Details

Autor(en) / Beteiligte

• Li, He-Jun
• Fu, Qian-Gang
• Shi, Xiao-Hong
• Li, Ke-Zhi
• Hu, Zhi-Biao

Titel

SiC whisker-toughened SiC oxidation protective coating for carbon/carbon composites

Ist Teil von

• Carbon (New York), 2006-03, Vol.44 (3), p.602-605

Ort / Verlag

Oxford: Elsevier Ltd

Erscheinungsjahr

2006

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Carbon/carbon (C/C) composites are one of the most promising high temperature structural materials for engine, aircraft and aerospace applications, in which C/C composites are required to operate in an oxidizing environment. However, the oxidation of C/C composites at temperatures above 723 K limits their use to inert atmosphere [1,2]. Oxidation protective coatings are the logical choice for preventing C/C from oxidation at high temperatures. SiC ceramics are considered as the most suitable coating materials for C/C composites due to their excellent oxidation resistance and good compatibility with C/C substrates [3-6]. However, thermal expansion mismatch between SiC and C/C composites will result in the crazing and debonding of SiC coating, and induce the failure of the coatings. According to the toughening mechanism including crack bridging due to whisker pull-out and crack deflection around whiskers [7,8], the toughness of SiC ceramic coatings could be increased by adding SiC whisker (SiCw) in them [9], which will improve the oxidation and thermal stress resistance of SiC ceramic coating. As far as the authors know, no literature has been published about using SiCw-toughened SiC ceramics as the oxidation protective coating for C/C composites. A twostep technique of preparing SiCw-toughened ceramic coatings was designed in this study. The first step technique was to form porous SiCw-toughened SiC coatings by slurry on the surface of C/C composites, and the second step technique was to obtain dense SiCw-toughened SiC coating by pack cementation technique on the surface of the porous coating. The microstructures, oxidation resistance and thermal stress resistance of the as-received coatings were investigated.