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Processing Aluminum Nitride‐Silicon Carbide Composites via Polymer Infiltration and Pyrolysis of Polymethylsilane, a Precursor to Stoichiometric Silicon Carbide

1999; Wiley; Volume: 82; Issue: 4 Linguagem: Inglês

10.1111/j.1151-2916.1999.tb01846.x

1551-2916

Kean W. Chew, Alan Sellinger, Richard M. Laine,

Advanced materials and composites

AlN‐SiC‐particle‐reinforced composites have been prepared at lessthan equal to1400°C using submicrometer AlN, ‐325 mesh alpha‐SiC particles, and polymethylsilane (PMS; ‐(CH 3 SiH) n ‐) via a polymer infiltration and pyrolysis (PIP) process. PMS is an organometallic SiC polymer precursor that can be modified with 16 wt% cross‐linking aid to provide mPMS. mPMS converts to nanocrystalline β‐SiC with >80% ceramic yield (1000°C in argon) with some excess (<5 wt%) graphitic carbon. mPMS has been used successfully as a nonfugitive binder for AlN‐SiC compacts. Densities of 2.5 versus 2.1 g/cm 3 have been obtained after nine PIP cycles for disk‐shaped compacts formulated with and without mPMS binder, respectively. alpha‐SiC seeds crystallization of β‐SiC derived from mPMS at temperatures as low as 1000°C. Some evidence suggests that AlN‐SiC solid solutions form at particle/matrix interfaces.