Fabrication, microstructure, and properties of Dy-doped (Y1−xDyx)3Si2C2 ceramics fabricated by in situ reactive spark plasma sintering

Dysprosium (Dy)-doped (Y_1−xDy_x)₃Si₂C₂ (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−xDy_x)₃Si₂C₂ ceramics was investigated. The (0 2 0) crystal plane spacing of (Y_0.5Dy_0.5)₃Si₂C₂ was 7.813 Å, which was smaller than that of Y₃Si₂C₂, 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−xDy_x)₃Si₂C₂, thus a highly dense (Y_0.5Dy_0.5)₃Si₂C₂ 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−xDy_x)₃Si₂C₂ ceramics increased from 88.3 to 90.7 wt.%, while the grain size of (Y_1−xDy_x)₃Si₂C₂ ceramics decreased from 0.59 to 0.46 µm. As a result, the Vickers hardness and thermal conductivity of the (Y_0.5Dy_0.5)₃Si₂C₂ material was 7.1 GPa and 9.8 W·m⁻¹·K⁻¹, respectively.