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

项目描述：本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博士的合作研究。他们的目的是制备和表征先进的陶瓷材料（纳米碳化硅），以废料（二氧化硅烟雾）为原料。知识价值：硅灰含有超过94-97%（按重量计）的二氧化硅（SiO2），是埃及硅和硅铁合金工业的废料。这种废料引起许多污染问题。pi将首先评估二氧化硅烟雾，然后通过一种新工艺制备纳米sic，即最近开发的用于合成大量低成本，高质量的纳米碳化物和氮化物的综合机械和热活化（IMTA）工艺。研究了不同的参数，如铣削速度、球粉重量比、铣削气氛、铣削环境温度和时间。粉体混合物的晶体结构、微观结构、粒度、颗粒形态、结构缺陷和非晶化等变化作为铣削参数的函数将被表征。在开罗的NRC和康涅狄格大学的各种分析仪器。在Storrs中，将利用x射线、扫描电镜和附带EDS的透射电镜来表征颗粒和晶体的尺寸、形貌、晶体结构、结构缺陷和相组成。还将研究在不同的烧成温度、压力和气氛下，使用和不使用烧结助剂，由废硅灰制备的纳米sic粉末的烧结。研究了烧结纳米陶瓷体的物理力学性能。更广泛的影响：从废料中制备先进材料有两个优点，一是消除了废料，二是生产纳米材料，纳米材料具有先进的应用，如切割和研磨工具、磨料介质、机械密封、喷砂喷嘴、装甲瓦和防弹背心。该项目成果可用于将废物二氧化硅烟雾转化为高级陶瓷SiC，并在生产有用陶瓷材料的同时减少二氧化硅烟雾的污染。可以想象，这一过程可以应用于在减少污染和将废物转化为有用材料方面具有广泛影响的其他情况。美国PI是新工艺的开发人员，将能够将这些技术大规模地应用于新材料，从而将它们投入有用的实践，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。该项目将包括支持至少一名美国研究生。该项目得到了美国-埃及联合基金项目的支持，该项目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.