Densification studies of refractory materials using Hot Isostatic Pressing (HIP) and tantalum containment
Powders of crystalline rohmbohedral boron were HIP processed to near full density at 1500-1800{degree}C and 206.8 MPa. At 1700{degree}C, the densification of boron was independent of particle size in the range of <37 {mu}m to 10 mm. At 1500{degree}C, only the <37-{mu}m powder reached near full density. Silicon and calcium impurities were found to segregate in the grain boundaries during densification. Results indicate that plastic yielding was to dominate densification mechanism. Boron nitride powder with 0.97% oxygen content was pressed to a density of 2.21 g/cm{sup 3} at 18000{degree}C and 206.8 MPa. The density of high-purity hot-pressed graphite was increased by 15% to 2.10 g/cm{sup 3} at 2200{degree}C and 206.8 MPa. These results show that refractory metal containers used in hot isostatic pressing significantly expand the availability of high-density-high purity materials. 3 refs., 7 figs., 2 tabs.
- Research Organization:
- Lawrence Livermore National Lab., CA (USA)
- Sponsoring Organization:
- DOE/DP
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 7155601
- Report Number(s):
- UCRL-102154; CONF-900634--2; ON: DE90013481
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360201* -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
360601 -- Other Materials-- Preparation & Manufacture
ARGON
BORON
BORON COMPOUNDS
BORON NITRIDES
CARBON
CONTAINERS
ELEMENTAL MINERALS
ELEMENTS
FABRICATION
FLUIDS
GASES
GRAPHITE
HOT PRESSING
MATERIALS WORKING
METALS
MINERALS
NITRIDES
NITROGEN COMPOUNDS
NONMETALS
PARTICLE SIZE
PNICTIDES
POWDERS
PRESSING
RARE GASES
SEMIMETALS
SIZE
TANTALUM
TRANSITION ELEMENTS