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Microstructure of silicon nitride ceramics sintered with rare-earth oxides

Journal Article · · Acta Metallurgica et Materialia
 [1];  [2]
  1. Lawrence Berkeley Lab., CA (United States). National Center for Electron Microscopy
  2. Univ. of California, Berkeley, CA (United States). Dept. of Materials Science
Microstructures of Si{sub 3}N{sub 4} with crystallized grain boundaries of rare-earth silicates were investigated. {beta}-Si{sub 3}N{sub 4} grains in samples sintered with Yb{sub 2}O{sub 3} were more elongated than those sintered with Dy{sub 2}O{sub 3}. Amorphous thin layers between crystallized grain boundaries of silicate and Si{sub 3}N{sub 4} grains were recognized for both specimens sintered with Dy{sub 2}O{sub 3} and with Yb{sub 2}O{sub 3}. In the sample sintered with Dy{sub 2}O{sub 3}, very clean grain boundaries between Si{sub 3}N{sub 4} grains which did not contain the heavy elements were frequently recognized, while samples with Yb{sub 2}O{sub 3} had an amorphous grain boundary phase containing Yb. Unusual structures with distorted lattice images in regions rich in Si and O were discovered in crystalline Dy-silicate phases.
DOE Contract Number:
AC03-76SF00098
OSTI ID:
31712
Journal Information:
Acta Metallurgica et Materialia, Journal Name: Acta Metallurgica et Materialia Journal Issue: 3 Vol. 43; ISSN 0956-7151; ISSN AMATEB
Country of Publication:
United States
Language:
English