Phase relations in silicon and germanium nitrides up to 98 GPa and 2400°C
2018; Wiley; Volume: 102; Issue: 4 Linguagem: Inglês
10.1111/jace.16063
ISSN1551-2916
AutoresNorimasa Nishiyama, Julia A. F. Langer, Takeshi Sakai, Yohei Kojima, Astrid Holzheid, Nico Alexander Gaida, Eleonora Kulik, Naohisa Hirao, Saori I. Kawaguchi, Tetsuo Irifune, Yasuo Ohishi,
Tópico(s)Metal and Thin Film Mechanics
ResumoAbstract Phase relations in silicon and germanium nitrides (Si 3 N 4 and Ge 3 N 4 ) were investigated using a Kawai‐type multianvil apparatus and a laser‐heated diamond anvil cell combined with a synchrotron radiation. The pressure‐induced phase transition from the β to γ (cubic spinel‐type structure) phase was observed in both compositions. We observed the coexistence of the β and γ phases in Si 3 N 4 at 12.4 GPa and 1800°C, while the appearance of single phase γ‐Ge 3 N 4 was observed at pressures above 10 GPa. Our observations under higher pressures revealed that γ‐Si 3 N 4 and γ‐Ge 3 N 4 have wide stability fields and no postspinel transition was observed up to 98 GPa and 2400°C in both compositions. Using the room‐temperature compression curves of these materials, the bulk moduli ( K 0 ) and their pressure derivatives ( K ′ 0 ) were determined: K 0 = 317 (16) GPa and K ′ 0 = 6.0 (8) for γ‐Si 3 N 4 ; K 0 = 254 (13) GPa and K ′ 0 = 6.0 (7) for γ‐Ge 3 N 4 .
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