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

0511931ShawDescription：该项目支持康涅狄格大学材料科学与工程系的Leon Shaw博士和埃及开罗国家研究中心(NRC)的Mahmoud Zawra博士之间的合作研究。他们的目标是以废料(硅灰)为原料制备和表征先进的陶瓷材料(纳米碳化硅)。智慧价值：硅烟含有超过94-97%(重量)的二氧化硅(SiO_2)，是埃及硅和硅铁合金工业的废料。这种废料造成了许多污染问题。PIS将首先评估硅灰，然后通过一种新的工艺-机械和热激活一体化(IMTA)工艺来制备纳米碳化硅，该工艺是最近开发的用于合成大量低成本、高质量的纳米结构碳化物和氮化物的工艺。考察了球磨速度、球粉质量比、球磨气氛、球磨环境温度和时间等参数对球磨效果的影响。将表征粉末混合物的晶体结构、微结构、颗粒大小、颗粒形态、结构缺陷和非晶化随球磨参数的变化。开罗NRC和康涅狄格州大学的各种分析仪器。在STORRS中，如X射线、扫描电子显微镜和电子能谱，将被用来表征颗粒和晶体的尺寸、形貌、晶体结构、结构缺陷和物相组成。还将研究在不同的烧成温度、压力和气氛下，在添加和不添加助烧剂的情况下，以废硅灰为原料生产的纳米碳化硅粉末的烧结。广泛的影响：从废物中制备先进材料有两个优点，第一是消除废物，第二是生产具有先进应用的纳米材料，如切割和磨削工具、磨料介质、机械密封、喷嘴、装甲瓦和防弹背心。该项目成果可用于将废弃材料硅烟转化为高级陶瓷碳化硅，并在生产有用的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，在减少污染和将废物转化为有用材料方面具有广泛的影响。美国PI是新工艺的开发商，将能够在相当大的范围内将这些技术应用于新材料，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，并帮助减少埃及制造硅和硅铁合金造成的污染。该项目将至少支持一名美国研究生。该项目得到了美国-埃及联合基金计划的支持，该计划为两国的科学家和工程师提供资助，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.