US-Turkey Cooperative Research: Characterization and Processing of Oxide Powders and Compacts

University Of Minnesota-Twin Cities, Minneapolis MN

Investigators

Abstract

0322622 Carter Description: This project supports a cooperative research between Dr. Barry Carter, Department of Chemical Engineering and Materials Science at the University of Minnesota (UM), Minneapolis, Minnesota and Dr. Mehmet Ali Gulgun, Department of Engineering and Natural Sciences, Sabanci University, Istanbul, Turkey. They plan to study the characterization and processing of oxide powders and compacts. The project emphasizes two important ceramic oxides, namely ceria and alumina, with which the two investigators are already independently working. Polycrystalline a-Al2O3 is one of the most important ceramics for industrial applications. Its strength, toughness, corrosion and wear resistance, and creep properties, for example, are closely related to its microstructure and interfacial chemistry. Extensive knowledge has been gathered in the literature about the influence of various impurities on the properties and microstructure of the ceramic. Analytical electron microscopy investigations, especially using energy-loss spectroscopy, will allow the study of the incipient formation of second phases, e.g. CA6, in highly doped alumina ceramics. The U.S. group's interest in ceria is due primarily to its critical role in chemical/mechanical polishing (CMP). The group in Turkey has experience in processing the same material for use in fuel cells. The collaboration will exploit the synergy of these two programs. Through collaboration with Oak Ridge National Laboratory (ORNL), the U.S. group has used EELS to probe the chemistry of ceria. This methodology will be applied to polycrystalline ceria samples, which have been doped and processed in Turkey using methods similar to those used to process alumina specimens. The U.S. team will provide the ceria material and, working with ORNL and the 3M Company, prepare and characterize the powders; the Turkish team will provide the expertise to process this material in a controlled manner. Scope: This project brings together a group in the USA which has been extensively working on the structural and chemical analysis of powders and their sintered products and a group in Turkey which is developing a program on the preparation and processing of high-purity powders. Both groups are including undergraduates and women in their research programs. The U.S. group has extensive interaction with other laboratories, e.g., ORNL, thus benefiting both the students and the other labs. Both Professors Carter and Gulgun have worked extensively on characterization of interfaces and interphases in alumina systems. The collaboration will involve the exchange of three graduate students, two from U. of Minnesota and one from Sabanci University.