Premium
High‐Temperature Mechanical Spectroscopy of Nitrogen‐Rich Ca–α‐SiAlON Ceramics
Author(s) -
Mazaheri Mehdi,
Mari Daniele,
Schaller Robert,
Cai Yanbing,
Esmaeilzadeh Saeid,
Shen Zhijian
Publication year - 2011
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.1551-2916.2010.04251.x
Subject(s) - spark plasma sintering , materials science , silicon nitride , ceramic , sialon , creep , composite material , relaxation (psychology) , phase (matter) , grain boundary , grain boundary sliding , spectroscopy , analytical chemistry (journal) , mineralogy , microstructure , chemistry , psychology , social psychology , organic chemistry , layer (electronics) , chromatography , physics , quantum mechanics
Nitrogen‐rich Ca–α‐SiAlON ceramics made with different starting powder compositions have been studied by high‐temperature mechanical spectroscopy in parallel with compressive deformation in a spark plasma sintering equipment. The mechanical loss spectra measured upon heating show a relaxation peak at about 1150 K and a high‐temperature exponential background at higher temperatures (>1400 K), which are attributed to the α‐relaxation in the glassy phase and to grain‐boundary sliding, respectively. A theoretical interpretation of the results shows that the peak position is mainly a function of glass viscosity. The amplitude of the peak is not only affected by the glassy phase quantity but also depends on the restoring force due to grain elasticity. Therefore, despite a higher amount of glassy phase specimens containing elongated grains may show a lower peak. The amplitude of the internal friction peak corresponding to α‐relaxation can be used to predict the compression creep of silicon‐nitride‐based ceramics.