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Low‐Temperature Formation of Ultra‐High‐Temperature Transition Metal Carbides from Salt–Polymer Precursors
Author(s) -
Adamczak Andrea D.,
Spriggs Adam A.,
Fitch Danielle M.,
Radovic Miladin,
Grunlan Jaime C.
Publication year - 2010
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2010.03724.x
Subject(s) - materials science , carbide , transition metal , polymer , polystyrene , carbothermic reaction , polyimide , halide , metal halides , chemical engineering , metal , polymer chemistry , inorganic chemistry , organic chemistry , chemistry , metallurgy , catalysis , nanotechnology , composite material , engineering , layer (electronics)
Refractory transition metal carbides were produced via carbothermal reduction of transition metal halides in a polymer precursor at low temperatures (<1200°C). This approach was used to generate TaC ( T m =3883°C), NbC ( T m =3610°C), and WC ( T m =2870°C) from TaBr 5 , NbBr 5 , and WCl 4 /WCl 6 , respectively. Solubility of transition metal halides and polymers in the same organic solvents allows for intimate mixing on the molecular level, which reduces the synthesis temperature. Greater than 90% TaC conversion was achieved by exposing a 50:50 weight ratio mixture of TaBr 5 and polyimide (or polystyrene) to 1200°C for 1 h. Even at temperatures as low as 1000°C, the major product remains TaC. The ability to process these high‐temperature materials so simply, and at relatively low temperatures, makes them accessible for different applications requiring thermal protection such as coatings for metallic components of hypersonic aircraft, rocket engine components, fibers, or refractory containers.