Microstructure and distribution of impurities in hot-pressed and sintered silicon nitrides

Journal Article · Thu Nov 01 04:00:00 EST 1979

DOI:https://doi.org/10.1111/j.1151-2916.1979.tb12737.x· OSTI ID:5523110

Krivanek, O L; Shaw, T M; Thomas, G

Two hot-pressed (HS 130 and NC 132) and two sintered silicon nitrides (with MgO + Al/sub 2/O/sub 3/ and Y/sub 2/O/sub 3/ additives) were examined in detail by x-ray diffraction, emission spectroscopy, medium- and high-resolution electron microscopy, and x-ray microanalysis. The overall morphologies of the four materials are quite comparable. Very thin (10 to 20 A) intergranular glassy films were detected in all the materials at almost all grain and interphase boundaries. The composition of these glasses was determined by x-ray microanalysis using a 200-A electron probe and the softening temperature was estimated from available phase diagrams. The results are in good agreement with the known softening temperatures for the four silicon nitrides, thereby confirming the central role played by glassy phases in determining the high-temperature mechanical properties of these materials.

• Research Organization: Univ. of California, Berkeley
• OSTI ID: 5523110
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
CRYSTAL STRUCTURE
DIAGRAMS
FABRICATION
GRAIN BOUNDARIES
HIGH TEMPERATURE
HOT PRESSING
IMPURITIES
MATERIALS WORKING
MICROSTRUCTURE
MORPHOLOGY
NITRIDES
NITROGEN COMPOUNDS
PHASE DIAGRAMS
PNICTIDES
PRESSING
SILICON COMPOUNDS
SILICON NITRIDES
SINTERING
TEMPERATURE EFFECTS