High-Temperature Fracture Strength of a CVD-SiC Coating Layer for TRISO Nuclear Fuel Particles by a Micro-Tensile Test Lee, Hyun Min; Park, Kwi-Il; Park, Ji-Yeon; Kim, Weon-Ju; Kim, Do Kyung;
Silicon carbide (SiC) coatings for tri-isotropic (TRISO) nuclear fuel particles were fabricated using a chemical vapor deposition (CVD) process onto graphite. A micro-tensile-testing system was developed for the mechanical characterization of SiC coatings at high temperatures. The fracture strength of the SiC coatings was characterized by the developed micro-tensile test in the range of to . Two types of CVD-SiC films were prepared for the micro-tensile test. SiC-A exhibited a large grain size (0.4 ~ 0.6 m) and the  preferred orientation, while SiC-B had a small grain size (0.2 ~ 0.3 mm) and the  preferred orientation. Free silicon (Si) was co-deposited onto SiC-B, and stacking faults also existed in the SiC-B structure. The fracture strengths of the CVD-SiC coatings, as measured by the high-temperature micro-tensile test, decreased with the testing temperature. The high-temperature fracture strengths of CVD-SiC coatings were related to the microstructure and defects of the CVD-SiC coatings.
SiC coating layer;TRISO;Micro-tensile-test;High temperature fracture strength;Weibull statistics;
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