LAUSR

Abstract The aim of this study was to evaluate the mechanical properties and coloration of silicon nitride ceramics in the presence of RE2O3 (RE = Nd, Eu or Dy). Dense Si3N4 ceramics were prepared by gas pressure sintering at 1800 °C for 2 h. XRD analysis confirmed the complete transformation of α-Si3N4 to β-Si3N4. The fracture toughness and flexure strengths were 11.93 ± 0.56 MPa·m1/2, 667 ± 40.98 MPa with the addition of Eu2O3 (SE). Base on the SEM image, the pull-out, bridging and deflection of large grains were observed and contributed to the increase in mechanical properties. The chromaticity of sintered bodies was measured using a spectrophotometer. The color difference of the ceramics is due to the formation of different color developing compounds according to the EDS. Results showed that high-toughness and colorful Si3N4 ceramics can be prepared using YAG:Ce3+ as sintering additive and RE2O3 as the colorant.