Fabrication, microstructure, and properties of Dy‐doped (Y 1− x Dy x ) 3 Si 2 C 2 ceramics fabricated by in situ reactive spark plasma sintering

Dysprosium (Dy)‐doped (Y 1− x Dy x ) 3 Si 2 C 2 ( x = 0, 0.1, 0.3, 0.5) solid solution ceramics were successfully fabricated using an in situ reaction spark plasma sintering technology, for the first time. The effect of various Dy doping contents ( x ) on the microstructure, mechanical, and thermal properties of (Y 1− x Dy x ) 3 Si 2 C 2 ceramics was investigated. The (0 2 0) crystal plane spacing of (Y 0.5 Dy 0.5 ) 3 Si 2 C 2 was 7.813 Å, which was smaller than that of Y 3 Si 2 C 2 , due to the fact that the atomic radius of Dy is smaller than that of Y. The Dy doping facilitated the consolidation of (Y 1− x Dy x ) 3 Si 2 C 2 , thus a highly dense (Y 0.5 Dy 0.5 ) 3 Si 2 C 2 ceramic material with a low open porosity of 0.14% was successfully obtained at a relatively low temperature of 1 200°C. As the content of Dy doping ( x ) increased from 0 to 0.5, the purity of (Y 1− x Dy x ) 3 Si 2 C 2 ceramics increased from 88.3 to 90.7 wt.%, while the grain size of (Y 1− x Dy x ) 3 Si 2 C 2 ceramics decreased from 0.59 to 0.46 µm. As a result, the Vickers hardness and thermal conductivity of the (Y 0.5 Dy 0.5 ) 3 Si 2 C 2 material was 7.1 GPa and 9.8 W·m −1 ·K −1 , respectively.