U.S.-Egypt Joint Cooperative Research: Preparation and Sintering of Nano-SiC from Waste Silica Fume via an Integrated Mechanical and Thermal Activation Process

0511931 Shaw描述：该项目支持康涅狄格大学（UConn）材料科学与工程系Leon Shaw博士和埃及开罗国家研究中心（NRC）Mahmoud Zawra博士之间的合作研究。他们的目标是从废料（硅烟）作为起始材料制备和表征先进的陶瓷材料（纳米碳化硅）。智力优势：硅灰含有超过94-97%（重量）的二氧化硅（SiO2），是埃及硅和硅铁合金工业产生的废料。这种废料造成许多污染问题。 PI将首先评估二氧化硅烟雾，然后通过一种新的工艺制备纳米SiC，即最近开发的综合机械和热活化（IMTA）工艺，用于合成大量低成本，高质量，纳米结构的碳化物和氮化物。将研究不同的参数，如研磨速度、球粉重量比、研磨气氛、研磨环境温度和时间。将表征粉末混合物的晶体结构、微观结构、粒度、颗粒形态、结构缺陷和非晶化随研磨参数的变化。开罗核管理委员会和康州大学的各种分析仪器。在斯托尔斯，如X-射线，SEM和TEM附加EDS，将用于表征颗粒和晶体尺寸，形态，晶体结构，结构缺陷，和相组成。本文还研究了在不同的烧成温度、压力和气氛下，在有和没有烧结助剂的情况下，由废硅灰生产的纳米SiC粉末的烧结。 更广泛的影响：从废料中制备先进材料有两个优点，第一是消除废料，第二是生产具有先进应用的纳米材料，如切割和研磨工具，磨料，机械密封，喷嘴，装甲砖和防弹衣。该项目的成果可用于将废弃材料硅烟转化为先进陶瓷SiC，并在生产有用陶瓷材料的同时减少硅烟的污染。 可以想象，这一过程可以应用于其他情况，对减少污染和将废物转化为有用材料产生广泛影响。 美国PI是新工艺的开发者，将能够将这些技术应用于相当大规模的新材料，从而将其投入实用，并提供大规模应用的第一次测试。 埃及PI将能够学习新技术，培训材料加工方面的年轻科学家，并帮助减少埃及硅和硅铁合金制造造成的污染。 该项目将涉及至少一名美国研究生的支持。 该项目得到了美国-埃及联合基金方案的支持，该方案向两国的科学家和工程师提供赠款，以开展这些合作活动。

0511931ShawDescription: This project supports a collaborative research between Dr. Leon Shaw, Department of Materials Science and Engineering, University of Connecticut (UConn) and Dr. and Mahmoud Zawra, National Research Center (NRC), Cairo, Egypt. They aim at preparation and characterization of advanced ceramic material (nano silicon carbide) from waste material (silica fumes) as starting material. Intellectual Merit: Silica fume contains more than 94-97% (by weight) of silicon dioxide (SiO2) and is produced as a waste material from silicon and ferro-silicon alloy industry in Egypt. This waste material causes many pollution problems. The PIs will first evaluate the silica fumes, then prepare nano-SiC by a novel process, the integrated mechanical and thermal activation (IMTA) process, developed recently for synthesizing large quantities of low cost, high quality, nanostructured carbides and nitrides. Different parameters such as milling speed, ball-to-powder weight ratio, milling atmosphere, milling environmental temperature and time will be investigated. Changes in crystal structure, microstructure, particle size, particle morphology, structural defects and amorphization of powder mixtures as a function of milling parameters will be characterized. A variety of analytical instruments at the NRC in Cairo and the Uconn. in Storrs, such as X-ray, SEM and TEM attached with EDS, will be utilized to characterize particle and crystal sizes, morphology, crystal structure, structural defects, and phase composition. Sintering of the nano-SiC powder produced from waste silica fume at different firing temperatures, pressures and atmospheres, with and without sintering aids, will also be studied. Physical and mechanical properties of the sintered nano-ceramic bodies will be investigated.Broader Impact: The preparation of advanced material from waste material has two advantages, first is eliminating the waste material, and second is the production of nano-materials which have advanced applications such as in the form of cutting and grinding tools, abrasive media, mechanical seals, blasting nozzles, armor tiles and bullet-proof vests. The project results can be applied to convert a waste material, silica fumes, to an advanced ceramic, SiC, and to reduce pollution from the silica fumes while producing a useful ceramic material. The process could conceivably be applied to other cases with broad impact in reducing pollution and converting waste to useful material. The U.S. PI is the developer of the new processes and will be able to apply the techniques to a new material in a reasonably large scale, thus putting them into useful practice and providing a first test of large-scale application. The Egyptian PI will be able to learn the new technologies and train younger scientists in materials processing, and help reduce pollution caused by the manufacture of silicon and ferrosilicon alloys in Egypt. The project will involve support for at least one U.S. graduate student. This project is being supported under the US-Egypt Joint Fund Program, which provides grants to scientists and engineers in both countries to carry out these cooperative activities.