Effect Of Eu₂O₃-SiO₂ On SPS Sintered Silicon Nitride Properties

Amir Hossein Kouchaki Foroshani¹, Aida Faeghinia²*

¹BS Candidate/Student Department of Ceramic, Materials and Energy Research Centere,
Karaj Alborz Iran, P.O. Box 14155-4777, (IRAN)
²Associate Professor Department of Ceramic, Materials and Energy Research Centere,
Karaj Alborz Iran, P.O. Box 14155-4777, (IRAN)

PAGE NO: 012-025

ABSTRACT – DOI: https://dx.doi.org/10.47204/EMSR.7.1.2025.012-025

In this research the density compression and mechanical properties of Si₃N₄-SiO₂ composites with different weight ratios of 5:3:0 and 7% Eu₂O₃ and 10% SiO₂ additives were studied and investigated. The production of composite ceramics in this research was first carried out by powder preparation using mixing and milling for 1 hour then shaping by cold pressing and cold isostatic pressing methods and finally sintering by spark plasma sintering process. The samples were sintered at 1750°C for 15 minutes with a heating rate of 100 °C/min and a pressure of 40 MPa in a vacuum atmosphere. After the milling process the initial powder mixture size was reduced by about 19%. The results show that after cold isostatic pressing the relative density of the samples increased by 14.67%. The presence of a high amount of beta phase in the sample 7 Eu₂O₃ indicates the sufficient amount of liquid phase during the sintering process and the progress of the mechanism of dissolution infiltration and deposition ultimately increasing the rate of phase transformation from alpha to beta. The highest hardness value of 1.61 GPa was observed in sample 5 Eu₂O₃ indicating high densification progress of the mechanism of dissolution infiltration and deposition of nitride compounds during sintering. Sample 7 Eu₂O₃ showed a fracture toughness value of 6.1 MPa.m^1/2 due to the presence of glass phases with high amounts compared to other samples.