Title:
Densification of nano-sized boron carbide
Densification of nano-sized boron carbide
Author(s)
Shupe, John
Advisor(s)
Speyer, Robert F.
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Abstract
Boron carbide nano-powders, singly-doped over a range of compositions, were
pressurelessly-sintered at identical temperature and atmospheric conditions in a dif-
ferential dilatometer to investigate sintering behavior. Samples that achieved relative
densities greater than 93% of theoretical density were post-HIPed. Post-HIPing re-
sulted in an increase in relative density as well as an increase in Vicker's hardness. To
optimize the sintering behavior, nano-powders with multiple dopants were prepared
based on the results of single dopant experiments. These powders were studied using
the same heating schedule as the single dopant samples. The powder with optimized
composition was selected, and 44.45 mm diameter disks were pressed to determine
the effects of sample size.
Powder composition #166 with Al, Ti, W and Mg additions was processed using
di¢çerent methods in order to create defect-free green bodies after uniaxial press-
ing. The 44.45 mm diameter compacts were heat-treated to remove organics and
B₂O₃coatings on particles and then encapsulated in an evacuated fused silica am-
pule. Encapsulated samples were HIPed at temperatures below the coarsening region
observed in the dilatometric traces of multiply-doped nano-powders. The E-HIPed
sample showed a relative density of 96% with a limited extent of nano-sized grain
microstructure.
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Date Issued
2009-01-12
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