Effect of the addition of glucose on the fabrication of nanosized mullite from a sol-gel by spark plasma sintering

Nanosized mullite with an average crystal size below 100 nm was synthesized by spark plasma sintering combined with a sol-gel process and the addition of glucose to the precursor materials. A suppression of grain growth was achieved by adding glucose. The influence of glucose was studied by evaluating samples with a glucose/Al3+ ratio of 0:1, 1:1, and 3:1, respectively. The sample prepared without glucose was the least homogeneous and showed a low relative density and irregular microstructure after sintering. In contrast, the sample prepared with a glucose/Al3+ ratio of 3:1 was the most homogeneous, leading nearly full densified mullite with nanosized grains at lower sintering temperature.