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Corrosion of SiC Mateials in N 2 –H 2 –CO Gaseous Environments: II, Durability and Mechanical Properties
Author(s) -
Butt Darryl P.,
Tressler Richard E.,
Spear Karl E.
Publication year - 1992
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.1151-2916.1992.tb04420.x
Subject(s) - durability , materials science , fractography , argon , composite material , degradation (telecommunications) , corrosion , nitrogen , nitrogen gas , metallurgy , ultimate tensile strength , chemistry , telecommunications , organic chemistry , computer science
Three SiC materials were exposed to two gas compositions in the N 2 –H 2 –CO system at 1200° and 1300°C, 133 Pa and 98.7 kPa for 50–1000 h. The durability was evaluated by fracturing bend bars at room temperature and C‐rings at room temperature and 1300°C in argon. Fractography was used to correlate changes in strength with changes in flaw populations. In all three materials, surface pitting was the primary cause of degradation. Under some conditions it was found that flaw healing and new flaw formation occurred simultaneously. C‐rings cut from tubes did not lose strength, although pitting occurred; however, machined bend bars lost strength under identical conditions. In the case of bend bars, following an initial loss of strength (∼10%–50%) after 50–150 h, there was typically no further loss observed with increased exposure time. Due to its higher P co , degradation in an endothermic gas was generally more severe than that in a nitrogen–based gas.