An investigation of crystal chemistry and luminescence properties of Eu-doped pure-nitride α–sialon fabricated by the alloy-nitridation method

A novel synthesis route of Eu2+-doped pure-nitride α-sialons has been reported. It is through an alloy-nitridation method at ∼2173 K in nitrogen atmosphere, with stable alloys (CaAl, SiEu), AlN, and α-Si3N4 powders as starting materials. A linear relationship between the lattice parameters and m values of (Ca0.995Eu0.005)m/2Si12−mAlmN16 compositions is obtained, indicating that our samples contain very little oxygen, i.e. herein so-called Eu-doped pure-nitride α-sialons. The (Ca0.995Eu0.005)m/2Si12−mAlmN16 compounds with 2.4≤m≤4.0 give the strongest emission. The emission shifts to longer wavelength with m values increasing as well as Eu contents increasing. (Ca0.995Eu0.005)m/2Si12−mAlmN16 compositions with smaller m values exhibit better thermal quenching properties.