The effect of the amount and size of alumina sintering aid particles on some mechanical properties and microstructure of silicon carbide bulky pieces via spark plasma sintering

In this paper, for sintering silicon carbide nanopowders via the spark plasma sintering method, nano-and micro-sized alumina sintering aids were used separately at 3 vol.%, 5 vol.%, and 7 vol.%. The sintering process was undertaken at 1900 ? for 10 min. To investigate some mechanical and physical properties of the resulting samples, density was obtained via the Archimedean method, and hardness was taken by the Vickers indenter method. The microstructure of the samples was examined through scanning electron microscopy. The results indicated that in the samples containing nano-alumina, the largest percentage of density and hardness was related to the sample containing 5 vol.% nano-alumina as a sintering aid and were obtained as 99% of theoretical density and 31.3 GPa, respectively. For the samples containing micro-alumina, the highest percentage of density and hardness was related to the sample containing 7 vol.% micro-alumina and obtained 93% of theoretical density and 20.1 GPa, respectively. By investigating the fractured surfaces of the samples and via the linear intercept method, the largest mean grain size was associated with the densest sample at 3.7 mu m.

Automated summary

In this study, silicon carbide nanopowders were sintered using the spark plasma sintering method, with nano-and micro-sized alumina sintering aids at different concentrations. The resulting samples were analyzed for density, hardness, and microstructure. The samples with nano-alumina at 5 vol.% exhibited the highest density (99% of theoretical density) and hardness (31.3 GPa), while the samples with micro-alumina at 7 vol.% showed the highest density (93% of theoretical density) and hardness (20.1 GPa). The densest sample had an average grain size of 3.7 μm, determined using the linear intercept method.