Lightweight, Robust and Low Cost Carbide/Tungsten Composites in Near Net Shapes for Advanced Solid-Fueled Rocket Nozzles for the IHPRPT Program

摘要

The DCP process has been used to synthesize very-high-melting, lightweight tungsten/carbide or tungsten/boride composites via conversion reactions of the following type: (M) + WX(s) = MX(s) + W(s) (1) where (M) is a reactive element dissolved within a Cu-bearing melt, and WX and MX are ceramic reactant and product phases, respectively. Reactions leading to ZrC/W, TiC/W, HfC/W, and ZrB2/W composites at <1300 deg C have been demonstrated. Conversion reactions leading to ZrC/W and HfC/W composites proceeded via the formation of a layer of ZrC or HfC on a layer of W that, in turn, formed on the WC reactant particles. Hence, upon complete reaction, the sizes and distributions of the carbide and tungsten products were directly related to the sizes and distributions of the WC reactant particles. Conversion reactions leading to ZrB2/W and TiC/W composite proceeded via the formation of discrete ZrB2 or TiC particles in the melt, so that the sizes and distributions of these product phases were not highly correlated to the sizes and distributions of the WB and WC reactant articles, respectively . Porous WC preforms with hourglass shapes (for rocket nozzle liners) were produced by gel casting.