method). To broaden application of the technique, a modification permits use of more soluble systems through secondary nucleation mechanisms. The product crystals are characterized to determine the extent of crystallinity and the uniformity of additive distribution by electron microscope and X-ray methods. The underlying model visualized and employed in devising the experiments is that continuous crystal growth occurs, i.e., the crystal surface is diffuse. The motivation for this work is to produce uniform solid mixtures suitable for several applications, such as raw materials for refractory materials, catalysts, and semiconductor systems. The work also provides insight into the basic mechanisms involved when rapid crystal growth from solution occurs.