Preparation of SiC layer with sub-micro grain structure in TRISO particles by spouted bed CVD

Abstract

The previous studies showed that the SiC layer with sub-micro grain structure can prevent fission products release more effectively. Usually, the silicon carbide (SiC) layer in TRISO (Tristructural isotropic) particles was deposited at 1500–1600 °C by spouted bed chemical vapor deposition (CVD) from methyltrichlorosilane in H2 environment. It has grain size in micro scale (1–10 μm). In this work, we proposed a novel method for preparation of sub-micro grained SiC layer by adjusting the deposition parameters. The as-prepared SiC layer had grain size about 200 nm and pure phase (β-SiC). The fined grain SiC layer also exhibited higher mechanical property than SiC layer with larger grain size.