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Strengthening of Silicon Carbide Ceramics by Surface Nitridation during Hot Isostatic Pressing
Author(s) -
Dongliang Jiang,
Jihong She,
Shouhong Tan,
Greil Peter
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.tb05616.x
Subject(s) - materials science , hot isostatic pressing , silicon carbide , ceramic , residual stress , surface layer , composite material , layer (electronics) , flexural strength , carbide , metallurgy , hot pressing , composite number , thermal expansion , microstructure
Surface strengthening of SiC by in situ surface nitridation during post‐hot isostatic pressing (post‐HIPing) in N 2 was investigated. The formation of a thin (5–15 μm) layer of submicrometer β‐Si 3 N 4 on the surface of SiC was obtained at 1850°C and 200 MPa. While SiC HIPed in Ar attained a mean bending strength of 660 MPa, a significant increase in strength (with a maximum fracture stress above 1000 MPa) was observed for the SiC/Si 3 N 4 ‐layer composite material. Generation of residual compressive stresses on the surface layer caused by the differences in thermal expansion may account for the observed strengthening. Thus, in situ surface nitridation by post‐HIPing in N 2 may offer an attractive way to improve surface‐sensitive mechanical properties of complex‐shaped SiC components.