KOSEN 한인과학기술자네트워크

Development of Advanced Crystalline Garnet Materials and Fibers Primary Sponsor: Department of Defense Deadline: 4/11/2001 KEYWORDS TECHNOLOGY AREAS: Materials / Processes OBJECTIVE: Develop fundamental understanding and processing procedures for economical manufacturing of strong, creep resistant crystalline yttria-alumina garnet oxide fibers for use in high temperature structural components in oxidizing conditions. DESCRIPTION: The cubic rare earth oxide - aluminum oxide garnets are promising candidates for use in high temperature structural applications requiring strength and creep resistance in oxidizing conditions. These materials are the best candidates for use in novel Air Force engine designs that require refractory ceramic fibers. The proposed research will provide the basis for synthesis of polycrystalline and single crystal rare earth aluminate fibers formed by heat treatment of precursors. The research will establish the use dopants and additives to: (i) control grain growth kinetics, (ii) stabilize microstructure at high temperatures, and (iii) obtain single crystal fibers by thermal treatment of polycrystalline materials. The Phase I research will focus on the yttrium aluminum oxide family of materials with addition/substitution of cations with different ionic radii and coordination number, oxidation number, and reaction phase stability to control grain boundary mobility. PHASE I: 1. Demonstration of the synthesis of polycrystalline fibers from yttrium oxide-aluminum oxide fiber materials containing substituted cations.2. Controlled thermal processing of fibers at temperatures from 0.75 to 0.95 times the melting point (1450-1900C) for periods up to 6 hours to achieve grain growth and microstructural evolution.3. Transmission electron microscopy and microchemical analysis of materials.4. Correlation of process-structure relationships to develop a roadmap for synthesis of high temperature structural oxide materials to be implemented in Phase II. PHASE II: Produce and demonstrate a prototype of advanced materials and provide samples to the Air Force for evaluation. PHASE III DUAL USE APPLICATIONS: Lightweight composites require advanced oxide fibers for structural applications in military applications such as airframe structures and advanced engine components. Civilian applications include use in composites for components of turbines used in power generation and engine components used in transportation, optical materials for transmission at infra-red wavelengths in opto-electronic devices, and hard, strong refractory ceramic materials for use in severe temperature environments. REFERENCES: 1. "Ceramic Fibers and Coatings – Advanced Materials for the Twenty First Century," National Materials Advisory Board, publication number NMAB-494, National Academy Press, Washington, DC, 1998.2. G.S. Corman, High Temperature Creep of Some Single Crystal Oxides," Ceram. Eng. Sci. Proc., 12, 1745-66 (1991).3. K.R. Brown and D.A. Bonnell, "Segregation in Yttrium Aluminum Garnet: I Experimental Determination," J. Am. Ceram. Soc., 82, 2423-30 (1999). KEYWORDS: Creep resistant fibers, engine materials, oxygen-resistant DoD Notice: Between January 2 and February 28, 2001, you may talk directly with the DoD scientists and engineers who authored the solicitation topics, to ask technical questions about the topics. The Topic Author is listed in the box below. For reasons of competitive fairness, direct communication between proposers and topic authors is not allowed after February 28, 2001, when DoD begins accepting proposals under this solicitation. TPOC: Dr. Craig Hartley, PHONE: 703-696-8523 EMAIL: alexander.pechenik@afosr.af.mil. After February 28, 2001 proposers may still submit written questions about solicitation topics through the SBIR/STTR Interactive Topic Information System (SITIS). If you have general questions about DoD SBIR program, please contact the DoD SBIR Help Desk at (800) 382-4634 or email to SBIRHELP@teltech.com. NOTE: The Solicitations listed on this site are copies from the various SBIR agency solicitations and are not necessarily the latest and most up-to-date. For this reason, you should use the agency link listed below which will take you directly to the appropriate agency server where you can read the official version of this solicitation and download the appropriate forms and rules. The official link for this solicitation is: http://www.acq.osd.mil/sadbu/sbir/sttr01/dod_sttr01.htm. DoD will begin accepting proposals on March 1, 2001. The solicitation closing date is April 11, 2001.