Chapter 35. Development of a Cost-Effective Silicon Nitride Powder in DOE's Ceramic Technology Project
- John B. Wachtman Jr.
Published Online: 28 MAR 2008
Copyright © 1993 The American Ceramic Society
A Collection of Papers Presented at the 94th Annual Meeting and the 1992 Fall Meeting of the Materials & Equipment/Whitewares Manufacturing: Ceramic Engineering and Science Proceedings, Volume 14, Issue 1/2
How to Cite
Winslow, S. G. (1993) Development of a Cost-Effective Silicon Nitride Powder in DOE's Ceramic Technology Project, in A Collection of Papers Presented at the 94th Annual Meeting and the 1992 Fall Meeting of the Materials & Equipment/Whitewares Manufacturing: Ceramic Engineering and Science Proceedings, Volume 14, Issue 1/2 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470314050.ch35
- Published Online: 28 MAR 2008
- Published Print: 1 JAN 1993
Print ISBN: 9780470375235
Online ISBN: 9780470314050
- ceramic technology;
- silicon nitride;
- powder synthesis;
- automotive propulsion systems;
- advanced gas turbine program
The Ceramic Technology for Advanced Heat Engines Project was initiated in 1983 to establish a technology base that will allow private industry to provide reliable and cost-effective structural ceramics for application in advanced heat engines. Significant progress has been made in the development of reliable ceramics. However, the high cost of ceramic parts relative to metallic parts remains an issue that must be resolved before ceramic parts can become commercially viable in the highly cost-competitive automotive market. The emphasis of the Ceramic Technology Project has now been shifted toward reducing the cost of ceramics in order to facilitate commercial introduction of ceramic components for engine applications in the near term (5-10 years). Issues to be addressed in the work plan for this expanded program are economic cost modeling ceramic machining powder synthesis, alternative forming and densification processes, yield improvement, system design studies, standards development, low-expansion ceramics, and testing and database development.
High-quality powders are required to produce reliable ceramic components. Although powders suitable for this application are currently being produced, they are expensive and, in the case of silicon nitride, are not always available domestically. Ford Motor Company and Carborundum did some work in the late 1980s on development of improved powders; however, their processes were not commercialized.
One objective of the expanded Ceramic Technology Project is to develop a commercial, domestic source of high-quality, low-cost ($10/lb sale price) silicon nitride powder with suitable properties for forming into components for heat engine applications. This objective will be achieved through a contract to a large chemical company with experience in both industrial chemical (powder) production and sales. The target cost for the powder was derived from a process-cost model for ceramic parts developed at MIT and enhanced at Oak Ridge National Laboratory. Purity requirements and mechanical property goals for sintered parts made using this powder have also been defined. There are five technical tasks to be addressed in the proposed program: (1) reference process flow sheet and cost estimate, (2) process development and scale-up, (3) powder and sintered part characterization, (4) final process flow sheet and cost estimate, and (5) process demonstration.
Availability of a low-cost, high-quality powder alone will not guarantee the success of ceramics in the commercial market. Ceramic machining and improved processing and yield are important issues being addressed in other Ceramic Technology Project efforts. The combination of a low-cost, high-quality powder and improvements in ceramic machining and processing should contribute positively toward the commercial viability of ceramic components in the near term.