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Show materials, such as metal alloys, for use in advanced gas-fired equipment. Because ceramics are lightweight, retain their strength at high temperature and have high corrosion resistance, they can increase process efficiency through higher temperature operation, and reduced equipment complexity and maintenance through the use of non-cooled components. To help ensure that the potential benefits of ceramic materials are fully realized, R&D is needed to address several technical issues which have impeded their wide market penetration. The use of ceramics in structural applications have been extremely limited due to their brittle nature and unpredictable behavior under load and thermally-induced stresses. The property variability which exists for current ceramic materials necessitates the use of novel design methodologies in their application to industrial process equipment. The design methodologies, however, are in an early stage of development and require much more extensive verification. Labor-intensive fabrication techniques geared toward limited-volume production of ceramics have resulted in high component and system costs. Reliability and cost are particularly important issues in the production of large components (i.e. radiant tubes) with variable geometries. Research is needed, therefore, to develop both (1) more systematic fabrication techniques for the forming and sintering of more reliable ceramic components and (2) reproducible and cost-effective manufacturing and quality control techniques for the large-scale production of reliable ceramic materials and components. In addition to these issues, several related factors have impeded the acceptance of ceramics components by industrial equipment manufacturers and end-users. For engineering ceramics which are commercially available with appropriate size and shape capability for application in industrial equipment, there is a lack of property data, virtually no design data base, and very limited information concerning long-term reliability and industrial process compatibility. With these limitations and a general lack of familiarity among equipment manufacturers of the unique engineering properties of ceramics, the lead time for successful application of these advanced materials is unacceptably long. GRI will continue to focus on manufacturing techniques · for monolithic ceramics for nearer-term application, and on improvements in the fabrication and manufacturing technology for advanced ceramic coatings and composites for longer-term application. ACKNOWLEDGEMENT The authors acknowledge Kathy Overby for typing and proof reading the manuscript. 311 References 1. R. V. Cut ts and A. Watson; "Recuperative Radiant Tubes for Energy Saving in Heat Treatment Furnaces," Heat Treatment of Metals, Vol. 3, pg. 65-69, 1981. 2. Metal Handbook Vol. 4, Heat Treating, ASM, pp. 375-336, 1981. 3. J. Skarda "Fabricability and Design Consideration of Heat Resistant Alloys." Paper present at Symposium on Industrial Combustion Technologies, Chicago, IL, April 39-30, 1986. 4. P.J. Wedge; "Ceramic Radiant Tubes for High Temperature Indirect Heating." Paper presented at Symposium on Modern Practice in Reheating and Heat Treatment Furnaces, Solihull, England, 21, March, 1985. 5. V. Jayaraman, "Ceramic Radiant Tube Heated Aluminum Melter," Die Casting Technology. Yesterday's Art Today's Science, Conference Proceedings, Minneapolis, MN, OCtober 31-November 3, 1983. 6. A.C. Thekdi, S.R. Huebner and M.A. Lukasi ewicz . "Development of an Indi rect Gas-Fired High Temperature Heating System", proceedings of the 1984 International Gas Research Conference, Washington, D.C., September 10-13, 1984. |