THE SYNTHESIS OF HIGH-QUALITY, LOW-COST SILICON-NITRIDE POWDER BY THE CARBOTHERMAL REDUCTION OF SILICA

The development and emergence of silicon nitride in the marketplace depends on the availability of a high quality, low cost powder which meets or exceeds the requirements for the customer's pan application. The Dow Chemical Company, funded by the United States Deparment of Energy* Oak Ridge National Laboratory, is engaged in developing a process which will economically synthesize commercial quantities of such a high quality powder. The Dow Chemical Company's approach is based on the carbothermal reduction of silica and has been shown to produce a sub-micron equi-axed powder with high alpha content (> 95%), low oxygen (< 2%), and minimal carbon and impurities. This paper will review The Dow Chemical Company program and present preliminary results of the synthesis and powder processing efforts.