| Abstract Scope |
Pressureless solid-state sintered silicon carbide (PSSS-SiC) is an excellent candidate for in-atmosphere, high temperature, high strain applications. Ensuring high dense, fine-grained microstructures is challenging due to the high temperatures required for sintering, thus exaggerated grain growth is common. This work examines the relationship between oxidation resistance and microstructure in PSSS-SiC. By using two-step sintering (TSS), grain growth can be suppressed, or encouraged, while attaining high densities. SiC pellets using a combination of boric acid and carbon as sintering aids reached an average sintered density of ~3.1 g/cm3. Samples treated using an optimal TSS sintering cycle yielded microstructures with an average grain size and aspect ratio of, respectively, 3 μm and φavg=0.62, contrasting samples conventionally treated at 2200 °C, which contain grains exceeding 100 μm in length, with aspect ratios of φavg<0.15. Samples were oxidized between the range of 1100-1600 °C, the extent of oxidation was evaluated using cross sectional SEM. |