Rapid carbothermal reduction of boron oxide in a graphite transport reactor

Journal Article · Wed May 01 00:00:00 EDT 1991 · AIChE Journal (American Institute of Chemical Engineers); (United States)

DOI:https://doi.org/10.1002/aic.690370513· OSTI ID:7188764

Weimer, A W; Roach, R P; Haney, C N ^[1]; Moore, W G; Rafaniello, W ^[2]

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1. Ceramics and Advanced Materials Research, Dow Chemical, Midland, MI (United States)
2. Advanced Ceramics Lab., Dow Chemical, Midland, MI (United States)

This paper reports that uniform submicron crystals of B[sub 4]C, boron-enriched boron carbide, and B[sub 4]C/TiB[sub 2] composite powders have been synthesized continuously by rapid carbothermal reduction at approximately 2,200 K in a 0.14 m ID [times] 1.68 m long pilot-scale graphite transport reactor. A unique reactor design allowed for continuous feeding of a meltable boron oxide containing precursor, rapid heating rates hat completed the carbothermal reduction reaction in seconds, and an expanded cooling that allowed for the precipitation in space of volatile excess boron oxides. Powder morphology resembled that of powder synthesized by laser pyrolysis of gaseous reactants. Rapid heating rates and minimized reaction times at high temperatures promoted nucleation and limited crystal growth. Dense parts fabricated from these powders have fine grains and extreme hardness.

• OSTI ID: 7188764
• Journal Information: AIChE Journal (American Institute of Chemical Engineers); (United States), Vol. 37:5; ISSN 0001-1541
• Country of Publication: United States
• Language: English

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SYNTHESIS
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DESIGN
POWDERS
FABRICATION
HARDNESS
REACTOR COMPONENTS
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DECOMPOSITION
ELECTROMAGNETIC RADIATION
MATERIALS
MECHANICAL PROPERTIES
MICROSTRUCTURE
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RADIATIONS
REACTORS
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