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Hot Isostatic Pressing of Silicon Nitride with Boron Nitride, Boron Carbide, and Carbon Additions
Author(s) -
Mieskowski Diane M.,
Sanders William A.
Publication year - 1989
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1989.tb06228.x
Subject(s) - materials science , hot isostatic pressing , scanning electron microscope , carbide , cladding (metalworking) , nitride , hot pressing , boron carbide , boron nitride , boron , metallurgy , fractography , amorphous solid , oxide , silicon nitride , analytical chemistry (journal) , composite material , silicon , sintering , crystallography , chemistry , layer (electronics) , organic chemistry , chromatography
Si 3 N 4 test bars containing additions of BN, B 4 C, and C, were hot isostatically pressed in Ta cladding at 1900° and 2050°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 3 N 4 sintered with Y 2 O 3 , Y 2 O 3 and Al 2 O 3 , or ZrO 2 . The 1370°C strengths were less than those obtained for additions of Y 2 O 3 or ZrO 2 but greater than those obtained from a combination of Y 2 O 3 and Al 2 O 3 . Scanning electron microscope fractography indicated that, as with other types of Si 3 N 4 , roomtemperature strength was controlled by processing flaws. The decrease in strength at 1370°C was typical of Si 3 N 4 having an amorphous grainboundary phase. The primary advantage of non‐oxide additions appears to be in facilitating specimen removal from the Ta cladding.