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Sintering of Boron Carbide Heat‐Treated with Hydrogen
Author(s) -
Lee Hyukjae,
Speyer Robert F.,
Hackenberger Wesley S.
Publication year - 2002
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.1151-2916.2002.tb00420.x
Subject(s) - sintering , boron carbide , materials science , hydrogen , boron , carbide , evaporation , metallurgy , precipitation , decomposition , condensation , analytical chemistry (journal) , chemistry , thermodynamics , chromatography , physics , organic chemistry , meteorology
Hydrogen gas (H 2 ) was used to extract B 2 O 3 coatings from boron carbide (B 4 C) particles, permitting a lower temperature onset of sintering and restricting coarsening via solution and precipitation of B 4 C in B 2 O 3 liquid. Remnant H 2 had to be removed from the furnace before specimens were heated through temperature ranges in which evaporation‐condensation coarsening competed with sintering (2010°–2140°C), because the presence of H 2 increased the B 4 C vapor pressure. Heat treatment of B 4 C compacts in a 50:50 H 2 ‐He mixture at 1350°C, followed by a purge of the H 2 gas and then rapid heating to 2230°C, resulted in a percentage of theoretical density of 94.7%. This is higher than the value of 92.8%, which was the highest achieved without the use of H 2 .