Hot isostatic pressing of silicon nitride with boron nitride, boron carbide, and carbon additions
- National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center
This paper reports how Si{sub 3}N{sub 4} test bars containing additions of BN, B{sub 4}C, and C, were hot isostatically pressed in Ta cladding at 1900{degrees} and 2050{degrees} C to 98.9% to 99.5% theoretical density. Room-temperature strength data on specimens containing 2 wt% BN and 0.5 wt% C were comparable to data obtained for Si{sub 3}N{sub 4} sintered with Y{sub 2}O{sub 3}, Y{sub 2}O{sub 3} and Al{sub 2}O{sub 3} or ZrO{sub 2}. The 1370{degrees} C strengths were less than those obtained for additions of Y{sub 2}O{sub 3} or ZrO{sub 2} but greater than those obtained from a combination of Y{sub 2}O{sub 3} and Al{sub 2}O{sub 3}. Scanning electron microscope fractography indicated that, as with other types of Si{sub 3}N{sub 4}, room-temperature strength was controlled by processing flaws. The decrease in strength at 1370{degrees} C was typical of Si{sub 3}N{sub 4} having an amorphous grain-boundary phase. The primary advantage of non-oxide additions appears to be in facilitating specimen removal from the Ta cladding.
- OSTI ID:
- 5154475
- Journal Information:
- Journal of the American Ceramic Society; (United States), Journal Name: Journal of the American Ceramic Society; (United States) Vol. 72:5; ISSN 0002-7820; ISSN JACTA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Fracture strength and microstructures of Si{sub 3}N{sub 4}/SiC nanocomposites
Continuous sintering of self-reinforced silicon nitride containing reduced amounts of sintering aids
Related Subjects
360601* -- Other Materials-- Preparation & Manufacture
ALLOYS
AMORPHOUS STATE
BORON CARBIDES
BORON COMPOUNDS
BORON NITRIDES
CARBIDES
CARBON ADDITIONS
CARBON COMPOUNDS
CLADDING
CRYSTAL STRUCTURE
DEPOSITION
ELECTRON MICROSCOPY
ELEMENTS
FABRICATION
GRAIN BOUNDARIES
HOT PRESSING
MATERIALS WORKING
MECHANICAL PROPERTIES
MEDIUM TEMPERATURE
METALS
MICROSCOPY
MICROSTRUCTURE
NITRIDES
NITROGEN COMPOUNDS
PNICTIDES
PRESSING
SCANNING ELECTRON MICROSCOPY
SILICON COMPOUNDS
SILICON NITRIDES
SURFACE COATING
TANTALUM
TRANSITION ELEMENTS
VERY HIGH TEMPERATURE
YIELD STRENGTH