Reaction-bonded silicon carbide tube fabricated by continuous sintering of double-walled preform

Abstract

A reaction-bonded silicon carbide radiant tube has been successfully fabricated by the continuous sintering of a double-walled preform which was composed of inner Si/C and outer SiC/C layers. Sequential centrifugal casting was employed to develop double-walled preform and process shrinkages were minimized by adjusting the particle packing characteristics with multimodal particle size distribution. Debinding behavior was optimized in a two-step process consisting of the capillary migration/surface evaporation of the thermoplastic resin and Subsequent thermal pyrolysis of the thermosetting resin. Reactive infiltration of liquid silicon was carried out in vacuum, during which liquid agglomeration of the liquid silicon by surface tension was prevented by in-situ formed porous silicon carbide network structure. Uniform and rapid infiltration was achieved with double-walled preform method due to reduced infiltration distance and increased area of infiltration front. (C) 2003 Elsevier Ltd and Techna Group S.r.l. All rights reserved.