Abstract
The inherent brittleness and uniform coloration of Si3N4 materials have traditionally limited their applicability. In this study, colored Si3N4 ceramics were synthesized utilizing alpha-Si3N4 powder, a ternary mixture of sintering additives, and rare earth oxides (Eu2O3, Dy2O3). The study focused on assessing the influence of varying Dy2O3 content and holding time on the coloration, mechanical properties, and electromagnetic shielding properties of Si3N4 ceramics. The incorporation of Eu2O3 induced a color shift from gray to yellow-green, while the addition of Dy2O3 facilitated the regulation of brightness in yellow-green Si3N4 ceramics. The results reveal that both hardness and bending strength decreased with prolonged holding time, correlating with changes in sample density. The addition of rare earth oxides can effectively improve the fracture toughness of the Si3N4 ceramics. Specifically, under conditions of 45 min holding time, 2%SED exhibited the highest fracture toughness at 8.45 MPa & sdot;m1/2. This enhancement can be primarily attributed to extended retention time, resulting in increased beta Si3N4 phase content, improved fracture energy absorption, and a larger aspect ratio. The introduction of Eu2O3 and Dy2O3 did not significantly alter the electromagnetic shielding properties of Si3N4 ceramics. This study offers novel pathways for the application of Si3N4 ceramics in emerging fields.
Keywords Plus：EARTH-OXIDE ADDITIVES，SILICON-NITRIDE，THERMAL-CONDUCTIVITY，SI3N4 CERAMICS，MICROSTRUCTURE，BETA-SI3N4，FABRICATION，TOUGHNESS，STRENGTH，BEHAVIOR
Published in CERAMICS INTERNATIONALVolume 50；10.1016/j.ceramint.2024.05.223，SEP 1 2024