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Degradation behavior of amorphous silicon nitride fibers in low atmospheric pressure.
- Source :
- Journal of Materials Science; Sep2021, Vol. 56 Issue 25, p13964-13974, 11p, 4 Black and White Photographs, 1 Diagram, 3 Charts, 3 Graphs
- Publication Year :
- 2021
-
Abstract
- We investigated the degradation behavior of amorphous silicon nitride (Si<subscript>3</subscript>N<subscript>4</subscript>) fibers in low air pressure and presumed the evolution mechanism. The obtained Si<subscript>3</subscript>N<subscript>4</subscript> fibers were characterized by tensile strength, X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and elemental analysis after being annealed (air pressure: 1 Pa–0.1 MPa, temperature: 1000–1600 °C, dwell time: 0–4 h). When air pressure was lower than 100 Pa or higher than 1000 Pa the strength of fibers dropped sharply. Due to the moderate partial pressure of oxygen in 100–1000 Pa, both active oxidation and passive oxidation were restrained resulting in the best mechanical property of fibers in 100–1000 Pa. Besides air pressure, annealing time also affected the thermal behavior of fibers. Firstly Si<subscript>3</subscript>N<subscript>4</subscript> fibers were passive oxidized to form SiO<subscript>2</subscript> layer on the surface, and then Si<subscript>3</subscript>N<subscript>4</subscript> decomposed into free Si and SiO<subscript>2</subscript> released gaseous SiO. Finally crystallization inside of fibers and formation of nanowires on the outer surface played the leading role in the progress of degradation. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00222461
- Volume :
- 56
- Issue :
- 25
- Database :
- Complementary Index
- Journal :
- Journal of Materials Science
- Publication Type :
- Academic Journal
- Accession number :
- 150854984
- Full Text :
- https://doi.org/10.1007/s10853-021-06195-4