Sintering of Boron Carbide Heat-Treated with Hydrogen |
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| Authors: | Hyukjae Lee Robert F Speyer Wesley S Hackenberger |
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| Affiliation: | School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332;TRS Ceramics, Inc., State College, Pennsylvania 16801 |
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| Abstract: | Hydrogen gas (H2) was used to extract B2O3 coatings from boron carbide (B4C) particles, permitting a lower temperature onset of sintering and restricting coarsening via solution and precipitation of B4C in B2O3 liquid. Remnant H2 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 H2 increased the B4C vapor pressure. Heat treatment of B4C compacts in a 50:50 H2-He mixture at 1350°C, followed by a purge of the H2 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 H2. |
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| Keywords: | boron carbide heat treatment hydrogen |
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