Preparation, characterization and luminescence properties of porous Si3N4 ceramics with Eu2O3 as sintering additive

Porous Si3N4 ceramics with photoluminescence properties were prepared by pressureless sintering using α-Si3N4 powder as raw material and Eu2O3 as sintering additive. Chemical composition, phase formation, microstructure and photoluminescence properties of porous Si3N4 ceramics were studied by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence measurements (PL/PLE). The results show that single Eu2O3 additive promotes α→β transformation but not significant densification. A broad band emission center at 570 nm assigned to Eu2+ is observed, Eu3+ in Eu2O3 is (partially) converted to Eu2+ by reaction with Si3N4, which results in a lower β aspect ratio and β-content compared to the other Ln (Ln=lanthanide) oxide additives.