Premium
High‐Temperature Properties of Mixed α′/β′‐SiAlON Materials
Author(s) -
Klemm Hagen,
Herrmann Mathias,
Reich Thomas,
Schubert Christian,
Frassek Lutz,
Wötting Gerhard,
Gugel Ernst,
Nietfeld Georg
Publication year - 1998
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.1151-2916.1998.tb02461.x
Subject(s) - sialon , materials science , raw material , creep , phase (matter) , composite material , microstructure , mineralogy , ceramic , chemistry , organic chemistry
The mechanical behavior of mixed α′/β′‐SiAlON materials was studied at elevated temperatures. Two different α′/β′‐SiAlON compositions along the Si 3 N 4 ‐Y 2 O 3 9AlN composition line in the Si 3 N 4 ‐Al 2 O 3 AlN‐YN3AlN plane (α′‐SiAlON plane) were prepared using three different raw‐material mixtures. Six different materials were obtained with significantly lower values in α′‐SiAlON than expected. The high‐temperature properties of the materials studied were influenced strongly by the chemical composition (α′ content and grain‐boundary phase) of the SiAlONs. A high content of α′‐SiAlON was beneficial in terms of creep behavior of the materials. The same materials, however, were characterized by a considerably degradated fracture behavior at elevated temperatures in air because of a crack‐growth process enhanced by the poor oxidation resistance of these materials. It was concluded that, despite some superior features of the materials studied, a long‐term application of mixed α′/β′‐SiAlON materials at 1400°C in air is problematical. A combination of all properties required for such applications was not observed. For that reason, it is suggested that the real high‐temperature potential of these materials in air should be limited to temperatures <1300°C.